Signal detection system

Abstract

The invention discloses a signal detection system, and relates to the technical field of laser detection, and the signal detection system comprises a light source which outputs laser of a first wavelength; the first optical mirror and the second optical mirror are arranged oppositely, the first optical mirror transmits the laser of the first wavelength and reflects the laser of the first wavelength and the laser of the second wavelength to the second optical mirror, and the second optical mirror reflects the laser of the first wavelength and the laser of the second wavelength to the first optical mirror; the frequency doubling crystal is used for converting the laser with the first wavelength penetrating through the first optical lens into laser with a second wavelength, and the laser with the second wavelength is circularly reflected between the first optical lens and the second optical lens and excites a sample in the sample bin to generate a first sample signal; a part of the laser with the first wavelength penetrating through the frequency doubling crystal is circularly reflected between the first optical lens and the second optical lens and excites a sample in the sample bin to generate a second sample signal; the signal collecting device is used for collecting and analyzing the first sample signal and / or the second sample signal.

Description

Technical Field

[0001] The present application relates to the field of laser detection technology, and in particular, to a signal detection system. Background Art

[0002] With the continuous development of laser technology, Raman detection technology and its application scope using laser as excitation source are becoming more and more extensive. The detection objects in practical applications are diverse, and solids, liquids and gases can all use laser as excitation source to detect Raman signals.

[0003] Existing Raman and fluorescence detection systems mostly use a single-path laser point excitation method, that is, the laser is focused on the sample to be tested, and then the fluorescence or scattering (Raman, Rayleigh) signal generated by the laser excitation on the sample is collected through the collection optical path to the spectral signal measurement device for detection.

[0004] However, the current method can only achieve single-channel laser excitation of samples, and can only obtain Raman signals at a single wavelength for quantitative analysis of samples. For some samples, the excitation light wavelength may be more sensitive to fluorescence interference, and its applicability is insufficient.

[0005] This section is intended to provide a background or context to the embodiments of the present application as recited in the claims. No admission is made that the description herein is prior art by inclusion in this section. Summary of the invention

[0006] The purpose of this application is to provide a signal detection system that can at least solve one of the above-mentioned technical problems existing in the current signal detection system.

[0007] The present application provides a signal detection system, including: A light source, outputting laser light of a first wavelength; A first optical mirror and a second optical mirror are arranged opposite to each other, the first optical mirror transmits the laser light of the first wavelength, and the first optical mirror reflects the laser light of the first wavelength and the laser light of the second wavelength to the second optical mirror, and the second optical mirror reflects the laser light of the first wavelength and the laser light of the second wavelength to the first optical mirror; a frequency doubling crystal, arranged between the first optical mirror and the second optical mirror, converting the laser light of the first wavelength transmitted through the first optical mirror into laser light of a second wavelength, so that the laser light of the second wavelength is cyclically reflected between the first optical mirror and the second optical mirror and excites the sample in the sample chamber to generate a first sample signal, wherein the sample chamber is arranged between the frequency doubling crystal and the second optical mirror, and a portion of the laser light of the first wavelength transmitted through the frequency doubling crystal is cyclically reflected between the first optical mirror and the second optical mirror and excites the sample in the sample chamber to generate a second sample signal; A signal collection device collects and analyzes the first sample signal and / or the second sample signal generated by the sample.

[0008] In some embodiments, the first optical mirror and the second optical mirror are respectively plano-concave mirrors, the surface of the first optical mirror facing the second optical mirror is a concave surface, and the surface of the second optical mirror facing the first optical mirror is a concave surface; wherein the flat surface of the first optical mirror is coated with a first wavelength laser anti-reflection film, and the concave surface is coated with a second wavelength laser reflective film; the concave surface of the second optical mirror is coated with a first wavelength laser reflective film and a second wavelength laser reflective film.

[0009] In some embodiments, the transmittance of the first wavelength laser anti-reflection film to the first wavelength laser is 60% to 80%; the reflectivity of the first wavelength laser reflective film to the first wavelength laser is above 99%; and the reflectivity of the second wavelength laser reflective film to the second wavelength laser is above 99%.

[0010] In some embodiments, a first convex lens is further included, and the first convex lens is disposed between the frequency doubling crystal and the sample chamber, and the first convex lens converges the laser light of the first wavelength and the laser light of the second wavelength that pass through the frequency doubling crystal to the sample chamber.

