A gas detection device and a gas detection method

Abstract

The application discloses a gas detection device and a gas detection method. The device comprises a laser, a ring resonator and a spectrometer. The first surfaces of the mirrors of the ring resonator are mutually at an angle. The laser is arranged on one side of the second surface of the first mirror. The excitation light is coupled into the ring resonator through the first mirror, and the excitation light is unidirectionally propagated in the ring resonator through the reflection of the first surfaces of the mirrors. The problem that the excitation light is back-reflected to the laser after propagation, causing damage to the device, is avoided. The spectrometer detects the Raman scattered light generated by the interaction between the excitation light in the ring resonator and the gas to be detected, and outputs the gas detection result. Since the spectrometer is arranged on one side of the second surface of one of the second mirrors, and the detection optical axis of the spectrometer is coaxial with the excitation light reflected by the first surface of the second mirror, the intensity of the back-detection Raman scattered light of the spectrometer is high, the signal-to-noise ratio is improved, and the sensitivity of the gas detection is also improved.

Description

Technical Field

[0001] The present application relates to the field of gas detection technology, and in particular to a gas detection device and a gas detection method. Background Art

[0002] Currently, trace gas detection has widespread application in production, construction, scientific research, medical treatment, industrial control, and other fields. The sensitivity and accuracy of trace gas composition and concentration detection are also of great concern. Raman scattering refers to the phenomenon that when a laser of a certain frequency is irradiated on a sample, the sample molecules absorb some of the laser energy, vibrate in different ways and to varying degrees (such as twisting and swinging), and then scatter light of a different frequency from the excitation light. The change in the scattered light frequency depends on the characteristics of the scattering material, and the change in the scattered light frequency of different molecules is different. Therefore, Raman scattering spectroscopy can be used to detect gas components and their concentrations.

[0003] Existing solutions for trace gas detection using the Raman effect after laser scattering typically combine cavity enhancement technology with laser Raman detection. For example, the laser beam is reflected multiple times by a spherical mirror within a passive cavity. After passing through the gas being measured, the laser beam undergoes Raman scattering. The scattered light is filtered by a filter and collected by a beam converging element mounted on the side of the cavity, ultimately entering a spectrometer. The spectrometer detects the spectrum and ultimately determines the concentration of the gas being measured.

[0004] Since the light beam is reflected multiple times in the cavity, it is possible that part of the light beam will be emitted from the light-transmitting hole through which the laser is injected. Therefore, the emitted light beam may affect the laser and even damage the laser. The impact on device performance increases the cost of gas detection. In addition, the intensity of the scattered light collected from the side of the cavity is weak, while the intensity of the excitation light is strong, resulting in a poor signal-to-noise ratio. In addition, the need to use complex beam converging elements and filters also weakens the intensity of the collected scattered light to a certain extent, increasing the detection cost. Therefore, the existing technology has a reduced gas detection sensitivity due to the poor signal-to-noise ratio and the use of additional optical devices. Summary of the Invention

[0005] Based on the above problems, the present application provides a gas detection device and a gas detection method, the purpose of which is to reduce the impact of reflected light on the laser, improve the signal-to-noise ratio of the optical signal, and enhance the sensitivity of gas detection.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, the present application provides a gas detection device, comprising: a laser, a ring resonator, and a spectrometer; the ring resonator comprises N reflectors, each reflector comprising a first surface and a second surface; the first surfaces of the reflectors form a non-zero angle with each other; N is a positive integer greater than 2, and the N reflectors comprise a first reflector and a plurality of second reflectors;

[0008] The laser is arranged on the side of the second surface of the first reflector; the excitation light emitted by the laser is coupled into the ring resonator through the first reflector, and the excitation light propagates in one direction in the ring resonator through the reflection effect of the first surface of each reflector;

[0009] The spectrometer is arranged on one side of the second surface of the second reflector, and the detection optical axis of the spectrometer is coaxial with the excitation light reflected by the first surface of the second reflector;

[0010] The spectrometer is used to detect Raman scattered light generated by the interaction of the excitation light with the gas to be detected in the ring resonant cavity, and output a gas detection result.

[0011] In an optional implementation, the gas detection device further includes: a photoelectric detection component;

[0012] The photoelectric detection component is arranged on one side of the second surface of a reflector, and the detection optical axis of the photoelectric detection component is coaxial with the excitation light received by the first surface of the reflector;

[0013] The photoelectric detection component is used to convert the received optical signal into an electrical signal, and the pulse performance of the electrical signal indicates whether the reflector in the ring resonator needs to be adjusted.

