WO2019183838A1

WO2019183838A1 - Optical coherence tomography system

Info

Publication number: WO2019183838A1
Application number: PCT/CN2018/080907
Authority: WO
Inventors: 杨旻蔚; 丁庆; 沈耀春
Original assignee: 深圳市太赫兹科技创新研究院; 深圳市太赫兹科技创新研究院有限公司
Priority date: 2018-03-28
Filing date: 2018-03-28
Publication date: 2019-10-03

Abstract

An optical coherence tomography system (100), comprising: a light source (110), an optical fiber coupler (120), a reference arm (130), a sample arm (140), a signal collection module (150) and a signal processing module (160). The light source (110) provides initial light; the optical fiber coupler (120) receives the initial light and splits the initial light into multiple paths of output light, wherein the multiple paths of output light comprise one path of reference light and one path of sample light; the reference arm (130) is used for receiving the reference light and transmitting reflected light of the reference light back to the optical fiber coupler (120); the sample arm (140) uses the sample light to detect a sample to be detected (200), wherein the sample light is scattered at the sample to be detected (200) to generate back-scattered light, the back-scattered light is transmitted back to the optical fiber coupler (120), the back-scattered light and the reflected light generate interference in the optical fiber coupler (120) to form interference light, and the interference light is split by the optical fiber coupler (120) into multiple paths of interference spectra; the signal collection module (150) is used for respectively collecting various paths of interference spectra; and the signal processing module (160) generates, according to spectral line signals of various paths of interference spectra, a detection image of the sample to be detected (200) so as to eliminate imaging interference on the sample to be detected (200).

Description

光学相干断层成像***Optical coherence tomography system

技术领域Technical field

本发明涉及光学检测技术领域，特别涉及一种光学相干断层成像***。The present invention relates to the field of optical detection technologies, and in particular, to an optical coherence tomography system.

背景技术Background technique

光学相干断层扫描技术(Optical CoherenceTomography，简称OCT)是上世纪90年代发展起来的一项无损光学检测技术。OCT基于光学低相干干涉仪的光信号延时和相位变化测量***，对于样品内部不同深度的后向散射和反射信号进行间接测量。OCT根据样品内部不同的折射率(代表样品内部的光学散射特性)产生不同对比度的信号，从而实现对样品内部横截面进行成像。由于OCT成像技术对被检样品具有非辐射，非接触，轴向方向分辨率高，无损，易于内窥集成和价格适中的特性，因而是一种极具前途的光学成像工具。目前，OCT技术已经广泛应用于眼科、皮肤组织、血管内窥镜、骨科等医疗诊断领域。OCT技术在工业应用领域也逐步得到应用，如药物包衣、材料厚度测量、车漆喷涂等。Optical Coherence Tomography (OCT) is a non-destructive optical inspection technology developed in the 1990s. The OCT is based on an optical low-coherence interferometer optical signal delay and phase change measurement system for indirect measurement of backscatter and reflected signals at different depths within the sample. The OCT produces signals of different contrasts based on different refractive indices inside the sample (representing the optical scattering characteristics inside the sample), thereby imaging the internal cross section of the sample. OCT imaging technology is a promising optical imaging tool because it has non-radiative, non-contact, high axial resolution, lossless, easy endoscopic integration and moderate price. At present, OCT technology has been widely used in the field of medical diagnosis such as ophthalmology, skin tissue, vascular endoscopy, orthopedics. OCT technology is also gradually being applied in industrial applications, such as drug coating, material thickness measurement, and car paint spraying.

OCT技术，根据其对于样品散射光间接延时和相位测量的不同，分为时域OCT，多普勒OCT，扫频OCT，光谱OCT等。其中，由于光谱OCT具有不使用机械扫描部件进行轴向深度扫描，样品轴向的分层次信息可通过光谱的傅立叶变换直接得到，因而能够大大提高***的成像速度，并避免机械运动扫描结构引入的噪声。同时，光谱OCT使用的波长的水分子吸收极小，因而在眼科医疗和诊断领域，取得了极大的成功。OCT technology is divided into time domain OCT, Doppler OCT, swept OCT, spectral OCT, etc. according to its different indirect delay and phase measurement of sample scattered light. Among them, since the spectral OCT has an axial depth scan without using a mechanical scanning component, the hierarchical information of the sample axial direction can be directly obtained by the Fourier transform of the spectrum, thereby greatly improving the imaging speed of the system and avoiding the introduction of the mechanical motion scanning structure. noise. At the same time, the absorption of water molecules at the wavelengths used in the spectral OCT is extremely small, and thus has achieved great success in the field of ophthalmology and diagnosis.

然而，传统的光谱OCT仍然基于双光束干涉的Michelson干涉仪(干涉仪两臂具有固定的π相位差)。光谱OCT在处理干涉谱线的时候会引入零光程差位置两侧的虚信号，这样，在光谱OCT成像中会有虚像干扰。另外，散射光、参考光、直流项等的干扰，也会造成干涉谱线信号的噪声较大。因此，传统的光谱OCT的干扰较大，导致成像结果中效果不好。However, the traditional spectral OCT is still based on a Michelson interferometer with two-beam interference (the two arms of the interferometer have a fixed π phase difference). Spectral OCT introduces virtual signals on both sides of the zero path difference position when processing the interference line, so that there is virtual image interference in spectral OCT imaging. In addition, interference of scattered light, reference light, DC term, etc., also causes a large noise of the interference line signal. Therefore, the interference of the conventional spectral OCT is large, resulting in poor imaging results.

发明内容Summary of the invention

根据本申请的各种实施例，提供一种光学相干断层成像***。In accordance with various embodiments of the present application, an optical coherence tomography system is provided.

