Multiband multi-pass absorption spectroscopy gas sensing

Abstract

The present disclosure provides a multi-band multi-pass absorption gas cell including a housing defining a chamber for receiving a gas sample to be analyzed. The cell includes a first multi-band mirror at a first end of the housing defining an entrance through-hole and including concentric dielectric coated regions corresponding to a plurality of wavebands. A second multi-band mirror is positioned at an opposite end, the second multi-band mirror including an exit through-hole and concentric dielectric coated regions corresponding to the wavebands. The cell includes an entrance wedge window positioned at the first end of the housing and an exit wedge window positioned at the second end.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 744,290, filed January 12, 2025, which is incorporated herein by reference in its entirety. Technical Field

[0003] The embodiments disclosed herein relate generally to gas sensing, and more specifically to compact multi-band multi-pass absorption spectroscopy gas sensing. Background Technology

[0004] The applicant has recognized the numerous technical challenges associated with gas sensing using multipass absorption spectroscopy. Through effort, ingenuity, and innovation, many of these identified problems have been addressed by the developed solutions, including those described in the embodiments of this disclosure, and numerous examples of these solutions are detailed herein. Summary of the Invention

[0005] According to one aspect of this disclosure, a multi-band multi-pass absorption chamber is provided. The multi-band multi-pass absorption chamber includes a housing defining a chamber for receiving a gas sample to be analyzed. The multi-band multi-pass absorption chamber includes a first multi-band reflector positioned at a first end of the housing. The first multi-band reflector defines a plurality of inlet vias and includes a first plurality of concentric dielectric coating regions corresponding to the plurality of wavelengths. The multi-band multi-pass absorption chamber includes a second multi-band reflector positioned at a second end of the housing opposite the first end. The second multi-band reflector includes a plurality of outlet vias and a second plurality of concentric dielectric coating regions corresponding to the plurality of wavelengths. The multi-band multi-pass absorption chamber includes a plurality of inlet wedge-shaped windows positioned at the first end of the housing and a plurality of outlet wedge-shaped windows positioned at the second end of the housing.

[0006] According to other aspects of this disclosure, a multi-band multi-pass absorption chamber may include one or more of the following features. The multi-band multi-pass absorption chamber may further include an inlet for introducing a gas sample into the chamber and an outlet for removing a gas sample from the chamber. Each of a first multi-band reflector and a second multi-band reflector may define an inner surface and an outer surface, wherein the inner surfaces of the first and second multi-band reflectors face each other, and wherein the inner surface of the first multi-band reflector may include a first plurality of concentric dielectric coating regions, and the inner surface of the second multi-band reflector may include a second plurality of concentric dielectric coating regions. A plurality of inlet wedge windows may be positioned adjacent to the outer surface of the first multi-band reflector, and a plurality of outlet wedge windows may be positioned adjacent to the outer surface of the second multi-band reflector. Each of the plurality of inlet through-holes may be conical and may define a first opening on the inner surface of the first multi-band reflector and a second opening on the outer surface of the first multi-band reflector, the second opening being larger than the first opening. Each of the plurality of outlet vias may be conical and may define a first opening on the inner surface of the second multiband reflector and a second opening on the outer surface of the second multiband reflector, the second opening being larger than the first opening. The plurality of inlet vias of the first multiband reflector may be defined within different dielectric coating regions of the first plurality of concentric dielectric coating regions, and the plurality of outlet vias of the second multiband reflector may be defined within different dielectric coating regions of the second plurality of concentric dielectric coating regions. The plurality of inlet vias of the first multiband reflector may be defined at different radial distances from the center of the first multiband reflector, and the plurality of outlet vias of the second multiband reflector may be defined at different radial distances from the center of the second multiband reflector. The first plurality of concentric dielectric coating regions and the second plurality of concentric dielectric coating regions may each include four concentric dielectric coating regions configured to provide a reflectance greater than 99.5% in each of the plurality of wavelength bands. The plurality of wavelength bands may include ultraviolet, visible, near-infrared, and short-infrared bands. The first and second multi-band reflectors may include concave mirrors.

[0007] According to another aspect of this disclosure, a multi-band multi-pass absorption gas sensing system is provided. The multi-band multi-pass absorption gas sensing system includes a broadband dual-comb laser source configured to emit light. The multi-band multi-pass absorption gas sensing system includes a fiber wavelength division multiplexer configured to generate multiple light beams, wherein the multiple light beams correspond to multiple wavelength bands. The multi-band multi-pass absorption gas sensing system includes a multi-band multi-pass absorption gas chamber configured to receive the multiple light beams. The multi-band multi-pass absorption gas chamber includes a housing defining a chamber for receiving a gas sample to be analyzed. The multi-band multi-pass absorption gas chamber includes a first multi-band reflector positioned at a first end of the housing. The first multi-band reflector defines multiple inlet vias and includes a first plurality of concentric dielectric coating regions corresponding to the multiple wavelength bands. The multi-band multi-pass absorption chamber includes a second multi-band reflector positioned at a second end of the housing opposite the first end. The second multi-band reflector includes multiple outlet through-holes and multiple concentric dielectric coating regions corresponding to multiple wavelength bands. The multi-band multi-pass absorption chamber includes multiple inlet wedge-shaped windows positioned at the first end of the housing and multiple outlet wedge-shaped windows positioned at the second end of the housing.

[0008] According to other aspects of this disclosure, the multi-band multi-pass absorption gas sensing system may include one or more of the following features: The multi-band multi-pass absorption gas sensing system may further include one or two fiber optic couplers configured to receive an output beam from the multi-band multi-pass absorption gas chamber and generate one or two output beams. The multi-band multi-pass absorption gas sensing system may further include one or two broadband photodetectors and a dual-comb spectroscopy processor. The multi-band multi-pass absorption gas sensing system may further include an inlet for introducing a gas sample into the chamber and an outlet for removing a gas sample from the chamber. Each of the first multi-band reflector and the second multi-band reflector may define an inner surface and an outer surface, wherein the inner surfaces of the first and second multi-band reflectors face each other, and wherein the inner surface of the first multi-band reflector may include a first plurality of concentric dielectric coating regions, and the inner surface of the second multi-band reflector may include a second plurality of concentric dielectric coating regions. Multiple inlet wedge windows can be positioned adjacent to the outer surface of a first multi-band reflector, and multiple outlet wedge windows can be positioned adjacent to the outer surface of a second multi-band reflector. Each of the multiple inlet vias can be conical and can define a first opening on the inner surface of the first multi-band reflector and a second opening on the outer surface of the first multi-band reflector, the second opening being larger than the first opening. Each of the multiple outlet vias can be conical and can define a first opening on the inner surface of the second multi-band reflector and a second opening on the outer surface of the second multi-band reflector, the second opening being larger than the first opening. The multiple inlet vias of the first multi-band reflector can be defined within different dielectric coating regions of a first plurality of concentric dielectric coating regions, and the multiple outlet vias of the second multi-band reflector can be defined within different dielectric coating regions of a second plurality of concentric dielectric coating regions. Attached Figure Description

[0009] Refer to the following figures to describe non-restrictive and non-exhaustive examples.

[0010] Figure 1 A perspective view of a multi-band multipass absorption spectroscopy gas cell according to at least some example embodiments of the present disclosure is shown.

[0011] Figure 2 At least some example embodiments according to this disclosure are shown. Figure 1 A top view of the gas chamber for multi-band multi-pass absorption spectroscopy.

[0012] Figures 3A to 3B An end view of a multiband reflector according to at least some example embodiments of the present disclosure is shown.

[0013] Figures 4A to 4CVarious views of a multiband reflector according to at least some example embodiments of the present disclosure are shown.

[0014] Figures 5A to 5C Various views of a wedge window according to at least some example embodiments of this disclosure are shown.

[0015] Figure 5D A front view of a multiband reflector according to at least some example embodiments of the present disclosure is shown, illustrating concentric dielectric coating regions.

[0016] Figure 6 A system diagram of a multi-band multi-pass absorption spectroscopy gas sensing system according to at least some example embodiments of the present disclosure is shown.

[0017] Figures 7A to 7B Reflective patterns according to at least some embodiments of the present disclosure are shown.

[0018] Figure 8 Reflective patterns are shown according to at least some example embodiments of the present disclosure.

[0019] Figure 9A A reflectance diagram of a dielectric-coated mirror according to at least some example embodiments of the present disclosure is depicted.

[0020] Figure 9B Reflectivity diagrams of mirrors according to at least some example embodiments of the present disclosure are depicted.

[0021] Figure 9C A reflectance diagram of the gold coating was depicted.

[0022] Figure 10 A block diagram of a multi-band multi-pass absorption spectroscopy gas sensing system according to at least some example embodiments of the present disclosure is shown. Detailed Implementation

[0023] Some embodiments of this disclosure will be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, embodiments of this disclosure. In fact, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will meet applicable legal requirements. Similar reference numerals always refer to similar elements.

[0024] Unless otherwise indicated, the term “or” as used herein has both alternative and combined meanings. The terms “illustrative” and “example” are used for examples without an indication of quality level. Terms such as “calculate,” “determine,” “generate,” and / or similar words are used interchangeably herein to refer to the creation, modification, or identification of data. Furthermore, the terms “based on,” “partially based on,” “at least based on,” “on the basis of,” and / or similar words are used interchangeably in an open-ended manner herein, such that they do not indicate that the data is based solely on or only on one or more of the referenced elements, unless so indicated.

[0025] As used herein, terms such as “front,” “rear,” “top,” “bottom,” “left,” “right,” etc., in the examples provided below, are used for illustrative purposes to describe the relative positions of certain parts or portions of parts. Furthermore, as will be apparent to those skilled in the art based on this disclosure, the terms “substantially” and “approximately” indicate that the referenced element or associated description is accurate within applicable engineering tolerances.

[0026] As used herein, the term “comprising” means including but not limited to, and should be interpreted in the manner in which it is typically used in the patent context. The use of broader terms such as “comprising,” “including,” and “having” should be understood to provide support for narrower terms such as “consisting of,” “substantially composed of,” and “substantially constituted by.”

[0027] The phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally mean that the specific feature, structure, or characteristic following the phrase may be included in at least one embodiment of this disclosure, and may be included in more than one embodiment of this disclosure (importantly, such phrases do not necessarily refer to the same embodiment).

[0028] The phrases “in one example,” “according to one example,” “in some examples,” etc. generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one example of this disclosure, and may be included in more than one example of this disclosure (importantly, such phrases do not necessarily refer to the same example).

[0029] If the specification states that a component or feature "may," "can," "should," "will," "preferably," "possibly," "usually," "optionally," "for example," "as an example," "in some examples," "often," or "may" (or other such language) be included or have that characteristic, then the specific component or feature is not required to be included or have that characteristic. Such a component or feature may be optionally included in some examples or excluded.

[0030] The terms “example” or “exemplary” as used herein mean “used as an example, instance, or illustration.” Any specific implementation described herein as an “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other specific implementations.

