CN103837520A - Optic travelling wave cavity enhanced laser raman gas concentration detection device - Google Patents

Abstract

Translated fromChinese

本发明涉及一种光学行波腔增强激光拉曼气体浓度检测装置，将腔增强技术与激光拉曼检测技术相结合，采用光学行波无源腔，由单一曲面环形内反射镜构成高精细度腔，利用激光器出射光束斜入射腔增强原理，是的光束在腔内多次反射以行波形式传播，激光束经过区域中的被测气体发生拉曼散射，拉曼散射光经滤波片和光束会聚后，被光电检测部件收集，光电检测部件检测被测气体的特征拉曼频移和对应拉曼峰强度，得到被测气体浓度。装置整体的结构简单，对机械定位要求低，稳定性好、可靠性高的特点，同时提高了检测装置的抗干扰性；可实时在线进行测量，提高过程的动态信息，可以测量除了惰性气体外几乎所有气体的浓度；灵敏度高；响应速度快，响应时间快。

The invention relates to an optical traveling wave cavity-enhanced laser Raman gas concentration detection device, which combines the cavity enhancement technology with the laser Raman detection technology, adopts an optical traveling wave passive cavity, and is composed of a single curved surface annular inner reflector to form a high-precision Cavity, using the principle of laser output beam oblique incident cavity enhancement, the beam is reflected multiple times in the cavity and propagates in the form of traveling waves, the laser beam passes through the measured gas in the area to undergo Raman scattering, and the Raman scattered light passes through the filter and the beam After converging, it is collected by the photoelectric detection part, which detects the characteristic Raman frequency shift of the gas to be measured and the corresponding Raman peak intensity to obtain the concentration of the gas to be measured. The overall structure of the device is simple, with low requirements for mechanical positioning, good stability and high reliability, and at the same time improves the anti-interference performance of the detection device; real-time online measurement can improve the dynamic information of the process, and can measure other than inert gas The concentration of almost all gases; high sensitivity; fast response, fast response time.

Description

A kind of optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus

Technical field

The present invention relates to a kind of gas concentration and detect, particularly a kind of optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus.

Background technology

Trace gas detection demand is extensively present in many fields such as environmental analysis, resource exploration, food security, life science, medical, industrial process control, national defense safety, and these fields require also more and more higher to the sensitivity of Trace gas detection.High-fineness cavity absorption spectroscopy techniques is high owing to having detection sensitivity, and multiplex trace gas concentration and the component analyzed, becomes one of trace materials measuring technique development trend, has obtained paying close attention to widely.

Formerly, in technology, there is a kind of high-fineness cavity spectroscopic analysis system (referring to United States Patent (USP) " Cavity ring down arrangement for non-cavity filing samples ", the patent No.: US6,452,680 B1).This high-fineness cavity spectroscopic analysis system has advantages of suitable, but, still come with some shortcomings: 1) adopt line style fineness cavity configuration, laser forms optical standing wave in high-fineness cavity, cause light distribution inequality, and the reflected light of light beam incident end chamber mirror easily produces and disturbs to laser instrument; 2) carry out test analysis flowing material; 3) when laser beam incident and outgoing sample cell, all will be with Brewster angle incidence and outgoing, so just increase sample cell machinery positioning requirements and the requirement of beam direction control accuracy; 4) high-fineness cavity has two or more high reflectivity mirror optical elements to form, complex structure.

Formerly in technology, also the trace gas detection device that exists the chamber based on Ramam effect to strengthen, referring to the laser gas analyzer product of Atmosphere Recovery company of the U.S., and Chinese utility model patent, patent name: a kind of well logging Raman spectrum gas detecting system, the patent No.: ZL201120284529.2, this laser laser gas analyzer has advantages of certain, but, also come with some shortcomings: 1) adopt equally line style fineness cavity configuration, laser forms optical standing wave in high-fineness cavity, cause light distribution inequality, and the reflected light of light beam incident end chamber mirror easily produces and disturbs laser instrument, 2) owing to adopting active cavity structure, laser working medium and gas compartment, all in intra resonant cavity, have increased system complexity like this, have reduced device anti-interference, affect the on-the-spot adaptive faculty that uses of device.

Summary of the invention

The present invention be directed to the problem that trace gas detection device exists, propose a kind of optical traveling-wave chamber and strengthened laser raman gas concentration detection apparatus, there is simple for structure, strong interference immunity while detecting, detect multiple gases, highly sensitive, fast response time, site environment adaptive faculty simultaneously, safeguard the features such as easy.