[0014] In an optional implementation, the ring resonant cavity of the gas detection device includes one first reflector and three second reflectors;

[0015] The first reflector and one second reflector are arranged in an eight-shaped shape, and the other two second reflectors are arranged in an inverted eight-shaped shape.

[0016] In an optional implementation, the ring resonant cavity of the gas detection device includes a first reflector and two second reflectors;

[0017] The first reflector and the two second reflectors are arranged in an "eight" shape.

[0018] In an optional implementation, each reflector in the ring resonator of the gas detection device transmits both forward scattered light and back scattered light in the Raman scattered light;

[0019] The forward scattered light transmitted through the reflector is coaxial and in the same direction as the excitation light received by the first surface of the reflector; the back scattered light transmitted through the reflector is coaxial and in the opposite direction to the excitation light reflected by the first surface of the reflector.

[0020] In an optional implementation, the excitation light emitted by the laser of the gas detection device is non-vertically incident on the second surface of the first reflector.

[0021] In an optional implementation, the first surface of at least one reflector in the ring resonant cavity of the gas detection device is a concave surface.

[0022] In an optional implementation, the reflectivity of each reflector in the ring resonant cavity of the gas detection device to the excitation light is greater than 99.9%, and the transmittance to the Raman scattered light is greater than 50%.

[0023] In an optional implementation, the gas detection device further includes: an optical path adjustment device; the optical path adjustment device specifically includes: a controller and N sets of adjustment components; the N sets of adjustment components are electrically connected to the controller, and the controller is also electrically connected to the photoelectric detection component; the N reflectors are mounted one-to-one on the N sets of adjustment components; each set of adjustment components includes a drive module and a motor module;

[0024] The controller is configured to determine the reflector to be adjusted and generate a control signal based on the electrical signal output by the photoelectric detection component, and send the control signal to the adjustment component corresponding to the reflector to be adjusted;

[0025] The driving module in the adjusting component is used to drive the motorized module to move according to the instruction of the control signal, so as to adjust the reflector to be adjusted.

[0026] A second aspect of the present application provides a gas detection method, which is applied to the gas detection device described in any implementation of the first aspect. The gas detection method includes:

[0027] The laser emits excitation light after being turned on;

[0028] The excitation light is coupled into the ring resonator through the first reflector, and propagates in one direction in the ring resonator through the reflection effect of the first surface of each reflector;

[0029] The spectrometer detects Raman scattered light generated by the interaction of the excitation light with the gas to be detected in the ring resonator;

[0030] The spectrometer outputs a gas detection result according to the detected spectrum.

[0031] The gas detection device provided by the present application includes: a laser, a ring resonator and a spectrometer. The ring resonator includes a number of reflectors greater than or equal to 2, one of which is a first reflector and the rest are second reflectors. Each reflector includes a first surface and a second surface; the first surfaces of each reflector form a non-0 degree angle with each other. The laser is arranged on one side of the second surface of the first reflector. The excitation light emitted by the laser is coupled into the ring resonator through the first reflector, and the excitation light propagates in one direction in the ring resonator through the reflection effect of the first surface of each reflector. Since the excitation light propagates in one direction in the ring resonator, the problem of the excitation light being reflected back to the laser after propagation, causing damage to the device, is avoided. The spectrometer detects the Raman scattered light generated by the interaction of the excitation light with the gas to be detected in the ring resonator, and outputs the gas detection result. Because the spectrometer is positioned on the second surface of a second reflector, and its detection optical axis is coaxial with the excitation light reflected from the first surface of the second reflector, this setup allows the spectrometer to detect backscattered Raman light with a higher intensity, improving the signal-to-noise ratio and, consequently, the sensitivity of gas detection. This solution eliminates the need for complex beam focusing elements and filters to improve the signal-to-noise ratio, and prevents the excitation light from interfering with the laser, thereby reducing gas detection costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 A schematic structural diagram of a gas detection device provided in an embodiment of the present application;

[0034] Figure 2 A schematic structural diagram of another gas detection device provided in an embodiment of the present application;

[0035] Figure 3 A schematic structural diagram of another gas detection device provided in an embodiment of the present application;