一种光学相干断层成像***，包括：An optical coherence tomography system comprising:

光源，提供初始光；a light source that provides initial light;

光纤耦合器，所述光纤耦合器接收所述初始光，并将所述初始光分为多路输出光，所述多路输出光包括一路参考光和一路样品光；a fiber coupler, the fiber coupler receives the initial light, and divides the initial light into multiple output lights, the multiple output lights including one reference light and one sample light;

参考臂，用于接收所述参考光，并将所述参考光的反射光传回至所述光纤耦合器；a reference arm for receiving the reference light and transmitting the reflected light of the reference light back to the fiber coupler;

样品臂，用于接收所述样品光；所述样品臂利用所述样品光检测待测样品，所述样品光在所述待测样品处发生散射，产生后向散射光，所述后向散射光传回至所述光纤耦合器；所述后向散射光与所述反射光在所述光纤耦合器内发生干涉，形成干涉光；所述干涉光被所述光纤耦合器分为多路干涉光谱，所述多路干涉光谱中的每一路分别输出；a sample arm for receiving the sample light; the sample arm detecting the sample to be tested by the sample light, the sample light is scattered at the sample to be tested, generating backscattered light, the backscattering Light is transmitted back to the fiber coupler; the backscattered light and the reflected light interfere in the fiber coupler to form interference light; the interference light is divided into multiple channels by the fiber coupler a spectrum, each of the plurality of interference spectra being output separately;

信号采集模块，用于分别采集各路所述干涉光谱；a signal acquisition module, configured to separately collect the interference spectra of each channel;

信号处理模块，根据各路所述干涉光谱的谱线信号生成所述待测样品的检测图像，以消除所述待测样品的成像干扰。The signal processing module generates a detection image of the sample to be tested according to a spectral line signal of each of the interference spectra to eliminate imaging interference of the sample to be tested.

本发明的一个或多个实施例的细节在下面的附图和描述中提出。本发明的其他特征、目的和优点将从说明书、附图以及权利要求书变得明显。Details of one or more embodiments of the invention are set forth in the accompanying drawings and description below. Other features, objects, and advantages of the invention will be apparent from the description and appended claims.

附图说明DRAWINGS

为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他实施例的附图。In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings to be used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present application, and those skilled in the art can obtain drawings of other embodiments according to the drawings without any creative work.

图1为一实施例的光学相干断层成像***的结构示意图；1 is a schematic structural view of an optical coherence tomography system according to an embodiment;

图2为一实施例的信号处理模块的运算框图。2 is a block diagram of the operation of the signal processing module of an embodiment.

具体实施方式detailed description

为了便于理解本申请，下面将参照相关附图对本申请进行更全面的描述。附图中给出了本申请的较佳实施例。但是，本申请可以以许多不同的形式来实现，并不限于本文所描述的实施例。相反地，提供这些实施例的目的是使对本申请的公开内容的理解更加透彻全面。In order to facilitate the understanding of the present application, the present application will be described more fully hereinafter with reference to the accompanying drawings. Preferred embodiments of the present application are shown in the drawings. However, the application can be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the understanding of the disclosure of the present application will be more thorough.

图1为一实施例的光学相干断层成像***100的结构示意图。该光学相干断层成像***100包括光源110、光纤耦合器120、参考臂130、样品臂140、信号采集模块150和信号处理模块160。本实施例中，光学相干断层成像***100中的各个器件之间的光信号的传播都通过光纤传播。1 is a schematic block diagram of an optical coherence tomography system 100 of an embodiment. The optical coherence tomography system 100 includes a light source 110, a fiber coupler 120, a reference arm 130, a sample arm 140, a signal acquisition module 150, and a signal processing module 160. In this embodiment, the propagation of optical signals between the various devices in the optical coherence tomography system 100 is propagated through the optical fibers.

光源110用于提供初始光。 Light source 110 is used to provide initial light.

光纤耦合器120接收初始光。光纤耦合器120将初始光分为多路输出光。其中有一路输出光为参考光，还有一路输出光为样品光。 Fiber coupler 120 receives the initial light. The fiber coupler 120 splits the initial light into multiple output lights. One of the output lights is the reference light, and one of the output lights is the sample light.

参考臂130接收参考光，并将参考光的反射光传回至光纤耦合器120。如图1所示，参考臂130包括第一准直透镜131和反射镜132。反射镜132与第一准直透镜131的光轴垂直。第一准直透镜131将参考光转变为平行光。平行光沿着反射镜的法线方向入射至反射镜132。反射镜132将平行光反射形成反射光。因此，反射光沿着参考光的光路返回至光纤耦合器120。The reference arm 130 receives the reference light and transmits the reflected light of the reference light back to the fiber coupler 120. As shown in FIG. 1, the reference arm 130 includes a first collimating lens 131 and a mirror 132. The mirror 132 is perpendicular to the optical axis of the first collimating lens 131. The first collimating lens 131 converts the reference light into parallel light. Parallel light is incident on the mirror 132 along the normal direction of the mirror. The mirror 132 reflects the parallel light to form reflected light. Therefore, the reflected light returns to the fiber coupler 120 along the optical path of the reference light.

样品臂140接收样品光。样品臂140利用样品光检测待测样品200。样品光在待测样品200处发生后向散射，产生后向散射光。后向散射光传回至光纤耦合器120。其中，后向散射光是指从样品光的方向(即入射光的方向)观测的散射波。如图1所示，样品臂140包括第二准直透镜141和探测物镜142，第二准直透镜141和探测物镜142构成共焦光路。其中，共焦光路是指光路第二准直透镜141和探测物镜142之间的光路可逆。共焦光路的应用可以避免杂散光的干扰，确保第二准直透镜141返回的是样品的后向散射光信号。第二准直透镜141将样品光转变为平行光。该平行光经由探测物镜142形成探测光。探测光会聚至待测样品200上。探测光在待测样品200上散射形成后向散射光。后向散射光经过共焦光路传回至光纤耦合器120。 Sample arm 140 receives sample light. The sample arm 140 detects the sample 200 to be tested using the sample light. The sample light is backscattered at the sample 200 to be tested, producing backscattered light. The backscattered light is passed back to the fiber coupler 120. Here, the backscattered light refers to a scattered wave observed from the direction of the sample light (that is, the direction of the incident light). As shown in FIG. 1, the sample arm 140 includes a second collimating lens 141 and a detecting objective lens 142, and the second collimating lens 141 and the detecting objective lens 142 constitute a confocal optical path. The confocal optical path means that the optical path between the optical path second collimating lens 141 and the detecting objective lens 142 is reversible. The application of the confocal optical path can avoid the interference of stray light, ensuring that the second collimating lens 141 returns the backscattered light signal of the sample. The second collimating lens 141 converts the sample light into parallel light. The parallel light forms probe light via the probe objective 142. The probe light is concentrated on the sample to be tested 200. The probe light is scattered on the sample to be tested 200 to form backscattered light. The backscattered light passes back to the fiber coupler 120 through the confocal optical path.

