Liquid sensing systems and methods using a ring resonator sensor

Abstract

Sensor system with a multi-pass interaction region, the system comprising: a waveguide (201) comprising: an input region (202, 302, 402) configured to receive emitted light; a multi-pass region (204, 304, 404) coupled to the input region (202, 302, 402), which is configured as a photonic crystal to absorb portions of the emitted light according to a sample (212) located immediately adjacent to the multi-pass region (204, 304, 404); and an output region (206, 306) coupled to the multi-pass region (204, 304, 404), which is configured to provide interacted light from the multi-pass region (204, 304, 404); and a flexible membrane (214) on which the input region (202, 302, 402), the multi-pass interaction region (204, 304, 404) and the output region (206, 306) are formed, wherein the flexible membrane (214) has a honeycomb structure on its back side in relation to the waveguide (201).

Description

BACKGROUND Sensors are used in sensing systems to detect properties such as light, temperature, motion, and the like. One type of sensor is a fluid (liquid and / or gas) sensor, which can be used to sense fluids. The sensor takes measurements of a specific property of the fluid, and these measurements are then used to determine the type of fluid itself or to determine another property of the fluid. A common sensor is an absorption sensor used to measure fluids, and a typical configuration is a straight waveguide. The straight waveguide configuration uses a straight rib (or fin) through which light passes. The rib is in contact with a sample. An output terminal of the waveguide provides outgoing light, and the output signal changes as the light interacts with the fluid within the waveguide. These variations can be measured and correlated with the fluid. However, such waveguides are relatively insensitive and require very long lengths to adequately identify different liquids. Alternatively, to increase sensitivity, multiple waveguides are generally needed and configured as a grid. This grid structure is fragile and therefore prone to damage. US Patent 2005 / 0210989 A1 describes a high-performance, high-pressure sensor and system based on a microresonator for pressure measurement in a cavity. The pressure sensor features a substrate-supported optical resonance structure. An optical input path couples light evanescently into the optical resonance structure. An optical output path collects light from the optical resonance structure. A light source provides a known light input to the input path, where the known light input is coupled evanescently into the optical resonance structure via the input path, and a portion of this light is collected from the optical resonance structure via the output path. A light detector receives the portion of light collected from the optical resonance structure and generates a light signal representing this portion.A temperature compensation sensor generates a temperature signal indicating the temperature near the optical resonance structure. A spectrum detector receives both the light and temperature signals. The spectrum detection device analyzes these signals using a detection algorithm to generate a pressure signal indicating the pressure inside the cavity. Against this background, an improved sensor is needed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic representation of a sensor system using a ring waveguide. Fig. 2 is a schematic representation showing a side view of a multi-pass ring waveguide sensor. Fig. 3A is a schematic representation showing a ring-shaped multi-pass waveguide 300 with four terminals. Fig. 3B is a schematic representation showing a ring-shaped multi-pass waveguide with two terminals. Fig. 4A is a schematic representation showing a ring-shaped multi-pass waveguide realized by a photonic crystal and having four terminals. Fig. 4B is a schematic representation showing a ring-shaped multi-pass waveguide realized by a photonic crystal and having two terminals. Fig. 5 is a schematic representation of a waveguide with wedge-shaped lattice regions.Figure 6 is a schematic representation of a waveguide with linear or non-wedge-shaped lattice regions. Figure 7 is a schematic representation showing the substrate of the structure realized as a membrane with hexagonally shaped components. Figure 8 is a flowchart showing a method for operating a sensor with a multi-pass interaction region. DETAILED DESCRIPTION The present invention will now be described with reference to the accompanying figures, wherein the same reference numerals serve to identify the same elements and wherein the structures and devices shown are not necessarily drawn to scale. Sensor systems and methods are disclosed that utilize sensors with multi-pass regions exhibiting straight and / or curved shapes. These multi-pass regions allow multiple passages of light through an interaction volume, thus enabling multiple interactions between the light and the sample. The size, shape, and composition of the waveguide can be varied or configured to measure different types of liquids and gases. Fig. 1 