[0011] In some embodiments, an optical component is further included between the light source and the first optical mirror, and the optical component guides the laser light of the first wavelength output by the light source into the first optical mirror.

[0012] In some embodiments, the optical component includes a half-wave plate and a second convex lens; wherein the half-wave plate is arranged on the optical path of the laser of the first wavelength output by the light source, and the half-wave plate adjusts the polarization direction of the laser of the first wavelength output by the light source to achieve phase matching with the frequency doubling crystal; the second convex lens is arranged on the optical path of the output light of the half-wave plate, and converges the laser adjusted by the half-wave plate to the first optical mirror / the frequency doubling crystal / between the first optical mirror and the frequency doubling crystal.

[0013] In some embodiments, the optical component also includes a Faraday optical isolator arranged between the light source and the half-wave plate, and the Faraday optical isolator isolates the first wavelength laser reflected by the second convex lens, the first optical mirror, the frequency doubling crystal and the second optical mirror, thereby preventing the reflected first wavelength laser from entering the light source.

[0014] In some embodiments, the signal collecting device includes a first sub-collecting device and a second sub-collecting device, the first sub-collecting device collects and analyzes a first sample signal generated by the sample, and the second sub-collecting device collects and analyzes a second sample signal generated by the sample.

[0015] In some embodiments, the first sub-collection device includes a first Edge filter, a first spectrometer, and a first CCD camera sequentially arranged along a first straight line, wherein the first straight line is perpendicular to the line connecting the first optical mirror and the second optical mirror, and one side of the first Edge filter is arranged toward the sample chamber; wherein the first Edge filter filters the light signal of the first wavelength band from the sample chamber and allows the light signal of the second wavelength band from the sample chamber to pass; the first spectrometer collects the first sample signal from the light signal of the second wavelength band by line integration and analyzes the spectral information of the first sample signal; the first CCD camera converts the spectral information of the first sample signal into a first electrical signal; The second sub-collection device includes a second Edge filter, a second spectrometer and a second CCD camera which are sequentially arranged along a second straight line, wherein the second straight line is perpendicular to the line connecting the first optical mirror and the second optical mirror, and one side of the second Edge filter is arranged toward the sample chamber; wherein the second Edge filter filters the light signal of the third band from the sample chamber and allows the light signal of the fourth band from the sample chamber to pass; the second spectrometer collects the second sample signal from the light signal of the fourth band by line integration and analyzes the spectral information of the second sample signal; and the second CCD camera converts the spectral information of the second sample signal into a second electrical signal.

[0016] In some embodiments, the first sub-collection device further includes a first collimating lens and a first focusing lens disposed on the first straight line; wherein the first collimating lens is disposed between the sample chamber and the first Edge filter, and collects light signals in the sample chamber and converts the light signals into parallel light; the first focusing lens is disposed between the first Edge filter and the first spectrometer, and the first focusing lens converges the light signals of the second wavelength band passing through the first Edge filter onto the slit of the first spectrometer; The second sub-collecting device also includes a second collimating lens and a second focusing lens arranged on the second straight line; wherein the second collimating lens is arranged between the sample chamber and the second Edge filter, and the second collimating lens collects the light signal in the sample chamber and converts the light signal into parallel light; the second focusing lens is arranged between the second Edge filter and the second spectrometer, and the second focusing lens converges the light signal of the fourth band passing through the second Edge filter onto the slit of the second spectrometer.

[0017] In some embodiments, the first sub-collecting device further comprises a first plano-concave mirror disposed opposite to the first collimating lens, the first plano-concave mirror and the first collimating lens are respectively located on both sides of the sample chamber, and the first plano-concave mirror collects light signals in the sample chamber and outputs the collected light signals to the first collimating lens; The second sub-collecting device also includes a second plano-concave mirror arranged opposite to the second collimating lens, the second plano-concave mirror and the second collimating lens are respectively located on both sides of the sample chamber, and the second plano-concave mirror collects the light signal in the sample chamber and outputs the collected light signal to the second collimating lens.

[0018] In some embodiments, the second optical mirror, the first plano-concave mirror, the second plano-concave mirror, the first collimating lens, and the second collimating lens are cofocused at the center of the sample chamber.

