WO2009070913A1 - Procédé et système de mesure spr - Google Patents

Procédé et système de mesure spr Download PDF

Info

Publication number
WO2009070913A1
WO2009070913A1 PCT/CN2007/003369 CN2007003369W WO2009070913A1 WO 2009070913 A1 WO2009070913 A1 WO 2009070913A1 CN 2007003369 W CN2007003369 W CN 2007003369W WO 2009070913 A1 WO2009070913 A1 WO 2009070913A1
Authority
WO
WIPO (PCT)
Prior art keywords
spr
time domain
light
pulse
detector
Prior art date
Application number
PCT/CN2007/003369
Other languages
English (en)
French (fr)
Inventor
Zheng ZHENG
Yuhang Wan
Xin Zhao
Jinsong Zhu
Jiangfeng Fan
Original Assignee
National Center For Nanoscience And Technology, China
Beihang University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by National Center For Nanoscience And Technology, China, Beihang University filed Critical National Center For Nanoscience And Technology, China
Priority to US12/745,444 priority Critical patent/US8416416B2/en
Priority to PCT/CN2007/003369 priority patent/WO2009070913A1/zh
Publication of WO2009070913A1 publication Critical patent/WO2009070913A1/zh

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/55—Specular reflectivity
    • G01N21/552—Attenuated total reflection
    • G01N21/553—Attenuated total reflection and using surface plasmons

Definitions

  • the invention relates to the field of sensors and sensing technology.
  • the present invention specifically relates to a surface plasmon resonance detecting method, and a detecting system implementing the same. Background technique
  • SP Surface Plasmon
  • SP is a vibration mode formed by a collective oscillation of metal surface charges along the interface between metal and dielectric; surface plasma waves exist in opposite signs of two dielectric constants ( It is usually at the interface of the material of metal and medium.
  • the field strength of this mode is maximized at the interface and is exponentially attenuated along the direction perpendicular to the interface on both sides of the interface, so that the mode field is confined near the interface.
  • the surface plasma wave dispersion relationship can be expressed as:
  • the propagation coefficient of the plasma wave on the metal surface, ⁇ , c are the wavelength, the angular frequency and the speed of light, respectively.
  • SPR Surface Plasmon Resonance
  • evanescent waves such as total internal reflection at the prism interface. Coupling to a plasma wave, causing free electrons on the metal surface to generate surface plasma oscillations.
  • a linearly polarized plane light wave parallel to the plane of incidence is incident on the medium/metal interface at a specific angle, the wave vector of the surface plasma matches the wave vector of the evanescent wave, and the incident light energy is coupled to the surface plasma wave to reach the surface plasma. Resonance, resulting in a significant reduction in reflected light energy.
  • the phase matching relationship of SPR can be expressed as:
  • the SPR generation condition is a function characterized by the incident light wavelength and the incident angle. Therefore, the currently applied SPR detection scanning methods are based on changing the incident light conditions. These scanning methods currently mainly have angle scanning, wavelength scanning, There are four types of intensity scanning and phase scanning, of which the first two methods are the most common:
  • Angular Interrogating This is the most common scanning method for conventional surface plasmon resonance sensors.
  • the method uses a fixed-wavelength light source to rotate the SPR detection structure or the incident light source by mechanical means to change the incident angle of the incident light at the interface of the SPR detection structure to find the SPR resonance angle.
  • the angle scan is intuitive and simple, the precision can be achieved in the current scanning method, but the precision mechanical rotary table on which it depends is very limited. Therefore, the scanning speed of the system is very slow, and it is difficult to achieve fast real-time measurement with high time resolution. .
  • Wavelength Interrogation This method is to measure the reflected light spectrum by using a spectrometer or a monochromator when the incident angle of the near-plane beam is fixed. The intensity response at the incident wavelength is used to find the wavelength of the corresponding light that produces the SPR resonance. This method works at longer wavelengths with system accuracy that meets or exceeds the accuracy of angular scanning methods. However, the measurement speeds of spectrometers and the like are very slow at present, and the scanning speed of the system in this method is limited by the speed of the optical language, etc., so the scanning frequency is very low, and real-time detection of the rapidly changing signal cannot be realized.