is a schematic representation of a sensor system 100 using a ring waveguide. For better understanding, the system 100 is provided in a simplified form. The system 100 is provided as an example of a system that uses a ring sensor for sensing (sampleting) liquids or gases. System 100 comprises an interface 102, a ring sensor 104, and a control unit 106. The interface 102 connects the ring sensor 104 to the control unit 106. The interface 102 can be configured to provide power and / or signals for communication. The control unit 106 is configured to control the ring sensor 104 and to receive and use measurements generated by the ring sensor 104. For example, the control unit 106 can be configured to determine a liquid and its composition based on a measurement or output signal from the ring sensor 104. The ring sensor 104 is configured to measure and / or detect one or more samples positioned directly next to it. The sensor 104 can also be configured to measure the chemical and / or environmental properties of a sample positioned directly next to it. The sample may be placed or positioned in contact with the sensor 104. The sensor 104 comprises a curved or ring-shaped waveguide. Some examples of suitable shapes are provided below. A light source is coupled to an input of the waveguide, and a light detector is coupled to an output of the waveguide. Light passes through the curved or ring-shaped interaction region multiple times. As the light passes through, it is attenuated. This attenuation varies depending on whether the sample is in contact with or immediately adjacent to the interaction region. The detector measures the emitted light. This information, or measurement, can be provided to the control unit 106 for analysis. The measurement correlates with the sample and includes, for example, sample type, liquid, gas, temperature, and the like. Fig. 2 is a schematic representation showing a side view of a multi-pass waveguide sensor 200. The sensor 200 is used to detect and / or measure fluid located immediately adjacent to the sensor 200. The sensor 200 uses a multi-pass region where light passes through multiple times to increase the absorption rate and reduce the sensor size. The sensor 200 comprises a waveguide 201, a light source 208, and a light detector 210. The light source 208 emits an electromagnetic field (or light). The light source 208 can be configured to emit a specific wavelength of light, such as infrared. The detector 210 is configured to detect or measure the wavelength of the light emitted by the light source 208 after it passes through the waveguide 201. A sample 212 is positioned directly adjacent to or in contact with the waveguide 201. The sample 212 can comprise a liquid and / or a gas. The waveguide 201 comprises an input region 202, a multi-pass interaction region 204, and an output region 206 and is formed on a membrane 214. The waveguide 201 is made of a suitable material, such as silicon, and has a suitable extent. In one example, the waveguide 201 has a width of 2 micrometers and a height of 600 nanometers. Other properties for the waveguide 201 can also be selected or set, including, but not limited to, the terminals used, the ring or disk shape for the interaction region 204, materials, and the like. Furthermore, in one example, the waveguide 201 is a finned waveguide as the guiding medium. The finned waveguide limits transmitted light in two dimensions. The waveguide is a photonic crystal or is formed in one. The photonic crystal can be formed with 2D or 3D structuring. In general, a photonic crystal is a periodic structure of two types: air holes in a block of material and material rods in air. In the case of air holes in a block of material, the air holes are arranged in a periodic lattice. In the case of material rods in air, the rods are arranged in a periodic lattice. An example of a photonic crystal is described below. The holes in the block can be filled with material that has a different refractive index than the material of the block. The input region 202 receives the emitted light from the light source 208 and directs the light into the multi-pass interaction region 204. In one example, the light source 208 is not positioned on the same plane as the waveguide 201, and the input region 202 is configured with a grating to allow the light to enter the waveguide 201. In another example, the light source 208 is positioned so that the emitted light is directed through the waveguide 201. The grating has suitable dimensions, such as grating period, grating height, and grating region length (e.g., 2 mm), to allow sufficient light to enter the waveguide 201. In yet another example, the light source 208 is located on the same chip as the waveguide 201 and is aligned with it. The membrane 214 consists of a suitable material to support the waveguide 201 and typically a number of other waveguides / sensors. Furthermore, the suitable material is selected to provide membrane properties, including, for example, refractive index, flexibility, and the like. The membrane 214 can be fairly rigid or flexible, depending on the materials used. The membrane 