CN104155004B - A kind of refraction rotary scanning interference instrument - Google Patents

Abstract

The invention discloses a refraction rotating scanning interferometer, comprising a beam splitter, a refraction window, a plane reflector 1, a plane reflector 2, a parabolic mirror 1, a parabola mirror 2, a corner reflector 1 and a corner reflector 2 The focal point of parabolic mirror 1 is provided with a light source, and the focal point of said parabolic mirror 2 is provided with a light detection system; the beam splitter divides the light beam from the light source into two parts, the transmitted beam and the reflected beam, and the refraction window is Driven by the motor connected to the central position, the high-speed rotation, the transmitted light beam and the reflected light beam pass through the refraction window in their respective optical paths and are returned to the beam splitter, with a certain optical path difference, and interference occurs, and the second parabolic mirror receives the interference The light beam is detected by the optical detector system, and the invention improves the stability of the interferometer during operation and speeds up the spectral measurement speed.

Description

A Refractive Rotating Scanning Interferometer

technical field

The invention relates to the field of optics, in particular to a refraction rotating scanning interferometer.

Background technique

Fourier Transform Infrared Spectroscopy (FTIR) instrument has the advantages of high luminous flux, low noise, fast measurement speed, etc., as well as the unique advantages of real-time multi-component simultaneous detection. It is widely used in environmental monitoring, chemical analysis, and drug composition analysis. There are a wide range of applications.

The main optical component of the Fourier transform infrared spectrometer is the classic Michelson interferometer. The classic Michelson interferometer requires the moving mirror and the fixed mirror to be strictly vertical. It is perpendicular to the fixed mirror, so that the optical path produces effects such as shearing and tilting, which reduces the interference efficiency, increases spectral noise, and limits the application field of the system.

The refraction rotating scanning interferometer proposed by the present invention uses rotation instead of linear motion to realize the change of optical path difference, can overcome the influence of optical path inclination and shear caused by the moving mirror in linear motion, and can realize fast spectral measurement at the same time, with the advantages of Good anti-interference and stability.

Contents of the invention

The invention proposes a refraction rotating scanning interferometer. The optical path difference is generated by means of the rotation of the plane refraction window in the interferometer, which improves the stability of the interferometer during operation and speeds up the spectral measurement speed.

The technical scheme adopted in the present invention is:

A refraction rotating scanning interferometer, comprising a beam splitter and a refraction window, characterized in that: the beam splitter is placed horizontally, the refraction window is located at a certain distance on the left side of the beam splitter, and the The front and rear symmetrical positions in the middle of the beam splitter and the refraction window are respectively provided with a plane mirror one and a plane mirror two, and also includes a parabolic mirror one and a parabolic mirror two, a corner mirror one and a corner mirror two, and the parabolic mirror 1 and parabolic mirror 2 are symmetrical to the center of the beam splitter with plane mirror 1 and plane mirror 2, and the corner mirror 1 and corner mirror 2 are symmetrical to the center of the refraction window ; The focal point of the first parabolic mirror is provided with a light source, and the focal point of the second parabolic mirror is provided with a light detection system;

The beam emitted by the light source is reflected by the parabolic mirror 1 to obtain a parallel beam incident on the beam splitter, and the beam splitter divides the parallel beam into beam 1 on the reflected light path and beam 2 on the transmitted light path. The light beam one on the reflected light path passes through the plane reflector one and the refraction window successively and arrives at the corner mirror two, and the light beam two on the transmitted light path passes through the plane reflector two and the refraction window successively and arrives at the corner mirror one, and the described refraction window The sheet rotates at a high speed, and the beams 1 and 2 are reflected by the corner mirror 2 and the corner mirror 1 and return to pass through the refraction window again to obtain the beam 3 and the beam 4. There is a certain optical path difference between the beam 3 and the beam 4. And according to the reversibility of the optical path, the beams three and four return to the beam splitter along the original path and interfere to generate interference beams, and the parabolic mirror two receives the interference beams and sends them to the detector for detection.

The first beam and the second beam intersect with an intersection on the refraction window, the intersection coincides with the center of the refraction window, and a rotating shaft connected to a high-speed motor is installed at the center of the refraction window. The refraction window rotates at a high speed under the control of a high-speed motor.

The first parabolic mirror and the second parabolic mirror are off-axis parabolic mirrors.

The optical path difference between the interference beams is determined by the thickness d of the refraction window, the refractive index n and the rotation angle θ of the refraction window. The optical path difference is

$\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; [</span>\sqrt{{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; -</span>\sqrt{{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; .</span>$

Advantages of the present invention:

The refraction window in the present invention is rotated by a high-speed motor to generate an optical path difference for the beam, and four interferograms are obtained for each rotation, which improves the measurement speed, and the refraction window is rotated at a constant speed through servo control without a laser reference interferometer. Reduced certain costs.