第一准直透镜131和第二准直透镜141都是光纤准直透镜。光纤准直透镜是具有光纤尾纤耦合的非球面透镜。光纤准直透镜可将光纤输入的宽带发散光准直成自由空间平行光输出。光纤准直透镜的工作波长范围应匹配前述宽带光源110的中心波长和谱宽。进一步地，光纤准直透镜在整个工作波长范围内的色差和像差应尽可能地小。这样可以以确保不同波长的输出光分量均能成为同一准直光束。同时也能将接收到的平行反射光的不同光分量以同样的耦合效率返回至光纤中。此外，光纤准直透镜和探测物镜142可以是凸透镜。The first collimating lens 131 and the second collimating lens 141 are both fiber collimating lenses. A fiber collimating lens is an aspherical lens with fiber pigtail coupling. The fiber collimating lens collimates the broadband divergence light input from the fiber into a free-space parallel light output. The operating wavelength range of the fiber collimating lens should match the center wavelength and spectral width of the broadband source 110 described above. Further, the chromatic aberration and aberration of the fiber collimating lens over the entire operating wavelength range should be as small as possible. This can be done to ensure that the output light components of different wavelengths can all be the same collimated beam. At the same time, different light components of the received parallel reflected light can be returned to the optical fiber with the same coupling efficiency. Further, the fiber collimating lens and the detecting objective 142 may be convex lenses.

后向散射光与反射光返回至光纤耦合器120中后，它们在光纤耦合器120内发生干涉，形成干涉光。干涉光被光纤耦合器120分为多路干涉光谱，每一路干涉光谱分别输出。After the backscattered light and the reflected light are returned to the fiber coupler 120, they interfere in the fiber coupler 120 to form interference light. The interference light is split into multiple interference spectra by the fiber coupler 120, and each of the interference spectra is output separately.

信号采集模块150分别采集各干涉光谱。信号采集模块150得到各路干涉光谱的谱线信号。The signal acquisition module 150 separately collects each interference spectrum. The signal acquisition module 150 obtains spectral line signals for each of the interfering spectra.

信号处理模块160根据各路干涉光谱的谱线信号生成待测样品200的检测图像，以消除对待测样品200的成像干扰。The signal processing module 160 generates a detection image of the sample to be tested 200 according to the spectral line signals of the respective interference spectra to eliminate imaging interference of the sample 200 to be tested.

上述光学相干断层成像***100，首先，参考光通过参考臂130形成反射光返回光纤耦合器120。样品光通过样品臂140形成后向散射光返回至光纤耦合器120。其次，光纤耦合器120接收后向散射光和反射光。后向散射光和反射光在光纤耦合器120内发生干涉，形成干涉光。并且，光纤耦合器120将干涉光分为多路干涉光谱。然后，信号采集模块150分别采集各路干涉光谱，并将各路干涉光谱的谱线信号传输给信号处理模块160。由信号处理模块160处理各路干涉光谱的谱线信号，并得出待测样品200深度分层次的图像信息。由于光纤耦合器120将干涉光分为了多路干涉光谱，所以信号处理模块160根据各路干涉光谱进行图像处理，便可以消除虚像干扰和光信号噪声干扰，从而使得上述***的成像效果较好。In the optical coherence tomography system 100 described above, first, the reference light is reflected by the reference arm 130 to return to the fiber coupler 120. The sample light passes through the sample arm 140 to form backscattered light back to the fiber coupler 120. Second, the fiber coupler 120 receives the backscattered light and the reflected light. The backscattered light and the reflected light interfere in the fiber coupler 120 to form interference light. Also, the fiber coupler 120 divides the interference light into multiple interference spectra. Then, the signal acquisition module 150 separately collects the interference spectra of the respective channels, and transmits the spectral line signals of the respective interference spectra to the signal processing module 160. The spectral line signal of each interference spectrum is processed by the signal processing module 160, and the image information of the depth of the sample 200 to be measured is obtained. Since the fiber coupler 120 divides the interference light into multiple interference spectra, the signal processing module 160 performs image processing according to each interference spectrum, thereby eliminating virtual image interference and optical signal noise interference, thereby making the imaging effect of the above system better.

本实施例中，光源110是超宽带光源110。初始光为低相干光。的超宽带光源110，是指基于半导体激光器或发光二极管的光源110。根据探测样品的不同，光源110光谱的中心波长可以选择在850nm，1310nm，1550nm等不同位置。但光源110光谱的中心波长不局限于此，可以依据待测样品200选择不同的中心波长。比如，初始光的波段可以为近红外波段。由于近红外波段透射率较高，所以***对对待测样品200的成像效果较高，可以达到高分辨率无损三维成像。超宽带光源110的特征是：光谱谱宽较大(半高全宽FWHM≥50nm，其中FWHM是full width at half maximum的缩写)，总输出光功率可达20mW(连续光)以上。光源110的光谱谱宽越宽，***探测的样品不同深度位置的散射信息的轴向分辨率越精细。而光功率越大，则样品臂140的散射光越强，信号采集模块150所接收到的信号越强，成像效果越好。进一步地，光源110的光强在整个谱宽范围内应具有较小的波动。比如，光源110可以集成有光纤准直器。这样，光源110将发射的自由空间光耦合进光纤中，以方便后续连接。In this embodiment, the light source 110 is an ultra-wideband light source 110. The initial light is low coherent light. The ultra-wideband light source 110 refers to a light source 110 based on a semiconductor laser or a light emitting diode. Depending on the sample being probed, the center wavelength of the source 110 spectrum can be selected at different locations such as 850 nm, 1310 nm, and 1550 nm. However, the center wavelength of the spectrum of the light source 110 is not limited thereto, and different center wavelengths may be selected depending on the sample to be tested 200. For example, the band of the initial light can be in the near infrared band. Due to the high transmittance in the near-infrared band, the system has a high imaging effect on the sample to be tested 200, and can achieve high-resolution non-destructive three-dimensional imaging. The ultra-wideband light source 110 is characterized by a large spectral width (full width at half maximum FWHM ≥ 50 nm, where FWHM is an abbreviation for full width at half maximum), and a total output optical power of up to 20 mW (continuous light). The wider the spectral width of the light source 110, the finer the axial resolution of the scattering information at different depth positions of the sample detected by the system. The greater the optical power, the stronger the scattered light of the sample arm 140, and the stronger the signal received by the signal acquisition module 150, the better the imaging effect. Further, the light intensity of the light source 110 should have less fluctuations over the entire spectral width. For example, the light source 110 can be integrated with a fiber collimator. Thus, source 110 couples the emitted free-space light into the fiber to facilitate subsequent connections.