[0031] In this disclosure, the terms “electrically connected,” “electrically coupled,” “electrically coupled,” “communicating with,” “electronically communicating with,” or “connection” refer to two or more elements or components connected by wired and / or wireless means such that signals, voltages / currents, data, and / or information can be transmitted to and / or received from these elements or components.

[0032] The term "component" can refer to an article of writing, device, or apparatus that may include one or more surfaces, portions, layers, and / or elements. For example, an example component may include one or more substrates that may provide one or more underlying layers for the component, and may include one or more elements that may form a portion on top of the substrate and / or one or more elements that may be disposed on top of the substrate. The term "element" can refer to an article of writing, device, or apparatus that may provide one or more functions.

[0033] Overview

[0034] Multipass absorption spectroscopy gas sensing technology utilizes multiple reflections of a light beam between mirrors in a gas chamber to multiply the gas absorption path length, thereby enhancing the sensitivity of gas detection and analysis. The light beam reflects back and forth between mirrors positioned at opposite ends of a chamber containing the gas sample to be analyzed. The extended optical path length achieved through multiple reflections allows for improved detection of low-concentration gases and gases with weak absorption characteristics.

[0035] Conventional multi-pass absorption chambers face several technical challenges that limit their performance and applicability. A major challenge involves mirror reflection loss with each reflection of the light beam. Conventional gold-plated mirrors offer no more than 95% reflectance in the short infrared wavelengths and approximately 90% in the near infrared wavelengths. The reflectance performance of gold-plated mirrors deteriorates further at shorter wavelengths, dropping below 90% at most visible wavelengths and becoming unusable in the ultraviolet wavelengths. These low reflectance values ​​limit the number of reflections that can be achieved before the signal becomes too weak to be accurately detected, thus limiting the enhancement factor and sensitivity of the gas sensing system.

[0036] The reflectivity limitations of conventional mirrors pose an additional challenge to broadband gas sensing applications. Different gas species exhibit absorption characteristics at different wavelengths across the electromagnetic spectrum, from the ultraviolet to the infrared region. To achieve comprehensive gas detection capabilities, gas sensing systems may need to operate simultaneously across multiple bands. However, conventional single-coated mirror systems cannot provide sufficient reflectivity over such a wide spectral range, thus limiting their effectiveness in multi-band applications.

[0037] Various embodiments of this disclosure provide a multi-band multi-pass absorption spectroscopy gas cell that addresses the aforementioned technical challenges by implementing a multi-band dielectric reflector with concentric dielectric coating regions that simultaneously provide reflectivity greater than 99.5% across multiple wavelength bands. In various embodiments, each dielectric coating region can be optimized for a specific wavelength band.

[0038] In various embodiments, the multi-band multi-pass absorption spectroscopy gas cell includes a first multi-band mirror and a second multi-band mirror positioned relative to each other to define a chamber for receiving a gas sample. In various embodiments, each multi-band mirror has multiple concentric dielectric-coated regions, each region providing high reflectivity in a specific wavelength band. In various embodiments, the gas cell includes inlet and outlet through-holes in the mirrors to allow light beams to enter and exit the chamber, and includes corresponding wedge-shaped windows to minimize back reflection interference. The multi-band approach allows a single gas cell to accommodate multiple wavelengths from ultraviolet to infrared without the reflectivity limitations associated with conventional mirror coatings.

[0039] Various embodiments of this disclosure provide a multi-band multi-pass absorption spectroscopy gas sensing system that combines a multi-band multi-absorption gas spectroscopy chamber as described herein with one or more optical components. In various embodiments, the system includes a broadband light source, a wavelength division multiplexing (WDM) component for splitting the broadband light into multiple bands, and a detection component for analyzing the output beams after they have passed through the chamber. In various embodiments, the system includes a processing component to analyze the spectral data and determine the presence and concentration of a target gas. Various embodiments of this disclosure provide a method for multi-band multi-pass absorption spectroscopy gas sensing involving splitting broadband light into multiple bands, introducing these bands into a chamber via multi-band mirrors to allow multiple reflections within the chamber, and subsequently detecting and analyzing the output beams to determine gas absorption characteristics. This method can achieve simultaneous analysis of multiple gas species across different bands using a single compact chamber system.

[0040] Example systems, apparatus and methods disclosed herein

[0041] refer to Figure 1 and Figure 2 A multi-band multi-pass absorption spectroscopy (MBMS) gas chamber 100 (chamber 100) can be configured to achieve enhanced gas detection through reflection of multiple light beams. The MBMS gas chamber 100 may include a chamber housing 102 defining an interior. In some embodiments, the chamber housing 102 may define an interior having a substantially cylindrical shape. In some embodiments, the chamber housing may include a cylindrical body or a substantially cylindrical body providing structural support for components of the gas chamber 100. In some embodiments, the gas chamber 100 further includes a pressure-temperature sensor (which may be disposed on the chamber housing). The pressure-temperature sensor may be configured to measure, detect, and collect gas flow pressure and temperature readings for gas sensing data analysis.

[0042] like Figure 1 and Figure 2 As shown, the multi-band multi-pass absorption spectroscopy chamber 100 may include a first multi-band reflector 110 positioned at one end of a cylindrical structure. A second multi-band reflector 120 may be positioned at the opposite end of the cylindrical structure. The first multi-band reflector 110 and the second multi-band reflector 120 may be substantially identical in design and construction. The first multi-band reflector 110 and the second multi-band reflector 120 may be fixed or coupled to the opposite ends of the chamber housing.

[0043] The first multiband mirror 110 and the second multiband mirror 120 may be positioned opposite each other to define a chamber 104 between them. The chamber 104 may be configured to receive a gas to be analyzed (e.g., a gas sample). In various embodiments, the first multiband mirror 110 and the second multiband mirror 120 may have a substantially circular shape. The first multiband mirror 110 and the second multiband mirror 120 may be concave mirrors facing each other across the chamber 104. For example, the first multiband mirror 110 and the second multiband mirror 120 may each define an inner surface and an outer surface, wherein the inner surfaces of the first and second multiband mirrors face each other. The concave configuration of the first multiband mirror 110 and the second multiband mirror 120 enables a controlled reflection pattern of a light beam passing through the chamber 104.

[0044] The multiband multipass absorption spectroscopy (MMAS) gas chamber 100 may include a gas inlet 106 (e.g., a gas inlet portion) through which the gas to be analyzed is added to the chamber 104. The MMAS gas chamber 100 may also include a gas outlet 108 (e.g., a gas outlet portion) through which the gas sample is removed from the chamber 104. The gas inlet and gas outlet portions may be configured to allow gas to flow through the chamber 104 for detection and analysis.

[0045] The configuration of the first multi-band reflector 110 and the second multi-band reflector 120 enables multi-pass absorption spectroscopy by reflecting the light beam multiple times between the reflectors. Multiple reflections increase the optical path length, thereby enhancing gas detection sensitivity. As the light beam passes through the chamber 104 and undergoes multiple reflections, the extended optical path length allows for improved detection of gases with low concentrations or weak absorption characteristics.

[0046] like Figure 1 and Figure 2 As shown, the multi-band multi-pass absorption spectroscopy chamber 100 may have an elongated structure along its longitudinal axis. A first multi-band mirror 110 and a second multi-band mirror 120 may be spaced apart along the length of the chamber to define an elongated cavity (e.g., cavity 104) between the mirrors. The first multi-band mirror 110 and the second multi-band mirror 120 may be oriented to face each other across the length of cavity 104 or housing 102. The spacing between the first multi-band mirror 110 and the second multi-band mirror 120 provides sufficient distance for multiple beam reflections occurring within the cavity. The orientation of the mirrors allows the beam to travel back and forth multiple times between the mirror surfaces before leaving the chamber.

[0047] like Figure 2 As shown, light can enter the multi-band multi-pass absorption spectroscopy chamber 100 through the first multi-band reflector 110. The beam then travels within the chamber 104 and undergoes multiple reflections between the first multi-band reflector 110 and the second multi-band reflector 120. These multiple reflections can occur in a controlled mode that maximizes the optical path length while avoiding interference between different beams.

[0048] After multiple reflections, the light beam exits the multi-band multi-pass absorption spectroscopy gas cell 100 via the second multi-band reflector 120. The extended optical path length achieved through multiple reflections between the first multi-band reflector 110 and the second multi-band reflector 120 provides enhanced sensitivity for gas absorption spectroscopy measurements. The longitudinal configuration allows the gas cell to achieve a large number of reflections within a compact form factor, making the system suitable for a variety of gas sensing applications.

[0049] refer to Figure 3A and Figure 3B An end view of a multi-band reflector according to at least some embodiments of the present disclosure is provided. Specifically, Figure 3A An end view of the first multi-band reflector 110 is shown, and Figure 3B An end view of the second multiband mirror 120 is shown. Multiband mirrors 110 and 120 define an inlet and an outlet portion, respectively, enabling multiband spectroscopy operations as described herein.

[0050] like Figure 3AAs shown, the first multiband mirror 110 may define a plurality of inlet vias 112 extending through the mirror body. The inlet vias 112 may be arranged in a certain pattern on the mirror surface to accommodate different wavelengths. For example, each inlet via 112 may be positioned or otherwise defined at different radial distances from the center of the first multiband mirror 110, wherein the positioning corresponds to different concentric coated dielectric regions on the mirror surface (e.g., the inner surface), as further described below. The arrangement of the inlet vias 112 allows multiple light beams to be introduced into the chamber 104 at different spectral bands.

[0051] The first multiband mirror 110 may include a plurality of entrance windows 113 corresponding to a plurality of entrance apertures 112. For example, the gas chamber 100 may include a plurality of entrance windows 113, wherein each entrance window 113 is positioned adjacent to a corresponding entrance aperture 112 to allow a light beam to enter the chamber 104. Each entrance window 113 may be positioned on the outer surface of the first multiband mirror 110, adjacent to a corresponding entrance aperture 112. The entrance window 113 may be configured to transmit a light beam while maintaining the structural integrity of the chamber 104. For example, the entrance window may include an optical transmission element configured to allow light beams of different wavelengths to enter the chamber while maintaining the structural integrity and optical performance of the gas chamber 100. The entrance window may be made of an optically transparent material, such as fused silica or other similar near-infrared optical materials, which provide suitable optical transmission characteristics across relevant wavelengths. In various embodiments, the entrance window may have a wedge geometry with angled surfaces configured to minimize back reflection interference when light passes through the window into the chamber.

[0052] Continue to refer to Figure 3A The positioning of the inlet via 112 and inlet window 113 at different radial distances corresponds to concentric dielectric coating regions on the first multi-band mirror 110. Each dielectric coating region can be optimized for a specific wavelength, and the corresponding inlet via 112 and inlet window 113 can be positioned to align with the corresponding region. The inlet via 112 can be confined within different dielectric coating regions on the first multi-band mirror 110. The radial arrangement allows multiple wavelengths to enter the chamber 104 without interference between different spectral channels.

