Compact multi-pass absorption gas cell

Abstract

The present disclosure provides a compact multi-pass absorption gas cell comprising a rectangular housing defining a chamber for receiving a sample to be analyzed, a light inlet positioned at a first end of the rectangular housing for introducing a light beam into the chamber, a light outlet positioned at a second end of the rectangular housing, a first mirror component positioned at the first end and comprising a first plane mirror and a first concave mirror array, and a second mirror component positioned at the second end and comprising a second plane mirror and a second concave mirror array, wherein the light beam is reflected multiple times between the first mirror component and the second mirror component and refocused by the first and second concave mirror arrays to achieve an optical path length for low absorption gas detection.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 744,285, filed January 12, 2025, the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] The applicant has recognized the numerous technical challenges associated with multi-pass absorption gas cells. 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] This invention is provided to introduce a series of concepts in a simplified form, which are further described in the detailed embodiments below. This invention is not intended to identify key or essential features of the claimed subject matter, nor is it intended to aid in determining the scope of the claimed subject matter.

[0006] According to one aspect of this disclosure, a compact multi-pass absorption gas cell is provided. The compact multi-pass absorption gas cell includes a rectangular housing defining a chamber for receiving a sample to be analyzed. The compact multi-pass absorption gas cell includes a light inlet located at a first end of the rectangular housing for introducing a light beam into the chamber. The compact multi-pass absorption gas cell includes a light outlet located at a second end of the rectangular housing. The compact multi-pass absorption gas cell includes a first mirror component located at the first end, the first mirror component including a first plane mirror and a first concave mirror array. The compact multi-pass absorption gas cell includes a second mirror component located at the second end, the second mirror component including a second plane mirror and a second concave mirror array, wherein the light beam is reflected multiple times between the first mirror component and the second mirror component and refocused by the first concave mirror array and the second concave mirror array to achieve an optical path length for low-absorption gas detection.

[0007] According to other aspects of this disclosure, the compact multi-pass absorption gas cell may include one or more of the following features: The first concave mirror array and the second concave mirror array may each include a plurality of concave mirrors. The light beam may be reflected between the first mirror component and the second mirror component in a rectangular row-by-row pattern. The light inlet and the light outlet may be positioned on opposite sides relative to the chamber, wherein the light beam exits the chamber from the light outlet. The first concave mirror array and the first plane mirror may be coupled together and attached to the first end of the rectangular housing. The second concave mirror array and the second plane mirror may be coupled together and attached to the second end of the rectangular housing. The optical path length may be determined based on: (i) the number of beam spots on the first plane mirror or the second plane mirror, (ii) the number of concave mirrors in the first plane mirror or the second plane mirror, and (iii) the mirror-to-mirror distance between the first mirror component and the second mirror component. The number of beam spots on the first plane mirror and the second plane mirror may be the same, and wherein the number of concave mirrors in the first plane mirror and the second plane mirror may be the same. The first and second mirror components define a mirror-to-mirror distance of approximately 400 mm, and each of the first and second mirror components has a height of approximately 33 mm and a width of approximately 111 mm. The first and second concave mirror arrays may each include 16 concave mirrors. The optical path length may be approximately 119 meters. Alternatively, the first and second concave mirror arrays may each include 8 concave mirrors. The optical path length may be approximately 61 meters.

[0008] According to another aspect of this disclosure, a gas detection system is provided. The gas detection system includes a compact multi-pass absorption gas cell, comprising: a rectangular housing defining a chamber for receiving a sample to be analyzed; a light inlet located at a first end of the rectangular housing for introducing a light beam into the chamber; a light outlet located at a second end of the rectangular housing; a first mirror component located at the first end, the first mirror component including a first plane mirror and a first concave mirror array; and a second mirror component located at the second end, the second mirror component including a second plane mirror and a second concave mirror array, wherein the light beam is reflected multiple times between the first mirror component and the second mirror component and refocused by the first concave mirror array and the second concave mirror array to achieve an optical path length for detecting low-absorption gases. The gas detection system includes a light emitter configured to emit a light beam toward the compact multi-pass absorption gas cell. The gas detection system includes a light receiver configured to receive light exiting the compact multi-pass absorption gas cell.

[0009] According to other aspects of this disclosure, the gas detection system may include one or more of the following features: The first concave mirror array and the second concave mirror array may each include a plurality of concave mirrors. The light beam may be reflected between the first mirror component and the second mirror component in a rectangular row-by-row pattern. The light inlet and the light outlet may be positioned on opposite sides relative to the chamber, wherein the light beam exits the chamber from the light outlet. The first concave mirror array and the first plane mirror may be coupled together and attached to the first end of the rectangular housing. The second concave mirror array and the second plane mirror may be coupled together and attached to the second end of the rectangular housing. The optical path length may be determined based on: (i) the number of beam spots on the first plane mirror or the second plane mirror, (ii) the number of concave mirrors in the first plane mirror or the second plane mirror, and (iii) the mirror-to-mirror distance between the first mirror component and the second mirror component.

[0010] The foregoing general description of the exemplary embodiments and the following detailed description are merely exemplary aspects of the teachings of this disclosure and are not restrictive. Attached Figure Description

[0011] The description of the exemplary embodiments can be read in conjunction with the accompanying drawings. It should be understood that, for simplicity and clarity of illustration, the elements illustrated in the figures are not necessarily drawn to scale unless otherwise described. For example, unless otherwise described, the dimensions of some elements may be exaggerated relative to others. Embodiments incorporating the teachings of this disclosure are shown and described with reference to the accompanying drawings, in which:

[0012] Figure 1 A perspective view of a compact multi-pass absorption gas cell according to at least some example embodiments of the present disclosure is illustrated.

[0013] Figure 2A At least some example embodiments according to this disclosure are illustrated. Figure 1 A top view of a compact multi-pass absorption gas cell.

[0014] Figure 2B At least some example embodiments according to this disclosure are illustrated. Figure 1 Side view of a compact multi-pass absorption gas cell.

[0015] Figure 3 At least some example embodiments according to this disclosure are illustrated. Figure 1 An end view of a compact multi-pass absorption gas cell, showing beam refocusing.

[0016] Figures 4A to 4D The beams of light according to at least some example embodiments of the present disclosure are illustrated. Figure 1 The reflection mode on the mirror component in the multi-pass absorption gas cell.

[0017] Figure 5 A perspective view of a compact multi-pass absorption gas cell according to at least some example embodiments of the present disclosure is illustrated.

[0018] Figure 6A At least some example embodiments according to this disclosure are illustrated. Figure 5 A top view of a compact multi-pass absorption gas cell.

[0019] Figure 6B At least some example embodiments according to this disclosure are illustrated. Figure 5 Side view of a compact multi-pass absorption gas cell.

[0020] Figure 7 At least some example embodiments according to this disclosure are illustrated. Figure 5 An end view of a compact multi-pass absorption gas cell, showing beam refocusing.

[0021] Figures 8A to 8D The beams of light according to at least some example embodiments of the present disclosure are illustrated. Figure 5 The reflection mode on the mirror component in the multi-pass absorption gas cell.

[0022] Figure 9 This is a block diagram of an example system for gas absorption spectroscopy according to at least some example embodiments of the present disclosure. 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…”, 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 an underlying layer for the component, and may include one or more elements that may form a portion on top of the substrate and / or be disposed on top of the substrate. The term "element" can refer to an article, device, or apparatus that provides one or more functions.