[0036] Figure 4 A schematic structural diagram of another gas detection device provided in an embodiment of the present application;

[0037] Figure 5 A schematic structural diagram of a gas detection device provided in an embodiment of the present application;

[0038] Figure 6 A schematic structural diagram of another gas detection device provided in an embodiment of the present application;

[0039] Figure 7 A flow chart of a gas detection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] In gas detection schemes based on the Raman effect of laser scattering, multiple reflections of laser light off a spherical mirror within a passive cavity are used to collect and detect Raman scattered light, ultimately enabling detection of gas composition and concentration. However, after multiple reflections, the excitation light can easily pass through the incident light aperture and back into the laser, damaging it. Furthermore, the intensity of the scattered light collected from the side is not ideal, resulting in a low signal-to-noise ratio. The additional introduction of optical devices (such as beam converging elements and filters) not only increases the cost of gas detection but also affects its sensitivity.

[0041] In order to solve the above problems, the inventors have provided a gas detection device and a gas detection method after research. In the proposed gas detection device, the excitation light propagates unidirectionally in the ring resonator, avoiding the problem of device damage caused by the excitation light being reflected back to the laser. In addition, the spectrometer is set on the back side (second surface) of the surface (first surface) of the reflector that reflects the excitation light, and the detection optical axis of the spectrometer is coaxial with the excitation light reflected by the reflector, which can collect more backscattered Raman scattered light, thereby obtaining a higher signal-to-noise ratio. There is no need to set up additional components such as beam converging elements and filters, which reduces the cost of gas detection and can also obtain a higher gas detection sensitivity.

[0042] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0043] An embodiment of the present application provides a gas detection device, which includes: a laser, a ring resonator and a spectrometer. The laser light directly emitted by the laser is called excitation light. The excitation light enters the ring resonator and is reflected multiple times in the cavity by a reflector provided in the ring resonator. In the ring resonator, the excitation light interacts with the gas to be detected in the cavity, thereby generating Raman scattered light. In the embodiment of the present application, the spectrometer provided outside the ring resonator is used to detect the Raman scattered light generated by the interaction between the excitation light and the gas to be detected in the cavity, and thus, the gas detection result can be obtained based on the spectral characteristics of the detected Raman scattered light.

[0044] In the embodiments of the present application, the laser may be a laser with a wavelength or frequency scanning function, such as a semiconductor laser, a fiber laser, a solid-state laser, a gas laser, a quantum cascade laser, a dye laser, etc.

[0045] In the embodiments of the present application, N reflectors are provided within the ring resonator, where N is a positive integer greater than 2. For example, N = 3 or N = 4 indicates that the ring resonator is provided with three or four reflectors. In practical applications, the value of N can be selected and set based on the specific size of the ring resonator and the required signal-to-noise ratio. The value of N is not specifically limited herein.

[0046] In an exemplary implementation, each mirror in the ring resonator has a reflectivity greater than 99.9% for the excitation light and a transmittance greater than 50% for the Raman scattered light. In a specific implementation, a reflective device with the aforementioned reflectivity can be selected based on the wavelength or frequency of the excitation light and the wavelength or frequency of the Raman scattered light.

[0047] In order to facilitate the explanation of the setting position of the spectrometer, the types of mirrors in the ring resonator are first classified. The N mirrors in the ring resonator include a first reflector and N-1 second reflectors. Among them, the reflector closest to the laser of the gas detection device is called the first reflector, and the first reflector first receives the excitation light emitted by the laser. Other reflectors except the first reflector are defined as second reflectors. Each reflector has at least two surfaces: a first surface and a second surface. The first surface and the second surface have different orientations. Assuming that the reflector is a plane reflector, the first surface and the second surface refer to the two surfaces of the plane reflector with the largest area and facing opposite directions. In the ring resonator, the first surfaces of each reflector form a non-zero angle with each other.