214 incorporates a honeycomb structure on its back side facing the waveguide, which provides strength while allowing flexibility. In one example, the suitable material is silicon nitride. In another example, the suitable material has a low refractive index. The multi-pass interaction region 204, also referred to as the resonator region, comprises a ring-shaped or curved structure configured to cause the guided light to pass through it multiple times or to propagate through the region. The ring shape and size are configured for a selected wavelength and absorption rate. As the guided light passes through the absorption region, it is attenuated according to the sample 212. Thus, varying sample types and properties, such as age and temperature, result in different absorption rates through the region. Consequently, the guided light exiting the multi-pass interaction region 204 is attenuated. The interacted light is attenuated compared to the emitted light or to the light without the sample 212. The interacting light exits the waveguide 201 at output region 206. The interacting light is measured by detector 210. In one example, output region 206 has a grating to allow the interacting light to exit waveguide 201. In another example, output region 206 has an output or opening that is aligned with detector 210. For example, the detector can be located on a chip and aligned with waveguide 201. The detector 210 measures the light emerging from the output region 206 of the waveguide 201. The emerging light is attenuated compared to the emitted light or to the light without the sample 212. The detector 210, or another component such as a controller, uses the measured light to determine the composition and other properties of the sample 212. The detector 210 can be configured to be in line with the waveguide 201. Alternatively, the detector 210 can be configured not to be in the same plane / line with the waveguide. The detector 210 can be configured to measure a selected range of light wavelengths, e.g., infrared. In one example, the waveguide 200 is configured to detect (sample) wavelengths of approximately 5 to 6 micrometers. It should be noted that the waveguide 201 can be configured to provide a wavelength or range of wavelengths referred to as the output wavelength, which may be a subset of the wavelengths of the emitted light. Essentially, the waveguide 201 can be configured to filter out or attenuate other wavelengths by selecting the terminals used, the radius / period size (in the case of a photonic crystal), the shape and size of region 204, the materials used, and the like. Fig. 3A is a schematic representation showing an annular multi-pass waveguide 300 with four terminals. The waveguide 300 can be integrated into the sensor 200 described above to measure or detect a sample. The waveguide 300 includes a multi-pass or resonator region that increases the absorption rate of the waveguide 300 without consuming significant area. The waveguide 300 comprises an input terminal 302, a multi-pass interaction region 304, an output terminal 306, a pass-through terminal 308, and an add / drop terminal 310. In this example, the pass-through terminal 308 and the add / drop terminal 310 are shown but not used. It is understood that variations of the waveguide 300 may employ the pass-through terminal 308 and the add / drop terminal 310 for additional functions. The input terminal 302 receives the emitted light from a light source and directs the light into the multi-pass interaction region 304. In one example, the input terminal 302 is configured with a grating to allow the light to enter. In another example, the light source is positioned in line with the input terminal 302 to feed the emitted light into the input terminal 302. The multi-pass interaction region 304, also referred to as the resonator region, comprises a ring-shaped or curved shape configured to cause the guided light to pass through it multiple times (e.g., to circulate). An arrow in Fig. 3 indicates the general rotation of the light through the region 304. The shape and size of the ring are configured for a selected wavelength and absorption rate. As the light passes through or propagates through the absorption and interaction region 304, it is attenuated according to a sample located immediately adjacent to the interaction region 304. The extent and / or rate of attenuation varies according to the sample and its properties. For example, varying sample types and properties, such as composition, temperature, or fluid age, result in different absorption rates through the region. Consequently, interacted light exits the multi-pass interaction region 304 attenuated.The interacting light is attenuated compared to the emitted light or to the light without sample 212. The interacting light emerges from region 304 and exits the waveguide 300 at output terminal 306. The interacting light is measured by a detector, such as the one shown above. In one example, output terminal 306 has a grating to allow the interacting light to exit the waveguide 300. In another example, output terminal 306 has an opening or port that is aligned with