[0053] like Figure 3BAs shown, the second multiband mirror 120 may define a plurality of exit vias 122 extending through the mirror body. The exit vias 122 may be patterned to correspond to the arrangement of the inlet vias 112 on the first multiband mirror 110. Each exit via 122 may be located or otherwise defined at a different radial distance from the center of the second multiband mirror 120, wherein the location corresponds to different concentric dielectric coating regions on the mirror surface (e.g., the inner surface).

[0054] The second multiband mirror 120 may include a plurality of exit windows 123 corresponding to a plurality of exit apertures 122. For example, the gas chamber 100 may include a plurality of exit windows 123, wherein each exit window 123 is positioned adjacent to a corresponding exit aperture 122 to allow a beam of light to exit the chamber 104 after multiple reflections between the first multiband mirror 110 and the second multiband mirror 120. The exit windows 123 may be configured to transmit the beam of light exiting the gas chamber 100 while maintaining the optical performance of the gas chamber. The inlet and outlet windows may be positioned adjacent to the outer surface of the corresponding multiband mirror.

[0055] The arrangement of the exit vias 122 and exit windows 123 at different radial distances corresponds to concentric dielectric coating regions on the second multiband mirror 120. The exit via 122 can be confined within different dielectric coating regions on the multiband mirror 120. Radial positioning allows multiple bands to exit the chamber 104 after completing the multi-pass reflection process. The exit configuration maintains spectral separation of different bands, thus allowing for subsequent detection and analysis of each band. The radial arrangement allows different bands to enter their respective coating regions without interference.

[0056] In some embodiments, the inlet via 112 and the outlet via 122 may each be conical, having a larger opening on the outer side (e.g., outer surface) of their respective mirrors. In this respect, each inlet via may be conical and define a first opening on the inner surface of the first multi-band mirror and a second opening on the outer surface of the first multi-band mirror, the second opening being larger than the first opening. Each outlet via may be conical and define a first opening on the inner surface of the second multi-band mirror and a second opening on the outer surface of the second multi-band mirror, the second opening being larger than the first opening. The conical configuration can facilitate beam introduction and extraction while minimizing optical losses. The larger opening on the outer side (e.g., outer surface) provides improved coupling with external optical components, while the smaller opening on the inner side (e.g., inner surface) preserves the optical properties within chamber 104.

[0057] The multiple inlet windows 113 and multiple outlet windows 123 may have a wedge geometry. In this respect, the multi-band multi-pass absorption spectroscopy chamber 100 may include a first set of wedge windows (e.g., multiple inlet wedge windows 113) corresponding to the multiple inlet through-holes 112 and a second set of wedge windows (e.g., multiple outlet wedge windows 123) corresponding to the multiple outlet through-holes 122. The multiple inlet wedge windows 113 may be configured to minimize back reflection interference when the beam enters the chamber 104. The multiple outlet wedge windows 123 may be configured to minimize back reflection interference when the beam exits the chamber 104.

[0058] The wedge-shaped window may comprise a wedge-shaped surface angled relative to the opposing surfaces of the window, thereby creating a non-parallel configuration that reduces back reflection interference. The angular orientation of the wedge-shaped surface directs any reflected light away from the optical path, thus preventing interference with the incident beam or multiple-pass reflection processes within the cavity. The wedge-shaped window may be constructed of optically transparent materials, such as fused silica or other similar near-infrared optical materials, which provide suitable optical transmission characteristics across relevant wavelengths while maintaining the structural integrity and optical performance of the chamber.

[0059] refer to Figures 4A to 4C Different views of a multi-band reflector (multi-band reflector 110 or multi-band reflector 120) according to at least some embodiments of the present disclosure are provided. Specifically, Figures 4A to 4C The structural configuration and optical properties for realizing multi-band spectroscopy are shown. Figures 4A to 4C The multi-band reflectors shown may represent a first multi-band reflector 110 or a second multi-band reflector 120 that may have substantially similar construction and characteristics.

[0060] like Figure 4A As shown, the multiband mirror described herein may have an inwardly curved concave reflective surface to provide controlled reflection characteristics for the light beam within the gas chamber 100. The concave configuration allows the multiband mirror to focus and guide the light beam in a predetermined pattern during a multi-pass reflection process. The concave reflective surface may be shaped to optimize the reflection geometry to achieve multiple reflections without interference between different optical paths.

[0061] As described above, a multi-band reflector may define a plurality of inlet vias 112 that extend from an outer surface (outer surface) through the reflector body to a concave reflective surface (e.g., a concave reflective inner surface). Figure 4A As shown, the entrance vias 112 can be patterned across the mirror surface in a manner corresponding to the concentric dielectric coating regions. Each entrance via 112 provides a pathway for a light beam to enter the chamber of the gas cell. The positioning of the entrance vias 112 can be coordinated with the concentric dielectric coating regions to ensure that each wavelength enters the gas cell at the appropriate location on the mirror surface.

[0062] Multiband mirrors can have a concave curvature that extends across the mirror surface to provide desired reflective properties. The concave reflective surface can be configured to support multiple concentric dielectric coatings, enabling multiband spectroscopy applications. Each concentric dielectric coating region can be optimized for a specific wavelength range, allowing the mirror to achieve high reflectivity simultaneously across different spectral bands. The concave geometry provides a suitable substrate for applying the dielectric coatings while maintaining the optical performance characteristics required for multipass absorption spectroscopy.

[0063] Multiband mirrors can be constructed from fused silica or other similar near-infrared optical materials, which provide suitable optical and mechanical properties for gas chamber applications. Fused silica offers low thermal expansion, high optical transmittance, and compatibility with dielectric coating processes. The material properties of fused silica enable the mirrors to maintain dimensional stability and optical performance across a range of operating conditions.

[0064] Concave reflective surfaces can be precisely shaped to achieve the desired reflection pattern for multi-pass absorption spectroscopy. The surface curvature can be designed to ensure that the beam undergoes multiple reflections in a controlled manner, maximizing the optical path length while avoiding interference between different reflection paths. The concave geometry also facilitates the application of multiple concentric dielectric coatings, where each coating region provides an optimized reflectance for its corresponding wavelength band.

[0065] The inlet vias can be formed through precision machining or other suitable manufacturing processes that maintain the optical quality of the mirror surface. The conical geometry of each inlet via can be carefully controlled to ensure proper optical coupling and minimal loss during light transmission. The transition from the larger external opening to the smaller internal opening can be smooth to avoid optical aberrations or scattering that could degrade the performance of the air chamber.

[0066] refer to Figures 5A to 5C The wedge window configuration provides optical properties that minimize interference and enhance the performance of the multi-band multi-pass absorption spectroscopy chamber 100. The wedge windows (e.g., inlet wedge window 113 and outlet wedge window 123) can be positioned at the inlet through-hole 112 and outlet through-hole 122 to facilitate beam transmission while reducing unwanted optical effects that could degrade spectral measurements.

[0067] like Figure 5AAs shown, the wedge window may have a generally cylindrical or disc-shaped shape with a circular cross-section that provides compatibility with the inlet and outlet through-holes of the multi-band mirror. A cylindrical configuration facilitates the mounting and alignment of the wedge window within the chamber assembly. The wedge window may include a wedge-shaped surface 117 angled relative to the opposing surface of the window. The wedge-shaped surface 117 may be oriented at a specific angle to reduce or eliminate back reflection interference as light passes through the window. The angled configuration of the wedge-shaped surface 117 directs any reflected light away from the optical path, thereby preventing interference with the incident beam or the multi-pass reflection process within chamber 104.

[0068] As described above, the wedge window can be configured to be positioned at one of the inlet aperture 112 or outlet aperture 122 of the first multiband mirror 110 or the second multiband mirror 120. Positioning of the wedge window allows light beams to enter or exit the chamber 104 while minimizing optical interference from reflected light. The wedge surface 117 can be oriented to guide any back reflections away from the chamber. The wedge window can have an angular relationship between the wedge surface 117 and its opposing surface. The wedge surface 117 can be angled to produce a non-parallel configuration that reduces back reflection interference. The angular orientation can be selected to optimize transmission characteristics while minimizing unwanted reflections that may interfere with spectral measurements. The wedge window can have a circular aperture that allows light transmission. Reduction of back reflection interference improves the signal-to-noise ratio of spectral measurements and enhances the overall performance of the multiband multipass absorption spectroscopy chamber 100. The circular configuration provides uniform optical characteristics across the aperture and facilitates alignment with the inlet aperture 112 or outlet aperture 122.

[0069] The wedge-shaped surface 117 can be formed by precision optical polishing or other suitable manufacturing processes that maintain the required surface quality and angular accuracy. The surface finish of the wedge-shaped surface 117 can be controlled to minimize scattering and maintain high optical transmittance. The angular tolerance of the wedge-shaped surface 117 can be precisely controlled to ensure consistent performance of all wedge windows in the gas chamber assembly.

[0070] refer to Figure 5D Example multiband mirrors (e.g., multiband mirror 110 or multiband mirror 120) according to at least some embodiments of the present disclosure are provided, showing their concentric dielectric coating region configurations. Figure 5D A circular cross-sectional view of a multi-band reflector is shown, depicting multiple concentric dielectric coating regions with different radii, defining boundaries for different dielectric coating types. Each concentric coating region can represent a wavelength band of the multi-band reflector. For example, each concentric coating region can be referred to as a concentric coating band. The concentric arrangement allows the multi-band multi-pass absorption spectroscopy chamber 100 to simultaneously accommodate multiple spectral bands while maintaining high reflectivity characteristics over a wide wavelength range.

[0071] In some embodiments, the multi-band mirrors may each include four concentric dielectric coating regions. For example, in some embodiments, the first multi-band mirror 110 and the second multi-band mirror 120 may be coated with a high-reflectivity dielectric coating in the four concentric regions to cover four spectral bands having high reflectivity (e.g., 99.5% reflectivity). In some embodiments, the first multi-band mirror 110 and the second multi-band mirror 120 may be coated in more or fewer than four concentric regions.

[0072] In some implementations, the concentric dielectric coating region can be optimized for a specific wavelength band. For example, in some implementations, the dielectric coating region in the corresponding multi-band mirror can have different dielectric coating configurations, different coating types, etc., with the concentric dielectric coating strip optimized for a specific wavelength band.

[0073] In some embodiments, the multiband mirror may include a first concentric dielectric coating region 119a (e.g., a first concentric dielectric coating strip) positioned at the center of a circular cross-section closest to the multiband mirror relative to other dielectric coating regions. In some embodiments, the first concentric dielectric coating region 119a may be positioned at the center of the circular cross-section of the multiband mirror. In some embodiments, the first concentric dielectric coating region 119a may occupy a central region of the multiband mirror surface and may be configured to provide high reflectance for specific wavelengths. In some embodiments, the first concentric dielectric coating region 119a may be optimized for ultraviolet wavelengths to provide reflectance characteristics capable of enabling efficient multipass absorption spectroscopy in the ultraviolet spectral range. For example, the first concentric dielectric coating region 119a may be configured to provide high reflectance for near-ultraviolet and blue wavelengths (such as, for example, in the range of 0.35 micrometers to 0.45 micrometers) for multiband multipass absorption spectroscopy gas sensing applications.