[0033] Overview

[0034] Various embodiments of this disclosure relate to compact multi-pass absorption gas cells used in gas spectrometry systems. Gas spectrometry analysis can be used to determine one or more components within a sample (e.g., a fluid sample) by illuminating the sample with light of a specific wavelength and monitoring light absorption along the optical path length. Each component of the sample may have a unique absorption characteristic that can be used to identify the presence and concentration of the component within the sample, or, in some cases, the absence of a target gas in the sample.

[0035] Many target gases exist at low concentrations (such as parts per million or parts per billion). When using spectroscopy to detect and determine the concentration of low-concentration gases, long optical path lengths can be utilized. An optical path can be the distance that emitted light travels between an illumination source and a receiver (such as a receiving photodetector). Long optical path lengths (such as greater than one meter) can result in sufficient absorption of the light emitted from the illumination source, which is then measured at the receiving photodetector.

[0036] Multi-pass absorbing gas detection cells can achieve long optical paths for detecting low-absorbing gases using multiple reflections. Conventional multi-pass absorbing gas cells may have a limited number of repeated reflections due to beam pattern inhomogeneity and the difficulty in controlling the spot size on the mirror surface. The compactness of conventional multi-pass absorbing gas cells can also be limited. For example, a multi-pass absorbing gas cell with two concave mirrors facing each other (such as a Heriotte cell) achieves the total path length by reflecting the input light multiple times between the two mirrors. The mirrors can be configured to refocus the light on each reflection to maintain the beam size. Because the same concave surface refocuses and redirects the beam during reflection, the beam pattern on the mirror surface may result in low surface utilization. Conventional multi-pass absorbing gas cells can produce circular light patterns, leaving the central portion of the mirror surface unused.

[0037] Various embodiments of this disclosure provide a compact multi-pass absorption gas cell that overcomes the technical challenges associated with multi-pass absorption gas cells. These embodiments provide a compact multi-pass absorption gas cell with high reflectivity and a longer total optical path for absorbing gas detection, as well as enhanced gas detection sensitivity for lower gas concentrations and lower absorbing gas detection. A compact multi-pass absorption gas cell with a smaller size compared to conventional gas cells can be provided.

[0038] Various embodiments provide compact multi-pass absorbing gas cells that utilize rectangular progressive reflection patterns to minimize mirror and gas cell size. Various embodiments utilize concave mirror arrays to provide a consistent beam size after refocusing, which minimizes the total mirror area. Various embodiments provide compact multi-pass absorbing gas cells with simplified cell structures that achieve high compactness using rectangular light patterns on rectangular mirrors. This cell structure may include a combination of plane mirrors and concave mirror arrays. Various embodiments can provide a highly compact rectangular multi-pass absorbing gas cell that meets the long optical path gas detection requirements of various applications, including mobile and other portable applications, with a small form factor.

[0039] Example systems and apparatus of this disclosure

[0040] As described above, various embodiments of this disclosure provide a compact multi-pass absorption gas cell that overcomes the technical challenges associated with multi-pass absorption gas cells. The various embodiments provide a compact multi-pass absorption gas cell with high reflectivity and a longer total optical path for absorbing gas detection, as well as enhanced gas detection sensitivity for detecting lower gas concentrations and lower absorbing gases.

[0041] refer to Figures 1 to 3The compact multi-port absorption gas cell 100 may include a housing 102 defining a chamber 104 for receiving the gas to be analyzed. In some embodiments, the housing 102 has a rectangular shape. In this respect, the compact multi-port absorption gas cell 100 may include a rectangular housing 102 in various embodiments. The compact multi-port absorption gas cell 100 may include an inlet through which the gas to be analyzed is added to the chamber 104 and through which it is removed from the chamber 104. A first mirror component 110 (also referred to herein as a first mirror assembly 110) may be attached (e.g., coupled, fixed, or similar terms) to or otherwise positioned at a first end of the rectangular housing, and a second mirror component 120 (also referred to herein as a second mirror assembly 120) may be attached to or otherwise positioned at a second end of the rectangular housing 102. The first mirror component 110 and the second mirror component 120 may be positioned opposite each other to define the chamber 104 between them.

[0042] The first mirror component 110 may include a first plane mirror 112 and a first concave mirror array 114 (also referred to herein as a first steering mirror array 114). In some embodiments, the first concave mirror array 114 may be positioned below the first plane mirror 112, as illustrated in the illustrative orientation. The first concave mirror array 114 may include a plurality of concave mirrors (also referred herein as concave mirror elements) arranged in a row. The gas pool 100 includes a light inlet 116 (also referred herein as a light inlet portion 116) positioned at a first end relative to the housing 102 or chamber 104, through which light can enter the chamber 104. In some embodiments, the first mirror component 110 may define the light inlet 116.

[0043] The second mirror component 120 may include a second plane mirror 122 and a second concave mirror array 124 (also referred to herein as a second steering mirror array 124). In some embodiments, the second concave mirror array 124 may be positioned above the second plane mirror 122, as illustrated in the illustrative orientation. The second concave mirror array 124 may include a plurality of concave mirrors arranged in a row. The gas pool 100 includes a light outlet 126 (also referred herein as a light outlet portion 126) positioned at a second end relative to the housing 102 or chamber 104, through which light exits the chamber 104. In some embodiments, the second mirror component 120 may define the light outlet 126. Figure 1 As shown, the optical inlet 116 and the optical outlet are positioned on opposite sides of the chamber 104.

[0044] like Figure 1As shown, the light beam 150 can enter the chamber 104 via the light inlet portion 116. The light beam 150 can be reflected back and forth between the first mirror component 110 and the second mirror component 120 within the chamber 104, thereby generating a multi-pass optical ray within the chamber 104. After being reflected between the first mirror component 110 and the second mirror component 120 according to a line-by-line reflection pattern, the light beam 150 can exit the chamber 104 through the light outlet portion 126.

[0045] In some embodiments, the first concave mirror array 114 and the first plane mirror 112 may be joined together to form an integrated component. In some examples, the first concave mirror array 114 and the first plane mirror 112 may be CNC machined together as an integrated component. Similarly, the second concave mirror array 124 and the second plane mirror 122 may be joined together to form an integrated component. In some examples, the second concave mirror array 124 and the second plane mirror 122 may be CNC machined together as an integrated component. In some cases, the first mirror component 110 and the second mirror component 120 may be the same component, which simplifies the manufacturing process.

[0046] The housing 102 may be constructed of materials suitable for optical applications, such as aluminum or other metals that provide structural stability. In some embodiments, the housing 102 may be anodized or coated to minimize internal reflections that could interfere with the optical path. The housing 102 may include mounting features for securing the mirror components in a precisely aligned manner. The inlet and outlet may be positioned to allow gas flow through the chamber 104 while minimizing interference with the optical path. In some embodiments, the inlet and outlet may include valves or flow control mechanisms to regulate gas introduction and gas removal from the chamber 104.

[0047] Chamber 104 may have internal dimensions optimized for specific optical path requirements and the gas volume needed for effective absorption measurements. Chamber 104 can be sealed to prevent gas leakage and maintain controlled atmospheric conditions during analysis. The rectangular cross-section of chamber 104 complements the rectangular reflection pattern of beam 150, thereby providing efficient use of the internal volume while accommodating a systematic arrangement of reflection points on the mirror surface.

[0048] Now for reference Figure 2A and Figure 2B Top and side views of a compact multi-pass absorption gas cell 100 according to at least some embodiments of the present disclosure are provided, showing a rectangular housing configuration. Specifically, Figure 2A and Figure 2B The elongated rectangular shape factor of the compact multi-pass absorption gas cell 100 is shown. The first mirror component 110 and the second mirror component 120 are aligned along the longitudinal axis of the housing. The rectangular housing configuration provides a compact shape factor, thereby facilitating efficient use of space while accommodating the optical path requirements of gas absorption analysis.