Technical scheme of the present invention is: a kind of optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus, comprise LASER Light Source, curved surface annular internal reflector high-fineness cavity, light beam convergent component, optical filter, Photoelectric Detection parts, catoptron, Photoelectric Detection parts, optical filter, light beam convergent component, curved surface annular internal reflector high-fineness cavity, catoptron successively coaxial-symmetrical is placed, curved surface annular internal reflector high-fineness cavity is the single high precision chamber being made up of curved surface annular internal reflector, the reflectivity in the inwall reflection horizon of high-fineness cavity is greater than 98%, curved surface annular internal reflector high-fineness cavity is opened the delivery outlet of formed objects in the symmetria bilateralis of axis of symmetry, one side delivery outlet limit is provided with light beam convergent component, opposite side delivery outlet arranges the catoptron that specific output mouth is large, detected gas is placed in curved surface annular internal reflector high-fineness cavity central area, LASER Light Source outgoing beam is through oblique being mapped in curved surface annular internal reflector high-fineness cavity of light hole of curved surface annular internal reflector high-fineness cavity, in curved surface annular internal reflector high-fineness cavity, forming row ripple transmits, detected region gas in curved surface annular internal reflector high-fineness cavity is subject to the capable ripple of laser beam and excites, launch Raman light, a Raman light part is through curved surface annular internal reflector high-fineness cavity delivery outlet, pass through again light beam convergent component, after filter plate is assembled light beam, collected by Photoelectric Detection parts, after another part reflects by another delivery outlet catoptron of curved surface annular internal reflector high-fineness cavity, pass through equally successively light beam convergent component, optical filter, focus on Photoelectric Detection parts, finally collected by Photoelectric Detection parts.

Described curved surface annular internal reflector high-fineness cavity is sphere concave surface annular internal reflector high-fineness cavity or wheel the form of the foetus loop concave reflector high-fineness cavity.

Light hole on described curved surface annular internal reflector high-fineness cavity is the manhole that is not coated with reflectance coating.

Described optical filter is low transmission to LASER Light Source outgoing beam, and transmitance is less than 5%, and optical filter is high permeability to detected gas laser raman light, and transmitance is greater than 95%.

Described LASER Light Source is gas laser, solid-state laser, dye laser, semiconductor laser, free electron laser, quantum cascade laser, biolaser, light fluid laser instrument one wherein.

Described light beam convergent component is composite sphere lens, non-spherical lens, convergence reflex mirror one wherein.

Described Photoelectric Detection portion is single sensing element photodetector group, monochromator, linear array photoelectric sensors spectrometer one wherein.

Described catoptron is plane mirror, concave mirror, return prism one wherein.

Beneficial effect of the present invention is: optical traveling-wave of the present invention chamber strengthens laser raman gas concentration detection apparatus, in device, high-fineness cavity forms simple, only form optical traveling-wave high-fineness cavity by an optical element, the inner light field row ripple that forms, light distribution is even, the reflected light of light beam incident end chamber mirror is difficult for laser instrument to produce and disturb, and entire system simple in structure is low to mechanical positioning requirements; Chamber is strengthened to technology to combine with laser raman detection technique, adopt passive cavity, laser instrument is arranged on to outside, utilize laser oblique incidence chamber to strengthen principle, avoid the complex structure of conventional infrared chamber enhancing technology, meanwhile, also there is no the labyrinth of active cavity Raman gas analytical equipment, have that system is simple, good stability, feature that reliability is high, improved the anti-interference of pick-up unit simultaneously; The Raman gas that has device detects and the strong multiple feature detecting of high-fineness, can measure by real-time online, improves the multidate information of process, is beneficial to carry out Optimal Control; Multimetering, generally can test tens kinds of gases, can whole process be analyzed and be monitored; Can measure the concentration of nearly all gas except inert gas; Highly sensitive; Fast response time, the response time is fast; Easily use, simple to operate, safeguard easily; The lateral reflector that simultaneously adopted this device reflects the Raman light beam that detection direction is propagated dorsad, makes this part Raman also can be detected and receive by Photoelectric Detection parts, has increased the light intensity of collecting, and has further improved gas content and has detected performance.