[0074] A multi-band reflector may include a second concentrically coated region 119b (e.g., a second concentrically coated strip) arranged concentrically around a first concentrically coated region 119a. The second concentrically coated region 119b may be positioned radially outward from the first concentrically coated region 119a. In some embodiments, the second concentrically coated region 119b may be configured to provide high reflectivity for a different wavelength band than the first concentrically coated region 119a. For example, in some embodiments, the second concentrically coated region 119b may be optimized for visible wavelengths to achieve efficient spectroscopic operation in the visible spectral range. The second concentrically coated region 119b may be configured to provide high reflectivity for near-visible wavelengths (such as, for example, in the range of 0.4 micrometers to 0.9 micrometers) for multi-band multi-pass absorption spectroscopy gas sensing applications.

[0075] The multi-band reflector may include a third concentric dielectric coating region 119c (e.g., a third concentric dielectric coating strip) concentrically arranged around the second dielectric concentric coating region 119b. The third concentric dielectric coating region 119c may be positioned radially outward from the second dielectric concentric coating region 119b. In some embodiments, the third concentric dielectric coating region 119c may be configured to provide high reflectivity for near-infrared wavelengths. The third concentric dielectric coating region 119c enables the multi-band multi-pass absorption spectroscopy gas cell 100 to perform spectroscopic operations with high efficiency in the near-infrared spectral range. For example, the third concentric dielectric coating region 119c may be configured to provide high reflectivity for near-infrared wavelengths (such as, for example, in the range of 0.8 μm to 1.25 μm) for multi-band multi-pass absorption spectroscopy gas sensing applications.

[0076] A multi-band reflector may include a fourth concentric dielectric coating region 119d (e.g., a fourth concentric dielectric coating strip) arranged concentrically around a third concentric dielectric coating region 119c as the outermost region. The fourth concentric dielectric coating region 119d may be positioned at the outermost radial location relative to the other coating regions. In some embodiments, the fourth concentric dielectric coating strip may be configured to provide high reflectivity for short infrared wavelengths. For example, the fourth concentric dielectric coating region 119d may be configured to provide high reflectivity for short infrared wavelengths (such as, for example, in the range of 1.25 micrometers to 1.75 micrometers) for multi-band multi-pass absorption spectroscopy gas sensing applications. The multi-band configuration of the fourth concentric dielectric coating region 119d can be achieved by enabling spectral operation within the short infrared spectral range.

[0077] Concentric dielectric coating regions (e.g., highly reflective concentric dielectric coating strips) can be defined by a specific radius that establishes boundaries between different coating regions. For example... Figure 5D As shown, the first radius R15 defines the boundary between the first concentric dielectric coating region 119a and the second concentric dielectric coating region 119b, thereby establishing the outer limit of the central coating region. The first radius R15 determines the area of ​​the mirror surface optimized for a first wavelength band (such as ultraviolet wavelength). The first radius R15 can establish a transition point between coating regions optimized for near-ultraviolet and blue wavelengths and coating regions optimized for visible wavelengths. The positioning of the first radius R15 can be selected based on the optical requirements of the corresponding wavelength band to provide an appropriate surface area for each coating region.

[0078] The second radius R17 defines the boundary between the second concentric dielectric coating region 119b and the third concentric dielectric coating region 119c. The second radius R17 establishes a transition point between coating regions optimized for visible wavelengths and coating regions optimized for near-infrared wavelengths. The positioning of the second radius R17 can be selected based on the optical requirements of the corresponding wavelength band to provide an appropriate surface area for each coating region.

[0079] The third radius R19 defines the boundary between the third concentric dielectric coating region 119c and the fourth concentric dielectric coating region 119d. The third radius R19 establishes a transition point between coating regions optimized for near-infrared wavelengths and coating regions optimized for short-infrared wavelengths. The positioning of the third radius R19 can be selected based on the optical requirements of the corresponding wavelength band to provide an appropriate surface area for each coating region.

[0080] The arrangement of concentric dielectric coating regions allows each coating region to correspond to a different wavelength band, enabling high reflectivity across a wide spectral range (from ultraviolet to infrared) in a multi-band multi-pass absorption spectroscopy gas cell. Four concentric dielectric coating regions can cover four spectral bands (e.g., four wavelength bands) with a reflectivity greater than 99.5%, providing enhanced performance compared to conventional mirror systems. These four spectral bands can include ultraviolet, visible, near-infrared, and short-infrared wavelengths, thus achieving comprehensive gas detection capabilities across multiple spectral regions.

[0081] For example, the first concentric dielectric coating region 119a may represent a first dielectric coating strip corresponding to a first wavelength band (e.g., ultraviolet band), the second concentric dielectric coating region 119b may represent a second dielectric coating strip corresponding to a second wavelength band (e.g., visible light band), the third concentric dielectric coating region 119c may represent a third dielectric coating strip corresponding to a third wavelength band (e.g., near-infrared band), and the fourth concentric dielectric coating region 119d may represent a fourth dielectric coating strip corresponding to a fourth wavelength band (e.g., short-infrared band).

[0082] In some embodiments, at least one coating type applied to the concentric regions may be a narrow-band, ultra-high reflectivity dielectric coating, selected such that a resonant optical cavity can be formed between a corresponding coating of the first multi-band mirror 110 and a corresponding coating of the second multi-band mirror 120. The narrow-band dielectric coating can provide high reflectivity within a specific wavelength range, thereby enhancing the sensitivity of gas detection applications targeting specific absorption lines.

[0083] In some implementations, at least one coating type applied to the concentric regions may have a reflectance of at least 99.99%, thereby providing near-ideal reflectivity that minimizes losses during the multi-pass reflection process. The ultra-high reflectance value allows for more reflections to occur before the signal strength becomes insufficient for accurate detection, thus extending the effective optical path length and enhancing the sensitivity of the gas sensing system.

[0084] In some embodiments, at least one of the coating types applied to the concentric regions may be a broadband metallic coating, selected such that a multi-pass cavity can be formed between the corresponding coating of the first multi-band mirror 110 and the corresponding coating of the second multi-band mirror 120. The broadband metallic coating can provide sufficient reflectivity over a wider wavelength range, thereby enabling multi-pass operation for applications requiring broader spectral coverage within a single coating region.

[0085] refer to Figure 6 A multi-band multi-pass absorption spectroscopy gas sensing system 600 according to at least some embodiments of the present disclosure is provided. For example... Figure 6 As shown, a multi-band multi-pass absorption spectroscopy gas sensing system 600 may include a multi-band multi-pass absorption spectroscopy gas cell, such as the multi-band multi-pass absorption spectroscopy gas cell 100 described above, and one or more optical components to provide comprehensive gas detection and analysis across multiple wavelengths. System 600 can provide enhanced sensitivity and broad spectral coverage by integrating advanced optical components with the multi-band gas cell configuration. System 600 can be configured to enable simultaneous analysis of multiple gas species while maintaining high detection sensitivity through extended optical path length. As described above, the concentric dielectric coating configuration of the multi-band mirrors in gas cell 100 allows the multi-band multi-pass absorption spectroscopy gas sensing system to utilize four concentric dielectric coating regions covering four spectral bands with a reflectance greater than 99.5%. The system configuration can incorporate a multi-band mirror design to simultaneously achieve enhanced performance across ultraviolet, visible, near-infrared, and short-infrared wavelengths within a single gas cell assembly.

[0086] The multi-band multi-pass absorption spectroscopy gas sensing system 600 may include a broadband dual-comb laser source 604 that generates light for spectral analysis. The broadband dual-comb laser source 604 emits coherent light across a wide wavelength range, encompassing multiple spectral bands to support comprehensive gas detection. The broadband dual-comb laser source 604 provides stable, high-quality optical output, enabling accurate spectral measurements across ultraviolet, visible, near-infrared, and short-infrared wavelengths.

[0087] like Figure 6 As shown, system 600 may include a fiber optic wavelength division multiplexer 606, which can be configured to split light from a broadband dual-comb laser source 604 into multiple input beams. The fiber optic wavelength division multiplexer 606 can receive broadband light output from the broadband dual-comb laser source 604 and split the light into different bands (e.g., different band input beams) corresponding to the concentric dielectric coating regions of the multi-band mirrors. The fiber optic wavelength division multiplexer 606 can split the light into multiple input beams 602 without amplitude drop in each beam, thereby ensuring that each beam / band maintains sufficient optical power for effective spectral analysis.

[0088] In this respect, the fiber optic wavelength division multiplexer 606 can output an input beam 602 guided into the multi-band multi-pass absorption spectroscopy chamber 100, wherein the input beam 602 includes multiple bands that have been separated from the original broadband light source. Each input beam in the input beam 602 may correspond to a specific spectral band that will interact with corresponding concentric dielectric coating regions on the first multi-band mirror 110 and the second multi-band mirror 120. The input beam 602 may be fed through the inlet wedge window 113 and the inlet through-hole 112 or otherwise introduced into the chamber 104 of the multi-band multi-pass absorption spectroscopy chamber 100.

[0089] Continue to refer to Figure 6 Each input beam in input beam 602 can pass through a corresponding entrance window 113 in a plurality of entrance wedge windows and through a corresponding entrance via 112. Input beam 602 can travel within cavity 104 toward the second multiband reflector 120 without back reflection interference due to the wedge window configuration. Input beam 602 can enter cavity 104 at different radial positions corresponding to concentric dielectric coating regions, allowing each band to interact with its optimized coating region.

[0090] The input beam 602 can undergo multiple reflections within chamber 104 to enhance the optical path length, thereby improving gas detection sensitivity. Due to the high reflectivity of the inner surfaces of the first multi-band mirror 110 and the second multi-band mirror 120, the input beam 602 can reflect back and forth between the mirrors according to a pattern that avoids collisions and interference between reflections. The inner surfaces of the first multi-band mirror 110 and the second multi-band mirror 120 can be shaped and positioned such that the input beam 602 reflects back and forth in a controlled manner, maximizing the optical path length while maintaining spectral separation.

[0091] In some implementations, each input beam in input beam 602 may be reflected approximately eighty times between the first multiband mirror 110 and the second multiband mirror 120 to enhance the sensing sensitivity for absorbing gases. Compared to a single-pass configuration, multiple reflections extend the effective optical path length, enabling the detection of gases with low concentrations or weak absorption characteristics. Eighty reflections provide an enhancement factor that improves the signal-to-noise ratio and detection limit of system 600.

[0092] like Figure 6As shown, a certain amount of input beam 602 can pass through the second multi-band reflector 120 and exit the chamber 104 as an output beam 608. The output beam 608 may include the transmitted portion of the input beam 602 after it has completed the multi-pass reflection process within the chamber 104. Each input beam can be output through a corresponding exit wedge window in a plurality of exit wedge windows and through a corresponding exit through-hole in the exit through-hole 122. The output beam 608 may carry spectral information about the gas sample present in the chamber 104 during the multi-pass reflection process.

