CN201429564Y - Trace substance analysis device based on near-field optical traveling wave absorption - Google Patents

Abstract

The utility model relates to a trace substance analysis device based on near-field optical traveling wave absorption. The existing technology has a complex structure and high optical-mechanical requirements, and it is impossible to obtain high-precision spectral information. The utility model adopts an annular high-precision cavity composed of a single optical element isosceles triangular prism, and the two isosceles surfaces are high reflectivity surfaces; the light beam is incident from a waist surface with high reflectivity, and internal total reflection occurs on the bottom surface of the prism to form a near field In the optical test area, an optical traveling wave is formed in the isosceles triangular prism, and exits from another high-reflectivity waist surface; the outgoing beam passes through the high-precision spectroscopic unit of the Fab cavity composed of two high-reflection mirrors, and the moving part drives the Fap cavity A high-reflection mirror moves along the axial direction to adjust and control the outgoing spectral information; the photodetector receives the outgoing light beam of the Farpert cavity to form a high-precision spectral signal to realize the detection of trace substances. The utility model has the characteristics of simple and stable system structure, high spectral information accuracy, less required measuring quantity, wide application range and the like.

Description

Trace substance analysis device based on near-field optical traveling wave absorption

technical field

The utility model belongs to the field of optical technology, and relates to a spectrum analysis device, in particular to a trace substance analysis device based on near-field optical traveling wave absorption, which is mainly used for fluids, films, tiny particles, biomolecules, residual pesticides and other substances trace concentration test.

technical background

In many fields such as advanced manufacturing industry, environmental analysis, life science, medical treatment, national defense and security, there are a large number of trace measurement requirements for substances, and the requirements for detection sensitivity of trace substances are getting higher and higher. High-precision cavity absorption spectroscopy has become one of the development trends of trace substance measurement technology due to its advantages of high detection sensitivity, absolute measurement, and good selectivity. High-precision cavity spectroscopy analysis technology is mostly used to analyze trace gas concentration and components. In recent years, researchers have also applied high-precision cavity spectroscopy analysis technology to fluid material analysis. In the prior art, there is a high-precision cavity spectroscopic analysis system (see US patent "Cavity ring down arrangement for non-cavity filing samples", patent number: US6,452,680B1). The high-definition cavity spectral analysis system has considerable advantages, but there are still some shortcomings: 1) the linear fine-scale cavity structure is adopted, and the laser forms an optical standing wave in the high-definition cavity, resulting in uneven distribution of light intensity, and The reflected light of the cavity mirror at the incident end of the beam is likely to interfere with the laser; 2) It can only be used to test and analyze fluid substances, and cannot test the trace concentration of thin films, interfaces, nano-materials and other morphological substances. When measuring fluids, it needs to be The detection fluid has a certain volume, and it is impossible to detect a small amount of the measured fluid; 3) when the laser beam enters and exits the sample cell, in order to prevent the loss of light energy at the interface, it must be incident and exited at the Brewster angle, so that The requirements for the mechanical positioning of the sample cell and the control accuracy of the beam direction are increased; 4) The high-precision cavity in the cavity ring-down spectroscopy analysis system is composed of two or more high-reflectivity mirror optical elements, and the structure is complex; 5) After the beam emerges from the high-precision cavity, it is received by the photoelectric sensor without high-precision light splitting, and high-precision spectral information of the outgoing light cannot be obtained. The spectral information is not accurate, which affects the detection accuracy and material discrimination ability.

Contents of the invention

The purpose of this utility model is to provide a trace substance analysis device based on near-field optical traveling wave absorption for the deficiencies of the prior art. It has the characteristics of rich spectral information, a wide range of measured substances, and a small amount of measured substances.

The utility model comprises a light source, a light beam collimating shaper, a near-field optical traveling wave cavity, a first reflector, a second reflector, a photoelectric sensor and a moving part.

