CN104483022A

CN104483022A - Fourier transform spectrometer based on Michelson interferometer with equivalent intersecting mirrors

Info

Publication number: CN104483022A
Application number: CN201410688169.0A
Authority: CN
Inventors: 彭月祥; 薛毅; 徐昕晨; 袁杰
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2014-11-25
Filing date: 2014-11-25
Publication date: 2015-04-01

Abstract

A Fourier transform spectrometer of a Michelson interferometer based on an equivalent intersection mirror belongs to the technical field of spectrum measuring instruments. The Michelson interference light path comprises a Michelson interference light path part and a circuit part, wherein the circuit part comprises a CCD signal collector (12), an amplifier (13), an AD converter (14), an embedded processor (15) and a display (16) related to the embedded processor, wherein the CCD signal collector (12) collects interference fringe signals generated by the Michelson interference light path, and the CCD signal collector (12), the amplifier (13), the AD converter (14), the embedded processor (15) and the display (16) related to the embedded processor are sequentially connected. The invention adopts an embedded computer, so that the measurement is more intelligent, the precision is greatly improved, and the liquid crystal screen is used for simultaneously displaying the light frequency corresponding to the peak value of the spectral line, thereby forming a simple, convenient and intelligent measuring system for the light wavelength and the frequency.

Description

Fourier transform spectrometer based on Michelson interferometer with equivalent intersecting mirrors

技术领域technical field

本发明是一种基于迈克尔逊干涉仪的傅里叶变换光谱仪，属于光谱测量仪器技术领域,包含计算机测量、光电子技术和干涉仪系统等方面。本发明可用于物体发光或反光的光谱分布，并可对典型特征谱线的波长进行精确计算，在光谱研究和物质分析领域有着广泛应用。The invention is a Fourier transform spectrometer based on a Michelson interferometer, which belongs to the technical field of spectrum measuring instruments and includes aspects such as computer measurement, optoelectronic technology and interferometer system. The invention can be used for the spectral distribution of light emission or reflection of objects, and can accurately calculate the wavelength of typical characteristic spectral lines, and has wide applications in the fields of spectrum research and material analysis.

背景技术Background technique

光谱仪在一般化学分析、DNA测序,在生物学和化学有害物质和其他应用越来越重要。傅里叶变换光谱仪(FTS)在过去的十年中吸引了大量的注意力,因为他们的特定的特性,如高准确性、高灵敏度和高光谱分辨率。Spectrometers are increasingly important in general chemical analysis, DNA sequencing, hazardous substances in biology and chemistry, and other applications. Fourier transform spectrometers (FTS) have attracted a lot of attention in the past decade because of their specific properties, such as high accuracy, high sensitivity, and high spectral resolution.

在传统的傅里叶变换光谱仪中,输出光束的强度通过扫描干涉仪测量，干涉仪的光程差(OPD)决定了傅里叶变换光谱仪的分辨率。最近,一些不同形式的傅里叶变换光谱仪被研究出来。一款通过使用皮瓦量级的超短脉冲激光源的傅里叶变换光谱仪研制出来,它可以精确测量化合物的性能。此外,基于光纤干涉仪非扫描傅里叶变换光谱仪也被研制出,它具有高分辨率和低成本。此外,也有利用双折射棱镜、一对偏振器和线阵CCD阵列的傅里叶变换光谱仪。这种设计提高了传统傅里叶变换光谱仪通过消除可动部分和传播过程中的光程差(OPD)空间,使系统更小、更可靠,大大减少测量时间。然而,这些方法总是需要复杂的组件,不适合在实际工程。In a traditional Fourier transform spectrometer, the intensity of the output beam is measured by a scanning interferometer, and the optical path difference (OPD) of the interferometer determines the resolution of the Fourier transform spectrometer. Recently, some different forms of Fourier transform spectrometers have been studied. A Fourier-transform spectrometer using a picowatt-scale ultrashort-pulse laser source was developed to precisely measure the properties of compounds. In addition, a non-scanning Fourier transform spectrometer based on a fiber-optic interferometer has also been developed, which has high resolution and low cost. In addition, there are Fourier transform spectrometers that utilize birefringent prisms, a pair of polarizers, and a linear CCD array. This design improves upon conventional Fourier transform spectrometers by eliminating moving parts and optical path difference (OPD) space during propagation, making the system smaller and more reliable, and greatly reducing measurement time. However, these methods always require complex components, which are not suitable for practical engineering.