[0048] For easier understanding, see Figure 1 This figure is a schematic diagram of the structure of a gas detection device provided in an embodiment of the present application. Figure 1 In the embodiment, the laser 10 emits excitation light, which is first incident on the second surface F2 of the first reflector S1 in the ring resonator 20, then propagates between the second surface F2 and the first surface F1 of the first reflector S1, and is emitted from the first surface F1 of the first reflector S1. Figure 1The gray arrows in the figure show the propagation path of the excitation light. After emitting from the first surface F1 of the first reflector S1, the excitation light enters the second reflector S2, is reflected from the first surface F1 of the second reflector S2 to the first surface F1 of the second reflector S3; from the first surface F1 of the second reflector S3 to the first surface F1 of the second reflector S4; and from the first surface F1 of the second reflector S4 to the first surface F1 of the first reflector S1. After the excitation light is first reflected by the second reflector S4 to the first reflector S1, the subsequent propagation path is the same as the propagation path of the excitation light within the ring resonator 20 described previously, that is, it is reflected multiple times in a "Z" shape between the four reflectors.

[0049] Combine Figure 1 As can be seen in the embodiment of the present application, the excitation light is coupled into the ring resonator 20 through the first reflector S1. When the excitation light resonates with the ring cavity, the laser power within the cavity is significantly enhanced. The excitation light propagates unidirectionally due to reflection from the first surface F1 of each reflector S1 to S4. For example, the first reflector S1 does not return the excitation light back to the second reflector S4; and the second reflector S3 does not return the excitation light back to the second reflector S2.

[0050] Combine Figure 1 As can be seen in the embodiment of the present application, the first surfaces F1 of the reflectors face each other, so that when the excitation light propagates between the reflectors, it is reflected by the first surfaces F1 of the reflectors. The laser 10 is disposed on the side of the second surface F2 of the first reflector S1, and the second surface F2 primarily transmits the excitation light emitted by the laser 10.

[0051] In the embodiment of the present application, the spectrometer 30 is arranged on the second surface side of a second reflector. The second reflector referred to here can be Figure 1 as well as Figure 2 The second reflector S3 shown in FIG. 3 may also refer to Figure 3 The second reflector S2 in, or Figure 4 The second reflector S4 in.

[0052] The spectrometer 30 is arranged on one side of the second surface of the second reflector, but it does not mean that the spectrometer 30 is arranged close to the second surface of the second reflector. Figure 1 For example, there is a certain distance between the spectrometer 30 and the ring resonator, which also indicates that there is a certain spatial distance between the spectrometer 30 and the second reflecting mirror S3. Figure 1 In FIG. 1 , the red arrow indicates the optical transmission path of the Raman scattered light collected by the spectrometer 30 .

[0053] from Figure 1The gray arrows overlapping the red arrows in FIG. 1 and FIG. 2 show the light transmission path of the excitation light between the second reflector S3 and the second reflector S4. The transmission direction is opposite to that of the red arrow. Figure 1 The gray arrow shown represents the optical axis of the excitation light, and the red arrow represents the detection optical axis of the spectrometer 30. Figure 1 The arrangement shown specifically shows that the detection optical axis of the spectrometer 30 is coaxial with the excitation light reflected by the first surface F1 of the second reflector F3.

[0054] Each reflector in the ring resonator 20 transmits both forward-scattered and back-scattered Raman scattered light. Each reflector has only one output port. Raman scattered light emitted by the gas being detected, stimulated by the excitation light, is divided into forward-scattered light and back-scattered light. Two beams with different axes can be output through a single reflector output port.

[0055] The forward scattered light transmitted through the reflector and the excitation light received by the first surface of the reflector are coaxial and in the same direction; the backscattered light transmitted through the reflector and the excitation light reflected by the first surface of the reflector are coaxial and in opposite directions.

[0056] Raman scattered light is scattered in all directions in space, but the scattering intensity is greater in the direction coaxial with the excitation light (forward and back). However, the forward scattered light is consistent with the direction of the laser emission, and the spectrometer will receive serious interference from the excitation light when detecting Raman scattered light. In order to avoid the background interference of the strong excitation light and reduce background noise, backscattered light is selected for signal detection, thereby ensuring the signal-to-noise ratio while eliminating the need for additional filters or complex beam converging elements, and achieving high-sensitivity detection of trace gases. The spectrometer 30 detects the Raman scattered light generated by the interaction of the excitation light with the gas to be detected in the ring resonator 20, and ultimately outputs the gas detection results.

[0057] exist Figures 1 to 4 In the gas detection device shown, the ring resonator 20 includes a first reflector S1 and three second reflectors S2 to S4. Figures 1 to 4 In the ring resonator 20 with four reflectors, the first reflector and one second reflector are arranged in an eight-shaped shape, and the other two second reflectors are arranged in an inverted eight-shaped shape.