[0049] The first mirror component 110 and the second mirror component 120 can be configured to reflect light beams between the first mirror component 110 and the second mirror component 120 in a rectangular row-by-row reflection pattern. The rectangular configuration of the housing and the arrangement of the mirror components allow the light beam to follow a systematic reflection pattern that maximizes the utilization of the mirror surface. The elongated rectangular shape factor accommodates multiple reflections while maintaining a compact overall size suitable for portable and mobile applications.

[0050] The longitudinal axis alignment of the mirror components ensures that the optical path remains centered within chamber 104, and the reflection pattern remains consistent along the entire length of gas cell 100. The rectangular shape factor contrasts with conventional circular or cylindrical gas cell designs, offering advantages in space utilization and integration into rectangular instrument housings or portable device enclosures. This compact design allows gas cell 100 to be incorporated into handheld devices or mobile monitoring systems where space constraints are a critical consideration.

[0051] refer to Figure 3 An end view of a compact multi-pass absorption gas cell 100 is provided, illustrating how the beam 150 is refocused between concave mirror arrays (e.g., a first concave mirror array 114 and a second concave mirror array 124) during operation. Figure 3 As shown, the beam 150 can pass between the mirror components while periodically refocusing between the first concave mirror array 114 and the second concave mirror array 124 to maintain consistent beam characteristics throughout the optical path. For example, the first concave mirror array 114 and the second concave mirror array 124 can be configured and positioned to refocus the beam 150 to maintain minimal beam divergence, for example, during multiple light reflections within the cavity 104.

[0052] As described above, the concave mirror arrays can be positioned at opposite ends of chamber 104, with the first concave mirror array 114 positioned in the lower portion and the second concave mirror array 124 positioned in the upper portion, as illustrated in the configuration. In some embodiments, the positions of the concave mirror arrays can be reversed. For example, in some embodiments, the concave mirror arrays can be positioned at opposite ends of chamber 104, with the first concave mirror array 114 positioned in the upper portion and the second concave mirror array 124 positioned in the lower portion. The refocusing action of the concave mirror arrays can maintain the beam size and minimize beam divergence during multiple reflections within chamber 104.

[0053] In some embodiments, the concave mirrors in the first concave mirror array 114 and the second concave mirror array 124 may have a radius of approximately 1800 mm. The concave mirror arrays can be configured to provide consistent refocusing of the beam 150 when it is reflected between the mirror components. A radius of approximately 1800 mm provides suitable focusing characteristics to maintain beam quality throughout the extended optical path. Specific radius values ​​can be selected based on the desired focal length and the physical dimensions of the chamber 104 to ensure that the beam 150 maintains optimal converging characteristics throughout the multipass system.

[0054] Beam 150 can have an input beam 1 / e of 1 mm. 2 The radius is set to focus at a distance of 1800 mm from the concave mirror. Selectable input beam parameters optimize the refocusing behavior of the concave mirror array and maintain a consistent beam size across multiple reflections. The 1800 mm focusing distance corresponds to the radius of the concave mirror, thus providing appropriate beam convergence and divergence characteristics for multi-pass optical systems. 1 / e 2 The radius specification defines the beam waist, i.e., the point where the intensity decreases to 1 / e of the peak intensity. 2 The beam waist, located at approximately 13.5%, is a standard metric used to characterize the distribution of Gaussian beams in an optical system.

[0055] Concave mirror arrays can be designed to operate in a confocal or near-confocal configuration, where the focal points of opposing mirrors can be positioned to optimize beam stability throughout the extended optical path. A confocal arrangement minimizes beam drift and maintains a consistent spot size at all reflection points. Each individual concave mirror within the array can be precisely aligned to ensure that refocusing occurs along the optical path at predetermined intervals, thus preventing cumulative beam degradation that can occur in conventional multipass systems.

[0056] The refocusing mechanism utilizes the principle of periodic focusing, where the beam 150 is allowed to diverge slightly between refocusing events while being brought back to the controlled beam waist with each interaction of the concave mirrors. This method balances the need for beam control with the practical constraints of mirror spacing and chamber size. Periodic refocusing can occur at intervals determined by the spacing between the concave mirror elements within each array, where the interval is selected to prevent excessive beam spread while maintaining efficient use of the available mirror surface area.

[0057] As described above, Figure 3This illustrates how beam 150 is systematically refocused within chamber 104 as it passes between first mirror component 110 and second mirror component 120 and is refocused by first concave mirror array 114 and second concave mirror array 124. The refocusing mechanism prevents excessive beam spread, which could otherwise reduce the effectiveness of the multi-pass absorption system. The concave mirror array 114 of first mirror component 110 and the concave mirror array 124 of second mirror component 120 can work together to maintain beam 150 within acceptable size parameters over the entire extended optical path length.

[0058] Beam refocusing offers several technical advantages over conventional multi-pass gas cells. Systematic refocusing enables higher reflection counts while maintaining beam quality because periodic correction of beam divergence prevents gradual degradation, which typically limits the number of useful reflections in conventional systems. The refocusing action also allows for more precise control over the beam's positioning on the mirror surface, facilitating rectangular progressive reflection modes that maximize mirror surface utilization. Furthermore, the maintained beam size ensures consistent interaction volume with the gas sample throughout the extended optical path, providing uniform sensitivity across all parts of the multi-pass system.

[0059] refer to Figure 4A and Figure 4B This illustrates the reflection patterns of a light beam on a first mirror component 110 and a second mirror component 120 according to at least some embodiments of the present disclosure. Specifically, Figure 4A and Figure 4B The following illustrates line-by-line pattern reflection of a light beam 150 on the surfaces of a first mirror component 110 and a second mirror component 120 in order to produce an extended optical length, according to at least some example embodiments of the present disclosure.

[0060] Figure 4A An example is shown: the beam 150 is displayed on the first mirror component 210 in a line-by-line pattern 152. Figure 4B An example is shown: a line-by-line spot pattern 154 of the beam 150 on the second mirror component 120. For example... Figure 4A and Figure 4B As shown, multiple light spots can be arranged in a rectangular pattern on the surface of the mirror component, thereby maximizing the utilization of the available mirror surface area. For example, as... Figure 4A and Figure 4B As shown, the light spot can be organized in horizontal rows across the mirror surface, where each row includes multiple reflection points, and the rectangular row-by-row pattern can make full use of the rectangular mirror surfaces of the first mirror component 110 and the second mirror component 120.

[0061] The systematic arrangement of the beam spot reflects the folding of the multi-pass optical rays within the compact chamber 104 (e.g., defined by multiple reflections of the beam 150 between mirror elements) to achieve an extended path length while maintaining a compact form factor. The beam 150 may be reflected a predetermined number of times between the first plane mirror 112 and the second plane mirror 122, such as 2m times, where m may represent the number of beam spots on a given plane mirror (e.g., the first plane mirror 112 or the second plane mirror 122). After these reflections, the beam can be refocused using the first concave mirror array 114 and the second concave mirror array 124, followed by additional reflections between the first plane mirror 112 and the second plane mirror 122. The refocusing process may occur 2n times, where n may represent the number of concave mirror elements in a given concave mirror array (e.g., the number of concave mirrors in the corresponding first concave mirror array 114 or second concave mirror array 124), followed by an additional 2m reflections between the first plane mirror 112 and the second plane mirror 122. In various embodiments, the number of concave mirrors in the first concave mirror array 114 is the same as the number of concave mirrors in the second concave mirror array 124.