The light path of the outgoing beam of the light source is provided with a beam collimator and a near-field optical traveling wave cavity in sequence; the near-field optical traveling wave cavity is an isosceles triangular prism, the two waist surfaces are high-reflectivity reflective surfaces, and the bottom surface is internal total reflection surface, the test area is the optical near-field area of total reflection in the bottom surface; the outgoing beam of the beam collimation shaper enters the near-field optical traveling wave cavity from the first waist surface, and the incident direction is parallel to the bottom surface of the isosceles triangular prism. Optical traveling waves are formed in the near-field optical traveling wave high-definition cavity formed by the surface, the second waist surface and the bottom surface, and are emitted from the second waist surface; The first reflector and the second reflector, the first reflector and the second reflector are perpendicular to the beam propagation direction, the reflective surface of the first reflector is opposite to the reflective surface of the second reflector, the first reflector and the second reflector The two reflectors form a F-P cavity; the photoelectric sensor is arranged on the optical path on the beam exit side of the second reflector; the moving part is connected with the second reflector to drive the second reflector to move along the beam direction, and adjust the first reflector and The pitch of the second mirror.

The light source is one of semiconductor laser, solid laser, gas laser and liquid laser.

The beam collimation and shaper is one of a Galileo type collimation shaper and a Kepler type collimation shaper.

The photoelectric sensor is one of photodiode, avalanche tube and photomultiplier tube.

The moving part is one of a stepping motor, a piezoelectric ceramic displacement device, and a nanometer displacement element.

Compared with the prior art, the utility model has the following advantages:

1) The structure of the high-definition cavity in the system is simple. Only one optical element constitutes a near-field optical traveling-wave high-definition cavity, which forms a light field traveling wave inside, and the light intensity is evenly distributed. The reflected light from the cavity mirror at the beam incident end is not easy to interfere with the laser , the overall structure of the system is simple, and the requirements for mechanical positioning are low;

2) Using near-field optical traveling wave absorption technology, the analysis and measurement objects are expanded to thin films, interfaces, nano-materials, and fluids, which expands the scope of application, and the amount of measured substances required for measurement is small;

3) After the beam emerges from the near-field optical traveling-wave high-definition cavity, it passes through the high-precision spectroscopic unit of the Farpert cavity composed of two high-reflection mirrors. Controlling the outgoing spectral information, the photodetector receives the outgoing light beam of the FAP cavity, and can obtain high-precision spectral information of the outgoing light. The spectral information has high precision, high detection accuracy, and strong material discrimination ability.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in Figure 1, the trace substance analysis device based on near-field optical traveling wave absorption includes a light source 1, a beam collimation shaper 2, a near-field optical traveling wave cavity 3, a first mirror 4, and a second mirror 5 , photoelectric sensor 6, moving part 7.

A beam collimator 2 and a near-field optical traveling wave cavity 3 are sequentially arranged on the optical path of the outgoing beam of the light source 1; the near-field optical traveling wave cavity 3 is an isosceles triangular prism, and the two waist surfaces 301 and 303 are high-reflectivity reflectors. surface, the bottom surface 302 is an internal total reflection surface, and the test area is the optical near-field area of the total reflection inside the bottom surface 302; Parallel to the bottom surface 302 of the isosceles triangular prism, an optical traveling wave is formed in the near-field optical traveling wave high-precision cavity formed by the first waist surface 301, the second waist surface 303 and the bottom surface 302, and the optical traveling wave is emitted from the second waist surface 303; The second waist surface 303 of the optical traveling wave cavity 3 exits the first reflector 4 and the second reflector 5 arranged in parallel on the optical path of the light beam in sequence, and the first reflector 4 and the second reflector 5 are both perpendicular to the beam propagation direction, The reflective surface of the first reflector 4 is opposite to the reflector of the second reflector 5, and the first reflector 4 and the second reflector 5 form a Fab cavity; the photoelectric sensor 6 is arranged on the beam output side of the second reflector 5 On the optical path; the moving part 7 is connected with the second reflector 5, and drives the second reflector 5 to move along the light beam direction, and adjusts the distance between the first reflector 4 and the second reflector 5.