[0058] like Figure 3 As shown, the spectrometer 30 is arranged on one side of the second surface of the second reflecting mirror S2; Figure 4 As shown, the spectrometer 30 is arranged on one side of the second surface of the second reflecting mirror S4. Figure 1 In the case of Figure 3In the structure of the gas detection device shown in FIG, the spectrometer 30 can collect backscattered light along the red arrow in the figure, which is coaxial with and opposite to the excitation light reflected by the second reflector S2. Figure 4 In the structure of the gas detection device shown in the figure, the spectrometer 30 can collect backscattered light along the red arrow in the figure, which is coaxial with and opposite to the excitation light reflected by the second reflector S4.

[0059] Figure 5 and Figure 6 In the gas detection device shown, the ring resonator 20 includes a first reflector S1 and two second reflectors (S2 and S5). Figure 5 and Figure 6 In the ring resonator 20 where three reflectors are set, the three reflectors are arranged in an eight-shaped pattern between two of them. Figure 5 In the figure, the spectrometer 30 is arranged on one side of the second surface of the second reflector S5, and can collect backscattered light along the red arrow in the figure, which is coaxial and opposite to the excitation light reflected by the second reflector S5. Figure 6 In the figure, the spectrometer 30 is arranged on one side of the second surface of the second reflector S2, and can collect backscattered light along the red arrow in the figure, which is coaxial and opposite to the excitation light reflected by the second reflector S2.

[0060] Figures 1 to 6 In FIG, the transmission direction of the excitation light is shown by the gray arrow in the corresponding figure; the transmission direction of the backscattered light detected by the spectrometer 30 is shown by the red arrow in the corresponding figure. Figures 1 to 6 In the structure of the gas detection device shown, the excitation light emitted by the laser 10 is not vertically incident on the second surface of the first reflector S1 . Therefore, the first reflector S1 will not reflect vertically to damage the laser 10 .

[0061] In the embodiment of the present application, among the N reflective mirrors provided in the ring resonator 20, the Figures 1 to 6 As shown, all reflectors are plane mirrors, meaning the first and second surfaces of the same reflector are parallel to each other. In other possible implementations, one or more concave reflectors can also be provided within the ring resonator 20. For example, one or more reflectors with concave first surfaces can be provided within the ring resonator 20. The provision of concave reflectors makes the ring resonator a stable cavity.

[0062] In the gas detection device provided in the embodiment of the present application, as described above, a plurality of reflectors are provided in the ring resonator, and these reflectors cooperate with each other to stably propagate the excitation light in one direction in the ring resonator. Figure 1The propagation direction of the light beam when performing gas detection is exemplarily shown. In actual applications, the positions of the mirrors, the laser, and other devices in the gas detection device can be adjusted in advance before gas detection, so as to ensure a high signal-to-noise ratio and sensitivity of gas detection. For this purpose, the present application combines Figure 2 Another gas detection device is provided. Referring to Figure 2 , compared with the device structure shown in Figure 1 , the gas detection device shown in Figure 2 is further provided with a photoelectric detection component 40. The photoelectric detection component 40 is arranged on the second surface side of a mirror, and the detection optical axis of the photoelectric detection component is coaxial with the excitation light received by the first surface of the mirror. As shown in Figure 2 , the photoelectric detection component 40 is arranged on the second surface side of the second mirror S2. Since the detection optical axis of the photoelectric detection component 40 is coaxial with the excitation light received by the first surface of the second mirror S2, the signal detected by the photoelectric detection component 40 can be used to analyze whether the current optical path has been adjusted to the expected effect. For example, if the photoelectric detection component 40 detects chaotic light waves, it indicates that the optical path needs to be adjusted; if the photoelectric detection component 40 detects significant light pulses, it indicates that the optical path has been adjusted perfectly. That is, in the gas detection device provided in the present application, the photoelectric detection component 40 is used to convert the received optical signal into an electrical signal, and the pulse performance of the electrical signal indicates whether the mirrors in the ring resonator 20 need to be adjusted. Here, the adjustment can include height adjustment, and can also involve angle, orientation, and other adjustments. It should be noted that when the optical path is adjusted, the photoelectric detection component 40 in the gas detection device can be detached from the device.

[0063] In the present application, the photoelectric detection component can be selected from a linear array photoelectric sensor, a single-sensor photoelectric detector group, etc. The number, model, and sensitivity of the photoelectric detection component can be reasonably selected according to specific detection requirements, and the number, model, and sensitivity of the photoelectric detection component are not limited here.