[0062] The progressive reflection pattern enables a large number of reflections within a limited space in the compact multi-pass absorption gas cell 100. The rectangular arrangement of the light spot contrasts with the conventional circular pattern, which may leave portions of the mirror surface unused. The progressive pattern provides more efficient use of the mirror surface area, contributing to a compact gas cell design while maintaining a long optical path length for gas absorption analysis. Furthermore, the rectangular pattern is more compatible with rectangular housing geometry, allowing for more efficient encapsulation of the entire gas cell system.

[0063] The spacing between adjacent spots within each row can be determined by beam size and optical design parameters to prevent overlap or interference between adjacent reflection points. Each spot can represent a discrete reflection event, where the beam interacts with the mirror surface before being redirected to the next reflection point in the sequence. Systematized spacing ensures that each reflection point receives a beam of full intensity without interference from adjacent reflections, thus maintaining signal quality throughout the extended optical path. The movement of the spot from one row to the next can be controlled by the interaction between a plane mirror and an array of concave mirrors. When the beam reaches the end of a row on one mirror component, the corresponding concave mirror array can redirect the beam 150 to begin a new row on the opposite mirror component. This row-to-row transition can be precisely controlled to ensure that the beam 150 follows a predictable path without missing reflection points or producing unwanted beam overlap.

[0064] By refocusing the concave mirror array, the spot size at each reflection point can be maintained within a predetermined tolerance. A consistent spot size ensures that the gas interaction volume is uniform at each reflection point, thereby guaranteeing consistent absorption measurements throughout the extended optical path. Spot size control also prevents beam cutoff at the mirror edges, which could otherwise introduce optical losses and reduce overall system efficiency.

[0065] Figure 4C The input characteristics 156 of the beam 150 before or during its entry into the compact multi-pass absorbing gas cell 100 are illustrated according to at least some example embodiments of the present disclosure, and Figure 4D The output characteristics 158 of the beam after it leaves the compact multi-pass absorption gas cell 100, according to at least some example embodiments of the present disclosure, are illustrated. The input characteristics may reflect initial beam parameters such as beam diameter, divergence angle, and intensity distribution. The input beam positioning can be precisely controlled to ensure the beam enters the chamber 104 at the correct location, thereby initiating a systematic line-by-line advance across the mirror surface. The output characteristics may reflect beam parameters after multiple reflections and after the beam leaves the chamber 104. The beam can maintain sufficient beam quality for effective detection and / or absorption measurements. For example, the output beam characteristics can be compared to the input characteristics to determine the absorption characteristics of a gas sample, where any variation in intensity or spectral content can be attributed to gas absorption within the chamber 104. The reflection mode ensures the beam follows a predictable path through the chamber 104, enabling reliable gas absorption measurements. Beam path predictability facilitates accurate gas concentration measurements.

[0066] In some embodiments, the compact multi-pass absorption gas cell 100 realizes a multi-pass optical beam folded into nine segments (33 folding planes) in a plane using a first concave mirror array 114 and a second concave mirror array 124. Folding the multi-pass optical beam into nine segments in a plane can be achieved through a systematic reflection pattern between the first mirror component 110 and the second mirror component 120. The 33 folding planes can be generated by the first mirror component and mirror components that redirect the beam, allowing it to travel between multiple vertical and horizontal levels within the chamber 104. The concave mirror arrays can refocus the beam to maintain minimal beam divergence throughout the extended optical path, thereby ensuring consistent beam quality across all 33 folding planes and the nine segments of each plane. In some embodiments, the nine segments of each plane may correspond to the beam advance across the width of the first mirror 112 and the second mirror 122 before being redirected to the next folding plane. In some implementations, the nine segments of each plane may correspond to the advance of the beam across the height of the first mirror 112 and the second mirror 122 before being redirected to the next folding plane.

[0067] The dimensions of the mirror component can be determined based on the maximum beam size and the number of mirror elements. The width W of the mirror component can be calculated using the equation W = (n + 2.5) × a, where a represents the maximum beam size. The height H of the mirror component can be determined using the equation H = (m + 1.5) × a, where a represents the maximum beam size. These dimensional relationships ensure that the mirror component provides sufficient surface area to accommodate rectangular reflection patterns while maintaining a compact overall size.

[0068] Width and height calculations can incorporate safety margins. For example, the width calculation W = (n + 2.5) × a incorporates a safety margin of 2.5 beam diameters to account for beam positioning tolerances and potential beam run-off during operation. This margin ensures that the beam remains within the effective mirror surface area even under conditions of mechanical vibration or thermal expansion of housing components. The height calculation H = (m + 1.5) × a provides sufficient clearance for the vertical arrangement of beam speckles while maintaining a compact form / configuration.

[0069] In some examples, the maximum beam size parameter "a" can range from 1 mm to 3 mm, depending on the specific application requirements and the characteristics of the light source. Smaller beam sizes allow for higher reflection density and more compact mirror dimensions, while larger beam sizes provide an improved signal-to-noise ratio for gas absorption measurements. The choice of beam size can involve trade-offs between compactness, optical efficiency, laser intensity damage level, and measurement sensitivity.

[0070] The total effective volume V of gas cell 100 can be calculated using the formula V = W × H × L = (m + 1.5) × (n + 2.5) × a 2 The volume is calculated using × L. This volume calculation demonstrates how a rectangular line-by-line ray pattern can fully utilize the rectangular mirror surface and achieve a minimum volume gas cell with a rectangular shape factor. This configuration provides a compact solution that meets long optical path requirements while maintaining a small physical footprint suitable for mobile and portable applications.

[0071] The optical path length can be calculated using the following formula: Optical path = (2m + 1) × (2n + 1) × L, where m represents the number of beamspot lines on a single plane mirror (e.g., first plane mirror 112 or second plane mirror 122), n represents the number of concave mirror elements in a single concave mirror array (e.g., first concave mirror array 114 or second concave mirror array 124), and L represents the mirror-to-mirror distance (e.g., the distance between first mirror element 110 and second mirror element 120). The optical path length calculation demonstrates the mathematical relationship between the physical dimensions of the gas pool and the achievable optical path extension. The formula / equation Optical path = (2m + 1) × (2n + 1) × L provides a systematic method for determining the total path length based on the number of reflecting segments and folded planes. The factor (2m + 1) illustrates the complete traversal of the beamspot lines on each plane mirror, including both the forward and return paths plus the initial entry. The factor (2n + 1) can represent the total number of interactions with the concave mirror array elements, encompassing all folded planes plus the initial beam entry.

[0072] In some embodiments, the compact multi-pass absorbing gas cell 100 may have a configuration that achieves a total optical path length of approximately 118.8 meters within a compact volume of 400 mm × 111 mm × 33 mm. For example, the compact multi-pass absorbing gas cell 100 may have a mirror-to-mirror distance L of approximately 400 m, a mirror component height of approximately 33 mm (e.g., the height of a single mirror component), and a mirror component width of approximately 111 mm (e.g., the width of a single mirror component), with 16 concave mirror elements in each concave mirror array (e.g., n=16), and where m = 4 (e.g., 4 beamspot rows on a single plane mirror), thereby producing a total optical path length of approximately 119 (9 x 33 x 0.4) meters within a compact volume of 400 mm × 111 mm × 33 mm.