The light source 1 is a solid-state laser, the beam collimator 2 is a Galilean collimator, the first reflector 4 and the second reflector 5 are plane reflectors with a reflectivity greater than 97%, and the photoelectric sensor 6 is an avalanche tube. The moving part 7 is a piezoelectric ceramic displacement device.

The working process of the utility model is as follows: the light beam emitted by the light source 1 is collimated and shaped by the beam collimation shaper 2 and then shoots to the near-field optical traveling wave cavity 3, and the incident light enters the near-field optical traveling wave cavity from the first waist surface 301 3. The incident direction is parallel to the bottom surface of the isosceles triangular prism; the optical traveling wave is formed in the near-field optical traveling wave high-definition cavity formed by the first waist surface 301, the second waist surface 303 and the bottom surface 302, and the optical traveling wave is emitted from the second waist surface 303 Total internal reflection occurs in the bottom surface 302, and the test area is the optical near-field region of the total internal reflection of the bottom surface 302. In the present embodiment, the measured fluid form substance contains trace pesticides, and the optical near-field area of the total internal reflection of the bottom surface 302 is arranged In the area; the light beam carrying the measured substance information exits from the second waist surface 303 , passes through the first reflector 4 and the second reflector 5 , and is received by the photoelectric sensor 6 . The first reflector 4 and the second reflector 5 constitute the Fap cavity, and the distance between the first reflector 4 and the second reflector 5 is changed by the moving part 7 to adjust the spectral transmission characteristics of the Fap cavity, so the photoelectric sensor 6 obtains The near-field optical traveling wave absorption spectrum signal of the measured substance is obtained, thereby realizing the high-precision trace concentration measurement. This embodiment successfully detects the trace concentration of the fluid form substance.

Claims (5)

1. A trace substance analysis device based on near-field optical traveling wave absorption, including a light source, a beam collimation shaper, a near-field optical traveling wave cavity, a first mirror, a second mirror, a photoelectric sensor, and moving parts, its characteristics It is that: a beam collimator and a near-field optical traveling-wave cavity are sequentially arranged on the optical path of the outgoing beam of the light source; the near-field optical traveling-wave cavity is an isosceles triangular prism, and the two waist surfaces are high-reflectivity reflective surfaces. The bottom surface is an internal total reflection surface, and the test area is the optical near-field area of total internal reflection on the bottom surface; the outgoing beam of the beam collimation shaper enters the near-field optical traveling wave cavity from the first waist surface, and the incident direction is parallel to the bottom surface of the isosceles triangular prism , the optical traveling wave is formed in the near-field optical traveling wave high-definition cavity composed of the first waist surface, the second waist surface and the bottom surface, and the optical traveling wave is emitted from the second waist surface; the second waist surface of the near-field optical traveling wave cavity emits beam light The first reflector and the second reflector are arranged in parallel on the road in turn, the first reflector and the second reflector are perpendicular to the beam propagation direction, the reflective surface of the first reflector is opposite to the reflective surface of the second reflector, and the reflective surface of the second reflector is opposite to the reflective surface of the second reflector. A reflector and a second reflector constitute a F-P cavity; the photoelectric sensor is arranged on the optical path on the beam exit side of the second reflector; the moving part is connected with the second reflector to drive the second reflector to move along the direction of the beam, and adjust The distance between the first reflector and the second reflector. 2. The device for analyzing trace substances based on near-field optical traveling wave absorption according to claim 1, wherein the light source is one of semiconductor lasers, solid lasers, gas lasers, and liquid lasers. 3. The trace substance analysis device based on near-field optical traveling wave absorption as claimed in claim 1, characterized in that: the collimation shaper is a Galileo type collimation shaper, a Kepler type collimation shaper One of. 4. The device for analyzing trace substances based on near-field optical traveling wave absorption according to claim 1, wherein the photoelectric sensor is one of a photodiode, an avalanche tube, and a photomultiplier tube. 5. The trace substance analysis device based on near-field optical traveling wave absorption according to claim 1, characterized in that: the moving part is one of a stepping motor, a piezoelectric ceramic displacement device, and a nano-displacement element .

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