[0064] In a possible implementation, the gas detection device further includes an optical path adjustment device. The optical path adjustment device is functionally used in cooperation with the photoelectric detection component 40. Specifically, the optical path adjustment device specifically includes a controller and N sets of adjustment components; the N sets of adjustment components are electrically connected with the controller, and the controller is further electrically connected with the photoelectric detection component. The N sets of adjustment components are matched with N mirrors, and the N mirrors are one-to-one arranged on the N sets of adjustment components. Each set of adjustment components is responsible for adjusting one mirror in the optical path. Each set of adjustment components includes a driving module and a motorized module.

[0065] In a specific implementation, the controller is configured to determine the reflector to be adjusted based on the electrical signal output by the photoelectric detection component, generate a control signal, and transmit the control signal to the adjustment component corresponding to the reflector to be adjusted. For example, the controller may analyze and determine the displacement, direction, angle, etc. of the reflector to be moved based on the electrical signal output by the photoelectric detection component, and generate the control signal accordingly.

[0066] The driving module in the adjustment assembly is configured to drive the motorized module to adjust the reflector to be adjusted according to the control signal. For example, the control signal may include an adjustment method and adjustment parameters (e.g., rotation angle, displacement, etc.). Thus, the motorized module can adjust the position of the reflector according to these parameters.

[0067] The photoelectric detection component in the gas detection device of this application improves the recognizability of the optical path adjustment effect, and can further assist in achieving the sensitivity and accuracy of subsequent gas detection by adjusting the reflector. The optical path adjustment device in the gas detection device increases the convenience of optical path adjustment, reduces the complex steps of manual operation, and achieves the adjustment effect of the automated process.

[0068] Based on the above embodiments, the present application also provides a gas detection method, which can be applied to the gas detection device of any implementation method described in the above embodiments. Figure 7 The flow of the gas detection method is shown. Figure 7 As shown, the gas detection methods include:

[0069] S701, the laser is turned on to emit excitation light.

[0070] The laser can be turned on manually or automatically through automated equipment or control methods. In actual applications, the laser can be turned on in stages. For example, the optical path is first calibrated using a photoelectric detection component, and the signal detected by the photoelectric detection component is used to instruct the reflector in the ring resonator to adjust its position or orientation. At this stage, a laser is needed. Afterwards, when gas detection is required, the laser is used again to generate excitation light. In another possible implementation scenario, the process of calibrating the optical path is carried out continuously with the actual gas detection process, so there is no need to repeatedly turn the laser on and off, and it only needs to be turned on once during the initial calibration. If the calibration is complete and the gas detection device needs to be reused to detect different gases, since the gas detection device does not need to change position frequently, it is only necessary to turn on the laser when performing gas detection, and there is no need to repeat the optical path calibration.

[0071] S702 , the excitation light is coupled into the ring resonant cavity through the first reflector, and propagates unidirectionally in the ring resonant cavity due to the reflection action of the first surface of each reflector.

[0072] In combination with the introduction to the gas detection device in the previous article, the embodiment of the present application applies the gas detection device. When the excitation light enters the ring resonator, due to the setting of the various reflectors in the ring resonator, the excitation light can propagate in one direction and will not return to the laser to affect the performance of the laser.

[0073] S703. The spectrometer detects the Raman scattered light generated by the interaction of the excitation light with the gas to be detected in the ring resonant cavity.

[0074] The spectrometer is arranged on one side of the second surface of a second reflector of the ring resonator, and the detection optical axis of the spectrometer is coaxial with the excitation light reflected by the first surface of the second reflector. The scattering intensity at the position coaxial with the excitation light (forward and backward) is relatively large. However, the forward scattered light is consistent with the direction of the laser emission, and the spectrometer will receive serious interference from the excitation light when detecting Raman scattered light. In order to avoid the background interference of the strong excitation light and reduce the background noise, in the technical solution of the present application, the setting orientation of the spectrometer can detect the backscattered light, avoid the background interference caused by the strong excitation light, and reduce the background noise. While ensuring the signal-to-noise ratio, no additional filters or complex beam converging elements are required, so that high-sensitivity detection of trace gases can be achieved and the cost of devices used for gas detection can be saved.