[0073] refer to Figures 5 to 8D Example compact multi-pass absorber gas pool 200 is provided according to at least some embodiments of the present disclosure. The example compact multi-pass absorber gas pool 200 may implement or otherwise represent a single steering configuration. The single steering configuration may utilize or create a column-by-column, row-by-row pattern on the mirror surface. Compared to the example higher path length configuration described with reference to the compact multi-pass absorber gas pool 100, the single steering configuration can utilize fewer folded planes. The column-by-column, row-by-row pattern provides efficient utilization of the rectangular mirror surface while accommodating reduced complexity of the single steering arrangement. The compact multi-pass absorber gas pool 200 may include components similar to those of the compact multi-pass absorber gas pool 100.

[0074] The compact multi-port absorption gas cell 200 may include a housing 202 defining a chamber 204 for receiving the gas to be analyzed. In some embodiments, the housing 202 has a rectangular shape. In this respect, the compact multi-port absorption gas cell 200 may include a rectangular housing 202 in various embodiments. The compact multi-port absorption gas cell 200 may include an inlet through which the gas to be analyzed is added to the chamber 204 and through which it is removed from the chamber 204. A first mirror component 210 (also referred to herein as a first mirror assembly 210) may be attached to or otherwise positioned at a first end of the rectangular housing, and a second mirror component 220 (also referred to herein as a second mirror assembly 220) may be attached to or otherwise positioned at a second end of the rectangular housing 202. The first mirror component 210 and the second mirror component 220 may be positioned opposite each other to define the chamber 204 between them. In this respect, the housing

[0075] The first mirror component 210 may include a first plane mirror 212 and a first concave mirror array 214 (also referred to herein as a first steering mirror array 214). In some embodiments, the first concave mirror array 214 may be positioned below the first plane mirror 212, as illustrated in the illustrative orientation. The first concave mirror array 214 may include a plurality of concave mirrors arranged in a row. The gas pool 200 includes a light inlet 216 (also referred herein as a light inlet portion 216) positioned at a first end relative to the housing 202 or chamber 204, through which light can enter the chamber 204. In some embodiments, the first mirror component 210 may define the light inlet 216.

[0076] The second mirror component 220 may include a second plane mirror 222 and a second concave mirror array 224 (also referred to herein as a second steering mirror array 224). In some embodiments, the second concave mirror array 224 may be positioned above the second plane mirror 222, as shown in the illustrated orientation. The second concave mirror array 224 may include a plurality of concave mirrors arranged in a row. The gas pool 200 includes a light outlet 226 (also referred herein as a light outlet portion 226) positioned at a second end relative to the housing 202 or chamber 204, through which light exits the chamber 204. In some embodiments, the second mirror component 220 may define the light outlet 226.

[0077] like Figure 5As shown, beam 250 can enter chamber 204 via light inlet portion 216 of first mirror component 210. Beam 250 can be reflected back and forth between first mirror component 210 and second mirror component 220 within chamber 204, thereby generating a multi-pass optical ray within chamber 204. After being reflected between first mirror component 210 and second mirror component 220 according to a column-by-column, row-by-row reflection pattern, beam 250 can exit chamber 204 through light outlet portion 226.

[0078] In some embodiments, the first concave mirror array 214 and the first plane mirror 212 may be coupled together to form an integrated component. In some examples, the first concave mirror array 214 and the first plane mirror 212 may be CNC machined together as an integrated component. Similarly, the second concave mirror array 224 and the second plane mirror 222 may be coupled together to form an integrated component. In some examples, the second concave mirror array 224 and the second plane mirror 222 may be CNC machined together as an integrated component.

[0079] The housing 202 may be constructed of materials suitable for optical applications, such as aluminum or other metals that provide structural stability. In some embodiments, the housing 202 may be anodized or coated to minimize internal reflections that could interfere with the optical path. The housing 202 may include mounting features for securing the mirror components in a precisely aligned manner. The inlet and outlet may be positioned to allow gas flow through the chamber 204 while minimizing interference with the optical path. In some embodiments, the inlet and outlet may include valves or flow control mechanisms to regulate gas introduction and gas removal from the chamber 204.

[0080] Chamber 204 may have internal dimensions optimized for specific optical path requirements and the gas volume needed for effective absorption measurements. Chamber 204 can be sealed to prevent gas leakage and maintain controlled atmospheric conditions during analysis. The rectangular cross-section of chamber 204 complements the rectangular reflection pattern of beam 250, thus providing efficient use of the internal volume while accommodating a systematic arrangement of reflection points on the mirror surface.

[0081] Now for reference Figure 6A and Figure 6B Top and side views of a compact multi-pass absorption gas cell 200 according to at least some embodiments of the present disclosure are provided, showing a rectangular housing configuration. Specifically, Figure 6A and Figure 6B The elongated rectangular shape factor of the compact multi-pass absorption gas cell 200 is shown. The first mirror component 210 and the second mirror component 220 are aligned along the longitudinal axis of the housing. The rectangular housing configuration provides a compact shape factor, thereby facilitating efficient use of space while accommodating the optical path requirements of gas absorption analysis.

[0082] The first mirror component 210 and the second mirror component 220 can be configured to reflect the light beam between the first mirror component 110 and the second mirror component 220 in a column-by-column, row-by-row reflection pattern. The rectangular configuration of the housing 202 and the arrangement of the mirror components allow the light beam 250 to follow a systematic reflection pattern that maximizes the utilization of the mirror surface. The elongated rectangular shape factor accommodates multiple reflections while maintaining a compact overall size suitable for portable and mobile applications.

[0083] The longitudinal axis alignment of the mirror components ensures that the optical path remains centered within the chamber 204, and the reflection mode remains consistent throughout the entire length of the gas cell 200. The compact form / configuration allows the gas cell 200 to be integrated into handheld devices or mobile monitoring systems where space constraints are a critical consideration.

[0084] refer to Figure 7 An end view of a compact multi-pass absorption gas cell 200 is provided, illustrating how the beam 250 is refocused between concave mirror arrays (e.g., a first concave mirror array 214 and a second concave mirror array 224) during operation. Figure 3 As shown, the beam 250 can pass between the mirror components while periodically refocusing between the first concave mirror array 214 and the second concave mirror array 224 to maintain consistent beam characteristics throughout the optical path. For example, the first concave mirror array 214 and the second concave mirror array 224 can be configured and positioned to refocus the beam 250 to maintain minimal beam divergence, for example, during multiple light reflections within the cavity 204.

[0085] As described above, the concave mirror arrays can be positioned at opposite ends of chamber 104, with the first concave mirror array 214 positioned in the lower portion and the second concave mirror array 224 positioned in the upper portion, as illustrated in the configuration. In some embodiments, the positions of the concave mirror arrays can be reversed. For example, in some embodiments, the concave mirror arrays can be positioned at opposite ends of chamber 204, with the first concave mirror array 214 positioned in the upper portion and the second concave mirror array 224 positioned in the lower portion. The refocusing action of the concave mirror arrays can maintain the beam size and minimize beam divergence through multiple reflections within chamber 204.

[0086] In some embodiments, the concave mirrors in the first concave mirror array 214 and the second concave mirror array 224 may have a radius of approximately 1800 mm. The concave mirror arrays can be configured to provide consistent refocusing of the beam 250 as it reflects between the mirror components. A radius of approximately 1800 mm provides suitable focusing characteristics to maintain beam quality throughout the extended optical path. Specific radius values ​​can be selected based on the desired focal length and the physical dimensions of the chamber 204, thereby ensuring that the beam 250 maintains optimal converging characteristics throughout the multipass system.

[0087] Beam 250 can have an input beam 1 / e of 1 mm. 2 The focusing radius is set at a distance of 1800 mm from the concave mirror. Selectable input beam parameters optimize the refocusing behavior of the concave mirror array and maintain a consistent beam size across multiple reflections. The 1800 mm focusing distance corresponds to the radius of the concave mirror, thus providing appropriate beam convergence and divergence characteristics for multi-pass optical systems.