发明内容Contents of the invention

本发明提出了一种基于等效相交镜的迈克尔逊干涉光路傅里叶变换光谱仪。11为反射镜Ⅴ10对反射镜Ⅳ9镜面所成的虚像，等效相交镜为反射镜Ⅳ9与11的相交，如附图1所示。被测光和参考光都入射到迈克耳孙干涉仪中,并通过电荷耦合元件(CCD)和嵌入式处理器采集得到干涉条纹的傅里叶变换光谱。参考光光谱的峰值点用于校准被测光的峰值点，被测光光谱可以通过参考光和被测光的傅里叶变换光谱计算出来。由于迈克耳孙干涉仪由等效相交镜构成,傅里叶变换光谱仪实现没有任何机械运动,通过将两束光共同照射到在同一个迈克耳孙干涉仪的光路提高了光谱仪的精度，提高了传播的光路。该方法具有高性能、高可靠性和低成本。The invention proposes a Michelson interference optical path Fourier transform spectrometer based on an equivalent intersection mirror. 11 is the virtual image formed by reflector V10 on the mirror surface of reflector IV9, and the equivalent intersecting mirror is the intersection of reflector IV9 and 11, as shown in Figure 1. Both the measured light and the reference light are incident into the Michelson interferometer, and the Fourier transform spectrum of the interference fringe is collected by a charge-coupled device (CCD) and an embedded processor. The peak point of the reference light spectrum is used to calibrate the peak point of the measured light, and the measured light spectrum can be calculated from the Fourier transform spectra of the reference light and the measured light. Since the Michelson interferometer is composed of equivalent intersecting mirrors, the Fourier transform spectrometer does not have any mechanical movement, and the accuracy of the spectrometer is improved by illuminating the two beams of light on the same optical path of the Michelson interferometer. Propagated light path. This method has high performance, high reliability and low cost.

本发明具体方案如下：Concrete scheme of the present invention is as follows:

本发明中的傅里叶变换光谱仪包括迈克尔逊干涉光路部分和电路部分，所述的电路部分包括CCD信号采集器12、放大器13、AD转换器14、嵌入式处理器15和嵌入式处理器相关的显示器16，其中CCD信号采集器12采集迈克尔逊干涉光路产生的干涉条纹信号，CCD信号采集器12、放大器13、AD转换器14、嵌入式处理器15、嵌入式处理器相关的显示器16依次相连。Fourier transform spectrometer among the present invention comprises Michelson interference light path part and circuit part, and described circuit part comprises CCD signal collector 12, amplifier 13, AD converter 14, embedded processor 15 and embedded processor relevant Display 16, wherein CCD signal collector 12 collects the interference fringe signal that Michelson interference optical path produces, CCD signal collector 12, amplifier 13, AD converter 14, embedded processor 15, embedded processor related display 16 successively connected.