  • Another object of the present invention is to provide a measurement system using the above measurement method.
  • the invention provides a method of measuring surface plasmon resonance, comprising the steps of:
  • a coherent broad-spectrum pulsed light having linear polarization is incident on the surface of the SPR sample to be tested, and a reflection occurs;
  • the second time domain signal is detected without being reflected by the SPR sample to be tested but passed through the chirped pulsed broad spectrum light, and the information of the S PR effect is obtained according to the first time domain signal and the second time domain signal.
  • the first time domain signal is compared with the second time domain signal to obtain a time position corresponding to the time domain signal change, and then the monotonously distributed distribution in the time domain is obtained according to the pulse frequency, and the obtained The time domain corresponds to the frequency domain wavelength, thereby obtaining SPR resonance wavelength information.
  • the incident coherent broad-spectrum pulsed light and the SPR reflected light may be monotonically modulated in the time domain at the same time.
  • the method further includes the step (4) of determining a refractive index change of the SPR sample to be measured by using a data processing method of wavelength scanning.
  • the time domain monotonic ⁇ is preferably a linear time domain monotonic ⁇ .
  • the coherent broad-spectrum pulsed light is incident on the surface of the SPR sample to be tested at a fixed angle.
  • the present invention also provides a surface plasmon resonance measuring system, comprising a coherent broad-spectrum pulse light source capable of generating linearly polarized light, a dispersion device capable of generating a time domain monotonous ⁇ , an SPR device to be tested, for receiving a first detector for reflecting light of the SPR and a data processing system for processing the detection result of the first detector, the dispersion device being disposed on an optical path before the first detector, that is, the dispersion device is disposed at the An optical path between the coherent broad-spectrum pulse source and the SPR device to be tested, or the dispersive device is disposed on an optical path between the SPR device and the first detector.
  • the measuring system may further include a second detector, wherein the dispersive device is disposed on an optical path between the coherent wide-spectrum pulse source and the SPR device to be tested, between the dispersive device and the SPR device
  • the optical path is further provided with a beam splitting device for dividing the incident light into a plurality of beams. After splitting, at least one beam splitting light is incident on the SPR device to be tested, and at least another beam splitting light is directly
  • a second detector receives and processes the detection results of the first and second detectors by the data processing system.
  • the coherent broad-spectrum pulse light source may select a supercontinuum source, a mode-locked laser, or the like.
  • the dispersive device can select a dispersive device capable of producing a time-domain monotonic linear chirp.
  • the dispersing device may select an optical fiber, a chirped fiber grating, a grating pair, a prism pair or an ultrashort pulse waveform controller, etc.; the optical fiber may be a common single mode fiber or a dispersion compensating fiber.
  • the detector can use a high speed photodetector, including a PIN detector and an APD detector.
  • the beam splitting device may be an optical splitting sheet or a fiber oriented split coupler or the like.
  • the invention converts the detection means from the frequency detection of the slow traditional wavelength scanning into the high-speed, real-time detection of the time domain pulse signal, which can realize the high-speed SPR scanning detection, compared with the existing SPR detection mode, the scanning speed thereof Can be increased by several orders of magnitude.
  • the present invention is based on a coherent broad-spectrum light source. For short pulses having a certain repetition frequency, each pulse can be subjected to an SPR detection, and the scanning speed is the same as the repetition frequency of the expanded pulse.
  • Existing coherent broad-spectrum sources typically produce repetition frequencies in the order of tens of MHz or more and can reach above 10 GHz.
  • the present invention can be used to meticulously monitor the SPR reaction process to obtain a kinetic curve with extremely high temporal resolution. Since the scanning speed is very high, for one SPR reaction process, the time of one scan is the width of one post-pulse pulse, which can be extremely short (up to ns, ps), so that continuous scanning can be achieved. The entire SPR reaction process is monitored on a fine time axis to obtain an accurate kinetic curve.