[0019] The signal detection system provided in the embodiment of the present application can use one light source to excite the sample with excitation light of different wavelengths, and collect the excited sample signals, so as to obtain the sample signals of one sample at two wavelengths at the same time. In this way, more chemical information about the sample can be obtained by comparing the sample signals at the two wavelengths, or, for some samples that are sensitive to fluorescence interference at a certain excitation light wavelength, accurate sample characteristics can be obtained by analyzing the sample signals obtained by another excitation light. In addition, the cyclic reflection of the laser in the resonant cavity realizes the doubling of the effective excitation power of the laser and a significant increase in the number of excitations, thereby multiplying the first sample signal and the second sample signal that can be obtained by an order of magnitude. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 creative work.

[0021] Figure 1 A schematic diagram of the structure of a signal detection system provided in an embodiment of the present application.

[0022] Figure 2 This is a front view of a signal detection system provided in an embodiment of the present application.

[0023] Figure 3 A top view of a signal detection system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] With reference to the following description and accompanying drawings, the specific embodiments of the present application are disclosed in detail, indicating the way in which the principles of the present application can be adopted. It should be understood that the embodiments of the present application are not limited in scope. Within the scope of the spirit and clauses of the appended claims, the embodiments of the present application include many changes, modifications and equivalents.

[0026] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0027] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components.

[0028] In order to solve at least one of the above problems existing in the prior art, the present application provides a signal detection system, such as Figure 1 As shown, the signal detection system 01 includes: A light source 10 outputs a laser beam of a first wavelength; A first optical mirror 20 and a second optical mirror 30 are arranged opposite to each other, wherein the first optical mirror 20 transmits the laser light of the first wavelength, and the first optical mirror 20 reflects the laser light of the first wavelength and the laser light of the second wavelength toward the second optical mirror 30, and the second optical mirror 30 reflects the laser light of the first wavelength and the laser light of the second wavelength toward the first optical mirror 20; A frequency doubling crystal 40 is arranged between the first optical mirror 20 and the second optical mirror 30, and converts the laser light of the first wavelength transmitted through the first optical mirror 20 into laser light of a second wavelength, so that the laser light of the second wavelength is circularly reflected between the first optical mirror 20 and the second optical mirror 30 and excites the sample 02 in the sample chamber (omitted in the figure) to generate a first sample signal, wherein the sample chamber is arranged between the frequency doubling crystal 40 and the second optical mirror 30, and a portion of the laser light of the first wavelength transmitted through the frequency doubling crystal 40 is circularly reflected between the first optical mirror 20 and the second optical mirror 30 and excites the sample 02 in the sample chamber to generate a second sample signal; The signal collecting device 50 collects and analyzes the sample 02 to generate a first sample signal and / or a second sample signal.

[0029] Specifically, the light source 10 may be a pulsed laser; the first optical mirror 20 and the second optical mirror 30 being arranged opposite to each other means that the first optical mirror 20 and the second optical mirror 30 are arranged face to face, and their center lines are aligned. The first optical mirror 20 can both transmit and reflect the laser light of the first wavelength, and in addition, the first optical mirror 20 also reflects the laser light of the second wavelength. The second optical mirror 30 can both reflect the laser light of the first wavelength and the laser light of the second wavelength. The first sample signal / the second sample signal may refer to a Raman signal or a fluorescence signal, etc.

[0030] The signal detection system provided in the embodiment of the present application can use a light source 10 to excite the sample 02 with excitation light of different wavelengths, and collect the excited sample signals, so as to obtain sample signals of a sample 02 at two wavelengths at the same time. In this way, more chemical information about the sample 02 can be obtained by comparing the sample signals at the two wavelengths, or, for some samples 02 that are sensitive to fluorescence interference at a certain excitation light wavelength, accurate sample characteristics can be obtained by analyzing the sample signals obtained from another excitation light; in addition, the cyclic reflection of the laser in the resonant cavity realizes the doubling of the effective excitation power of the laser and a significant increase in the number of excitations, thereby multiplying the first sample signal and the second sample signal that can be obtained by an order of magnitude.