the detector. It should be noted that the configuration of waveguide 300 prevents light from passing directly through waveguide 300, as can happen with other straight waveguides. Fig. 3B is a schematic representation showing a ring-shaped multi-pass waveguide 300 with two terminals. The waveguide 300 can be integrated into the sensor 200 described above to measure or detect a sample. The waveguide 300 includes a multi-pass or resonator region that increases the absorption rate of the waveguide 300 without consuming significant area. The waveguide 300 comprises an input port 302, a multi-pass interaction region 304, and an output port 306. The input port 302 receives the emitted light from a light source, propagates it along the straight waveguide, and couples the light into the ring 304. After being confined within the ring 304 (where interaction with the sample takes place), the partially attenuated light is coupled out of the straight waveguide toward the output port. In one example, the input port 302 is configured with a grating to allow the light to enter. In another example, the light source is positioned in line with the input port 302 to feed the emitted light into the input port 302. The multi-pass interaction region 304, also referred to as the resonator region, comprises a ring-shaped or curved shape configured to cause guided light to pass through it multiple times. An arrow in Fig. 3B indicates the general rotation / propagation of the light through region 304. The shape and size of the ring are configured for a selected wavelength and absorption rate. As the light passes through the absorption and interaction region 304, it is attenuated according to a sample located immediately adjacent to the interaction region 304. The extent and / or rate of attenuation varies according to the sample and its properties. For example, varying sample types and properties, such as composition, temperature, or fluid age, result in different absorption rates through the region. Consequently, interacted light exits the multi-pass interaction region 304 attenuated.The interacting light is attenuated compared to the emitted light or to the light without sample 212. The interacting light emerges from region 304 and exits the waveguide 300 at output terminal 306. The interacting light is measured by a detector, such as the one shown above. In one example, output terminal 306 has a grating to allow the interacting light to exit the waveguide 300. In another example, output terminal 306 has an opening or port that is aligned with the detector. It should be noted that the configuration of the waveguide 300 in Fig. 3B allows light to pass directly through the waveguide 300. Additionally, the light travels counterclockwise through the entire multi-pass region 304 when viewed from above. Fig. 4A is a schematic representation showing an annular multi-pass waveguide 400, realized as a photonic crystal (PhC) and having four terminals. The waveguide 400 can be incorporated into the sensor 200 described above to measure or detect a sample. The waveguide 400 includes a PhC multi-pass or resonator region that increases the absorption rate of the waveguide 400 without consuming significant area. The Waveguide 400 is constructed using a photonic crystal. An example structure is shown to illustrate the photonic crystal; however, it should be understood that this structure is for illustrative purposes only and that other structures can also be used. The structure is two- or three-dimensional and configured for properties such as wavelength, absorption, transmittance, and the like, without being limited to these. The Waveguide 400 is shown with a cubic lattice, but other configurations, such as a hexagonal lattice, a hexagonal ring, and the like, can also be used. The Waveguide 400 uses a suitable material or is made of one. In one example, the photonic crystal and / or the Waveguide 400 are formed on a silicon wafer. Additionally, an epoxy resin and / or an imide can be used as a photonic layer within the Waveguide 400. Another material that can be used for the Waveguide 400 is PMMI (polymethacrylmethylimide) – an amorphous, crystal-clear plastic with a transmittance of 90% and a thickness of 3 mm. The refractive index of the PMMI increases with the concentration of imide. The waveguide 400 comprises an input terminal 402, a multi-pass PhC interaction region 404, an output terminal 406, a pass-through terminal 408, and an add / drop terminal 410. The pass-through terminal 408 and the add / drop terminal 410 are shown but not used. It is understood that variations of the waveguide 400 may employ the pass-through terminal 408 and the add / drop terminal 410 for additional functions. The functions of the waveguide 400 are similar to those of the waveguide 300 described in Fig. 3A. The input terminal 402 receives the emitted light from a light source and directs the light into the multi-pass interaction region 404. In one example, the input terminal 402 is configured with a grating to allow the light to enter. In another example, the light source is positioned in line with the input terminal 402 to feed the