[0093] A multi-band multi-pass absorption spectroscopy gas sensing system 600 may include one or more fiber optic couplers 610 configured to combine output beams 608 from a multi-band multi-pass absorption spectroscopy gas chamber 100. For example, the multi-band multi-pass absorption spectroscopy gas sensing system 600 may include one or two fiber optic couplers 610 configured to combine output beams 608 from a multi-band multi-pass absorption spectroscopy gas chamber 100. The fiber optic coupler 610 may receive multiple wavelengths exiting the gas chamber as individual output beams 608 and combine them into one or more optical outputs. For example, the fiber optic coupler 610 may receive multiple wavelengths exiting the gas chamber as individual output beams 608 and combine them into one or more optical outputs 610, maintaining spectral information from each wavelength while achieving effective coupling with the detection element.

[0094] like Figure 6 As shown, the system may include a broadband photodetector 612 configured to receive the combined output beam from the fiber optic combiner coupler 610. The broadband photodetector 612 can convert the optical signal from the fiber optic combiner coupler 610 into an electrical signal that can be processed for spectral analysis. The broadband photodetector 612 may have sensitivity across multiple wavelength bands used in the system, thereby enabling the detection of spectral information from ultraviolet, visible, near-infrared, and short-infrared wavelengths.

[0095] The multi-band multi-pass absorption spectroscopy gas sensing system 600 may include a dual-comb spectroscopy processor 614, which is configured to analyze signals from a broadband photodetector 612. The dual-comb spectroscopy processor 614 receives and processes electrical signals from the broadband photodetector 612 to recover the absorption spectral characteristics of the target gas. The dual-comb spectroscopy processor 614 analyzes the spectral data to determine the presence and concentration of the target gas in the sample analyzed within chamber 104.

[0096] In this regard, a method for gas sensing using multi-band multi-pass absorption spectroscopy may include splitting broadband light into multiple bands using an optical fiber wavelength division multiplexer 606. The method may include introducing multiple bands into a multi-band multi-pass absorption spectroscopy gas chamber 100 through an inlet wedge window 113 and an inlet aperture 112 in a first multi-band reflector 110, wherein the first multi-band reflector 110 may have multiple concentric dielectric coating regions. The method may include reflecting each band multiple times between the first multi-band reflector 110 and a second multi-band reflector 120 within a chamber 104, wherein the second multi-band reflector 120 may have multiple concentric dielectric coating regions.

[0097] The method may include outputting multiple bands from a multi-band multi-pass absorption spectroscopy chamber 100 through an outlet wedge window 123 and an outlet through-hole 122 in a second multi-band reflector 120. The method may include combining the multiple bands using an optical fiber combiner coupler 610 and detecting the combined bands using a broadband photodetector 612. The method may include processing the detected signals using a dual-comb spectroscopy processor 614 to determine the absorption spectral characteristics of the target gas, thereby enabling comprehensive gas analysis across multiple spectral bands using a single integrated system.

[0098] refer to Figure 7A and Figure 7B The multi-band multi-pass absorption spectroscopy chamber 100 can generate different reflection patterns on the surface of the mirrors, which demonstrate the controlled propagation of the beam during the multi-pass absorption process. The reflection patterns can show how the input beam 602 interacts with the first multi-band mirror 110 and the second multi-band mirror 120 to achieve multiple reflections while maintaining spectral separation and avoiding optical interference between different bands.

[0099] like Figure 7A As shown, a concentric pattern 702 may be formed on the first multi-band mirror 110, representing the input beam reflection pattern that occurs during the multi-pass absorption spectroscopy process. The concentric pattern 702 may demonstrate the spatial distribution of light reflection across the surface of the first multi-band mirror 110, wherein the pattern includes a plurality of rings concentrically arranged around a central point. Each ring within the concentric pattern 702 may correspond to the successive reflections of the input beam 602 as it passes through the chamber 104 and interacts with the concentric dielectric coating region.

[0100] The concentric pattern 702 illustrates how the input beam 602 produces different reflection points on the first multi-band mirror 110 during each reflection cycle. The rings within the concentric pattern 702 can be arranged such that the optical paths do not overlap, thereby avoiding interference between different reflections and maintaining the integrity of the spectral measurements. The spatial arrangement of the rings can be determined by the concave geometry of the first multi-band mirror 110 and the positioning of the inlet aperture 112 relative to the concentric dielectric coating region.

[0101] Continue to refer to Figure 7A The concentric pattern 702 illustrates how each band of the input beam 602 interacts with its corresponding coating region on the first multi-band mirror 110. The pattern shows that different bands generate reflection points at different radial distances from the center of the first multi-band mirror 110, corresponding to the first concentric dielectric coating region 119a, the second concentric dielectric coating region 119b, the third concentric dielectric coating region 119c, and the fourth concentric dielectric coating region 119d. This radial separation of the reflection points allows for simultaneous operation of multiple bands without cross-interference.

[0102] like Figure 7B As shown, a concentric pattern 704 may be formed on the second multiband reflector 120 to represent the input beam reflection pattern that appears when the beam completes its multi-pass journey through the chamber 104. The concentric pattern 704 may show the spatial distribution of light reflection across the surface of the second multiband reflector 120, wherein the pattern includes a plurality of rings arranged concentrically in a configuration corresponding to the concentric pattern 702 on the first multiband reflector 110.

[0103] The concentric pattern 704 illustrates how the input beam 602 produces different reflection points on the second multiband mirror 120 during each reflection cycle before exiting through the exit aperture 122. Each ring within the concentric pattern 704 corresponds to a successive reflection that has occurred during the multipass process, where the final reflection causes the output beam 608 (e.g., the input beam 602 after multiple reflections within chamber 104) to transmit through the exit window. In various embodiments, the output beam 608 refers to the input beam 602 after multiple reflections within chamber 104. The concentric pattern 704 demonstrates how the reflection geometry is maintained throughout the multipass process, thereby ensuring consistent optical performance.

[0104] The concentric pattern 704 illustrates how the light beams maintain their spectral separation and spatial organization as they approach the exit point of the chamber 104. The rings within the concentric pattern 704 are positioned at a radial distance corresponding to the concentric dielectric coating regions on the second multi-band reflector 120, allowing each band to exit through its appropriate exit via 122. This pattern demonstrates how the multi-pass reflection process preserves the wavelength-specific characteristics of each beam while achieving the desired optical path length enhancement.

[0105] Concentric patterns 702 and 704 collectively demonstrate that the multi-band multi-pass absorption spectroscopy chamber 100 achieves multiple reflections while maintaining distinct optical paths for each band. The spatial organization of the patterns shows that the concave geometry of the first multi-band mirror 110 and the second multi-band mirror 120 enables a controlled reflection sequence that maximizes the optical path length without interference between different spectral channels. Concentric patterns 702 and 704 demonstrate the effectiveness of the concentric dielectric coating region configuration in achieving multi-band operation. The patterns show that each coating region maintains its spectral selectivity throughout the multi-pass process, with reflection points remaining within designated radial regions on the first and second multi-band mirrors 110 and 120. The consistent spatial organization of the patterns demonstrates that the multi-band multi-pass absorption spectroscopy chamber 100 provides stable and predictable optical performance across all bands.

[0106] The reflection patterns provide visual confirmation that the wedge-shaped surfaces 117 of the inlet and outlet windows effectively minimize back reflection interference. The defining rings within the concentric patterns 702 and 704 indicate successful suppression of unwanted reflections, allowing the main reflection sequence to proceed without degradation. These patterns demonstrate that the optical design achieves the desired multi-pass performance while maintaining the spectral purity required for accurate gas detection and analysis.

[0107] refer to Figure 8 The multi-band multi-pass absorption spectroscopy chamber 100 can generate frequency band-specific light patterns. These frequency band-specific light patterns can be defined by the spatial distribution of spectral bands within the chamber 104. The reflection sequence of the frequency band light can be controlled by the concave geometry of the first multi-band mirror 110 and the second multi-band mirror 120 to achieve a desired increase in optical path length. Figure 8 As shown, each frequency band of light visualization may include a scale indicating the physical dimensions of chamber 104, thereby providing a reference for the spatial extent of the reflection pattern.

[0108] Figure 8The band 4 ray 802a depicted corresponds to a fourth spectral band within the multi-band multi-pass absorption spectroscopy chamber 100, illustrating how the fourth spectral band propagates between the first multi-band mirror 110 and the second multi-band mirror 120 during the multi-pass reflection process. Band 4 ray 802a interacts with a fourth concentric dielectric coating region 119d on both the first and second multi-band mirrors 110 and 120 to achieve high reflectivity characteristics for the corresponding wavelength range. The reflection point along band 4 ray 802a can be located radially on the mirror surface corresponding to the fourth concentric dielectric coating region 119d, which can be optimized for short infrared wavelengths. The spatial positioning of band 4 ray 802a allows the fourth spectral band to undergo multiple reflections without interfering with the optical path of other bands. The controlled reflection sequence of band 4 ray 802a can be optimized to provide enhanced optical path length for the short infrared wavelength range while avoiding interference with other spectral bands.

[0109] Figure 8 The band 4 ray footprint 802b depicted illustrates a reflection pattern formed by the reflection of the band 4 ray 802a on the surface of the mirror. The band 4 ray footprint 802b can define a circular pattern with reflection points arranged in a ring configuration, while maintaining separation from patterns generated by other bands. For example, the band 4 ray footprint 802b can define a circular reflection pattern on the surface of the mirror that does not overlap with patterns generated by other bands. The band 4 ray footprint 802b can define a circular reflection pattern at a radial position on the surface of the mirror corresponding to the fourth concentric dielectric coating region 119d. The reflection points within the band 4 ray footprint 802b can correspond to continuous reflections that occur when the band 4 ray 802a passes through the cavity 104 multiple times between the mirrors.

[0110] Figure 8The band 3 ray 804a depicted represents the beam path of a third spectral band within the multi-band multi-pass absorption spectroscopy chamber 100, illustrating how the third spectral band propagates between the first multi-band mirror 110 and the second multi-band mirror 120 during the multi-pass reflection process. Band 3 ray 804a can interact with a third concentric dielectric coating region 119c on the mirror surface to achieve optimized reflectivity for near-infrared wavelengths. Compared to band 4 ray 802a, band 3 ray 804a can be positioned at a different radial location. For example, the reflection point along band 3 ray 804a can be positioned radially on the mirror surface corresponding to the third concentric dielectric coating region 119c, which is optimized for near-infrared wavelengths. The spatial positioning of band 3 ray 804a allows the third spectral band to undergo multiple reflections without interfering with the optical paths of other bands. The controlled reflection sequence of band 3 rays 804a can be optimized to provide an enhanced optical path length close to the infrared wavelength range, while avoiding interference with other spectral bands.