[0031] like Figure 1 As shown, in some embodiments, the first optical mirror 20 and the second optical mirror 30 are respectively plano-concave mirrors, the surface of the first optical mirror 20 facing the second optical mirror 30 is a concave surface, and the surface of the second optical mirror 30 facing the first optical mirror 20 is a concave surface; wherein, the flat surface of the first optical mirror 20 is coated with a first wavelength laser anti-reflection film, and the concave surface is coated with a second wavelength laser reflective film; the concave surface of the second optical mirror 30 is coated with a first wavelength laser reflective film and a second wavelength laser reflective film.

[0032] In some embodiments, the transmittance of the first wavelength laser anti-reflection film to the first wavelength laser is 60% to 80%, and accordingly, the reflectivity of the first wavelength laser anti-reflection film to the first wavelength laser is approximately the difference obtained by subtracting the transmittance from 100%; for example, if the transmittance of the first wavelength laser transmissive film to the first wavelength laser is 70%, then the reflectivity of the first wavelength laser transmissive film to the first wavelength laser is approximately 30%. In this way, the power of the first wavelength laser and the power of the second wavelength laser can be relatively balanced in the resonant cavity.

[0033] In some embodiments, the reflectivity of the first wavelength laser reflective film to the first wavelength laser is above 99%; the reflectivity of the second wavelength laser reflective film to the second wavelength laser is above 99%. In this way, the concave surface of the first optical mirror 20 can reflect the second wavelength laser, and the concave surface of the second optical mirror 30 can reflect the first wavelength laser and the second wavelength laser.

[0034] like Figure 1 As shown, in some embodiments, the signal detection system 01 also includes a first convex lens 60, which is disposed between the frequency doubling crystal 40 and the sample chamber, and the first convex lens 60 converges the laser of the first wavelength and the laser of the second wavelength passing through the frequency doubling crystal 40 to the sample chamber.

[0035] like Figure 1 As shown, in some embodiments, the signal detection system 01 further includes an optical component 70 disposed between the light source 10 and the first optical mirror 20 , and the optical component 70 guides the laser light of the first wavelength output by the light source 10 into the first optical mirror 20 .

[0036] like Figure 1 As shown, in some embodiments, the optical component 70 includes a half-wave plate 71 and a second convex lens 72; wherein the half-wave plate 71 is arranged on the optical path of the laser light of the first wavelength output by the light source 10, and the half-wave plate 71 adjusts the polarization direction of the laser light of the first wavelength output by the light source 10 to achieve phase matching with the frequency doubling crystal 40; the second convex lens 72 is arranged on the optical path of the output light of the half-wave plate 71, and converges the laser light adjusted by the half-wave plate 71 to the first optical mirror 20 / the frequency doubling crystal 40 / between the first optical mirror 20 and the frequency doubling crystal 40. Specifically, the second convex lens 72 can converge the laser light adjusted by the half-wave plate 71 to the first optical mirror 20; or converge the laser light adjusted by the half-wave plate 71 to the frequency doubling crystal 40; or converge the laser light adjusted by the half-wave plate 71 to between the first optical mirror 20 and the frequency doubling crystal 40, for example, to the center position between the first optical mirror 20 and the frequency doubling crystal 40.

[0037] like Figure 1 As shown, in some embodiments, the optical component 70 also includes a Faraday optical isolator 73 arranged between the light source 10 and the half-wave plate 71, and the Faraday optical isolator 73 isolates the first wavelength laser reflected by the second convex lens 72, the first optical mirror 20, the frequency doubling crystal 40 and the second optical mirror 30, thereby preventing the reflected first wavelength laser from entering the light source 10.

[0038] like Figure 1 As shown, in some embodiments, the signal collecting device 50 includes a first sub-collecting device 51 and a second sub-collecting device 52, the first sub-collecting device 51 collects and analyzes the first sample signal generated by the sample 02, and the second sub-collecting device 52 collects and analyzes the second sample signal generated by the sample 02.