[0088] Concave mirror arrays 214 and 224 can be designed to operate in a confocal or near-confocal configuration, where the focal points of opposing mirrors can be positioned to optimize beam stability throughout the extended optical path. A confocal arrangement minimizes beam drift and maintains a consistent spot size at all reflection points. Each individual concave mirror within the array can be precisely aligned to ensure that refocusing occurs along the optical path at predetermined intervals, preventing cumulative beam degradation that might occur in conventional multipass systems. The refocusing mechanism can utilize the principle of periodic focusing, where the beam 250 is allowed to diverge slightly between refocusing events while being brought back to a controlled beam waist with each concave mirror interaction. Periodic refocusing occurs at intervals determined by the spacing between the concave mirror elements within each array, where the intervals are selected to prevent excessive beam spread while maintaining efficient use of the available mirror surface area.

[0089] like Figure 7 As shown, when the beam 250 passes between the first concave mirror array 214 and the second concave mirror array 224, the beam 250 can be systematically refocused. The refocusing mechanism prevents excessive beam spread, which could otherwise reduce the effectiveness of the multi-pass absorption system. The concave mirror array 214 of the first mirror component 210 and the concave mirror array 224 of the second mirror component 220 can work together to maintain the beam 250 within acceptable size parameters over the entire extended optical path length.

[0090] As described above, beam refocusing technology offers several advantages over conventional multipass gas cells. Systematic refocusing enables higher reflection counts while maintaining beam quality because periodic correction of beam divergence prevents gradual degradation, which typically limits the number of useful reflections in conventional systems. The refocusing action also allows for more precise control over the beam's positioning on the mirror surface, facilitating column-by-column and row-by-row reflection modes that maximize mirror surface utilization. Furthermore, a consistent beam size ensures a uniform interaction volume with the gas sample throughout the extended optical path, providing uniform sensitivity across all parts of the multipass system.

[0091] refer to Figures 8A to 8B This illustrates the reflection patterns of the light beam 250 on the first mirror component 210 and the second mirror component 220 according to at least some embodiments of the present disclosure. Specifically, Figure 8A An example is shown of the column-by-column, row-by-row pattern 252 of the beam 250 on the first mirror component 210, and Figure 8B The beam 250 is illustrated in column-by-column, row-by-row pattern 254 on the second mirror component 220.

[0092] Column-by-column, row-by-row reflection modes can provide a grid pattern (e.g., a perfect grid pattern) of light spots on the mirror surface, which minimizes interference noise. Similar to the example compact multi-pass absorbing gas cell 100, beam 250 can be reflected a predetermined number of times, such as 2m times, between the first plane mirror 212 and the second plane mirror 222, where m can represent the number of beam spots on a given plane mirror (e.g., the first plane mirror 212 or the second plane mirror 222). After these reflections, beam 250 can be refocused using a first concave mirror array 214 and a second concave mirror array 224, followed by additional reflections between the first plane mirror 212 and the second plane mirror 222. The refocusing process can occur n times, where n can represent the number of concave mirror elements in a given concave mirror array (e.g., the first concave mirror array 214 or the second concave mirror array 224), followed by an additional 2m reflections between the first plane mirror 212 and the second plane mirror 222.

[0093] This reflection mode enables the compact multi-pass absorption gas cell 200 to achieve a large number of reflections within a limited space. The systematic arrangement of column-by-column and row-by-row modes ensures that each reflection point can be positioned to avoid interference with adjacent reflection points, thereby helping to improve signal quality for gas absorption measurements.

[0094] The spacing between adjacent spots within each row can be determined by beam size and optical design parameters to prevent overlap or interference between adjacent reflection points. Systematic spacing ensures that each reflection point receives a beam of full intensity without interference from adjacent reflections, thus maintaining signal quality throughout the extended optical path. The movement of the spot from one row to the next is controlled by the interaction between a plane mirror and an array of concave mirrors. When the beam reaches the end of a row on one mirror element, the corresponding concave mirror array redirects the beam to begin a new row on the opposite mirror element. This row-to-row transition can be precisely controlled to ensure the beam follows a predictable path without losing reflection points or producing unwanted beam overlap. The refocusing action of the concave mirror array maintains the spot size at each reflection point within predetermined tolerances.

[0095] Figure 8C The input characteristics 256 of the beam 250 as it enters the compact multi-pass absorbing gas cell 200 are illustrated according to at least some example embodiments of the present disclosure, and Figure 8D The output characteristics 258 of the beam 250 after it leaves the compact multi-pass absorbing gas cell 100 are illustrated according to at least some example embodiments of the present disclosure. For example... Figure 8C As shown, beam 250 can maintain sufficient beam quality for effective detection and / or absorption measurement.

[0096] In some embodiments, the compact multi-pass absorbing gas cell 200 achieves a multi-pass optical beam folded into nine segments (17 folding planes) in a plane using a first concave mirror array 214 and a second concave mirror array 224. Folding the multi-pass optical beam into nine segments (17 folding planes) in a plane can be achieved through a systematic column-by-column, row-by-row reflection pattern between the first mirror element 210 and the second mirror element 220. The concave mirror array can refocus the beam to maintain minimal beam divergence throughout the extended optical path, thereby ensuring consistent beam quality across the 17 folding planes and the nine segments of each plane. In some embodiments, the nine segments of each plane may correspond to the beam advance across the width of the first mirror 212 and the second mirror 222 before being redirected to the next folding plane. In some embodiments, the nine segments of each plane may correspond to the beam advance across the height of the first mirror 212 and the second mirror 222 before being redirected to the next folding plane.

[0097] The dimensions of the mirror components can be determined based on the maximum beam size and the number of mirror elements, as described in the above example of the compact multi-pass absorbing gas cell 100. The total effective volume V of the gas cell 200 can be calculated using a formula similar to that described in the above example of the compact multi-pass absorbing gas cell 100. The optical path length can be calculated using a formula similar to that described in the above example of the compact multi-pass absorbing gas cell 100.

[0098] The optical path length can be calculated using the following formula: Optical path = (2m + 1) × (n + 1) × L, where m represents the number of beamspot lines on a single plane mirror (e.g., the first plane mirror 212 or the second plane mirror 222), n represents the number of concave mirror elements in a single concave mirror array (e.g., the first concave mirror array 214 or the second concave mirror array 224), and L represents the mirror-to-mirror distance (e.g., the distance between the first mirror element 210 and the second mirror element 220). The optical path length calculation demonstrates the mathematical relationship between the physical dimensions of the gas pool and the achievable optical path extension. The formula / equation Optical path = (2m + 1) × (n + 1) × L provides a systematic method for determining the total path length based on the number of reflecting segments and folded planes. The factor (2m + 1) illustrates the complete traversal of the beamspot lines on each plane mirror, including both the forward and return paths.

[0099] In some embodiments, the compact multi-pass absorbing gas cell 200 may have a configuration that achieves a total optical path length of approximately 61.2 meters within a compact volume of 400 mm × 111 mm × 33 mm. For example, the compact multi-pass absorbing gas cell 200 may have a mirror-to-mirror distance L of approximately 400 m, a mirror component height of approximately 33 mm (e.g., the height of a single mirror component), and a mirror component width of approximately 111 mm (e.g., the width of a single mirror component), with 16 concave mirror elements in each concave mirror array (e.g., n=16), and where m = 4 (e.g., 4 beamspot rows on a single plane mirror), thereby producing a total optical path length of approximately 61.2 (9 x 17 x 0.4) meters within a compact volume of 400 mm × 111 mm × 33 mm.