[0111] Figure 8 The band 3 ray footprint 804b depicted shows a reflection pattern formed by the band 3 ray 804a on the surface of the mirror. The band 3 ray footprint 804b can define a circular reflection pattern with reflection points arranged in a ring configuration. The band 3 ray footprint 804b can define a reflection pattern generated by a third spectral band, which maintains spatial separation from other bands while achieving multiple reflections within the cavity 104. The band 3 ray footprint 804b can define a circular reflection pattern at a radial position on the mirror surface corresponding to the third concentric dielectric coating region 119c. The reflection points within the band 3 ray footprint 804b can correspond to continuous reflections that occur when the band 3 ray 804a passes through the cavity 104 multiple times between the mirrors.

[0112] Figure 8The band 2 ray 806a depicted represents the beam path of a second spectral band within the multi-band multi-pass absorption spectroscopy chamber 100, illustrating how the second spectral band propagates between the first multi-band mirror 110 and the second multi-band mirror 120 during the multi-pass reflection process. The band 2 ray 806a can interact with a second dielectric concentric coating region 119b on the mirror surface to achieve high reflectivity for visible wavelengths. The band 2 ray 806a can be positioned radially corresponding to the second dielectric concentric coating region 119b, which surrounds the first concentric dielectric coating region 119a and is surrounded by a third concentric dielectric coating region 119c. For example, the reflection point along the band 2 ray 806a can be positioned radially on the mirror surface corresponding to the second dielectric concentric coating region 119b, which can be optimized for visible wavelengths. The spatial positioning of the band 2 ray 806a allows the second spectral band to undergo multiple reflections without interfering with the optical paths of other bands. For example, the positioning of the band 2 ray 806a enables the second spectral band to achieve multiple reflections while maintaining spatial separation from rays in other bands. The controlled reflection sequence of the band 2 ray 806a can be optimized to provide an enhanced optical path length for the visible wavelength range while avoiding interference with other spectral bands.

[0113] Figure 8 The band 2 ray footprint 806b depicted illustrates the reflection pattern formed by the band 2 ray 806a on the surface of the mirror. The band 2 ray footprint 806b can define a circular pattern with reflection points arranged in a ring configuration, while maintaining separation from patterns generated by other bands. The band 2 ray footprint 806b can define a circular reflection pattern at a radial position on the surface of the mirror corresponding to the second dielectric concentric coating region 119b. The reflection points within the band 2 ray footprint 806b can correspond to continuous reflections that occur when the band 2 ray 806a passes through the cavity 104 multiple times between the mirrors.

[0114] Figure 8The band 1 ray 808a depicted represents the beam path of a first spectral band within the multi-band multi-pass absorption spectroscopy chamber 100, illustrating how the first spectral band propagates between the first multi-band reflector 110 and the second multi-band reflector 120 during the multi-pass reflection process. The band 1 ray 808a can interact with a first concentric dielectric coating region 119a at the reflector surface to achieve optimized reflectivity for ultraviolet wavelengths. The band 1 ray 808a can be positioned radially corresponding to the first concentric dielectric coating region 119a. For example, the reflection point along the band 1 ray 808a can be positioned radially on the reflector surface corresponding to a second concentric dielectric coating region 119a, which is optimized for ultraviolet wavelengths. The spatial positioning of the band 1 ray 808a allows the first spectral band to undergo multiple reflections without interfering with the optical paths of other bands. For example, the positioning of band 1 ray 808a allows the first spectral band to undergo multiple reflections while maintaining spatial separation from rays in other bands. The controlled reflection sequence of band 1 ray 808a can be optimized to provide enhanced optical path length for the ultraviolet wavelength range while avoiding interference with other spectral bands.

[0115] Figure 8 The band 1 ray footprint 808b depicted illustrates the reflection pattern formed by the band 1 ray 808a on the surface of the mirror. The band 1 ray footprint 808b can define a circular reflection pattern with reflection points arranged in a ring, while maintaining separation from patterns generated by other bands. The band 1 ray footprint 808b can define a reflection pattern at a radial position on the surface of the mirror corresponding to the second dielectric concentric coating region 119b. The reflection points within the band 1 ray footprint 808b can correspond to continuous reflections that occur when the band 1 ray 808a passes through the cavity 104 multiple times between the mirrors.

[0116] Figure 8 The frequency band-specific ray patterns shown collectively demonstrate that each band produces a distinct circular pattern on the mirror surface, without overlap between different spectral bands. The spatial separation of the ray footprints 802b (band 4), 804b (band 3), 806b (band 2), and 808b (band 1) enables simultaneous processing of multiple bands within the multi-band multi-pass absorption spectroscopy chamber 100. The different patterns demonstrate that the concentric dielectric coating configuration successfully maintains spectral separation while achieving multi-band operation.

[0117] The light footprint pattern shows that each spectral band undergoes a specific amount of reflection between the first multiband mirror 110 and the second multiband mirror 120, which enhances absorption sensitivity. For example, in some embodiments, the multiband multipass absorption spectroscopy gas sensing method may involve multiple reflections of each band, wherein multiple reflections of each band may include approximately eighty reflections of each band between the first multiband mirror 110 and the second multiband mirror 120. Eighty reflections can provide a significant enhancement in the optical path length, thereby enabling improved detection sensitivity for gases with low concentrations or weak absorption characteristics across all spectral bands.

[0118] The visualization of band-specific ray patterns demonstrates that the multi-band multi-pass absorption spectroscopy gas cell 100 maintains consistent optical performance across all wavelengths while achieving the desired enhancement factor through multiple reflections. The different spatial organization of the reflection patterns of the rays in each band shows that the concentric dielectric coating configuration enables efficient multi-band operation without compromising the performance of individual spectral channels.

[0119] refer to Figure 9A A dielectric-coated mirror reflectance diagram 900a is provided. The dielectric-coated mirror reflectance diagram 900a illustrates example reflectance performance characteristics of concentric dielectric-coated regions used in the first multi-band mirror 110 and the second multi-band mirror 120. The dielectric-coated mirror reflectance diagram 900a shows the percentage of reflectance as a function of wavelength across the electromagnetic spectrum, demonstrating how the multi-band coating configuration simultaneously achieves high reflectance values ​​across multiple spectral bands. The dielectric-coated mirror reflectance diagram 900a provides quantitative data supporting enhanced performance capabilities of the multi-band multi-pass absorption spectroscopy chamber 100.

[0120] like Figure 9A As shown in Figure 900a, the reflectance of the dielectric-coated mirror exhibits four distinct spectral bands with reflectance exceeding 99.5%, enabling efficient multi-pass absorption spectroscopy over a wide wavelength range. These four spectral bands correspond to a first concentric dielectric coating region 119a, a second concentric dielectric coating region 119b, a third concentric dielectric coating region 119c, and a fourth concentric dielectric coating region 119d, all concentrically arranged on the mirror surface. Each spectral band achieves a reflectance value significantly exceeding that of conventional mirror coatings, thereby increasing the optical path length by multiplying the number of reflections.

[0121] The reflectance diagram 900a of the dielectric-coated mirror depicts a first band 902a (e.g., near-ultraviolet and blue bands), which covers near-ultraviolet and blue wavelengths from approximately 0.35 micrometers to 0.45 micrometers. The first band 902a corresponds to a first concentric dielectric coating region 119a located at the innermost region in a concentric coating arrangement, thereby providing optimized reflectance characteristics for ultraviolet and blue wavelengths. The first band 902a can achieve a reflectance value exceeding 99.5% in the near-ultraviolet and blue wavelength range, thus enabling efficient multi-pass absorption spectroscopy for gas species exhibiting absorption characteristics in the ultraviolet and blue wavelength regions.

[0122] Continue to refer to Figure 9A The reflectance diagram 900a of the dielectric-coated mirror depicts a second band 902b (e.g., the visible band), which covers wavelengths from approximately 0.4 to 0.9 micrometers. The second band 902b corresponds to a second concentric dielectric coating region 119b surrounding the first concentric dielectric coating region 119a on the mirror surface. The second band 902b provides a reflectance value exceeding 99.5% across the entire visible wavelength range, thereby improving the sensitivity of gas detection applications utilizing visible light absorption spectroscopy. Visible band coverage enables the detection of gas species with absorption characteristics in the visible spectrum while maintaining the high reflectance required for efficient multi-pass operation.

[0123] The reflectance diagram 900a of the dielectric-coated mirror depicts a third band 902c (e.g., the near-infrared band), which covers wavelengths from approximately 0.8 micrometers to 1.25 micrometers. The third band 902c corresponds to a third concentric dielectric coating region 119c, which is concentrically arranged around a second concentric dielectric coating region 119b. The third band 902c achieves a reflectance value exceeding 99.5% in the near-infrared wavelength range, thereby providing enhanced performance for gas sensing applications targeting absorption characteristics in the near-infrared spectral region. The near-infrared band enables the detection of various gas species exhibiting characteristic absorption lines within this wavelength range.

[0124] like Figure 9A As shown, the reflectance diagram 900a of the dielectric-coated mirror depicts a fourth band 902d (e.g., a short infrared band), which covers wavelengths from approximately 1.25 micrometers to 1.75 micrometers. The fourth band 902d corresponds to the fourth concentric dielectric coating region 119d located in the outermost region of a concentric coating arrangement. The short infrared band provides a reflectance value exceeding 99.5% in the 1.25 to 1.75 micrometer range, enabling efficient multi-pass absorption spectroscopy for gas species with absorption characteristics in the short infrared wavelength region. The fourth band 902d can achieve multi-band coverage by addressing longer wavelength applications that may be associated with comprehensive gas detection capabilities.

[0125] The reflectance of the dielectric-coated mirror, as shown in Figure 900a, demonstrates that the combined coverage of four spectral bands achieves a reflectance greater than 99.5% for wavelengths ranging from 0.35 μm to 1.75 μm. This combined coverage provides consistently high reflectance performance across a broad spectral range encompassing ultraviolet, visible, near-infrared, and short-infrared wavelengths. The four-band combined coverage allows the multi-band multi-pass absorption spectroscopy gas cell 100 to be adapted to various gas sensing applications requiring different wavelength ranges for optimal detection sensitivity.

[0126] In some examples, the high reflectivity of the dielectric-coated mirror, as shown in Figure 900a, enables the multi-band multi-pass absorption spectroscopy cell 100 to achieve approximately eighty reflections per band without significant optical loss. A reflectivity exceeding 99.5% provides a significant improvement compared to conventional mirrors. This enhanced reflectivity characteristic allows for a higher enhancement factor and improved detection sensitivity across all spectral bands.

[0127] The wavelength coverage shown in the dielectric-coated mirror reflectivity diagram 900a enables the multi-band multi-pass absorption spectroscopy gas cell 100 to detect a wide variety of gases exhibiting absorption characteristics across the ultraviolet to short-infrared spectral range. This broad wavelength coverage provides comprehensive gas sensing capabilities that may not be achievable with conventional single-coated mirror systems. High reflectivity across all four spectral bands ensures sufficient enhancement is received in each wavelength range through the multi-pass reflection process, resulting in consistent detection performance across the entire spectral range.