[0039] like Figure 1 and Figure 2 As shown, in some embodiments, the first sub-collection device 51 includes a first Edge filter 511, a first spectrometer 512, and a first CCD camera 513 arranged in sequence along a first straight line, wherein the first straight line is perpendicular to the line connecting the first optical mirror 20 and the second optical mirror 30, and one side of the first Edge filter 511 is arranged toward the sample chamber; wherein the first Edge filter 511 filters out the light signal of the first wavelength band from the sample chamber, and allows the light signal of the second wavelength band from the sample chamber to pass; the first spectrometer 512 collects the first sample signal in the light signal of the second wavelength band by line integration and analyzes the spectral information of the first sample signal; the first CCD camera 513 converts the spectral information of the first sample signal into a first electrical signal. It can be understood that the first sample signal is contained in the light signal of the second wavelength band. For example, when the first wavelength laser is a 1064nm laser and the second wavelength laser is a 532nm laser, the first Edge filter 511 can be a 535nm high-pass filter, which is used to filter out light signals below 535nm from the sample chamber and allow light signals above 535nm to pass through. Then the first spectrometer 512 collects the first sample signal from the light signals above 535nm by line integration and analyzes the spectral information of the first sample signal.

[0040] Similar, such as Figure 1 and Figure 3As shown, the second sub-collection device 52 includes a second Edge filter 521, a second spectrometer 522 and a second CCD camera 523 arranged in sequence along a second straight line, wherein the second straight line is perpendicular to the line connecting the first optical mirror 20 and the second optical mirror 30, and one side of the second Edge filter 521 is arranged toward the sample chamber; wherein the second Edge filter 521 filters out the light signal of the third band from the sample chamber, and allows the light signal of the fourth band from the sample chamber to pass; the second spectrometer 522 collects the second sample signal in the light signal of the fourth band by line integration and analyzes the spectral information of the second sample signal; the second CCD camera 523 converts the spectral information of the second sample signal into a second electrical signal. It can be understood that the second sample signal is contained in the light signal of the fourth band. For example, when the first wavelength laser is a 1064nm laser and the second wavelength laser is a 532nm laser, the second Edge filter 521 can be a 1066nm high-pass filter, which is used to filter out light signals below 1066nm from the sample chamber and allow light signals above 1066nm to pass through. Then the second spectrometer 522 collects the second sample signal from the light signals above 1066nm by line integration and analyzes the spectral information of the second sample signal.

[0041] like Figure 1 and Figure 2 As shown, in some embodiments, the first sub-collecting device 51 also includes a first collimating lens 514 and a first focusing lens 515 arranged on the first straight line; wherein, the first collimating lens 514 is arranged between the sample chamber and the first Edge filter 511, and the first collimating lens 514 collects the light signal in the sample chamber and converts the light signal into parallel light; the first focusing lens 515 is arranged between the first Edge filter 511 and the first spectrometer 512, and the first focusing lens 515 converges the light signal of the second band passing through the first Edge filter 511 onto the slit 512a of the first spectrometer 512.

[0042] Similar, such as Figure 1 and Figure 3As shown, the second sub-collecting device 52 also includes a second collimating lens 524 and a second focusing lens 525 arranged on the second straight line; wherein the second collimating lens 524 is arranged between the sample chamber and the second Edge filter 521, and the second collimating lens 524 collects the light signal in the sample chamber and converts the light signal into parallel light; the second focusing lens 525 is arranged between the second Edge filter 521 and the second spectrometer 522, and the second focusing lens 525 converges the light signal of the fourth band passing through the second Edge filter 521 onto the slit 522a of the second spectrometer 522.

[0043] like Figure 1 and Figure 2 As shown, in some embodiments, the first sub-collecting device 51 also includes a first plano-concave mirror 516 arranged opposite to the first collimating lens 514, and the first plano-concave mirror 516 and the first collimating lens 514 are respectively located on both sides of the sample chamber, and the first plano-concave mirror 516 collects the light signal in the sample chamber and outputs the collected light signal to the first collimating lens 514.

[0044] Similar, such as Figure 1 and Figure 3 As shown, the second sub-collecting device 52 also includes a second plano-concave mirror 526 arranged opposite to the second collimating lens 524, and the second plano-concave mirror 526 and the second collimating lens 524 are respectively located on both sides of the sample chamber, and the second plano-concave mirror 526 collects the light signal in the sample chamber and outputs the collected light signal to the second collimating lens 524.

[0045] In order to better understand the present application, the signal detection system provided by the present application is described in detail below through a specific embodiment.