Accompanying drawing explanation

Fig. 1 is that optical traveling-wave of the present invention chamber strengthens laser raman gas concentration detection apparatus structural representation;

Fig. 2 is that optical traveling-wave of the present invention chamber strengthens the capable ripple mode of propagation of laser raman gas concentration detection apparatus mean camber annular internal reflector high-fineness cavity cut-open view inner light beam schematic diagram.

Embodiment

The present invention strengthens technology by chamber and combines with laser raman detection technique, adopt optical traveling-wave passive cavity, form high-fineness cavity by single curved surface annular internal reflector, utilize laser emitting light beam oblique incidence chamber to strengthen principle, the light beam that is multiple reflections in chamber is propagated with row waveshape, laser beam is through the tested gas generation Raman scattering in region, Raman diffused light is after filter plate and light beam convergence, collected by Photoelectric Detection parts, Photoelectric Detection parts detect feature Raman frequency shift and the corresponding Raman peaks intensity of tested gas, obtain tested gas concentration.

Optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus structural representation as shown in Figure 1, and device comprises: LASER Light Source 1, curved surface annular internal reflector high-fineness cavity 2, light beamconvergent component 3,optical filter 4,Photoelectric Detection parts 5, catoptron 6.The rotation axes of symmetry of curved surface annular internal reflector high-fineness cavity 2, light beamconvergent component 3,optical filter 4,Photoelectric Detection parts 5 and catoptron 6 coincides, constituent apparatus axis of symmetry O1O2; LASER Light Source 1 outgoing beam is through oblique being mapped in curved surface annular internal reflector high-fineness cavity 2 oflight hole 201 of curved surface annular internal reflector high-fineness cavity 2, in curved surface annular internal reflector high-fineness cavity 2, forming row ripple transmits, curved surface annular internal reflector high-fineness cavity 2 is the single high precision chambeies that are made up of curved surface annular internal reflector, and the reflectivity that curved surface annular internal reflector forms the inwall reflection horizon of high-fineness cavity 2 is greater than 98%; Detected region 8 gases in curved surface annular internal reflector high-fineness cavity 2 are subject to the capable ripple of laser beam and excite, and launch Raman light; Curved surface annular internal reflector high-fineness cavity 2 is opened the delivery outlet of formed objects in the symmetria bilateralis of axis of symmetry O1O2, a side delivery outlet is disposed with light beamconvergent component 3,optical filter 4,Photoelectric Detection parts 5; Opposite side delivery outlet arranges the catoptron 6 that specific output mouth is large.Optical filter 4 is low transmission to LASER Light Source outgoing beam, and transmitance is less than 5%, andoptical filter 4 is high permeability to detected gas laser raman light, and transmitance is greater than 95%.

Curved surface annular internal reflector high-fineness cavity is sphere concave surface annular internal reflector high-fineness cavity and wheel the form of the foetus loop concave reflector high-fineness cavity one wherein.Light hole on curved surface annular internal reflector high-fineness cavity is the manhole that is not coated with reflectance coating.

LASER Light Source is gas laser, solid-state laser, dye laser, semiconductor laser, free electron laser, quantum cascade laser, biolaser, light fluid laser instrument one wherein.

Light beam convergent component is composite sphere lens, non-spherical lens, convergence reflex mirror one wherein.

Photoelectric Detection portion is single sensing element photodetector group, monochromator, linear array photoelectric sensors spectrometer one wherein.

Described catoptron is plane mirror, concave mirror, return prism one wherein.

LASER Light Source 1 adopts LD pumped solid laser light source, it is 1 millimeter that laser goes out 1 irradiating light beam diameter, curved surface annular internal reflector high-fineness cavity 2 is sphere annular internal reflector high-fineness cavity, light beamconvergent component 3 is apochromatic composite sphere lens combination,optical filter 4 is 2% to LASER Light Source outgoing beam transmitance, andoptical filter 4 is that transmitance is 99% to detected gas laser raman light.Photoelectric Detection portion 5 adopts spectrometer.Catoptron 6 is concave mirror.

The course of work of the embodiment of the present invention is: LASER Light Source 1 outgoing beam is through oblique being mapped in curved surface annular internal reflector high-fineness cavity 2 oflight hole 201 of curved surface annular internal reflector high-fineness cavity 2, in curved surface annular internal reflector high-fineness cavity 2, forming row ripple transmits, curved surface annular internal reflector high-fineness cavity 2 is the single high precision chambeies that are made up of curved surface annular internal reflector, detected region 8 gases in curved surface annular internal reflector high-fineness cavity 2 are subject to the capable ripple of laser beam and inspire Raman light, a part is through light beam convergent component, after filter plate is assembled light beam, collected by Photoelectric Detection parts, another part reflects by catoptron 6, pass through equally successively light beamconvergent component 3,optical filter 4, focus onPhotoelectric Detection parts 5, finally collected by Photoelectric Detection parts.