emitted light into the input terminal 402. The multi-pass interaction region 404, also referred to as the PhC resonator region, comprises a ring-shaped or curved shape configured to cause guided light to pass through it multiple times (e.g., to circulate). An arrow in Fig. 4A indicates the general rotation of the light through region 404. The shape and size of the ring are configured for a selected wavelength and absorption rate. As the light passes through or propagates through the absorption and interaction region 404, it is attenuated according to a sample located immediately adjacent to the interaction region 404. The extent and / or rate of attenuation varies according to the sample and its properties. For example, varying sample types and properties, such as composition, temperature, or fluid age, result in different absorption rates through the region. Consequently, interacted light exits the multi-pass interaction region 404 attenuated.The interacting light is dimmed compared to the emitted light. The interacting light emerges from region 404 and exits the waveguide 400 at output terminal 406. The interacting light is measured by a detector, such as the one shown above. In one example, output terminal 406 has a grating to allow the interacting light to exit the waveguide 400. In another example, output terminal 406 has an opening or port that is aligned with the detector. Fig. 4B is a schematic representation showing an annular multi-pass waveguide 400 using a four-terminal photonic crystal. The waveguide 400 can be incorporated into the sensor 200 described above to measure or detect a sample. The waveguide 400 includes a multi-pass or resonator region that increases the absorption rate of the waveguide 400 without consuming significant area. The Waveguide 400 is constructed using a photonic crystal. An example structure is shown to illustrate the photonic crystal; however, it should be understood that this structure is for illustrative purposes only and that other structures can also be used. The structure is two- or three-dimensional and configured for properties such as wavelength, absorption, transmittance, and the like, without being limited to these. The Waveguide 400 is shown with a cubic lattice, but other configurations, such as a hexagonal lattice, a hexagonal ring, and the like, can also be used. The Waveguide 400 uses a suitable material or is made of one. In one example, the photonic crystal and / or the Waveguide 400 are formed on a silicon wafer. Additionally, an epoxy resin and / or an imide can be used as a photonic layer within the Waveguide 400. Another material that can be used for the Waveguide 400 is PMMI (polymethacrylmethylimide) – an amorphous, crystal-clear plastic with a transmittance of 90% and a thickness of 3 mm. The refractive index of the PMMI increases with the concentration of imide. The waveguide 400 comprises an input port 402, a PhC multi-pass interaction region 404, and an output port 406. The input port 402 receives the emitted light from a light source, propagates it along the straight waveguide, and couples the light into the ring 404. After being confined within the ring 404 (where interaction with the sample takes place), the partially attenuated light is coupled out of the straight waveguide toward the output port. In one example, the input port 402 is configured with a grating to allow the light to enter. In another example, the light source is positioned in line with the input port 402 to feed the emitted light into the input port 402. The multi-pass interaction region 404, also called the resonator region, comprises a ring-shaped or curved shape configured to cause the guided light to pass through it multiple times. An arrow in Fig. 4B indicates the general rotation of the light through region 404. The shape and size of the ring are configured for a selected wavelength and absorption rate. As the emitted light passes through the absorption and interaction region 404, it is attenuated according to a sample located immediately adjacent to the interaction region 404. The extent and / or rate of attenuation varies according to the sample and its properties. For example, varying sample types and properties, such as sample age and temperature, result in different absorption rates through the region. Consequently, interacted light exits the multi-pass interaction region 404 attenuated.The interacting light is attenuated compared to the emitted light or to the light without sample 212. The interacting light emerges from region 404 and exits the waveguide 400 at output terminal 406. The interacting light is measured by a detector, such as the one shown above. In one example, output terminal 406 has a grating to allow the interacting light to exit the waveguide 400. In another example, output terminal 406 has an opening or port that is aligned with the detector. It should be noted that, due to the configuration of waveguide 400, light can pass directly through waveguide 400. Additionally, the light travels clockwise through the entire multi-pass region 404 when viewed from above. Fig. 5 is a schematic representation of a waveguide 