  • the invention can be used to monitor rapid biochemical reaction processes. SPR sensor parts are mostly used for biochemical detection, and dynamic monitoring of biochemical reaction processes, and then obtaining biodynamic information is one of the most meaningful contents.
  • SPR sensor parts are mostly used for biochemical detection, and dynamic monitoring of biochemical reaction processes, and then obtaining biodynamic information is one of the most meaningful contents.
  • the invention greatly improves the scanning speed while greatly improving the time resolution on the time axis of the kinetic curve. For the rapid biochemical reaction, the continuous high-speed scanning can dynamically monitor the reaction process.
  • the light source, detection structure, photodetector, and the like of the scanning portion in the sensing system implemented by the method of the present invention can be fixed, facilitating integration, miniaturization, and portability.
  • the signal in the scanning portion of the sensing system implemented in accordance with the method of the present invention is only required for one signal To achieve a high-speed photodetector without the need for a high-speed detector array, the implementation is simpler and less expensive.
  • the method according to the present invention is compatible with various SPR detecting devices and components including a conventional single-layer metal SPR structure, long-range surface plasmon resonance (LRSPR), coupled plasma waveguide resonance (CP), waveguide coupled surface plasmon resonance (WCSPR), It can be easily applied to the detection of these devices.
  • DRAWINGS long-range surface plasmon resonance
  • CP coupled plasma waveguide resonance
  • WCSPR waveguide coupled surface plasmon resonance
  • Figure 1 is a schematic diagram of a high-speed SPR real-time detection system device and its working principle.
  • Figure 2 shows the time domain waveform and instantaneous frequency distribution of the input chirped pulse.
  • Figure 3 is a time-domain waveform of a chirped pulse modulated by the SPR effect for different detected layers.
  • Fig. 4 is a spectrum waveform of a pulse modulated by the SPR effect in the case of the refractive index of the different detected layers obtained from the results of Fig. 3.
  • Figure 5 is the SPR frequency response of the different detected layers obtained from the results of Figures 2 and 4.
  • the currently common coherent wide light sources with a wide output spectral range mainly include: a mode-locked pulsed laser source and a supercontinuum source.
  • the mode-locking technology includes active mode-locking and passive mode-locking:
  • the intensity or phase modulator is generally used to analyze the amplitude or frequency of the optical field in the cavity.
  • the rate (phase) is repeatedly modulated to continuously generate a new modulation sideband, so that the output optical signal has an all-optical nonlinear technique, and a short pulse output is realized without using an active device such as a modulator in the cavity.
  • the principle is to use the nonlinear optical device to reduce the intensity of the output pulse, to achieve compression of the pulse, and to obtain a pulse pulse with a narrow pulse width.
  • the mode-locking technology is a technology that has been quite mature and easy to implement, and has various implementation methods such as a solid mode-locked laser, a fiber-locked mode-locked laser, and a semiconductor mode-locked laser.
  • a high repetition rate pulse source with a large duty cycle of f ⁇ can be realized by using mode-locking technology with a pulse width of less than tens of fs, a peak power of more than 1 kW, a repetition frequency of more than 10 GHz, and a time jitter of less than several fs.
  • the center wavelength of the output light produced can be either visible or infrared.
  • various types of mode-locked lasers in various bands have been available for many mature commercial products.
  • Supercontinuum generation refers to the combination of nonlinear effects such as self-phase modulation, cross-phase modulation, stimulated Raman scattering or four-wave mixing, and velocity dispersion of material groups when high-power short-light pulses pass through a nonlinear medium.
  • the supercontinuum source is a light source technology that uses the physical phenomenon to achieve a spectral width of several tens of nm or more, or even hundreds or thousands of nm.
  • the width of the output spectrum can further exceed the spectral width of the mode-locked pulsed laser, covering the wavelength range commonly used in SPR systems such as visible or near-infrared.
  • the short light pulse is generally generated by a mode-locked laser or a Q-switched laser and amplified by an optical amplifier.