本实施例中，光纤耦合器120具有三个输入端和三个输出端。参考光和样品光的光强相等。光纤耦合器120将干涉光分为三路干涉光谱，任意两路干涉光谱的光强相等，且三路干涉光谱的相位呈等相位差排列。在本***中，样品光至三个输出端的分光比为1：1：1。干涉光至三个输入端的分光比也为1：1：1。这样可以确保三路干涉光谱的相位呈等相位差排列。即三路干涉光谱的相位的公差为

3×3光纤耦合器120的特性可以确保所产生的3条干涉谱线的固定相位差分别为：

0，

In this embodiment, the fiber coupler 120 has three inputs and three outputs. The light intensity of the reference light and the sample light are equal. The fiber coupler 120 divides the interference light into three-way interference spectra, and the intensity of the interference spectra of any two channels is equal, and the phases of the three-way interference spectrum are arranged in an equal phase difference. In this system, the split ratio of the sample light to the three outputs is 1:1:1. The split ratio of the interference light to the three inputs is also 1:1:1. This ensures that the phases of the three-way interference spectra are arranged in equal phase differences. That is, the tolerance of the phase of the three-way interference spectrum is

The characteristics of the 3x3 fiber coupler 120 ensure that the fixed phase differences of the three interference lines produced are:

0,

本实施例中，光纤耦合器120是3×3光纤耦合器120。这样，可以有效提高任一路干涉光谱的信噪比，从而使得信号处理模块160恢复出的样品深度信息的信号幅度最强。3×3光纤耦合器120是一种六端口的光纤器件。每个端口通过光纤尾纤与外部光路进行连接。光纤耦合器120具有第一输入端c1、第二输入端c2、第三输入端c3、第一输出端c4、第二输出端c5和第三输出端c6。如图1所示，3×3耦合器的六个端口分为左右两组，图1上左边一组的三个端口全为输入端(分别为第一输入端c1、第二输入端c2、第三输入端c3)。图2上右边的三个端口全为输出端(分别为第一输出端c4、第二输出端c5、第三输出端c6)。任意一个输入端均可作为光输入端口。从输入端输入的光可通过任意一个输出端输出。左右两组端口具有互易性。耦合器的工作波长范围应匹配前述宽带光源110的中心波长和谱宽。输入端至输出端的额外损耗尽可能小。光纤耦合器120的分光比在整个工作波长范围内尽可能保持一致。In this embodiment, the fiber coupler 120 is a 3 x 3 fiber coupler 120. In this way, the signal-to-noise ratio of the interference spectrum of any channel can be effectively improved, so that the signal amplitude of the sample depth information recovered by the signal processing module 160 is the strongest. The 3 x 3 fiber coupler 120 is a six port fiber optic device. Each port is connected to an external optical path through a fiber pigtail. The fiber coupler 120 has a first input terminal c1, a second input terminal c2, a third input terminal c3, a first output terminal c4, a second output terminal c5, and a third output terminal c6. As shown in Figure 1, the six ports of the 3×3 coupler are divided into two groups. The three ports on the left side of Figure 1 are all input terminals (the first input terminal c1 and the second input terminal c2, respectively). The third input c3). The three ports on the right side of Figure 2 are all output terminals (first output terminal c4, second output terminal c5, and third output terminal c6, respectively). Any one of the inputs can be used as an optical input port. Light input from the input can be output through any of the outputs. The left and right groups of ports have reciprocity. The operating wavelength range of the coupler should match the center wavelength and spectral width of the aforementioned broadband source 110. The extra loss from the input to the output is as small as possible. The split ratio of the fiber coupler 120 is as uniform as possible over the entire operating wavelength range.

如图1所示，光学相干断层成像***100还包括光纤环形器170。光纤环形器170具有第一端口p1、第二端口p2和第三端口p3。第二端口与第一输入端光纤连接。第一端口接收初始光。第一端口将初始光传输至第二端口。初始光通过第二端口传输至光纤耦合器120的一输入端。本实施例中，初始光由第二端口p2传输至第一输入端c1。三路干涉光谱中，一路干涉光谱由第一输入端c1经过第二端口p2传输至信号采集模块150。另一路干涉光谱由第二输入端c2传输至信号采集模块150。还有一路干涉光谱由第三输入端c3传输至信号采集模块150。As shown in FIG. 1, optical coherence tomography system 100 also includes a fiber optic circulator 170. The fiber circulator 170 has a first port p1, a second port p2, and a third port p3. The second port is coupled to the first input fiber. The first port receives the initial light. The first port transmits the initial light to the second port. Initial light is transmitted through an second port to an input of fiber coupler 120. In this embodiment, the initial light is transmitted from the second port p2 to the first input terminal c1. In the three-way interference spectrum, an interference spectrum is transmitted from the first input terminal c1 to the signal acquisition module 150 via the second port p2. The other interference spectrum is transmitted from the second input c2 to the signal acquisition module 150. There is also an interference spectrum transmitted from the third input c3 to the signal acquisition module 150.

光纤环形器170中，初始光由第一端口p1输入，通过第二端口p2输出。第二端口p2输入的光(干涉光谱)通过第三端口p3输出。而第三端口p2输入的光被隔离而不会返回至第一端口p1。这样既可以将初始光引入至光纤耦合器120中，又可将某一路干涉光谱信号取出并保护光源110不被干涉光谱干扰。In the fiber circulator 170, initial light is input from the first port p1 and output through the second port p2. The light (interference spectrum) input from the second port p2 is output through the third port p3. The light input by the third port p2 is isolated and does not return to the first port p1. This allows both initial light to be introduced into the fiber coupler 120, and a certain interferometric spectral signal to be taken out and protected from interference by the interference spectrum.

需要说明的是，光纤耦合器120的第二输出端c5不使用，可通过打结等方式，防止第二输出端c5的端面光反射回光纤耦合器120引入干扰。It should be noted that the second output end c5 of the fiber coupler 120 is not used, and the end face light of the second output end c5 is prevented from being reflected back to the fiber coupler 120 to introduce interference by means of knotting or the like.