300 with wedge-shaped grid regions. It is understood that other waveguides with multi-pass regions can also use the wedge-shaped grid regions, including, for example, the waveguide 300 from Fig. 3B. The waveguide 300 comprises an input terminal 302, a multi-pass region 304, and an output terminal 306. The input terminal 302 is coupled to or includes a wedge-shaped input grid region 512. The output terminal 306 is coupled to or includes a wedge-shaped output grid region 514. Grating region 512 has a wedge shape that tapers towards the waveguide 300. The wedge shape allows a light source to achieve a wider beam dispersion, or simply a larger beam diameter relative to the width of the waveguide 300. For example, the wedge shape allows an increase in the amount of light from the source coupled into the waveguide 300 via the input port. Consequently, a less restrictive light source can be used. The grating includes spaced or separated apertures within the region and is configured to allow light to enter the waveguide 300. Sections are present between the apertures within grating region 512. As shown, the grating also has a wedge shape. The grating is configured to have a diffraction order that depends on the dimensions of the apertures. The output grating region 514 also has a wedge shape and extends or rises away from the waveguide 300. The wedge shape disperses light exiting the waveguide 300 and allows the use of a larger detector. Fig. 6 is a schematic representation of a waveguide 300 with linear or non-wedge-shaped grid regions. The waveguide 300 is shown here with the linear grid regions. It is understood that other waveguides with multi-pass regions can also use the linear grid regions, including, for example, the waveguide 300 from Fig. 3B. The waveguide 300 comprises an input terminal 302, a multi-pass region 304, and an output terminal 306. The input terminal 302 is coupled to or includes an input grid region 612. The output terminal 306 is coupled to or includes an output grid region 614. The grating region 612 has a non-wedge-shaped, linear form that generally fits the waveguide 300. The shape generally requires a suitable light source with a narrower dispersion (or a smaller beam diameter) than the light source used for Fig. 5. The grating is configured to allow light to enter the waveguide 300. The output grating region 614 also has a linear shape, aligned with the waveguide 300. This linear shape maintains a narrow width of light exiting the waveguide 300, allowing the use of a smaller detector. It is understood that variations of the grid regions are considered. For example, a wedge-shaped input grid region 512 according to Fig. 5 can be used with a linear output grid region 614 using waveguides 400 or 300. As another example, a linear input grid region 612 can be used with a wedge-shaped output grid region 514 using waveguides 400 or 300. Fig. 7 is a schematic representation showing a membrane 700 with hexagonally shaped components. The membrane 700 serves to support or attach one or more waveguides, typically with multi-pass interaction regions. The membrane 700 can be used for the membrane 214 described above. The Membrane 700 comprises a variety of hexagonally shaped components to form a honeycomb structure. The individual components can be relatively rigid; however, connecting lines between components are flexible and improve overall flexibility. The Membrane 700 is made of a suitable material and has a selected refractive index. The Membrane 700 can be configured to accommodate additional components, such as, but not limited to, sensors, light sources, light detectors, interconnects, and the like. Fig. 8 is a flow diagram illustrating Method 800 for operating a sensor with a multi-pass interaction region. Method 800 uses multiple passes through an interaction region to reduce the space required and improve the absorption rate. Method 800 begins at block 802, where a wavelength or wavelength range is selected. The wavelength can be chosen according to the sample and / or types of samples to be detected. Additionally, the wavelength can be selected to detect specific chemical and environmental properties. In one example, the wavelength is selected to include only infrared light. Block 804 configures a waveguide with a multi-pass interaction region according to the selected wavelength. The waveguide is configured to have selected properties, such as height, width, and length. Other selected properties can include material, shape of the multi-pass region, and the like. In one example, the multi-pass interaction region is configured to have a radius selected according to the chosen wavelength and / or according to the chemical and environmental properties to be detected. At block 806, a light source emits light of the selected wavelength. In one example, the light source is controlled to provide only the selected wavelength. In another example, the light source is configured to emit the selected wavelength. The light source is also configured to emit a known amount of light, which can later be used to determine the attenuation by the waveguide. In yet another