使用上述光谱仪测量被测光的频率，其步骤如下：Use the above-mentioned spectrometer to measure the frequency of the light to be measured, and the steps are as follows:

1)迈克尔逊干涉光路中，光源I1和光源Ⅱ2可分别作为参考光光源和被测光光源。光源I1产生光束I，光束I通过反射镜I3入射到半透半反镜4。光源Ⅱ2产生光束II，光束II通过反射镜Ⅱ5、Ⅲ6后入射到半透半反镜4。半透半反镜4将光束I反射和光束II透射，并汇聚成光束III。光束III再通过准直透镜组7入射到偏振分束器8中。光束经过偏振分束器8分别入射到反射镜Ⅳ9、Ⅴ10中，经反射后通过偏振分束器8后被CCD信号采集器12接收，并将其转换成模拟信号输出给电路部分进行处理；1) In the Michelson interference optical path, the light source I1 and the light source II2 can be used as the reference light source and the measured light source respectively. The light source I1 generates a light beam I, and the light beam I enters the half mirror 4 through the reflector I3. The light source II2 generates the light beam II, and the light beam II enters the half-mirror 4 after passing through the mirrors II5 and III6. The half mirror 4 reflects the light beam I and transmits the light beam II, and converges the light beam III into light beam III. The light beam III enters the polarizing beam splitter 8 through the collimating lens group 7 . The light beam enters the mirrors IV9 and V10 respectively through the polarization beam splitter 8, and after being reflected, passes through the polarization beam splitter 8 and is received by the CCD signal collector 12, which is converted into an analog signal and output to the circuit part for processing;

2)CCD信号采集器12输出信号通过放大器13后输入给AD转换器14采样信号输入端；2) The output signal of the CCD signal collector 12 is input to the sampling signal input end of the AD converter 14 after passing through the amplifier 13;

3)AD转换器14将模拟信号转换成数字信号，将数字信号发送给嵌入式处理器15，嵌入式处理器15将信号进行傅里叶变换，并将傅里叶变换光谱显示到显示器16上。3) AD converter 14 converts the analog signal into a digital signal, sends the digital signal to the embedded processor 15, and the embedded processor 15 performs Fourier transform on the signal, and displays the Fourier transform spectrum on the display 16 .

4)通过显示器16显示出傅里叶变换光谱的二位坐标图。横坐标为频率点，也代表了频率值。纵坐标表示光谱强度。参考光和被测光对应的峰值频率点分别为Nr和Nm。从显示的傅里叶变换光谱分别读出被测光和参考光的峰值所对应的横坐标值Nr和Nm，Nr表示被测光的横坐标值，Nm表示参考光的横坐标值，根据公式可以计算出被测光频率，f_m表示被测光频率，f_r表示参考光频率。4) The display 16 displays the binary coordinate diagram of the Fourier transform spectrum. The abscissa is the frequency point, which also represents the frequency value. The ordinate represents spectral intensity. The peak frequency points corresponding to the reference light and the measured light are Nr and Nm respectively. From the displayed Fourier transform spectrum, read out the abscissa values Nr and Nm corresponding to the peak values of the measured light and the reference light, Nr represents the abscissa value of the measured light, Nm represents the abscissa value of the reference light, according to the formula The measured light frequency can be calculated, f _m represents the measured light frequency, f _r represents the reference light frequency.

本发明中的频谱测量方法与迈克尔逊干涉光路有关，下面对其原理进行说明：Spectrum measurement method in the present invention is related to Michelson interference optical path, and its principle is described below:

本发明使用的测量光路采用干涉式，基于迈克尔逊干涉原理：两束光相互叠加，产生干涉条纹，对比已知频率的参考激光和未知频率的被测光的干涉信号的波形，利用嵌入式处理器采集干涉条纹强度的模拟信号，同时并做傅里叶变换获得干涉条纹的光谱，从而精确计算出被测光频率。The measurement optical path used in the present invention adopts the interference type, based on the Michelson interference principle: two beams of light are superimposed on each other to generate interference fringes, compared with the waveform of the interference signal of the reference laser of known frequency and the measured light of unknown frequency, using embedded processing The detector collects the analog signal of the interference fringe intensity, and at the same time performs Fourier transform to obtain the spectrum of the interference fringe, so as to accurately calculate the frequency of the measured light.