The invention replaces the working mode of the traditional linear or swing arm interferometer in a rotating manner, reduces the size of the traditional interferometer, facilitates the integration of a compact and portable spectrometer, and can meet the requirements of the current Fourier transform infrared spectrometer in environments such as greenhouse gases and volatile organic compounds. The monitoring requirements can also meet the application requirements of miniaturized Fourier transform infrared interferometers in other fields such as food safety and drug analysis.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

detailed description

As shown in Figure 1, a refraction rotating scanning interferometer includes a beam splitter 3 and a refraction window 10, the beam splitter 3 is placed horizontally, and the refraction window 10 is located at a certain distance on the left side of the beam splitter At the interval, the front and rear symmetrical positions in the middle of the beam splitter 3 and the refraction window 10 are respectively provided with a plane mirror one 8 and a plane mirror two 6, and also include a parabolic mirror one 1 and a parabolic mirror two 4, corner mirrors One 9 and corner reflector two 11, described parabolic mirror one 1 and paraboloid mirror two 4 and plane reflector one 8 and plane reflector two 6 light are symmetrical in beam splitter 3 centers, described corner reflector one 9 And angle reflector two 11 and plane reflector one 8 and plane reflector two 6 are symmetrical about the center of refraction window 10; The focal point of described parabolic mirror one 1 is provided with light source 2, and the focal point of described parabolic mirror two 4 It is equipped with a light detection system 5;

The beam emitted by the light source 2 is reflected by the parabolic mirror 1 to obtain a parallel beam incident on the beam splitter 3, and the beam splitter 3 divides the parallel beam into beam 1 on the reflected light path and beam 2 on the transmitted light path , the light beam one on the reflected light path passes through the plane reflector one 8 and the refraction window 10 and arrives at the corner mirror two 11 successively, and the light beam two on the transmitted light path passes through the plane reflector two 6 and the refraction window 10 successively and arrives Corner mirror one 9, the refraction window 10 rotates at a high speed, and the corner mirror two 11 and corner mirror two 9 reflect beam one and beam two and return to pass through the refraction window 10 again to obtain beam three and beam four. There is a certain optical path difference between the beam three and the beam four, and according to the reversible optical path, the beam three and the beam four return to the beam splitter 3 along the original path and interfere to generate an interference beam, and the parabolic mirror two 4 receives The beam is interfered and sent to the detector 5 for detection.

The first beam and the second beam intersect with an intersection 7 on the refraction window 10, the intersection 7 coincides with the center of the refraction window, and the center of the refraction window is equipped with a rotating shaft of a high-speed motor , the refraction window is rotated at a high speed under the control of a high-speed motor, so that the beam split by the beam splitter 3 produces an optical path difference between the transmitted light path and the reflected light path.

Since the described system uses a small-volume refraction window, the size of the entire instrument can be reduced. At the same time, four interferograms can be obtained by rotating the refraction window for one revolution, so the measurement speed is increased and a correspondingly fast acquisition speed is also required. .

Claims (1)

1. a refraction rotary scanning interference instrument, including beam splitter and refraction window, it is characterised in that: described beam splitter level Placing, described refraction window is positioned on the left of beam splitter at certain distance interval, in the middle of described beam splitter and refraction window Front and back symmetric position is respectively equipped with plane mirror one and plane mirror two, also includes paraboloidal mirror one and paraboloidal mirror two, Angle mirror one and angle mirror two, described paraboloidal mirror one and paraboloidal mirror two and plane mirror one and plane mirror two are about dividing Bundle device centrosymmetry, described angle mirror one and angle mirror two and plane mirror one and plane mirror two are about refraction window center Symmetrical；The focus of described paraboloidal mirror one is provided with light source, and the focus of described paraboloidal mirror two is provided with optical detection system；

The light beam that described light source is launched obtains parallel beam incident to beam splitter through paraboloidal mirror one reflection, described beam splitting Light beam two on light beam one that collimated light beam is divided on reflected light path by device and transmitted light path, the described light beam on reflected light path One sequentially passes through plane mirror one, refraction window arrival angle mirror two, and the light beam two on described transmitted light path sequentially passes through flat Face reflecting mirror two, refraction window arrive angle mirror one, and described refraction window high speed rotating, described angle mirror two and angle mirror one reflect Light beam one and light beam two return again pass by refraction window and obtain light beam three and light beam four, between described light beam three and light beam four There is certain optical path difference, and reversible according to light path, and described light beam three and light beam four and occur along backtracking to beam splitter Interfering and produce interfering beam, described paraboloidal mirror two receives interfering beam and is sent in detector detect；

Described light beam one and light beam two are submitted and a cross point at refraction window, described cross point and described refraction window Center superposition, described refraction window center is provided with the rotating shaft of high-speed electric expreess locomotive, and described refraction window is in the control of high-speed electric expreess locomotive The lower high speed rotating of system；

Described paraboloidal mirror one and paraboloidal mirror two are off axis paraboloidal mirror；

Described optical path difference is by the thickness reflecting window, refractive indexAnd the refraction window anglec of rotationTogether decide on, optical path difference For

。