example, the light source can emit broadband light, and the selection of the wavelength(s) is achieved using a filter, such as a photonic crystal. At block 808, the emitted light passes through the waveguide and the multi-pass interaction region. Since the light undergoes multiple passes, some of it is absorbed by a sample located immediately adjacent to the waveguide and the interaction region. The absorption rate depends, at least in part, on the sample. At block 810, the interacting light exits the waveguide and is measured by a detector. Once the light has passed through the waveguide several times and interacted with the sample, it exits the waveguide through an output region. The light detector captures and measures this interacting light that has exited the waveguide. At block 812, sample properties are determined based on the emitted and measured light. These properties include chemical and / or environmental characteristics. Additionally, the sample type can be determined at block 812. The light detector and / or a separate control unit can be configured to perform this determination. Although the process is shown and described below as a series of actions or events, it is understood that the sequence of such actions or events shown is not to be interpreted in a restrictive sense. For example, some actions may occur in different sequences and / or simultaneously with other actions or events besides those shown or described herein. In addition, actions not shown may be required to implement one or more aspects or embodiments of the disclosure herein. Furthermore, one or more of the actions shown herein may be carried out in one or more separate actions and / or phases. It is understood that the claimed subject matter can be implemented as a method, device, or product using standard programming and / or engineering methods to produce software, firmware, hardware, or any combination thereof, for controlling a computer to implement the disclosed subject matter (e.g., the systems shown in Figures 1, 2, etc., are non-limiting examples of a system that can be used to implement the above methods). The term "product," as used herein, is intended to include a computer program accessible from any computer-readable device, medium, or carrier. Naturally, those skilled in the art will recognize that numerous modifications can be made to this configuration without altering the scope of protection or the concept of the claimed subject matter. A sensor system with a multi-pass interaction region is disclosed. The system comprises an input region, a multi-pass region, and an output region. The input region is configured to receive emitted light. The multi-pass region is coupled to the input region and configured to absorb portions of the emitted light according to a sample located immediately adjacent to the multi-pass region. The output region is coupled to the multi-pass region and configured to provide interacted light from the multi-pass region. A sensor system with a multi-pass interaction region is disclosed. The system comprises a sensor and a control unit. The sensor includes a light source, a waveguide, and a detector. The light source is configured to emit light at one or more selected wavelengths. The waveguide is configured to receive the emitted light, provide interaction with the sample, and deliver the interacted light. The detector is configured to measure the interacted light from the waveguide. The control unit is coupled to the sensor and configured to determine sample properties based on the measured and emitted light. A method for operating a sensor with a multi-pass interaction region is disclosed. A detection wavelength is selected. In one example, the wavelength is infrared. A waveguide with a multi-pass interaction region is configured according to the selected wavelength. Light with the selected wavelength is received at the waveguide. The received light interacts in the multi-pass interaction region. Light exiting the waveguide is measured. The measured light and the received light can be used to determine or detect a sample. With particular regard to the various functions performed by the components or structures (arrangements, devices, circuits, systems, etc.) described above, the terms used to describe such components (including any reference to a “means”) shall correspond to any component or structure that performs the specified function of the described component (e.g., that is functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function in the implementations of the invention illustrated herein as examples, unless otherwise specified.Although a particular feature of the invention may have been disclosed with respect to only one of several implementations, such a feature may be combined with one or more other features of the other implementations, as may be desirable or advantageous for any or a particular application. Furthermore, the terms "including," "includes," "having," "has," "with," or variants thereof, when used in the detailed description and in the claims, shall be understood to mean inclusively, similar to the term "comprehensive."