[0100] Example of a multi-pass absorption gas detection system

[0101] Now for reference Figure 9A block diagram of an example multi-pass absorption gas detection system 900 according to an example embodiment of the present disclosure is provided. The example system 900 may include a compact multi-pass absorption gas cell (such as example gas cell 100 or gas cell 200), a control device 901, a light emitter 910, and / or a light receiver 912. The light emitter 910 may be configured to emit light toward and / or emit light into the gas cell 100, as described above. The light receiver 912 may be configured to receive light exiting the gas cell 100, as described above.

[0102] Figure 9 Example control device 901 includes a processor or processing circuitry 902, a memory circuitry 904, an input / output circuitry 906, and a communication circuitry 908. In some embodiments, one or more portions of control device 901 (e.g., one or more components thereof) are configured to perform and conduct the operations described herein. In some embodiments, control device 901 may be configured to control the operation of light emitter 910, light receiver 912, and / or gas pool 100. For example, in some such embodiments, control device 901 may function as a controller within system 900. In some embodiments, control device 901 may be configured to analyze output from gas pool 100 or received by light receiver 912 to determine the presence of one or more target gases.

[0103] Control device 901 can communicate with both light emitter 910 and light receiver 912. Control device 901 can control the operation of light emitter 910 to emit light at a specified wavelength and intensity. Control device 901 can receive signals corresponding to the detected light from light receiver 912. Processing circuitry 902 can analyze the received signals to determine the absorption characteristics of the gas sample, thereby identifying the presence and concentration of one or more target gases within the chamber of the gas cell.

[0104] 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.

[0105] The processing circuitry 902 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 901, and / or one or more remote or cloud processors external to the example device 901. In some example embodiments, the processing circuitry 902 may include one or more processing devices configured to execute independently. Alternatively or additionally, the processing circuitry 902 may include one or more processors configured in series via a bus to enable independent execution of operations, instructions, pipelines, and / or multithreading.

[0106] In example embodiments, processing circuitry 902 may be configured to execute instructions stored in memory circuitry 904 or otherwise accessible by a processor. Alternatively or additionally, processing circuitry 902 may be configured to perform hard-coded functionality. Thus, whether configured by hardware or software methods, or by a combination thereof, processing circuitry 902 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 902 may be embodied as an executor of software instructions that may specifically configure processing circuitry 902 to perform various algorithms embodied in one or more operations described herein when executing such instructions. In some embodiments, processing circuitry 902 includes hardware, software, firmware, and / or combinations thereof for performing one or more operations described herein.

[0107] Processing circuit 902 can implement various signal processing algorithms to extract meaningful absorption data from the received optical signal. Processing circuit 902 can perform baseline correction to account for variations in light source intensity and detector response characteristics. Processing circuit 902 can apply digital filtering techniques to reduce noise and improve the signal-to-noise ratio in absorption measurements. Processing circuit 902 can execute spectral analysis algorithms that identify characteristic absorption peaks corresponding to specific molecular transitions in the target gas.

[0108] In some implementations, processing circuitry 902 (and / or coprocessor or assistant processor or any other processing circuitry otherwise associated with the processor) communicates with memory circuitry 904 via a bus for transferring information between components of example device 901.

[0109] The memory or memory circuitry 904 may be non-transitory and may include, for example, one or more volatile and / or non-volatile memories. In some embodiments, the memory circuitry 904 includes or embodies an electronic storage device (e.g., a computer-readable storage medium). In some embodiments, the memory circuitry 904 is configured to store information, data, content, applications, instructions, etc., for enabling the example device 901 to perform various operations and / or functions according to the example embodiments of this disclosure.

[0110] Memory circuit 904 can store reference absorption spectra for various target gases, enabling processing circuit 902 to perform pattern matching and identification of unknown gas components. Memory circuit 904 can maintain 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. Memory circuit 904 can store historical measurement data for trend analysis and long-term monitoring applications. Memory circuit 904 may include volatile memory for real-time data processing and non-volatile memory for persistent storage of calibration parameters and reference data.

[0111] Example device 901 may include input / output circuitry 906. In some embodiments, input / output circuitry 906 may provide output to a user and / or receive input from a user. Input / output circuitry 906 may communicate with processing circuitry 902 to provide such functionality. Input / output circuitry 906 may include one or more user interfaces. In some embodiments, the user interface may include a display that includes an interface presented as a web user interface, application user interface, user device, back-end system, etc. In some embodiments, input / output circuitry 906 may also include a keyboard, mouse, joystick, touchscreen, touch area, softkeys, microphone, speaker, or other input / output mechanism. Processing circuitry 902 and / or input / output circuitry 906 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 processor-accessible memory (e.g., memory circuitry 904, etc.). In some embodiments, input / output circuitry 906 includes or utilizes user-oriented applications to provide input / output functionality to a computing device and / or other display associated with a user. In some implementations, the input / output circuit 906 includes one or more indicator lights, etc., for providing user notifications (e.g., alerts or warnings).

[0112] Example device 901 may include communication circuitry 908. Communication circuitry 908 may include any means, such as devices or circuits 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 901. In some embodiments, communication circuitry 908 includes, for example, a network interface for enabling communication with wired or wireless communication networks. Additionally or alternatively, communication circuitry 908 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 908 may include circuitry for interacting with antennas and / or other hardware or software to enable the transmission of signals via the antenna and / or the processing of signals received via the antenna. In some embodiments, communication circuitry 908 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 901.

[0113] In some embodiments, two or more circuits of the group 902 to 908 are composable. Alternatively or additionally, one or more circuits of the group 902 to 908 perform some or all of the operations and / or functionalities described herein as associated with another circuit. In some embodiments, two or more circuits of the group 902 to 908 are combined into a single module embodied in hardware, software, firmware, and / or combinations thereof.

[0114] The optical emitter 910 can be configured to provide broadband illumination covering multiple absorption bands of interest, thereby enabling simultaneous detection of multiple gaseous substances within a single measurement cycle. The optical emitter 910 may include a wavelength stabilization mechanism to ensure consistent spectral output under varying environmental conditions, such as temperature fluctuations. The optical emitter 910 may incorporate intensity modulation capabilities that enable phase-locked detection to improve sensitivity and suppress noise. The optical emitter 910 can be designed to have sufficient optical power to compensate for losses during extended multi-pass optical paths while maintaining a safe level of operation.

[0115] The light receiver 912 may include a photodetector optimized for a specific wavelength range of interest for the detection of a target gas. The light receiver 912 may include multiple detector elements arranged to simultaneously monitor different spectral regions, thereby achieving multi-gas detection capability within a single compact system. The light receiver 912 may incorporate signal conditioning electronics that amplify and filter the detected optical signals before converting them into a digital format for processing by the control device 901. The light receiver 912 may include a temperature stabilization or compensation mechanism to maintain consistent detector response characteristics under varying operating conditions.

[0116] Methods for gas absorption spectroscopy may include introducing a gas sample into a chamber of a gas cell (such as gas cell 100 or gas cell 200). The gas sample may be introduced through an inlet of a compact multi-pass absorption gas cell 100 and may fill the chamber for analysis. The method may also include guiding a light beam into chamber 104 through an optical inlet.

[0117] The method may include: reflecting a light beam multiple times between a first mirror component and a second mirror component positioned opposite to the first mirror component, wherein the first mirror component includes a first plane mirror and a first concave mirror array, and the second mirror component includes a second plane mirror and a second concave mirror array. The multiple reflections may follow a line-by-line pattern as described above, thereby enabling the light beam to traverse an extended optical path within a compact cavity.