迈克尔逊干涉光路附图1.反射镜Ⅳ9和偏振分束器8之间的距离与反射镜Ⅴ10和偏振分束器8之间的距离都是相同的，反射镜Ⅳ9和反射镜Ⅴ10镜面成90°夹角。11为反射镜Ⅴ10对反射镜Ⅳ9镜面所成的虚像，反射镜Ⅳ9相对于11进行小角度旋转。因此,当迈克耳孙干涉光路的光程差通过反射镜Ⅳ9和11的角度不同而产生。Michelson interference optical path accompanying drawing 1. The distance between mirror IV9 and polarizing beam splitter 8 is the same as the distance between mirror V10 and polarizing beam splitter 8, and the mirror surface of mirror IV9 and mirror V10 is 90° ° Angle. 11 is the virtual image formed by the reflector V10 on the mirror surface of the reflector IV9, and the reflector IV9 rotates at a small angle relative to 11. Therefore, when the optical path difference of the Michelson interference optical path passes through the different angles of mirrors Ⅳ 9 and 11, it is produced.

在附图2中，假设θ角是反射镜Ⅳ9和11之间夹角,O点是两个镜子之间的交叉点,O'点是O点在CCD的对应点。光程差可以表示为In accompanying drawing 2, it is assumed that angle θ is the angle between mirror IV 9 and 11, point O is the intersection point between the two mirrors, and point O' is the corresponding point of point O on the CCD. The optical path difference can be expressed as

d＝2xtanθ (1)d=2xtanθ (1)

其中d是光程差,x是在CCD中像素点和O'点之间的距离的绝对值。Where d is the optical path difference, and x is the absolute value of the distance between the pixel point and the O' point in the CCD.

因此,被测光和参考光的干涉条纹可以表示为Therefore, the interference fringes of the measured light and the reference light can be expressed as

${I I}_{m m} = = {I I}_{b b 11} + + {I I}_{c c 11} cos cos ((\frac{22 π π}{{λ λ}_{m m}} d d)) - - - - - - ((22))$

${I I}_{r r} = = {I I}_{b b 22} + + {I I}_{c c 22} cos cos ((\frac{22 π π}{{λ λ}_{r r}} d d)) - - - - - - ((33))$

其中I_m和I_r分别是被测光和参考光的强度,I_b1和I_b2仪器所在环境的背景光,I_c1和I_c2分别是被测光和参考光,λ_m和λ_r是被测光和参考光的波长。Among them, I _m and I _r are the intensity of the measured light and the reference light respectively, I _b1 and I _b2 are the background light of the environment where the instrument is located, I _c1 and I _c2 are the measured light and the reference light respectively, λ _m and λ _r are the measured light Wavelength of photometric and reference light.

然后被测光和参考光的干涉条纹通过CCD转换成电信号，通过嵌入式计算机计算出干涉条纹的傅里叶变换光谱。干涉条纹的傅里叶变换光谱G_m和G_r,可以表示为Then the interference fringes of the measured light and the reference light are converted into electrical signals by the CCD, and the Fourier transform spectrum of the interference fringes is calculated by the embedded computer. The Fourier transform spectra G _m and G _r of interference fringes can be expressed as

${G G}_{m m} ((f f)) = = {A A}_{b b 11} + + {B B}_{c c 11} ((f f + + {f f}_{m m})) + + {B B}_{c c 11}^{* *} ((f f - - {f f}_{m m})) - - - - - - ((44))$

${G G}_{r r} ((f f)) = = {A A}_{b b 22} + + {B B}_{c c 22} ((f f + + {f f}_{r r})) + + {B B}_{c c 22}^{* *} ((f f - - {f f}_{r r})) - - - - - - ((55))$