  • Nonlinear media generally employ a nonlinear photonic crystal fiber, a dispersion decreasing fiber, a dispersion flat fiber, or a dispersion shifted fiber. Since supercontinuum can provide ultrashort optical pulses over a wide range of wavelengths, it has been applied to optical communication technologies such as all-optical sampling, all-optical conversion, optical wavelength division multiplexing (0WDM), and optical time division multiplexing (OTDM). . At the same time, companies such as Koheras and Fianium have launched related products.
  • the main scheme for the generation of supercontinuum in optical fibers is to use a fiber with anomalous dispersion to obtain a broadening of the spectrum by using a soliton-effect compression pulse, and the other is to use an optical fiber with normal dispersion to utilize the optical Kerr effect.
  • the resulting frequency ⁇ achieves pulse broadening. The latter can more easily produce short light pulses with linear chirps.
  • the time domain monotony described below refers to monotonous expansion of the pulse frequency in the time domain, and the monotonic expansion refers to a pulse after the time domain is broadened, and one frequency component corresponds to only one.
  • the linear ⁇ means that the time position of each frequency component in the pulse after the ⁇ is linear with its relative frequency offset.
  • this embodiment mainly utilizes the ⁇ dispersion technique and the optical pulse ⁇ technique.
  • dispersion When a beam of light interacts with the bound electrons of the dielectric, the response of the shield is usually related to the frequency of the light. This property is called dispersion.
  • a pulse passes through a dispersion shield or a dispersive element, frequency components of different wavelengths experience different transmission delays.
  • materials and devices that achieve such dispersion effects, such as: fiber optics, chirped fiber gratings, grating pairs, prism pairs, ultrashort pulse waveform controllers, and the like.
  • the coherent pulse source can be used.
  • the output short-light pulse passes through the dispersive device to obtain a broadened optical pulse waveform with a linear chirp.
  • the non-coherent wide-spectrum light source is used as the light source.
  • the monochromator and the optical detector are used as the detection equipment, and the detection speed is very limited.
  • the dispersion component is broadened into a pulse waveform having a chirp, so that the frequency position and the time position are corresponding in one pulse, and the frequency domain SPR is determined only by detecting the time domain waveform distribution. response.
  • the time domain waveform distribution can achieve high speed and real time detection through high speed photodetectors.
  • Figure 1 shows an embodiment of a high speed SPR real time detection system.
  • the system includes a coherent wide-spectrum pulse light source 1, a dispersing device 2, an SPR device 3, a detector 4, and a data processing system 11 that are sequentially disposed on an optical path capable of outputting linearly polarized light, and the first output by the coherent broad-spectrum pulse light source 1
  • the pulse 8 passes through the dispersing device 2, it becomes a second pulse 9 having a chirp
  • the second pulse 9 is incident on the SPR device 3 at a fixed angle
  • the third pulse 10 is obtained by the reflection of the SPR device 3, and the detector 4 receives the third pulse. Pulse 10, and the obtained data is transferred to data processing system 11 for processing.
  • the coherent broad-spectrum pulse light source 1 adopts a femtosecond pulse laser, and the output pulse has a center wavelength of 1550 nm, a pulse repetition frequency of 50 MHz, a pulse shape of Gaussian type, a pulse width of 200 fs, and a spectrum width of 26 nm (all defined in the intensity peak). Width of 1/e);
  • DCF dispersion compensating fiber
  • a chirped fiber grating a grating pair.
  • prism pairs or ultrashort pulse waveform controllers.
  • the SPR sensor In the SPR sensor, a conventional prism-coupled Kretschmann structure is used.
  • the material of the coupling prism 5 is ZF-4, and its refractive index is 1.69855 (at a wavelength of 1550 nm), and the sensing layer 6 is a gold film having a thickness of 50 nra;
  • the measured solution in the sample cell 7 is a 1% aqueous solution of alcohol having a refractive index of about 1.3303, and the buffer solution is an aqueous solution having a refractive index of 1.33;
  • Detector 4 is a high speed photodetector using a PIN photodiode detector with a bandwidth of 40 GHz.