[0128] Figure 9B An example reflectivity diagram 900b of a reflective mirror is shown. Specifically, Figure 9B The diagram illustrates the relationship between the number of mirror reflections and the chamber enhancement factor for different mirror types / configurations and / or reflectance values. Mirror reflectance plot 900b shows how the reflectance characteristics of the mirrors in gas chamber 100 affect the performance capabilities of the multi-band multi-pass absorption spectroscopy gas chamber 100. Mirror reflectance plot 900b provides quantitative analysis that supports the selection of high-reflectance dielectric coatings to achieve enhanced gas detection sensitivity through extended optical path lengths.

[0129] like Figure 9B As shown, the x-axis of the mirror reflectivity diagram 900b represents the number of reflections by the mirror, and the y-axis represents the chamber enhancement factor. The mirror reflectivity diagram 900b depicts four different reflectance curves 904a to 904d representing different mirror reflectivity values, illustrating the impact of reflectance performance on the overall enhancement capability of the air chamber system.

[0130] The mirror reflectivity diagram 900b includes a first reflectivity curve 904a representing a mirror reflectivity of 0.95, which corresponds to the performance characteristics of a conventional gold-plated mirror. The first reflectivity curve 904a offers limited enhancement capability, especially when the number of reflections increases to more than approximately twenty. The first reflectivity curve 904a shows that a conventional gold-plated mirror with a reflectivity of 0.95 achieves only a minimal enhancement factor even at moderate numbers of reflections, illustrating the limitations of conventional mirror technology for high-performance gas sensing applications.

[0131] Continue to refer to Figure 9B The mirror reflectivity diagram 900b includes a second reflectivity curve 904b representing a mirror reflectivity of 0.99, which demonstrates the improved enhancement performance compared to the first reflectivity curve 904a. The second reflectivity curve 904b shows how a modest improvement in mirror reflectivity can improve the enhancement factor, particularly with increasing reflection count. Figure 900b shows that a 0.99 reflectivity enables more efficient multi-pass operation compared to conventional mirror coatings, but the enhancement factor may still be limited compared to higher reflectivity values.

[0132] The mirror reflectivity diagram 900b includes a third reflectivity curve 904c representing a mirror reflectivity of 0.995, which corresponds to the performance characteristics achievable using a dielectric mirror (such as the dielectric-coated mirror described above). The third reflectivity curve 904c illustrates the enhanced performance compared to lower reflectivity values, demonstrating how a high-reflectivity dielectric coating, as described above, can achieve efficient multi-pass operation with a significant enhancement factor. The third reflectivity curve 904c shows that a reflectivity of 0.995 provides a significant improvement in enhancement capability, enabling the practical realization of a high-reflectivity counting gas sensing system. Specifically, the third reflectivity curve 904c shows that a dielectric mirror or dielectric-coated mirror can achieve a 50-fold increase in gas sensing enhancement (e.g., an enhancement factor of 50) using 80 mirror reflections.

[0133] like Figure 9B As shown, the mirror reflectivity diagram 900b includes a fourth reflectivity curve 904d representing a mirror reflectivity of 0.99995, which represents near-ideal mirror performance approaching the theoretical limit of a reflection-based enhancement system. The fourth reflectivity curve 904d demonstrates that even with a large number of reflections, extremely high reflectivity values ​​can achieve a significant enhancement factor, thus approaching the theoretical limit where the enhancement factor equals the number of reflections.

[0134] As described above, the dielectric-coated mirror achieves an enhancement factor of 50 at 80 mirror reflections. An enhancement factor of approximately 50 represents a significant improvement compared to conventional mirror systems, while remaining achievable using practical dielectric coating techniques. A reflectance of 0.995 enables the multi-band multi-pass absorption spectroscopy gas cell 100 to achieve enhanced gas detection sensitivity across all four spectral bands.

[0135] At eighty reflections, the first reflectance profile (e.g., a 0.95 reflectance profile) achieves a gas sensing enhancement factor of approximately 2, demonstrating the limitations of conventional gold-plated mirrors for high reflectance counting applications. At eighty reflections, the second reflectance profile (e.g., a mirror reflectance of 0.99) achieves a chamber enhancement factor of approximately 33, indicating improved performance compared to conventional mirrors, but reduced enhancement compared to mirrors with higher reflectance, such as the dielectric-coated mirrors described herein.

[0136] Figure 900b shows that the gas sensing enhancement factor becomes increasingly sensitive to mirror reflectivity as the number of reflections increases. The reflectance curves demonstrate that when operating at high reflectance counts, such as in various multi-pass absorption spectroscopy applications, small differences in reflectance values ​​can lead to significant differences in gas sensing enhancement. Figure 900b illustrates that a reflectance of 0.995 achieved by a dielectric-coated mirror provides a practical balance between achievable coating performance and meaningful enhancement capabilities.

[0137] like Figure 9C As shown in Figure 900c, which depicts the reflectance of a gold-coated mirror, for limited multi-pass absorption spectroscopy gas sensing applications, gold-coated mirrors can only provide 95% reflectance at IR wavelengths (>1.4µm). Figure 9C It was further shown that the gold-plated reflector can only provide 90% reflectance in deep red and near-IR wavelengths (>0.65µm), which is too low for multi-pass applications and cannot provide usable reflectance in most visible wavelengths (<0.65µm).

[0138] Figure 10 A block diagram of an exemplary apparatus that can be specially configured according to an exemplary embodiment of the present disclosure is shown. Specifically, Figure 2 An example computing device 1000 (“device 1000”) with a specific configuration according to at least some example embodiments of this disclosure is depicted. In some embodiments, system 600 and / or a portion thereof comprises one or more systems (such as... Figure 10 The device 1000 depicted and described is embodied in this.

[0139] Device 1000 may include a processor or processing circuitry 1002, a memory circuitry 1004, an input / output circuitry 1006, and a communication circuitry 1008, an optical input circuitry 1010, and / or an optical output circuitry 1012. In some embodiments, one or more portions of device 1000 (e.g., one or more components thereof) are configured to perform and implement the operations described herein.

[0140] While these components are described with respect to functional limitations, it should be understood that at least some specific implementations in a particular embodiment necessarily include the use of specific computing hardware. It should also be understood that in some implementations, some of the components described herein include similar or common hardware. For example, in some implementations, two circuit groups utilize the same processor, memory, circuitry, etc., to perform their associated functions, so that each circuit group does not require duplicate hardware.

[0141] The processing circuitry 1002 can be embodied in a variety of different ways. In various embodiments, the term "processor" or "processing circuitry" should be understood to include a single-core processor, a multi-core processor, multiple processors within the example device 1000, and / or one or more remote or "cloud" processors external to the example device 1000. In some example embodiments, the processing circuitry 1002 may include one or more processing devices configured to execute independently. Alternatively or additionally, the processing circuitry 1002 may include one or more processors configured in series via a bus to enable independent execution of operations, instructions, pipelines, and / or multithreading.

[0142] In example embodiments, processing circuitry 1002 may be configured to execute instructions stored in memory circuitry 1004 or otherwise accessible by a processor. Alternatively or additionally, processing circuitry 1002 may be configured to perform hard-coded functionality. Thus, whether configured by hardware or software methods, or by a combination thereof, processing circuitry 1002 may represent an entity (e.g., physically embodied in circuit form) capable of performing operations according to embodiments of this disclosure. Alternatively or additionally, processing circuitry 1002 may be embodied as an executor of software instructions that may specifically configure processing circuitry 1002 to perform various algorithms embodied in one or more operations described herein when executing such instructions. In some embodiments, processing circuitry 1002 includes hardware, software, firmware, and / or combinations thereof for performing one or more operations described herein.

[0143] Processing circuit 1002 can implement various signal processing algorithms to extract meaningful absorption data from the received optical signal. Processing circuit 1002 can perform baseline correction to account for variations in light source intensity and detector response characteristics. Processing circuit 1002 can apply digital filtering techniques to reduce noise and improve the signal-to-noise ratio in absorption measurements. Processing circuit 1002 can execute spectral analysis algorithms that identify characteristic absorption peaks corresponding to specific molecular transitions in the target gas.

[0144] In some embodiments, processing circuitry 1002 (and / or a coprocessor or any other processing circuitry that assists the processor or otherwise associates with the processor) communicates with memory circuitry 1004 via a bus for transferring information between components of example device 1000.

[0145] The memory or memory circuitry 1004 may be non-transitory and may include, for example, one or more volatile and / or non-volatile memories. In some embodiments, the memory circuitry 1004 includes or embodies an electronic storage device (e.g., a computer-readable storage medium). In some embodiments, the memory circuitry 1004 is configured to store information, data, content, applications, instructions, etc., for enabling the example device 1000 to perform various operations and / or functions according to the example embodiments of this disclosure.

[0146] The memory circuit 1004 can store reference absorption spectra of various target gases, enabling the processing circuit 1002 to perform pattern matching and identification of unknown gas components. The memory circuit 1004 can store calibration data that correlates measured absorption signals with actual gas concentrations, taking into account factors such as variations in temperature, pressure, and optical path length. The memory circuit 1004 can store historical measurement data for trend analysis and long-term monitoring applications. The memory circuit 1004 may include volatile memory for real-time data processing and non-volatile memory for persistent storage of calibration parameters and reference data.

[0147] Input / output circuitry 1006 may be included in example device 1000. In some embodiments, input / output circuitry 1006 may provide output to a user and / or receive input from a user. Input / output circuitry 1006 may communicate with processing circuitry 1002 to provide such functionality. Input / output circuitry 1006 may include one or more user interfaces. In some embodiments, the user interface may include a display, which may be presented as a web user interface, application user interface, user device, back-end system, etc. In some embodiments, input / output circuitry 1006 may also include a keyboard, mouse, joystick, touchscreen, touch area, softkeys, microphone, speaker, or other input / output mechanism. Processing circuitry 1002 and / or input / output circuitry 1006 may be configured to control one or more operations and / or functions of one or more user interface elements via computer program instructions (e.g., software and / or firmware) stored in memory accessible by a processor (e.g., memory circuitry 1004, etc.). In some embodiments, the input / output circuit 1006 includes or utilizes user-facing applications to provide input / output functionality to a computing device and / or other display associated with the user. In some embodiments, the input / output circuit 1006 includes one or more indicator lights, etc., for providing user notifications (e.g., alarms or warnings).

[0148] Communication circuitry 1008 may be included in example device 1000. Communication circuitry 1008 may include any component, such as a device or circuit embodied in hardware or a combination of hardware and software, configured to receive and / or transmit data from / to a network and / or any other device, circuitry, or module communicating with example device 1000. In some embodiments, communication circuitry 1008 includes, for example, a network interface for enabling communication with wired or wireless communication networks. Additionally or alternatively, communication circuitry 1008 may include one or more network interface cards, antennas, buses, switches, routers, modems, and supporting hardware, firmware, and / or software, or any other device suitable for enabling communication via one or more communication networks. In some embodiments, communication circuitry 1008 may include circuitry for interacting with antennas and / or other hardware or software to induce reception of signals transmitted via the antenna and / or processing of signals received via the antenna. In some embodiments, communication circuitry 1008 enables the transmission and / or reception of data to and / or from user equipment, one or more sensors, and / or other external computing devices communicating with example device 1000.