[0046] like Figures 1 to 3 As shown, the signal detection system 01 provided in this embodiment includes an excitation optical path 1, a collection optical path 2 and a collection optical path 3. The collection optical path 2 and the collection optical path 3 are arranged in a spatial orthogonal shape.

[0047] The excitation optical path 1 is provided with a light source 10 (specifically a pulsed laser), a Faraday optical isolator 73, a half-wave plate (1 / 2λ wave plate) 71, a second convex lens 72, a first optical mirror (specifically a plano-concave mirror) 20, a frequency doubling crystal 40, a first convex lens 60, and a second optical mirror (specifically a plano-concave mirror) 30.

[0048] The collecting light path 2 is provided with a first plano-concave mirror 516 , a first collimating lens 514 , a first edge filter 511 , a first focusing lens 515 , a first spectrometer 512 , and a first CCD camera 513 .

[0049] The collecting light path 3 is provided with a second plano-concave mirror 526 , a second collimating lens 524 , a second edge filter 521 , a second focusing lens 525 , a second spectrometer 522 , and a second CCD camera 523 .

[0050] Take the 1064nm pulse laser pumping frequency-doubled output 532nm laser for excitation as an example, where: Excitation optical path 1: The light source 10 is a 1064nm laser. The output laser passes through the Faraday optical isolator 73, the half-wave plate 71, the second convex lens 72, and the first optical mirror 20, and then focuses on the frequency doubling crystal 40 to generate a 532nm laser. The Faraday optical isolator 73 is used to isolate the 1064nm laser reflected by the second convex lens 72, the first optical mirror 20, the frequency doubling crystal 40, the first convex lens 60, and the second optical mirror 30 from entering the laser to avoid damage to the laser. The half-wave plate 71 is used to adjust the polarization direction of the laser to achieve phase matching with the frequency doubling crystal 40 to achieve the best frequency doubling efficiency. The second convex lens 72 is used to focus the 1064nm laser onto the frequency doubling crystal 40 in the resonant cavity composed of the first optical mirror 20 and the second optical mirror 30. The first optical mirror 20 is coated on both sides: the flat surface is coated with an anti-reflection film with a transmittance of 70% for 1064nm laser, and the concave surface is coated with a 532nm laser high-reflection film for 70% transmission of 1064nm laser, while the doubled frequency 532nm laser is highly reflected. The first convex lens 60 converges the 532nm laser generated by the 1064nm laser through the doubled frequency crystal 40 and the remaining 1064nm laser into the sample chamber. The second optical mirror 30 is coated with a double-layer film: the concave surface is coated with a 532nm laser high-reflection film and a 1064nm laser high-reflection film. The second optical mirror 30 and the first optical mirror 20 form a 532nm laser and 1064nm laser resonant cavity, so that the pumped 1064nm laser and the 532nm laser generated by the doubled frequency crystal 40 can circulate almost infinitely in the resonant cavity and continuously cyclically excite the sample 02, thereby doubling the sample signal.

[0051] The collecting optical path 2 is a 532nm laser excited sample signal collecting optical path: the first plano-concave mirror 516 is a collecting reflector, which further collects the sample signal and outputs it to the signal collecting end. The first collimating lens 514 is used to convert the excited sample signal into parallel light. The first focusing lens 515 is used to converge the sample signal onto the slit 512a of the first spectrometer 512. The first Edge filter 511 is a 535nm high-pass filter, which is used to filter out stray light below 535nm doped in the collected sample signal, so that the excited sample effective signal (first sample signal) is high-pass. The first spectrometer 512 and the first CCD camera 513 form a signal collecting device for splitting, collecting and analyzing the signal.

[0052] The collecting optical path 3 is a 1064nm laser excitation sample signal collecting optical path: the second plano-concave mirror 526 is a collecting reflector, which further collects the sample signal and outputs it to the signal collecting end. The second collimating lens 524 is used to convert the excited sample signal into parallel light. The second focusing lens 525 is used to converge the sample signal onto the slit 522a of the second spectrometer 522. The second Edge filter 521 is a 1066nm high-pass filter, which is used to filter out stray light below 1066nm doped in the collected sample signal, so that the excited sample effective signal (second sample signal) is high-pass. The second spectrometer 522 and the second CCD camera 523 form a signal collecting device for splitting, collecting and analyzing the signal.