  • the W response time is 9 ps, and its corresponding wavelength is about 0.2 nm.
  • Those skilled in the art will appreciate that other high speed photodetectors such as avalanche photodiodes PD) can also be used.
  • the coherent broad-spectrum pulse source can also adopt other super-continuous spectrum light sources, mode-locked lasers, etc.
  • the functions of the coherent broad-spectrum light source are mainly as follows: (i) the output spectrum includes an excitation SPR device. The surface plasmon resonance effect corresponds to the spectral component, (ii) its output spectrum has a certain spectral width, contains rich frequency components, (iii) its output spectrum has coherence, and the waveform of its output light is pulsed in the time domain. (i V) The output light is a pulse sequence with a higher repetition frequency. The repetition frequency reaches the order of ⁇ z or even GHz, and each pulse can complete one measurement scan, and the detection speed can reach the order of hall z or GHz.
  • the output pulse sequence generated by it has high stability, that is, the pulse repetition frequency is stable, and the start time position of each pulse in the sequence has strict periodicity, stability and accuracy, and the time domain waveform of each pulse in the pulse sequence is
  • the frequency domain spectrum is the same, (vi) its output bandwidth determines the detection range, and (vi i) the output light has TM linear polarization characteristics. If the output light of a coherent broad-spectrum source does not have the required linear polarization, it is also necessary to add a polarizing device before the output light is incident on the SPR device.
  • the dispersive device can also use a chirped fiber grating, a grating pair, a prism pair or an ultrashort pulse waveform controller.
  • the main functions of the dispersive device are: (i) the detection light before reaching the detector has a time domain, The time domain position within the pulse waveform may correspond to the wavelength in the frequency domain.
  • the time domain position within the pulse waveform may linearly correspond to the wavelength in the frequency domain; (ii) the detection before reaching the detector
  • the light is spread over time and the time resolution of the signal waveform is increased (ie, the wavelength-resolved dispersive device can be placed in front of the SPR device, the incident light is broadened, used to excite the SPR effect, or the dispersive device can be placed behind the SPR device.
  • the signal light after the SPR effect is broadened, ⁇ , or one or more dispersion devices are respectively disposed before and after the SPR device to jointly realize the broadening and ⁇ of the detected light.
  • the selected coherence broad spectrum is selected The output of the light source has a large linear chirp and pulse broadening that meets the requirements of the resolution of the detection system, Device may be omitted.
  • the SPR device is mainly used for detecting SPR structural systems that can generate SPR effects.
  • the detection method involved in this embodiment is applicable to various SPR structures, and the conventional single-layer metal SPR Structure, long-range surface plasmon resonance (LRSPR), coupled plasma waveguide resonance (CPWR), waveguide coupled surface plasmon resonance (WCSPR), etc. can be directly applied to the above measurement system.
  • the SPR device further includes an optical device that couples the incident beam and the reflected beam into and out of the SPR structure. When the incident light is not polarized, the polarization control device disposed before the SPR device is further included to detect the light at a specific angle. The polarization state is incident on the SPR component to excite the corresponding SPR effect.
  • the main functions of the detector are: (i) converting the optical signal into an electrical signal for signal storage and processing; (ii) preferably having a higher response speed so that rapid changes in the input time domain waveform can be measured, This makes it possible to resolve the change in response over a small frequency interval.
  • the main functions of the data acquisition and processing unit may be: (i) collecting the electrical signals output by the detector for the time domain amplitude information of each electrical pulse signal according to the output frequency of the coherent wide pulsed light source, (ii) The set of pulses for each pulse needs to be strictly synchronized with the pulse frequency, that is, to ensure that the time positions of the individual pulses after acquisition are the same, and (iii) the time of each pulse waveform according to the chirp characteristics of the pulse realized by the light source and the dispersive device. The position information is in one-to-one correspondence with the corresponding optical frequency information. (iv) The detected pulse waveform is compared with the pulse waveform without the SPR effect, thereby converting the amplitude data of the time domain into the relationship between the wavelength and the SPR spectral response. To obtain the interest of the SPR effect.