本实施例中，参考臂130中，反射镜132相对于第一准直透镜131的距离可调节。具体地，反射镜132是一种平面镜，安装在光学调整镜架上，通过调整反射镜132的俯仰和偏转角度，将参考光反射回第一准直透镜131并再次耦合回光纤。进一步地，为了避免反射光强功率过大导致信号采集模块150接收出现饱和甚至损坏，可将反射镜132的俯仰和偏转角调离最佳反射角。也可选择窗口片(工作波长匹配光源110的中心波长和谱宽)作为反射镜132。利用空气与窗口片之间的镜面反射形成反射光。优选的，反射镜132及光学调整镜架可固定在一个一维线形移动平台上，通过调节移动平台，改变反射镜132及第一准直透镜131之间的距离，从而改变参考臂130光路的光程。因此，反射镜132用于调节参考臂130的反射光和样品臂140的散射光的光程差，确保其光程差位于干涉距离内。In the present embodiment, the distance of the mirror 132 relative to the first collimating lens 131 can be adjusted in the reference arm 130. Specifically, the mirror 132 is a plane mirror mounted on the optical adjustment frame. By adjusting the pitch and deflection angle of the mirror 132, the reference light is reflected back to the first collimating lens 131 and coupled back to the fiber again. Further, in order to avoid excessive reflection power intensity, the signal acquisition module 150 receives saturation or even damage, and the pitch and yaw angle of the mirror 132 can be adjusted from the optimal reflection angle. A window (the operating wavelength matches the center wavelength and spectral width of the light source 110) may also be selected as the mirror 132. The reflected light is formed by specular reflection between the air and the window. Preferably, the mirror 132 and the optical adjustment frame are fixed on a one-dimensional linear moving platform, and the distance between the mirror 132 and the first collimating lens 131 is changed by adjusting the moving platform, thereby changing the optical path of the reference arm 130. Optical path. Therefore, the mirror 132 is used to adjust the optical path difference of the reflected light of the reference arm 130 and the scattered light of the sample arm 140 to ensure that the optical path difference is within the interference distance.

如图1所示，样品臂140中，第二准直透镜141和探测物镜142的光轴垂直。样品臂140还包括扫描振镜143。扫描振镜143同时设置于第二准直透镜141和探测物镜142的光轴上。第二准直透镜141出射的平行光由扫描振镜143反射至探测物镜142。第二准直透镜141的平行光相对于扫描振镜143的入射角可调节。具体地，扫描振镜143是一种通过电流驱动可以快速改变偏转角度的镀金属膜平面反射镜132。平面反射镜132具有零色差和像差。在***中，扫描振镜143安装在样品臂140光路中。扫描振镜143的初始状态的反射面法线与第二准直透镜141光轴成45度角。通过快速改变法线与第二准直透镜141光轴的夹角，起到光束扫描的作用，以得到待测样品200不同横向位置处的轴向深度光信息。扫描振镜143的扫描频率在100Hz以内。此处横向是指待测样品200垂直于探测物镜142光轴的方向。轴向是指待测样品200平行于探测物镜142光轴的方向。As shown in FIG. 1, in the sample arm 140, the optical axes of the second collimating lens 141 and the detecting objective lens 142 are perpendicular. The sample arm 140 also includes a scanning galvanometer 143. The scanning galvanometer 143 is simultaneously disposed on the optical axes of the second collimating lens 141 and the detecting objective lens 142. The parallel light emitted from the second collimating lens 141 is reflected by the scanning galvanometer 143 to the detecting objective lens 142. The incident angle of the parallel light of the second collimating lens 141 with respect to the scanning galvanometer 143 can be adjusted. Specifically, the scanning galvanometer 143 is a metallized film plane mirror 132 that can rapidly change the deflection angle by current driving. The planar mirror 132 has zero chromatic aberration and aberrations. In the system, scanning galvanometer 143 is mounted in the optical path of sample arm 140. The normal of the reflecting surface of the initial state of the scanning galvanometer 143 is at an angle of 45 degrees with respect to the optical axis of the second collimating lens 141. By rapidly changing the angle between the normal and the optical axis of the second collimating lens 141, the beam scanning function is performed to obtain axial depth light information at different lateral positions of the sample 200 to be tested. The scanning frequency of the scanning galvanometer 143 is within 100 Hz. Here, the lateral direction means that the sample to be tested 200 is perpendicular to the direction in which the optical axis of the objective lens 142 is detected. The axial direction means that the sample to be tested 200 is parallel to the direction in which the optical axis of the objective lens 142 is detected.

探测物镜142是将由第二准直透镜141和扫描振镜143出射的平行光束，汇聚至被探测样品表面。由于输入光的波长范围较大，因此，需选择消色差透镜组构成。探测物镜142的工作波长范围应匹配光源110的中心波长和谱宽。探测物镜142的焦距应小些，而口径则应大些，这样能够将探测样品的散射光尽可能地加以接收。同时，较大的口径也能够使得汇聚点的光斑尺寸缩小，有利于实现高待测样品200横向分辨率的探测。本***中，因为第二准直透镜141和探测物镜142构成共焦光路，需将探测样品严格放置与探测物镜142的焦平面位置，以使得检测准确。The probe objective 142 is a parallel beam that is emitted by the second collimator lens 141 and the scanning galvanometer 143, and is concentrated on the surface of the sample to be detected. Since the wavelength range of the input light is large, it is necessary to select an achromatic lens group. The operating wavelength range of the probe objective 142 should match the center wavelength and spectral width of the source 110. The focal length of the probe objective 142 should be smaller and the aperture should be larger so that the scattered light of the probe sample can be received as much as possible. At the same time, the larger aperture can also reduce the spot size of the convergence point, which is advantageous for realizing the detection of the lateral resolution of the sample to be tested 200. In the present system, since the second collimating lens 141 and the detecting objective lens 142 constitute a confocal optical path, the detecting sample is strictly placed and the focal plane position of the detecting objective lens 142 to make the detection accurate.