其中A_b1和A_b2的位置是背景光的傅里叶变换,B_c1和B_c2是对比光的傅里叶变换,f是光谱分布的频率，*表示一个复共轭,f_m和f_r是干涉条纹的频率,并给出Among them, the position of A _b1 and A _b2 is the Fourier transform of the background light, B _c1 and B _c2 are the Fourier transform of the contrast light, f is the frequency of the spectral distribution, * represents a complex conjugate, f _m and f _r is the frequency of the interference fringes, and gives

${f f}_{m m} = = \frac{22 tan the tan θ θ}{{λ λ}_{m m}} - - - - - - ((66))$

${f f}_{r r} = = \frac{22 tan the tan θ θ}{{λ λ}_{r r}} - - - - - - ((77))$

因此,被测光波长可以通过比较被测光和参考光干涉条纹的傅里叶变换的频率计算出来,即Therefore, the wavelength of the measured light can be calculated by comparing the frequency of the Fourier transform of the interference fringes of the measured light and the reference light, that is,

${λ λ}_{m m} = = {λ λ}_{r r} \frac{{f f}_{r r}}{{f f}_{m m}} - - - - - - ((88))$

参考光和被测光对应的峰值频率点分别为N_r和N_m。通过公式(6)和(7)，被测光峰值频率点N_m和频率f_m、波长λ_m之间关系可表达为The peak frequency points corresponding to the reference light and the measured light are N _r and N _m , respectively. Through formulas (6) and (7), the relationship between the measured light peak frequency point N _m and frequency f _m and wavelength λ _m can be expressed as

${N N}_{m m} = = {f f}_{m m} \times \times \frac{N N}{{F f}_{s the s}} = = \frac{22 N N tan the tan θ θ}{{λ λ}_{m m} {F f}_{s the s}} - - - - - - ((99))$

参考光峰值频率点N_r和频率f_r、波长λ_r之间关系可表达为The relationship between the peak frequency point N _r of the reference light, the frequency f _r , and the wavelength λ _r can be expressed as

${N N}_{r r} = = {f f}_{r r} \times \times \frac{N N}{{F f}_{s the s}} = = \frac{22 N N tan the tan θ θ}{{λ λ}_{r r} {F f}_{s the s}} - - - - - - ((1010))$

其中N是采样数据的一半，F_s是采样频率。where N is half of the sampled data and F _s is the sampling frequency.

将公式10带入公式9得出Substituting Equation 10 into Equation 9 yields

$\frac{{N N}_{r r}}{{N N}_{m m}} = = \frac{{f f}_{r r}}{{f f}_{m m}} = = \frac{{λ λ}_{m m}}{{λ λ}_{r r}}$

因此,被测光的波长可以从参考光和被测光对应的峰值频率点计算出来,可以表示为Therefore, the wavelength of the measured light can be calculated from the peak frequency points corresponding to the reference light and the measured light, which can be expressed as

${λ λ}_{m m} = = \frac{{N N}_{r r}}{{N N}_{m m}} {λ λ}_{r r} - - - - - - ((1212))$

${f f}_{m m} = = \frac{{N N}_{m m}}{{N N}_{r r}} {f f}_{r r} - - - - - - ((1313))$

对于(12)(13)式，N_r和N_m可通过输出的液晶屏图像中直接读出，并且f_r和λ_r为参考光频率和波长已知，分别带入(12)(13)时候看分别求出被测光的波长λ_m和频率f_m。For formulas (12) and (13), N _r and N _m can be read directly from the output LCD screen image, and f _r and λ _r are known as the reference light frequency and wavelength, respectively brought into (12) (13) In time, the wavelength λ _m and frequency f _m of the light to be measured are calculated respectively.