[0149] In some embodiments, device 1000 includes optical input circuitry 1010. Optical input circuitry 1010 may include hardware components, software components, and / or combinations thereof, configured to perform one or more functions associated with broadband dual-comb laser source 604 and / or fiber wavelength division multiplexer 606 (as referenced above) together with processor 1002, memory 1004, input / output circuitry 1006, and / or communication circuitry 1008. Figure 6 In some embodiments, the optical input circuit 1010 includes a broadband dual-comb laser source (such as broadband dual-comb laser source 604) and an optical fiber wavelength division multiplexer (such as optical fiber wavelength division multiplexer 606).

[0150] In some embodiments, device 1000 includes optical output circuitry 1012. Optical input circuitry 1010 may include hardware components, software components, and / or combinations thereof, configured to perform one or more functions associated with fiber optic combiner coupler 610, broadband photodetector 612, and / or dual-comb spectroscopy processor 614 (as referenced above) together with processor 1002, memory 1004, input / output circuitry 1006, and / or communication circuitry 1008. Figure 6 (as described above). In some embodiments, the optical output circuit 1012 includes an optical fiber combiner coupler (such as optical fiber combiner coupler 610), a broadband photodetector (such as broadband photodetector 612), and / or a dual-comb spectroscopy processor (such as dual-comb spectroscopy processor 614).

[0151] In some embodiments, device 1000 includes absorption circuitry 1014. Absorption circuitry 1014 may include hardware components, software components, and / or combinations thereof, configured to perform one or more functions associated with the multi-band multi-pass absorption spectroscopy chamber 100 as described herein, together with processor 1002, memory 1004, input / output circuitry 1006, and / or communication circuitry 1008. In some embodiments, absorption circuitry 1014 includes multi-band multi-pass absorption spectroscopy chamber 100.

[0152] In some embodiments, two or more circuits in groups 1002 to 1014 are composable. Alternatively or additionally, one or more circuits in groups 1002 to 1014 implement some or all of the operations and / or functionalities described herein as associated with another circuit. In some embodiments, two or more circuits in groups 1002 to 1014 are combined into a single module embodied in hardware, software, firmware, and / or combinations thereof.

[0153] While the foregoing description provides for an apparatus 1000, it should be noted that the scope of this disclosure is not limited to the foregoing description. In some examples, the example apparatus 1000 according to this disclosure may be of other forms. In some examples, the example apparatus 1000 may include one or more additional and / or alternative elements, and / or may be compatible with... Figure 10 The structures shown are different.

[0154] The operations and procedures described herein support combinations of components for performing specified functions and combinations of operations for performing specified functions. It should be understood that one or more operations, and combinations of operations, can be implemented by a computer system based on dedicated hardware or a combination of dedicated hardware and computer instructions to perform the specified functions.

[0155] In some example implementations, some of the operations described herein may be modified or further expanded as described below. Additionally, in some implementations, additional optional operations may be included. It should be understood that each of the modifications, optional additions, or expansions described herein may be included in the operations herein, either individually or in combination with any other feature described herein.

[0156] The foregoing description of methods and processes is provided as illustrative examples only and is not intended to require or imply that the steps of the various embodiments must be performed in the presented order. As those skilled in the art will understand, the order of steps in the above embodiments can be performed in any order. Words such as “after,” “then,” “next,” and similar terms are not intended to limit the order of steps; these words are merely used to guide the reader through the description of the method. Furthermore, any reference to singular claim elements, for example, using the articles “a,” “an,” or “the,” should not be construed as limiting the element to the singular and, in some cases, may be interpreted in the plural form.

[0157] Although various embodiments based on the principles disclosed herein have been shown and described above, modifications can be made by those skilled in the art without departing from the teachings of this disclosure. The embodiments described herein are representative only and not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of this disclosure. Alternative embodiments resulting from the merging, integration, and / or omission of features of the embodiments are also within the scope of this disclosure. Therefore, the scope of protection is not limited by the description set forth above, but is defined by the following claims, which include all equivalents of the subject matter of the claims. Each claim is incorporated into the specification as further disclosure, and the claims are embodiments of this disclosure. Furthermore, any of the foregoing advantages and features may relate to specific embodiments, but the application of such published claims should not be limited to methods and structures that achieve any or all of the above advantages or have any or all of the above features.

[0158] Furthermore, the chapter titles used in this article are intended to correspond with 37 CFR. The recommendations in 1.77 are consistent with or provide organizational clues. These headings should not limit or characterize the disclosure set forth in any of the claims published in this disclosure. For example, the description of the technology in “Background Art” should not be interpreted as an admission that a certain technology is prior art to any disclosure in this disclosure. Nor should “Summary of the Invention” be considered a limiting characterization of the disclosure set forth in the published claims. Furthermore, any reference in this disclosure to the singular forms “Disclosure” or “Simplification” should not be used to prove that there is only one novel point in this disclosure. Multiple embodiments of this disclosure may be set forth according to the limitations of the multiple claims published in this disclosure, and such claims accordingly define the disclosure protected by them and its equivalents. In all cases, the scope of these claims should be considered in accordance with the advantages of the claims themselves, and should not be limited by the headings set forth herein.

[0159] Furthermore, without departing from the scope of this disclosure, the systems, subsystems, apparatuses, techniques, and methods described and illustrated in various embodiments in a discrete or separate manner can be combined or integrated with other systems, modules, techniques, or methods. Other devices or components shown or discussed as being interconnected or communicating with each other can be indirectly interconnected through some intermediate devices or components, whether such interconnection is made electrically, mechanically, or otherwise. Other examples of variations, substitutions, and modifications that can be identified by those skilled in the art without departing from the scope of this disclosure are also provided.

[0160] Those skilled in the art to which these embodiments pertain will recognize numerous modifications and other embodiments of the disclosure set forth herein, which benefit from the teachings presented in the foregoing description and associated drawings. Although the drawings show only certain components of the apparatuses and systems described herein, various other components may be used in conjunction with the components and structures disclosed herein. Therefore, it should be understood that this disclosure is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. For example, various elements or components may be combined, rearranged, or integrated into another system, or certain features may be omitted or not implemented. Furthermore, the steps in any of the methods described above may not necessarily occur in the order depicted in the drawings, and in some cases, one or more of the depicted steps may occur substantially simultaneously, or additional steps may be involved. Although specific terms are used herein, they are used only in a general and descriptive sense and not for limiting purposes.

Claims

1. A multi-band multi-pass absorption gas chamber, the multi-band multi-pass absorption gas chamber comprising: A housing that defines a chamber for receiving a gas sample to be analyzed; A first multi-band reflector is positioned at a first end of the housing. The first multi-band reflector defines a plurality of inlet vias and includes a plurality of first concentric dielectric coating regions corresponding to a plurality of bands. The second multi-band reflector is positioned at the second end of the housing opposite to the first end. The second multi-band reflector includes multiple outlet through holes and a second plurality of concentric dielectric coating areas corresponding to the multiple bands. Multiple inlet wedge-shaped windows, the multiple inlet wedge-shaped windows being positioned at the first end of the housing; and Multiple outlet wedge windows are positioned at the second end of the housing.

2. The multi-band multi-pass absorption chamber according to claim 1, wherein the multi-band multi-pass absorption chamber further comprises: An inlet, the inlet being used to introduce the gas sample into the chamber; and An outlet, the outlet being used to remove the gas sample from the chamber.

3. The multi-band multi-pass absorption chamber according to claim 1, wherein each of the first multi-band reflector and the second multi-band reflector defines an inner surface and an outer surface, wherein the inner surface of the first multi-band reflector and the inner surface of the second multi-band reflector face each other, and wherein the inner surface of the first multi-band reflector includes the first plurality of concentric dielectric coating regions, and the inner surface of the second multi-band reflector includes the second plurality of concentric dielectric coating regions.

4. The multi-band multi-pass absorption chamber according to claim 3, wherein the plurality of inlet wedge windows are positioned adjacent to the outer surface of the first multi-band reflector, and the plurality of outlet wedge windows are positioned adjacent to the outer surface of the second multi-band reflector.

5. The multi-band multi-pass absorption chamber according to claim 3, wherein each of the plurality of inlet through holes is conical and defines a first opening on the inner surface of the first multi-band reflector and a second opening on the outer surface of the first multi-band reflector, the second opening being larger than the first opening.

6. The multi-band multi-pass absorption chamber according to claim 3, wherein each of the plurality of outlet through holes is conical and defines a first opening on the inner surface of the second multi-band reflector and a second opening on the outer surface of the second multi-band reflector, the second opening being larger than the first opening.

7. The multi-band multi-pass absorption chamber according to claim 1, wherein the plurality of inlet vias of the first multi-band reflector are defined within different dielectric coating regions of the first plurality of concentric dielectric coating regions, and wherein the plurality of outlet vias of the second multi-band reflector are defined within different dielectric coating regions of the second plurality of concentric dielectric coating regions.

8. The multi-band multi-pass absorption chamber according to claim 1, wherein the plurality of inlet holes of the first multi-band reflector are defined at different radial distances from the center of the first multi-band reflector, and wherein the plurality of outlet holes of the second multi-band reflector are defined at different radial distances from the center of the second multi-band reflector.

9. The multi-band multi-pass absorption chamber of claim 1, wherein the first plurality of concentric dielectric coating regions and the second plurality of concentric dielectric coating regions each comprise four concentric dielectric coating regions, the four concentric dielectric coating regions being configured to provide a reflectance greater than 99.5% in each of the plurality of bands.

10. A multi-band multi-pass absorption gas sensing system, the multi-band multi-pass absorption gas sensing system comprising: A broadband dual-comb laser source, wherein the broadband dual-comb laser source is configured to emit light; An optical fiber wavelength division multiplexer configured to generate multiple beams from the light, wherein the multiple beams correspond to multiple wavelength bands; and A multi-band multi-pass absorption chamber, configured to receive the plurality of light beams, the multi-band multi-pass absorption chamber comprising: A housing that defines a chamber for receiving a gas sample to be analyzed; A first multi-band reflector is positioned at a first end of the housing. The first multi-band reflector defines a plurality of inlet vias and includes a plurality of first concentric dielectric coating regions corresponding to a plurality of bands. The second multi-band reflector is positioned at the second end of the housing opposite to the first end. The second multi-band reflector includes multiple outlet through holes and a second plurality of concentric dielectric coating areas corresponding to the multiple bands. Multiple inlet wedge-shaped windows, the multiple inlet wedge-shaped windows being positioned at the first end of the housing; and Multiple outlet wedge windows are positioned at the second end of the housing.

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