光学相干断层成像***100还包括光路选择模块180。光路选择模块180选择在不同时刻接收各路干涉光谱，并将各路干涉光谱分别传输至信号采集模块150。光路选择模块180在光纤耦合器120与信号采集模块150之间，起到选通干涉光谱的作用。这样可以避免各路干涉光谱的干扰。Optical coherence tomography system 100 also includes an optical path selection module 180. The optical path selection module 180 selects to receive the interference spectra of the respective channels at different times, and transmits the respective interference spectra to the signal acquisition module 150, respectively. The optical path selection module 180 functions to strobe the interference spectrum between the fiber coupler 120 and the signal acquisition module 150. This avoids interference from the interference spectrum of each channel.

光路选择模块180是电控光开关。电控光开关是一种使用电信号触发控制的光路通断选择模块。电控光开关的工作波长范围应匹配前述宽带光源110的中心波长和谱宽。电控光开关的通断切换响应时间可以小于1ns，且工作波长范围能够达到100nm以上。因此电控光开关适合在本***中，进行高速的通道信号切换。这样可以通过时分选择接收的方式节省信号采集模块150的数量，节约成本。具体地，电控光开关带有光纤尾纤接头，以便同光纤耦合器120和光纤环行器相连。The optical path selection module 180 is an electrically controlled optical switch. The electronically controlled optical switch is an optical path on/off selection module that uses an electrical signal to trigger control. The operating wavelength range of the electrically controlled optical switch should match the center wavelength and spectral width of the broadband source 110 described above. The on-off switching response time of the electronically controlled optical switch can be less than 1 ns, and the operating wavelength range can reach more than 100 nm. Therefore, the electronically controlled optical switch is suitable for high-speed channel signal switching in the system. In this way, the number of signal acquisition modules 150 can be saved by time-division selection and the cost can be saved. Specifically, the electronically controlled optical switch has a fiber pigtail connector for connection to the fiber coupler 120 and the fiber circulator.

信号采集模块150是光谱仪。进一步地，光谱仪可采用快速光谱仪。快速光谱仪是一种探测输入光信号的不同波长分量的相对功率强度的设备。其所能响应的波长范围应匹配光源110的中心波长和谱宽。具体地，光谱仪可以是基于高速线列CMOS(Complementary Metal Oxide Semiconductor)相机的架构。即输入光通过准直透镜(部分情况需增加扩束镜)转变为自由空间平行光出射。自由空间平行光出射具有一定光斑尺寸。平行光入射至衍射光栅(可以是反射型或透射型光栅)。平行光由光栅按照布拉格衍射将不同波长分量的光信号通过不同的衍射角进行分离。平行光的入射角选择光栅衍射效率最大的入射角度。出射的衍射光，通过消色差聚焦透镜汇聚至线列CMOS相机的接收面上。CMOS相机的每一个接收像元(根据工作波长，像元可以是Si，AlGaAs或InGaAs等感光材料)对应于快速光谱仪入射光的某一波长分量。根据每一个像元的感光强度，即可得到入射光的光谱信息。具体地，快速光谱仪带有光纤耦合接口。快速光谱仪的光谱采集速率可达到100k谱线/秒。光谱仪具有高速的数据读出接口和大容量缓存，以便将高速采集的大量谱线数据实时提供于信号处理模块160进行数据处理。应用快速光谱仪，可以准确地得到每一路干涉光谱的谱线数据。The signal acquisition module 150 is a spectrometer. Further, the spectrometer can employ a fast spectrometer. A fast spectrometer is a device that detects the relative power intensity of different wavelength components of an input optical signal. The range of wavelengths that it can respond to should match the center wavelength and spectral width of source 110. Specifically, the spectrometer may be an architecture based on a High Speed Line CMOS (Complementary Metal Oxide Semiconductor) camera. That is, the input light is converted into free-space parallel light by a collimating lens (in some cases, a beam expander is added). The free space parallel light exit has a certain spot size. Parallel light is incident on the diffraction grating (which may be a reflective or transmissive grating). The parallel light is separated by a grating according to Bragg diffraction to optical signals of different wavelength components through different diffraction angles. The incident angle of the parallel light selects the angle of incidence at which the diffraction efficiency of the grating is the greatest. The diffracted light that emerges is concentrated by an achromatic focusing lens onto the receiving surface of the line CMOS camera. Each of the receiving pixels of the CMOS camera (which may be a photosensitive material such as Si, AlGaAs or InGaAs depending on the operating wavelength) corresponds to a certain wavelength component of the incident light of the fast spectrometer. According to the intensity of each pixel, the spectral information of the incident light can be obtained. Specifically, the fast spectrometer has a fiber coupled interface. The fast spectrometer's spectral acquisition rate can reach 100k lines per second. The spectrometer has a high-speed data readout interface and a large-capacity buffer to provide a large amount of spectral line data acquired at high speed to the signal processing module 160 for data processing in real time. Using a fast spectrometer, the spectral line data of each interference spectrum can be accurately obtained.

快速光谱仪通过电控光开关获取三路干涉光谱。这三路干涉光谱光强度分别记为I ₁(k)，I ₂(k)，I ₃(k)(分别对应于光纤耦合器120的第一输入端c1、第二输入端c2和第三输入端c3)。由3×3光纤耦合器120的特性可知，假设I ₁(k)的固有相位为

I ₂(k)的固有相位为0，I ₃(k)的固有相位为

The fast spectrometer acquires three-way interference spectra through an electrically controlled optical switch. The three interferometric spectral light intensities are denoted as I ₁ (k), I ₂ (k), I ₃ (k), respectively (corresponding to the first input c1, the second input c2 and the third of the fiber coupler 120, respectively) Input c3). It can be known from the characteristics of the 3×3 fiber coupler 120 that the inherent phase of I ₁ (k) is

The intrinsic phase of I ₂ (k) is 0, and the intrinsic phase of I ₃ (k) is

图2为一实施例的信号处理模块160的运算框图。信号处理模块160接收三路快速光谱仪谱线。信号处理模块160运用等三相位算法恢复出图像。首先消除虚像，再通过系数运算消除直流项和干扰噪声项，从而获得包含样品内部不同深度处的散射信号幅度值a(z)。每条处理后的谱线对应某一位置处的轴向信息，即所谓的A-Scan谱线。再通过和扫描振镜143进行同步，形成被测物品不同横向位置处的轴向深度信息图。这样便构成待测样品200的横截面散射幅度图像，即所谓得B-Scan图像。***的等三相位算法如下：2 is a block diagram of the operation of the signal processing module 160 of an embodiment. The signal processing module 160 receives the three fast spectrometer lines. The signal processing module 160 recovers the image using an equal three-phase algorithm. First, the virtual image is eliminated, and the DC term and the interference noise term are eliminated by the coefficient operation, thereby obtaining the amplitude value a(z) of the scattered signal at different depths inside the sample. Each processed spectral line corresponds to axial information at a certain location, the so-called A-Scan line. Then, by synchronizing with the scanning galvanometer 143, an axial depth information map at different lateral positions of the measured object is formed. This constitutes a cross-sectional scattering amplitude image of the sample to be tested 200, a so-called B-Scan image. The system's equal three-phase algorithm is as follows:

首先，按照传统的SD-OCT***的数据处理方法，将快速光谱仪获取的3条干涉光谱的谱线S _i(λ)从波长域转换成波数域S _i(k)。变换方式为：k＝2π/λ(i＝1，2，3，是每条谱线的标识；S _i(k)与3×3光纤耦合器120的第一输入端c1、第二输入端c2和第三输入端c3一一对应)。将S _i(k)进行波数域的样条插值，获得波数域均匀采样的谱线信号I _i(k)，根据SD-OCT性质，有： First, according to the data processing method of the conventional SD-OCT system, the spectral lines S _i (λ) of the three interference spectra acquired by the fast spectrometer are converted from the wavelength domain to the wavenumber domain S _i (k). The transformation mode is: k=2π/λ (i=1, 2, 3, which is the identification of each spectral line; S _i (k) and the first input terminal c1 and the second input end of the 3×3 fiber coupler 120 C2 corresponds to the third input terminal c3 one by one). S _i (k) is interpolated in the spline field to obtain a spectral line signal I _i (k) uniformly sampled in the wave number domain. According to the SD-OCT nature, there are:

式(1)中，E _R是参考光光强，a(z)待测样品200内部分层次的后向散射信息，k为波数自变量，n是样品折射率，

即为三条谱线的对应相位分量(依次为

0，

)，i为虚数单位。 In equation (1), E _R is the reference light intensity, a(z) is the backscattering information of the partial layer in the sample 200 to be tested, k is the wave number independent variable, and n is the refractive index of the sample.

That is, the corresponding phase components of the three spectral lines (in order

0,

), i is an imaginary unit.

其次，如图2所示，对于I _i(k)执行如下等三相位算法运算： Next, as shown in FIG. 2, the following three-phase arithmetic operations are performed for I _i (k):

H _i(z)＝FT[I _i(k)]，(i＝1，2，3) (2) H _i (z)=FT[I _i (k)], (i=1,2,3) (2)

式(2)中，FT表示傅立叶变换。In the formula (2), FT represents a Fourier transform.

通过式(3)和式(4)的运算，可以消除待测样品200的虚像。By the operations of equations (3) and (4), the virtual image of the sample to be tested 200 can be eliminated.

通过式(5)即可消除三路干涉光谱的直流项干扰和噪声干扰。The DC term interference and noise interference of the three-way interference spectrum can be eliminated by the formula (5).

从上述运算即可从三条干涉光谱得到一条消除直流项，虚像和噪声干扰的优化谱线H(z)。样品内部分层次后向散射信息a(z)正比于H(z)，即A-Scan谱线。通过扫描振镜143的来回运动，可以得到样品表面横向不同位置处的A-Scan谱线，最后，将所有A-Scan谱线组合，即可得到样品的横截面B-Scan图像。From the above operation, an optimized spectral line H(z) which eliminates DC term, virtual image and noise interference can be obtained from the three interference spectra. The partial gradation backscattering information a(z) in the sample is proportional to H(z), which is the A-Scan line. Through the back and forth movement of the scanning galvanometer 143, the A-Scan line at different positions in the lateral direction of the sample surface can be obtained, and finally, all the A-Scan lines are combined to obtain a cross-sectional B-Scan image of the sample.

以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。The technical features of the above-described embodiments may be arbitrarily combined. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be considered as the scope of this manual.

以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。The above-described embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

一种光学相干断层成像***，包括：An optical coherence tomography system comprising:

光源，提供初始光；a light source that provides initial light;

光纤耦合器，所述光纤耦合器接收所述初始光，并将所述初始光分为多路输出光，所述多路输出光包括一路参考光和一路样品光；a fiber coupler, the fiber coupler receives the initial light, and divides the initial light into multiple output lights, the multiple output lights including one reference light and one sample light;

参考臂，用于接收所述参考光，并将所述参考光的反射光传回至所述光纤耦合器；a reference arm for receiving the reference light and transmitting the reflected light of the reference light back to the fiber coupler;

样品臂，用于接收所述样品光；所述样品臂利用所述样品光检测待测样品，所述样品光在所述待测样品处发生散射，产生后向散射光，所述后向散射光传回至所述光纤耦合器；所述后向散射光与所述反射光在所述光纤耦合器内发生干涉，形成干涉光；所述干涉光被所述光纤耦合器分为多路干涉光谱，所述多路干涉光谱中的每一路分别输出；a sample arm for receiving the sample light; the sample arm detecting the sample to be tested by the sample light, the sample light is scattered at the sample to be tested, generating backscattered light, the backscattering Light is transmitted back to the fiber coupler; the backscattered light and the reflected light interfere in the fiber coupler to form interference light; the interference light is divided into multiple channels by the fiber coupler a spectrum, each of the plurality of interference spectra being output separately;

信号采集模块，用于分别采集各路所述干涉光谱；a signal acquisition module, configured to separately collect the interference spectra of each channel;

信号处理模块，根据各路所述干涉光谱的谱线信号生成所述待测样品的检测图像，以消除所述待测样品的成像干扰。The signal processing module generates a detection image of the sample to be tested according to a spectral line signal of each of the interference spectra to eliminate imaging interference of the sample to be tested.
根据权利要求1所述的***，其特征在于，所述光纤耦合器将所述干涉光分为三路干涉光谱；The system of claim 1 wherein said fiber optic coupler divides said interference light into three-way interference spectra;

其中，所述三路干涉光谱中任意两路干涉光谱之间的光强相等，且所述三路干涉光谱之间的相位呈等相位差排列。Wherein, the light intensity between any two interference spectra in the three-way interference spectrum is equal, and the phases between the three-way interference spectra are arranged in an equal phase difference.
根据权利要求2所述的***，其特征在于，所述***还包括光纤环形器；所述光纤环形器具有第一端口、第二端口和第三端口；The system of claim 2, wherein the system further comprises a fiber optic circulator; the fiber optic circulator having a first port, a second port, and a third port;