[0075] S704: The spectrometer outputs a gas detection result based on the detected spectrum.

[0076] The spectrometer detects Raman scattered light generated by the interaction of the excitation light with the gas under test within the ring resonator, generating a Raman spectral signal. By analyzing the Raman spectral signal and generating a Raman spectrum, users can determine gas composition and concentration. Furthermore, the Raman spectrum can be automatically analyzed to output the corresponding composition and concentration detection results.

[0077] In the embodiments of the present application, multiple gases to be detected can be detected simultaneously with a fast response speed, which can meet the detection needs of various fields such as environmental analysis, resource exploration, food safety, life sciences, medicine, and industrial control.

[0078] The above is merely one specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A gas detection device, characterized in that: include: A laser, a ring resonator and a spectrometer; the ring resonator includes N reflectors, each of which includes a first surface and a second surface; The first surfaces of the reflectors form a non-zero angle with each other; N is a positive integer greater than 2, and the N reflectors include a first reflector and a plurality of second reflectors; The laser is arranged on the side of the second surface of the first reflector; the excitation light emitted by the laser is coupled into the ring resonator through the first reflector, and the excitation light propagates in one direction in the ring resonator through the reflection effect of the first surface of each reflector; The spectrometer is arranged on one side of the second surface of the second reflector, and the detection optical axis of the spectrometer is coaxial with the excitation light reflected by the first surface of the second reflector; no beam converging element or filter is provided; The spectrometer is used to detect Raman scattered light generated by the interaction of the excitation light with the gas to be detected in the ring resonant cavity, and output a gas detection result.

2. The device according to claim 1, characterized in that The device further comprises: a photoelectric detection component; The photoelectric detection component is arranged on one side of the second surface of a reflector, and the detection optical axis of the photoelectric detection component is coaxial with the excitation light received by the first surface of the reflector; The photoelectric detection component is used to convert the received optical signal into an electrical signal, and the pulse performance of the electrical signal indicates whether the reflector in the ring resonator needs to be adjusted.

3. The device according to claim 1, characterized in that The ring resonator comprises a first reflector and three second reflectors; The first reflector and one second reflector are arranged in an eight-shaped shape, and the other two second reflectors are arranged in an inverted eight-shaped shape.

4. The device according to claim 1, characterized in that The ring resonator comprises a first reflector and two second reflectors; The first reflector and the two second reflectors are arranged in an "eight" shape.

5. The device according to claim 1, characterized in that Each reflector in the ring resonator transmits forward scattered light and back scattered light in the Raman scattered light; The forward scattered light transmitted through the reflector is coaxial and in the same direction as the excitation light received by the first surface of the reflector; the back scattered light transmitted through the reflector is coaxial and in the opposite direction to the excitation light reflected by the first surface of the reflector.

6. The device according to claim 1, characterized in that The excitation light emitted by the laser is non-vertically incident on the second surface of the first reflector.

7. The device according to claim 1, characterized in that The first surface of at least one reflector in the ring resonator is a concave surface.

8. The device according to claim 1, characterized in that The reflectivity of each reflector in the ring resonant cavity to the excitation light is greater than 99.9%, and the transmittance to the Raman scattered light is greater than 50%.

9. The device according to claim 2, characterized in that Also includes: Optical path adjustment device; The optical path adjustment device specifically includes: a controller and N sets of adjustment components; the N sets of adjustment components are electrically connected to the controller, and the controller is also electrically connected to the photoelectric detection component; the N reflectors are mounted one-to-one on the N sets of adjustment components; each set of adjustment components includes a drive module and a motor module; The controller is configured to determine the reflector to be adjusted and generate a control signal based on the electrical signal output by the photoelectric detection component, and send the control signal to the adjustment component corresponding to the reflector to be adjusted; The driving module in the adjusting component is used to drive the motorized module to move according to the instruction of the control signal, so as to adjust the reflector to be adjusted.

10. A gas detection method, characterized in that: The method is applied to the gas detection device according to any one of claims 1 to 9, and the method comprises: The laser emits excitation light after being turned on; The excitation light is coupled into the ring resonator through the first reflector, and propagates in one direction in the ring resonator through the reflection effect of the first surface of each reflector; The spectrometer detects Raman scattered light generated by the interaction of the excitation light with the gas to be detected in the ring resonator; The spectrometer outputs a gas detection result according to the detected spectrum.

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