[0053] like Figure 1 As shown, in some embodiments, the second optical mirror 30, the first plano-concave mirror 516, the second plano-concave mirror 526, the first collimating lens 514, and the second collimating lens 524 are cofocused at the center of the sample chamber.

[0054] like Figure 1 As shown, in some embodiments, the optical axis of the excitation light path 1, the optical axis of the collection light path 2, and the optical axis of the collection light path 3 are spatially orthogonally distributed.

[0055] The signal detection system provided in this embodiment can realize the power doubling of the 532nm laser generated by the frequency doubling of the 1064nm laser in the resonant cavity through resonance in the cavity: stability is achieved when the power of the 532nm laser generated by the frequency doubling of the 1064nm laser is the same as the loss in the cavity, and the power of the 532nm laser in the cavity can be doubled by an order of magnitude by increasing the 1064nm pump power and the frequency doubling efficiency, and controlling the loss in the cavity (reflection and diffraction loss of the device in the cavity and absorption and scattering loss of the sample).

[0056] Moreover, this embodiment uses a laser to realize linear excitation of the sample with excitation light of different wavelengths, and collects the excitation sample signals separately, so that the Raman signals of a sample at two wavelengths can be obtained at the same time. By comparing the Raman signals at two wavelengths, more chemical information about the sample can be obtained. In addition, the sample signal can be collected by line integral collection to further enhance the signal intensity. In other words, this embodiment uses a dual laser to perform linear excitation on the sample to be tested, and the Raman and fluorescence signal spectra generated by the excitation are respectively multiplied and collected by line integral collection, and the energy multiplication of the excitation light is achieved by gain enhancement in the resonant cavity.

[0057] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. The orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In the description of this specification, the description of reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

[0059] Specific embodiments are used in this application to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core idea of ​​this application. At the same time, for those skilled in the art, according to the idea of ​​this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on this application.

Claims

1. A signal detection system, characterized in that: include: A light source, outputting laser light of a first wavelength; A first optical mirror and a second optical mirror are arranged opposite to each other, the first optical mirror transmits the laser light of the first wavelength, and the first optical mirror reflects the laser light of the first wavelength and the laser light of the second wavelength to the second optical mirror, and the second optical mirror reflects the laser light of the first wavelength and the laser light of the second wavelength to the first optical mirror; a frequency doubling crystal, arranged between the first optical mirror and the second optical mirror, converting the laser light of the first wavelength transmitted through the first optical mirror into laser light of a second wavelength, so that the laser light of the second wavelength is cyclically reflected between the first optical mirror and the second optical mirror and excites the sample in the sample chamber to generate a first sample signal, wherein the sample chamber is arranged between the frequency doubling crystal and the second optical mirror, and a portion of the laser light of the first wavelength transmitted through the frequency doubling crystal is cyclically reflected between the first optical mirror and the second optical mirror and excites the sample in the sample chamber to generate a second sample signal; A signal collection device collects and analyzes the first sample signal and / or the second sample signal generated by the sample.

2. The signal detection system according to claim 1, characterized in that: The first optical mirror and the second optical mirror are respectively plano-concave mirrors, the surface of the first optical mirror facing the second optical mirror is a concave surface, and the surface of the second optical mirror facing the first optical mirror is a concave surface; wherein, The flat surface of the first optical mirror is coated with a first wavelength laser anti-reflection film, and the concave surface is coated with a second wavelength laser reflective film; The concave surface of the second optical mirror is coated with a first wavelength laser reflection film and a second wavelength laser reflection film.

3. The signal detection system according to claim 2, characterized in that: The transmittance of the first wavelength laser antireflection film to the first wavelength laser is 60% to 80%; The reflectivity of the first wavelength laser reflective film to the first wavelength laser is above 99%; The reflectivity of the second wavelength laser reflective film to the second wavelength laser is greater than 99%.

4. The signal detection system according to claim 1 or 2, characterized in that: It also includes a first convex lens, which is arranged between the frequency doubling crystal and the sample chamber, and the first convex lens converges the laser light of the first wavelength and the laser light of the second wavelength that pass through the frequency doubling crystal to the sample chamber.

5. The signal detection system according to claim 1, characterized in that: The optical component is arranged between the light source and the first optical mirror, and the optical component guides the laser light of the first wavelength output by the light source into the first optical mirror.