光谱分析与测量的研究领域以及激光高精密测量或计算领域需要更高精度、更广测量范围的光谱测量方法。同时，在传统的傅里叶光谱仪中，迈克尔逊干涉光路的光程差是两个镜子之间的距离，因此为了改变光程差需要移动一个镜子。本发明中采用的是通过两个镜子角度不同产生迈克尔逊干涉光路的光程差，傅里叶变换光谱仪整体没有任何机械运动。傅里叶光谱仪可以被制作成更小的尺寸，并可以除机械运动带来的影响，提高光谱仪的精度。本发明采用嵌入式计算机，使得测量更智能化，精度也有很大的提高，用液晶屏同时显示光谱谱线峰值对应的光频率，构成了一个简便智能的光波长和频率的测量系统。The research field of spectral analysis and measurement and the field of laser high-precision measurement or calculation require spectral measurement methods with higher precision and wider measurement range. Meanwhile, in a traditional Fourier spectrometer, the optical path difference of the Michelson interference optical path is the distance between two mirrors, so one mirror needs to be moved in order to change the optical path difference. In the present invention, the optical path difference of the Michelson interference optical path is generated by the different angles of the two mirrors, and the Fourier transform spectrometer does not have any mechanical movement as a whole. The Fourier spectrometer can be made into a smaller size, and the influence of mechanical movement can be removed to improve the accuracy of the spectrometer. The invention uses an embedded computer to make the measurement more intelligent, and the accuracy is also greatly improved. The liquid crystal screen is used to simultaneously display the optical frequency corresponding to the peak of the spectral line, forming a simple and intelligent optical wavelength and frequency measurement system.

1.本发明采用嵌入式计算机，通过嵌入式处理器15精准控制CCD信号采集器12和AD转换器14，将采集的模拟信号转换成数字信号并输入到嵌入式处理器15中。嵌入式处理器15对采集到的干涉条纹数字信号进行傅里叶变换后，并将干涉条纹的傅里叶变换通过显示器16显示。通过嵌入式处理器15完成采集、计算和显示功能，使得光谱仪的系统体积小、成本低、速度快、运行稳定、精度高。1. The present invention uses an embedded computer to accurately control the CCD signal collector 12 and the AD converter 14 through the embedded processor 15, and convert the collected analog signal into a digital signal and input it into the embedded processor 15. The embedded processor 15 performs Fourier transform on the collected interference fringe digital signal, and displays the Fourier transform of the interference fringe through the display 16 . The collection, calculation and display functions are completed by the embedded processor 15, so that the system of the spectrometer is small in size, low in cost, fast in speed, stable in operation and high in precision.

2.为保证测量精度在10^‐9以上。本发明采用迈克尔逊干涉方法，解决了分辨率低的问题，并将测量范围扩大到了红外和可见光范围。另外，采用等效相交镜产生干涉条纹的迈克尔逊干涉光路，使得参考光和被测光信号同步，并避免了机械运动带来的误差。同时，每次CCD信号采集器12采样像素点在2ⁿ点，其中N为整数。AD转换器14选用8位以上分辨率，并且嵌入式处理器15采用FFT模块进行快速计算傅里叶变换频谱，并显示。2. To ensure that the measurement accuracy is above 10 ^‐9 . The invention adopts the Michelson interference method, solves the problem of low resolution, and expands the measurement range to the range of infrared and visible light. In addition, the Michelson interference optical path that produces interference fringes by equivalent intersecting mirrors makes the reference light and the measured light signal synchronized, and avoids the error caused by mechanical movement. At the same time, each time the CCD signal collector 12 samples 2 ⁿ pixels, where N is an integer. The AD converter 14 selects a resolution of more than 8 bits, and the embedded processor 15 uses an FFT module to quickly calculate the Fourier transform spectrum and display it.

3.根据参考光的波长和频率已知，参考光并采用稳频激光光源，再通过本发明中液晶屏显示的测量结果，读出N_r和N_m位置值，用(12)(13)式可精确计算出被测光的波长和频率。3. Known according to the wavelength and the frequency of reference light, reference light adopts the frequency-stabilized laser light source, then by the measurement result displayed on liquid crystal screen in the present invention, read out N _r and N _m position value, use (12) (13) The formula can accurately calculate the wavelength and frequency of the measured light.