所述光纤耦合器具有三个输入端；所述三个输入端分别为第一输入端、第二输入端、第三输入端；The fiber coupler has three input ends; the three input ends are a first input end, a second input end, and a third input end respectively;

其中，所述第一端口与所述光源连接，用于接收所述初始光；所述第二端口与所述第一输入端连接，所述第二端口用于将所述光纤环形器所接收的所述初始光传输至所述光纤耦合器；The first port is connected to the light source for receiving the initial light; the second port is connected to the first input end, and the second port is configured to receive the optical fiber circulator The initial light is transmitted to the fiber coupler;

一路干涉光谱依次经过所述第一输入端传输、所述第二端口和所述第三端口传输至所述信号采集模块；另一路所述干涉光谱由所述第二输入端传输至所述信号采集模块；还有一路所述干涉光谱由所述第三输入端传输至所述信号采集模块。An interference spectrum is sequentially transmitted through the first input, the second port and the third port are transmitted to the signal acquisition module; and another interference spectrum is transmitted from the second input to the signal An acquisition module; and a path of the interference spectrum transmitted from the third input to the signal acquisition module.
根据权利要求3所述的***，其特征在于，所述光纤耦合器具有三个输出端；所述三个输出端包括第一输出端、第二输出端和第三输出端；所述参考光由所述第一输出端传输至所述参考臂；所述样品光由所述第三输出端传输至所述样品臂；所述第二输出端打结。The system of claim 3 wherein said fiber coupler has three outputs; said three outputs comprising a first output, a second output, and a third output; said reference light The first output is transmitted to the reference arm; the sample light is transmitted from the third output to the sample arm; the second output is knotted.
根据权利要求1所述的***，其特征在于，还包括光路选择模块，所述光路选择模块选择在不同时刻接收各路所述干涉光谱，并将各路所述干涉光谱分别传输至所述信号采集模块。The system of claim 1 further comprising an optical path selection module, said optical path selection module selecting to receive said interference spectra at different times and transmitting said interference spectra to said signals separately Acquisition module.
根据权利要求5所述的***，其特征在于，所述光路选择模块是电控光开关。The system of claim 5 wherein said optical path selection module is an electrically controlled optical switch.
根据权利要求1所述的***，其特征在于，所述参考臂包括第一准直透镜和反射镜，所述反射镜与所述第一准直透镜的光轴垂直；所述第一准直透镜将所述参考光转变为平行光；所述平行光沿着法线方向入射至所述反射镜；所述反射镜将所述平行光反射形成所述反射光。The system of claim 1 wherein said reference arm comprises a first collimating lens and a mirror, said mirror being perpendicular to an optical axis of said first collimating lens; said first collimating A lens converts the reference light into parallel light; the parallel light is incident on the mirror in a normal direction; the mirror reflects the parallel light to form the reflected light.
根据权利要求7所述的***，其特征在于，所述反射镜相对于所述第一准直透镜的距离可调节。The system of claim 7 wherein the distance of the mirror relative to the first collimating lens is adjustable.
根据权利要求1所述的***，其特征在于，所述样品臂包括第二准直透镜和探测物镜，所述第二准直透镜和所述探测物镜构成共焦光路；所述第二准直透镜将所述样品光转变为平行光；该平行光经由所述探测物镜形成探测光会聚至所述待测样品上，所述探测光在所述待测样品上散射形成的所述后向散射光经过所述共焦光路传回至所述光纤耦合器。The system of claim 1 wherein said sample arm comprises a second collimating lens and a detecting objective, said second collimating lens and said detecting objective constitute a confocal optical path; said second collimating The lens converts the sample light into parallel light; the parallel light forms a probe light concentrated on the sample to be tested via the probe objective, and the backscatter formed by scattering of the probe light on the sample to be tested Light passes back through the confocal optical path to the fiber optic coupler.
根据权利要求9所述的***，其特征在于，所述第二准直透镜和所述探测物镜的光轴垂直；所述样品臂还包括扫描振镜；所述扫描振镜同时设置于所述第二准直透镜和所述探测物镜的光轴上；所述第二准直透镜出射的平行光由所述扫描振镜反射至所述探测物镜；所述第二准直透镜的平行光相对于所述扫描振镜的入射角可调节。The system according to claim 9, wherein said second collimating lens and said detecting objective have an optical axis perpendicular; said sample arm further comprising a scanning galvanometer; said scanning galvanometer being simultaneously disposed in said a second collimating lens and an optical axis of the detecting objective; the parallel light emitted by the second collimating lens is reflected by the scanning galvanometer to the detecting objective lens; and the parallel light of the second collimating lens is opposite The angle of incidence of the scanning galvanometer can be adjusted.
根据权利要求10所述的***，其特征在于，所述第二准直透镜的平行光相对于所述扫描振镜的入射角的调节频率小于100Hz。The system of claim 10 wherein the frequency of adjustment of the parallel light of said second collimating lens relative to the angle of incidence of said scanning galvanometer is less than 100 Hz.
根据权利要求1所述的***，其特征在于，所述光源是超宽带光源。The system of claim 1 wherein said light source is an ultra-wideband light source.
根据权利要求12所述的***，其特征在于，所述光源的光谱的半高全宽不小于50nm。The system according to claim 12, wherein the full width at half maximum of the spectrum of the light source is not less than 50 nm.
根据权利要求1所述的***，其特征在于，所述光源的输出功率不小于20mW。The system of claim 1 wherein said source has an output power of no less than 20 mW.
根据权利要求1所述的***，其特征在于，所述光源为半导体激光器、发光二极管中的一种。The system of claim 1 wherein said light source is one of a semiconductor laser and a light emitting diode.
根据权利要求1所述的***，其特征在于，所述初始光的波段为近红外波段。The system of claim 1 wherein said initial light band is in the near infrared band.
根据权利要求1所述的***，其特征在于，所述初始光为低相干光。The system of claim 1 wherein said initial light is low coherent light.
根据权利要求1所述的***，其特征在于，所述信号采集模块是光谱仪。The system of claim 1 wherein said signal acquisition module is a spectrometer.