[0118] The method may further include refocusing the light beam via a first concave mirror array and a second concave mirror array to maintain the beam size during multiple reflections. The refocusing action prevents beam divergence, which could otherwise reduce the effectiveness of gas absorption measurements. The method may include detecting the light beam passing through the light exit after multiple reflections. A light receiver can detect the beam and convert the optical signal into an electrical signal for subsequent analysis.

[0119] This method may include performing a system calibration procedure prior to gas sample analysis to establish baseline optical characteristics and verify correct system operation. The calibration procedure may involve introducing a reference gas sample with a known concentration to establish a calibration curve that correlates the measured absorption signal with the actual gas concentration. The method may include temperature and pressure compensation procedures that account for environmental variations that may affect gas absorption characteristics or optical system performance.

[0120] This method may include implementing real-time quality control measures during gas sample analysis to ensure the reliability and accuracy of measurements. Quality control measures may include monitoring system parameters such as light source stability, detector response consistency, and optical alignment integrity. The method may also include automated error detection and correction procedures that identify and compensate for systematic measurement errors or drift in system performance over time.

[0121] The method may further include analyzing the detected light beam to determine the presence and concentration of one or more target gases in the gas sample. Processing circuitry 902 may compare the detected light properties with reference absorption characteristics to identify specific gases and quantify their concentrations. Each gas component may have a unique absorption characteristic that can be used to distinguish different gases within the sample.

[0122] The analysis process may involve spectral deconvolution techniques, which separate overlapping absorption features from different gas components, thereby enabling accurate quantification of individual gas concentrations in complex gas mixtures. The analysis may include statistical processing methods that provide confidence intervals and uncertainty estimates for the measured concentration values. The analysis may also incorporate machine learning algorithms that improve recognition accuracy and reduce false alarm rates through pattern recognition and adaptive learning from historical measurement data.

[0123] For example, a compact multi-pass absorption gas cell can be configured to detect methane and carbon dioxide gases, which are common targets in environmental monitoring and industrial applications. The compact multi-pass absorption gas cell is particularly suitable for detecting gases present at low concentrations (such as parts per million or parts per billion). The extended optical path length achieved through multiple reflections provides sufficient absorption signal strength to detect these low-concentration gases with acceptable sensitivity.

[0124] This system can be configured to detect other target gases, including but not limited to hydrogen sulfide, ammonia, carbon monoxide, nitrogen oxides, sulfur dioxide, and various volatile organic compounds, depending on specific application requirements. The wavelength range and optical configuration can be optimized for specific gas detection applications, with the light emitter 910 and light receiver 912 selected to provide optimal sensitivity to the target gas's absorption band. The system may include interchangeable optical filter or detector elements, allowing for reconfiguration for different target gas substances without requiring a complete system replacement.

[0125] Thanks to its compact form factor achieved through a rectangular progressive reflection pattern and efficient mirror surface utilization, the compact multi-pass absorption gas cell can be configured for mobile and portable applications. Its compact design allows gas detection capabilities to be deployed in field applications, rather than being limited to laboratory environments. The compact multi-pass absorption gas cell 100 can be used in industrial, environmental, healthcare, and pharmaceutical fields where gas detection and monitoring may be required for safety, compliance, or process control purposes.

[0126] Mobile and portable configurations may include battery-powered systems that enable extended operation in remote locations without access to an external power source. Portable designs may incorporate robust housings and shock-resistant mounting systems to protect optics during transport and field deployment. Mobile configurations may include GPS positioning capabilities, enabling location-tagged measurements for environmental mapping and compliance monitoring applications.

[0127] This system can be configured for integration into vehicle-mounted monitoring platforms for mobile emissions monitoring, leak detection investigations, or environmental assessment applications. Its compact form factor allows for installation in space-constrained environments where conventional gas detection systems are limited, such as aircraft, ships, or industrial equipment. The portable design facilitates rapid deployment for emergency response applications where immediate gas detection capabilities are required at accident sites or disaster zones.

[0128] While the foregoing description provides an example system 900 and an example control device 901, it should be noted that the scope of this disclosure is not limited to the above description. In some examples, the example system 900 and / or control device according to this disclosure may be of other forms. In some examples, the example system 900 and control device 901 may include one or more additional and / or alternative elements, and / or may be compatible with... Figure 9 The examples illustrate different construction methods.

[0129] The operations and procedures described herein support combinations of means for performing a specified function and combinations of operations for performing a specified function. 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 function.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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 examples, 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 compact multi-pass absorption gas cell, the compact multi-pass absorption gas cell comprising: A rectangular housing defining a chamber for receiving a sample to be analyzed; An optical inlet, located at the first end of the rectangular housing, is used to introduce a light beam into the chamber; A light outlet, wherein the light outlet is located at the second end of the rectangular housing; A first mirror component, positioned at the first end, the first mirror component includes a first plane mirror and a first concave mirror array; and The second mirror component, positioned at the second end, includes a second plane mirror and a second concave mirror array, wherein the light beam is reflected multiple times between the first mirror component and the second mirror component and refocused by the first concave mirror array and the second concave mirror array to achieve an optical path length for low-absorption gas detection.

2. The compact multi-pass absorption gas cell according to claim 1, wherein the first concave mirror array and the second concave mirror array each include a plurality of concave mirrors.

3. The compact multi-pass absorption gas cell of claim 1, wherein the light beam is reflected between the first mirror component and the second mirror component in a rectangular row-by-row pattern.

4. The compact multi-pass absorption gas cell of claim 1, wherein the light inlet and the light outlet are positioned on opposite sides of the chamber, wherein the light beam exits the chamber from the light outlet.

5. The compact multi-pass absorption gas cell according to claim 1, wherein the first concave mirror array and the first planar mirror are coupled together and attached to the first end of the rectangular housing.

6. The compact multi-pass absorption gas cell according to claim 1, wherein the second concave mirror array and the second planar mirror are coupled together and attached to the second end of the rectangular housing.

7. The compact multi-pass absorption gas cell of claim 1, wherein the optical path length is determined based on: (i) the number of beam spots on the first or second plane mirror, (ii) the number of concave mirrors in the first or second plane mirror, and (iii) the mirror-to-mirror distance between the first and second mirror components.

8. The compact multi-pass absorption gas cell of claim 7, wherein the number of beam spots on the first plane mirror and the second plane mirror is the same, and wherein the number of concave mirrors in the first plane mirror and the second plane mirror is the same.

9. The compact multi-pass absorption gas cell of claim 1, wherein the first mirror component and the second mirror component define a mirror-to-mirror distance of about 400 mm, and wherein each of the first mirror component and the second mirror component has a height of about 33 mm and a width of about 111 mm.

10. A gas detection system, the gas detection system comprising: A compact multi-pass absorption gas cell, the compact multi-pass absorption gas cell comprising: A rectangular housing defining a chamber for receiving a sample to be analyzed; An optical inlet, located at the first end of the rectangular housing, is used to introduce a light beam into the chamber; A light outlet, wherein the light outlet is located at the second end of the rectangular housing; A first mirror component, positioned at the first end, includes a first plane mirror and a first concave mirror array; and The second mirror component is positioned at the second end and includes a second plane mirror and a second concave mirror array. The light beam is reflected multiple times between the first mirror component and the second mirror component and is refocused by the first concave mirror array and the second concave mirror array to achieve an optical path length for low-absorption gas detection. A light emitter configured to emit a light beam toward the compact multi-pass absorption gas cell; and A light receiver configured to receive light exiting the compact multi-pass absorption gas cell.

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