附图说明：Description of drawings:

图1：迈克尔逊干涉光路；Figure 1: Michelson interference optical path;

图2：反射镜10和11之间的干涉光路图；Fig. 2: Interference light path diagram between mirrors 10 and 11;

图3：干涉条纹傅里叶变换频谱；Figure 3: Fourier transform spectrum of interference fringes;

图4：光谱仪信号采集处理方框图；Figure 4: Block diagram of spectrometer signal acquisition and processing;

图5：干涉条纹傅里叶变换频谱实例图Figure 5: Example diagram of interference fringe Fourier transform spectrum

具体实施方式Detailed ways

下面结合附图对本发明做进一步说明。The present invention will be further described below in conjunction with the accompanying drawings.

按照迈克尔逊干涉原理，光谱仪光路按附图1布局。参考光选择稳频激光器作为标准光源，参考光的频率的稳定度决定了光谱仪的测量精度。光源Ⅰ1作为参考光输出光束Ⅰ，镜反射镜Ⅰ3进入半透半反镜4，半透半反镜4将入射光束Ⅰ部分反射。同时，光源Ⅱ2作为被测光输出光束Ⅱ，经反射镜Ⅱ5和反射镜Ⅲ6反射后进入半透半反镜4。光束Ⅱ部分光透射过半透半反镜4与Ⅱ经过半透半反镜4的反射光形成光束Ⅲ。光束Ⅲ经准直透镜组7后射到偏振分束器8中，光束经偏振分束器8将分别照射到反射镜Ⅳ9和反射镜Ⅴ10。反射镜Ⅳ9和反射镜Ⅴ10将入射光反射后经偏振分束器8后被CCD信号采集器12采集。According to the principle of Michelson interference, the optical path of the spectrometer is laid out according to Figure 1. A frequency-stabilized laser is selected as the standard light source for the reference light, and the frequency stability of the reference light determines the measurement accuracy of the spectrometer. The light source I1 is used as a reference light to output the beam I, the mirror reflector I3 enters the half mirror 4, and the half mirror 4 partially reflects the incident beam I. At the same time, the light source II2 is used as the output beam II of the light to be measured, and enters the half-mirror 4 after being reflected by the mirror II5 and the mirror III6. Part of the light beam II passes through the half-mirror 4 and the reflected light from the second half-mirror 4 forms the beam III. The light beam III passes through the collimating lens group 7 and then enters the polarizing beam splitter 8, and the light beam passes through the polarizing beam splitter 8 to respectively irradiate the mirror IV9 and the mirror V10. The incident light is reflected by the mirror IV9 and the mirror V10 and collected by the CCD signal collector 12 after passing through the polarization beam splitter 8 .

CCD信号采集器12采集到光谱的模拟信号后将光信号转换为模拟电信号，模拟电信号经放大器13放大后将信号输入到AD转换器14，AD转换器14将模拟电信号转换成数字电信号传输给嵌入式处理器15，嵌入式处理器15将输入的数字电信号进行处理分析并通过显示器16显示出附图5图像。After the analog signal of the spectrum is collected by the CCD signal collector 12, the optical signal is converted into an analog electrical signal. After the analog electrical signal is amplified by the amplifier 13, the signal is input to the AD converter 14, and the AD converter 14 converts the analog electrical signal into a digital electrical signal. The signal is transmitted to the embedded processor 15, and the embedded processor 15 processes and analyzes the input digital electrical signal and displays the image of FIG. 5 through the display 16.