Fig. 2 is the capable ripple mode of propagation of mean camber annular internal reflector high-fineness cavity cut-open view inner light beam of the present invention schematic diagram, and the oblique light being mapped in curved surface annular internal reflector high-fineness cavity 2 oflight hole 201 can form the propagation of closed loop in cavity.Laser is gone into closed light path in cavity, can improve Raman scattering light intensity and sensitivity.

In the present invention, the technology of Raman spectrum principle and the detection feature Raman line frequency displacement of Photoelectric Detection parts and intensive analysis content of material is mature technology.Inventive point of the present invention is that chamber is strengthened to technology to combine with laser raman detection technique, adopt passive cavity, utilize laser emitting light beam oblique incidence chamber to strengthen principle, provide that a system is simple, good stability, reliability are high, detect multiple gases, highly sensitive chamber strengthens laser raman gas concentration detection apparatus simultaneously.

Claims (8)

1. an optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus, it is characterized in that, comprise LASER Light Source, curved surface annular internal reflector high-fineness cavity, light beam convergent component, optical filter, Photoelectric Detection parts, catoptron, Photoelectric Detection parts, optical filter, light beam convergent component, curved surface annular internal reflector high-fineness cavity, catoptron successively coaxial-symmetrical is placed, curved surface annular internal reflector high-fineness cavity is the single high precision chamber being made up of curved surface annular internal reflector, the reflectivity in the inwall reflection horizon of high-fineness cavity is greater than 98%, curved surface annular internal reflector high-fineness cavity is opened the delivery outlet of formed objects in the symmetria bilateralis of axis of symmetry, one side delivery outlet limit is provided with light beam convergent component, opposite side delivery outlet arranges the catoptron that specific output mouth is large, detected gas is placed in curved surface annular internal reflector high-fineness cavity central area, LASER Light Source outgoing beam is through oblique being mapped in curved surface annular internal reflector high-fineness cavity of light hole of curved surface annular internal reflector high-fineness cavity, in curved surface annular internal reflector high-fineness cavity, forming row ripple transmits, detected region gas in curved surface annular internal reflector high-fineness cavity is subject to the capable ripple of laser beam and excites, launch Raman light, a Raman light part is through curved surface annular internal reflector high-fineness cavity delivery outlet, pass through again light beam convergent component, after filter plate is assembled light beam, collected by Photoelectric Detection parts, after another part reflects by another delivery outlet catoptron of curved surface annular internal reflector high-fineness cavity, pass through equally successively light beam convergent component, optical filter, focus on Photoelectric Detection parts, finally collected by Photoelectric Detection parts.

2. optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus according to claim 1, it is characterized in that, described curved surface annular internal reflector high-fineness cavity is sphere concave surface annular internal reflector high-fineness cavity or wheel the form of the foetus loop concave reflector high-fineness cavity.

3. optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus according to claim 2, it is characterized in that, the light hole on described curved surface annular internal reflector high-fineness cavity is the manhole that is not coated with reflectance coating.

4. optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus according to claim 1, it is characterized in that, described optical filter is low transmission to LASER Light Source outgoing beam, and transmitance is less than 5%, optical filter is high permeability to detected gas laser raman light, and transmitance is greater than 95%.

5. optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus according to claim 1, it is characterized in that, described LASER Light Source is gas laser, solid-state laser, dye laser, semiconductor laser, free electron laser, quantum cascade laser, biolaser, light fluid laser instrument one wherein.

6. optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus according to claim 1, it is characterized in that, described light beam convergent component is composite sphere lens, non-spherical lens, convergence reflex mirror one wherein.

7. optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus according to claim 1, it is characterized in that, described Photoelectric Detection portion is single sensing element photodetector group, monochromator, linear array photoelectric sensors spectrometer one wherein.

8. optical traveling-wave chamber strengthens laser raman gas concentration detection apparatus according to claim 1, it is characterized in that, described catoptron is plane mirror, concave mirror, return prism one wherein.

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