Claims

Sensor system with a multi-pass interaction region, the system comprising: a waveguide (201) comprising: an input region (202, 302, 402) configured to receive emitted light; a multi-pass region (204, 304, 404) coupled to the input region (202, 302, 402), which is configured as a photonic crystal to absorb portions of the emitted light according to a sample (212) located immediately adjacent to the multi-pass region (204, 304, 404); and an output region (206, 306) coupled to the multi-pass region (204, 304, 404), which is configured to provide interacted light from the multi-pass region (204, 304, 404); and a flexible membrane (214) on which the input region (202, 302, 402), the multi-pass interaction region (204, 304, 404) and the output region (206, 306) are formed, wherein the flexible membrane (214) has a honeycomb structure on its back side in relation to the waveguide (201). System according to claim 1, wherein the input region (202, 302, 402) has a wedge shape. System according to claim 1, wherein the input region (202, 302, 402) has a linear shape. System according to any one of claims 1 to 3, wherein the input region (202, 302, 402) has a grid configured to receive the emitted light. System according to any one of claims 1 to 4, further comprising a light source (208) configured to provide the emitted light in selected wavelengths. System according to any one of claims 1 to 5, wherein the emitted light has an infrared wavelength. System according to any one of claims 1 to 6, wherein the multi-pass region (204, 304, 404) has a curvature configured to allow multiple passes of at least part of the emitted light. System according to any one of claims 1 to 7, wherein the multi-pass region (204, 304, 404) is circular and has a radius according to a selected wavelength of the emitted light. System according to one of claims 1 to 8, which further comprises a pass-through port (308, 408) coupled to the multi-pass region (204, 304, 404). System according to any one of claims 1 to 9, wherein the output region (206, 306, input region) lies on a line with the input region (202, 302, 402). System according to any one of claims 1 to 10, further comprising a detector (210) configured to measure the interacting light from the output region (206, 306, input region). System according to claim 11, further comprising a control unit (106) configured to measure the interacting light from the detector (210) and to determine chemical properties of a sample (212) arranged immediately next to the multi-pass region (204, 304, 404). Sensor system with a multi-pass interaction region, the system comprising: a sensor (200) with: a light source (208) configured to emit light at a selected wavelength; a waveguide (201) formed on a flexible membrane (214), comprising a multi-pass region (204, 304, 404) formed as a photonic crystal and configured to receive the emitted light and absorb a portion of the light according to a sample (212) and provide interacted light, wherein the flexible membrane (214) has a honeycomb structure on its back side with respect to the waveguide (201); and a detector (210) configured to measure the interacted light from the waveguide (201); and a control unit (106) coupled to the sensor (200) and configured to determine properties of the sample (212) based on the measured light and the emitted light. System according to claim 13, wherein the waveguide (201) has a curved section configured to cause at least part of the emitted light to pass through it in multiple passes. System according to claim 13 or 14, wherein the waveguide (201) has a multi-pass interaction region (204) having a circular shape, the circular shape being configured for the selected wavelength. System according to one of claims 13 to 15, which further comprises an interface (102) coupled to the sensor (200) and the control unit (106). Method for operating a sensor with a multi-pass interaction region (204), the method comprising: selecting a wavelength for detection; configuring a waveguide (201) formed on a flexible membrane (214) with a multi-pass interaction region (204) formed as a photonic crystal according to the selected wavelength, wherein the flexible membrane (214) has a honeycomb structure on its back side with respect to the waveguide (201); receiving light of the selected wavelength at the waveguide (201); the interaction of the received light in the multi-pass interaction region (204); and measuring the light emitted from the waveguide (201). The method of claim 17, wherein the selection of the wavelength comprises the selection of the wavelength for the detection of chemical and environmental properties. Method according to claim 17 or 18, wherein the interaction of the received light comprises the interaction of the received light with a sample (212) arranged directly next to the multi-pass interaction region (204). The method according to claims 17 to 19, further comprising comparing the measured light with the received light to detect a sample.

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