测量实例Measurement example

电路部分中嵌入式处理器15选用FPGA，CCD信号采集器12采样像素点为2¹¹点，选用分辨率12位的AD转换器14。并使用531.5nm固体激光器作为参考光光源Ⅰ1，被测光光源Ⅱ2使用632.8nm固体激光器。其中θ角是1.90°。经使用本发明进行测量后，显示器显示干涉条纹的傅里叶变换光谱，如附图5所示。参考光和被测光对应的峰值频率点分别为917和769,。通过公式12可计算出被测光波长λ_m＝633.79nm。In the circuit part, FPGA is selected as embedded processor 15, sampling pixels of CCD signal collector 12 are ²¹¹ points, and AD converter 14 with 12-bit resolution is selected. A 531.5nm solid-state laser is used as the reference light source I1, and a 632.8nm solid-state laser is used as the measured light source II2. where the angle θ is 1.90°. After using the present invention to measure, the display shows the Fourier transform spectrum of the interference fringes, as shown in Figure 5. The peak frequency points corresponding to the reference light and the measured light are 917 and 769, respectively. The measured light wavelength λ _m =633.79nm can be calculated by formula 12.

同时，选用471.5nm固体激光器作为被测光光源，θ角是1.71°，经测量后结果为470.41nm。选用648.7nm固体激光器作为被测光光源，θ角是1.90°，经测量后结果为649.85nm。全部测量结果及误差如表1.At the same time, a 471.5nm solid-state laser is selected as the light source to be measured, the θ angle is 1.71°, and the measured result is 470.41nm. A 648.7nm solid-state laser is selected as the light source to be measured, the θ angle is 1.90°, and the measured result is 649.85nm. All measurement results and errors are listed in Table 1.

表1.实例测量结果及误差Table 1. Example measurement results and errors

Claims

1. based on the Fourier transform spectrometer of the Michelson interferometer of equivalent intersecting mirror, it is characterized in that: comprise Michelson interference optical path part and circuit part, described circuit part comprises CCD signal collector (12), amplifier (13 ), AD converter (14), embedded processor (15) and related display (16) of embedded processor, wherein CCD signal collector (12) collects the interference fringe signal that Michelson interference optical path produces, and CCD signal acquisition device (12), amplifier (13), AD converter (14), embedded processor (15), and a display (16) related to the embedded processor are connected in sequence.

2. the Fourier transform spectrometer based on the Michelson interferometer of equivalent intersecting mirror according to claim 1, is characterized in that:

Using the spectrometer to measure the frequency of the measured light, the specific steps are as follows:

1) In the Michelson interference optical path, the light source I(1) and the light source II(2) are respectively used as the reference light source and the measured light source; the light source I(1) generates the beam I, and the beam I enters the half-mirror (4); light source II (2) generates light beam II, and light beam II is incident on half-mirror (4) after passing through reflector II (5) and reflector III (6); The mirror (4) reflects the beam I and transmits the beam II, and converges it into a beam III; the beam III enters the polarizing beam splitter (8) through the collimating lens group (7); the beam passes through the polarizing beam splitter (8) Respectively incident into mirrors IV (9) and V (10), after reflection, pass through polarizing beam splitter (8) and then be received by CCD signal collector (12), and convert it into an analog signal and output it to the circuit part for further processing. deal with;

2) The output signal of the CCD signal collector (12) is input to the sampling signal input terminal of the AD converter (14) after passing through the amplifier (13);

3) The AD converter (14) converts the analog signal into a digital signal, and sends the digital signal to the embedded processor (15), and the embedded processor (15) performs Fourier transform on the signal, and the Fourier transform The spectrum is displayed on the display (16);

4) The display (16) displays a two-dimensional coordinate diagram of the Fourier transform spectrum; the abscissa is a frequency point, which also represents a frequency value; the ordinate indicates the spectral intensity. The peak frequency points corresponding to the reference light and the measured light are Nr and Nm respectively; from the displayed Fourier transform spectrum, read the abscissa values Nr and Nm corresponding to the peaks of the measured light and the reference light respectively, and Nr represents the measured The abscissa value of the light; Nm represents the abscissa value of the reference light; according to the formula The measured light frequency can be calculated, f _m represents the measured light frequency, f _r represents the reference light frequency.