6. The signal detection system according to claim 5, characterized in that: The optical component includes a half-wave plate and a second convex lens; wherein, The half-wave plate is arranged on the optical path of the laser light of the first wavelength output by the light source, and the half-wave plate adjusts the polarization direction of the laser light of the first wavelength output by the light source to achieve phase matching with the frequency doubling crystal; The second convex lens is arranged on the optical path of the output light of the half-wave plate, and converges the laser light adjusted by the half-wave plate to the first optical mirror / the frequency doubling crystal / between the first optical mirror and the frequency doubling crystal.

7. The signal detection system according to claim 6, characterized in that: The optical component also includes a Faraday optical isolator arranged between the light source and the half-wave plate, and the Faraday optical isolator isolates the laser of the first wavelength reflected by the second convex lens, the first optical mirror, the frequency doubling crystal and the second optical mirror, thereby preventing the reflected laser of the first wavelength from entering the light source.

8. The signal detection system according to claim 1 or 2, characterized in that: The signal collecting device includes a first sub-collecting device and a second sub-collecting device. The first sub-collecting device collects and analyzes a first sample signal generated by the sample, and the second sub-collecting device collects and analyzes a second sample signal generated by the sample.

9. The signal detection system according to claim 8, characterized in that: The first sub-collection device comprises a first Edge filter, a first spectrometer and a first CCD camera which are sequentially arranged along a first straight line, wherein the first straight line is perpendicular to a line connecting the first optical mirror and the second optical mirror, and one side of the first Edge filter is arranged toward the sample chamber; wherein the first Edge filter filters out light signals of a first wavelength band from the sample chamber and allows light signals of a second wavelength band from the sample chamber to pass; the first spectrometer collects the first sample signal from the light signals of the second wavelength band by means of line integration and analyzes the spectral information of the first sample signal; the first CCD camera converts the spectral information of the first sample signal into a first electrical signal; The second sub-collection device includes a second Edge filter, a second spectrometer and a second CCD camera which are sequentially arranged along a second straight line, wherein the second straight line is perpendicular to the line connecting the first optical mirror and the second optical mirror, and one side of the second Edge filter is arranged toward the sample chamber; wherein the second Edge filter filters out the light signal of the third band from the sample chamber and allows the light signal of the fourth band from the sample chamber to pass; the second spectrometer collects the second sample signal from the light signal of the fourth band by line integration and analyzes the spectral information of the second sample signal; and the second CCD camera converts the spectral information of the second sample signal into a second electrical signal.

10. The signal detection system according to claim 9, characterized in that: The first sub-collection device further includes a first collimating lens and a first focusing lens arranged on the first straight line; wherein the first collimating lens is arranged between the sample chamber and the first Edge filter, and collects the light signal in the sample chamber and converts the light signal into parallel light; the first focusing lens is arranged between the first Edge filter and the first spectrometer, and the first focusing lens converges the light signal of the second wavelength band passing through the first Edge filter onto the slit of the first spectrometer; The second sub-collecting device also includes a second collimating lens and a second focusing lens arranged on the second straight line; wherein the second collimating lens is arranged between the sample chamber and the second Edge filter, and the second collimating lens collects the light signal in the sample chamber and converts the light signal into parallel light; the second focusing lens is arranged between the second Edge filter and the second spectrometer, and the second focusing lens converges the light signal of the fourth band passing through the second Edge filter onto the slit of the second spectrometer.

11. The signal detection system according to claim 10, characterized in that: The first sub-collecting device further includes a first plano-concave mirror disposed opposite to the first collimating lens, the first plano-concave mirror and the first collimating lens are respectively located on two sides of the sample chamber, and the first plano-concave mirror collects light signals in the sample chamber and outputs the collected light signals to the first collimating lens; The second sub-collecting device also includes a second plano-concave mirror arranged opposite to the second collimating lens, the second plano-concave mirror and the second collimating lens are respectively located on both sides of the sample chamber, and the second plano-concave mirror collects the light signal in the sample chamber and outputs the collected light signal to the second collimating lens.

12. The signal detection system according to claim 11, characterized in that: The second optical mirror, the first plano-concave mirror, the second plano-concave mirror, the first collimating lens and the second collimating lens are cofocused at the center of the sample chamber.

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