  • the detection method of the above high-speed SPR real-time detection system is as follows:
  • the SPR device is moved out of the optical path, and the laser output from the femtosecond pulse laser is coupled into the single-mode fiber.
  • the width of the laser pulse is broadened from 200 fs to 10 ns, and linearity is obtained.
  • the pulsed coherent broad spectrum light that has not been reflected by the SPR sample to be tested but received by the PIN detector is received by the PIN detector to obtain a second time domain signal; and then, the SPR device with the sample to be tested is moved in The optical path, the laser light emitted by the single-mode optical fiber is incident on the coupling prism 5 at a fixed angle, and the reflected laser beam is received by the PIN detector, and the optical signal is converted into an electrical signal, that is, the first time domain signal (0) ;
  • another method for obtaining the first and second time domain signals is: first, adjusting the incident angle of the laser light emitted by the single mode fiber according to the sample to be tested, and the laser is incident at the fixed incident angle.
  • the SPR device injects other samples that are significantly different in properties from the sample to be tested, such as: air, so that the incident light is in the corresponding wave
  • the SPR condition is not satisfied within a long range so that the SPR effect does not occur.
  • the width of the laser pulse is stretched from 200f s to 10 ns, and the linear ⁇ characteristic is obtained without the SPR response signal, and the reflected laser beam is received by the PIN detector. And converting the optical signal into an electrical signal, that is, obtaining the second time domain signal
  • the sample to be tested is injected into the SPR device, and the laser light emitted by the single mode fiber is incident on the coupling prism 5 at a fixed angle, and the reflected laser beam is received by the PIN detector, and the optical signal is converted into electricity.
  • the signal that is, the first time domain signal is obtained.
  • the time domain impulse reflectance function has a relative depression at the corresponding SPR position, and the corresponding relationship between the time domain and the frequency domain is converted to the frequency domain, and the obtained frequency domain reflectivity is obtained.
  • the function has a relative depression at the corresponding SPR wavelength position, as shown in FIG. Specifically how to convert from time domain to frequency domain as shown above, and carry out corresponding analysis.
  • the analysis of the frequency domain SPR signal is a common technique and means in the art, and will not be described herein.
  • the fixed incident angle is selected to be 52. 411 degrees, which is the angle at which the SPR response is generated at the wavelength of I 550 nm.
  • the shape of the pulse waveform modulated by the SPR effect corresponds to the SPR response of the aqueous layer of the sensing layer 6 to the aqueous alcohol solution and the buffer solution. From this waveform, the spectral intensity of the corresponding pulse with SPR effect can be obtained, as shown in FIG. By comparing with the background waveform, the corresponding SPR wavelength response can be obtained, as shown in FIG.
  • one of ordinary skill in the art can extract information such as the refractive index of the measured medium according to the data processing method in the wavelength scanning mode.
  • the system further comprising a second PIN detector
  • the single mode fiber is disposed on the optical path between the femtosecond pulse laser and the SPR device to be tested, and the single mode fiber and the SPR device
  • the coherent broad-spectrum pulse light emitted by the single-mode fiber is split into two beams by the beam splitting device, and one beam of the split coherent broad-spectrum pulse light is incident on the SPR device to be tested.
  • another bundle of coherent broad-spectrum pulsed light that is split is directly incident on the second PIN detector, and the data processing system analyzes and processes the detection result of the second PIN detector.
  • the second PIN detector can also be replaced by a photodetector such as an avalanche photodiode detector (ADP), which can select an optical splitter, an optical fiber directional split coupler, and the like.
  • ADP avalanche photodiode detector
  • the measurement method of the above second detection system is as follows:
  • the laser output from the femtosecond pulse laser is coupled into the single mode fiber.
  • the width of the laser pulse is from 200 fs to 10 ns, and a linear time domain monotonic characteristic is obtained.
  • the laser light emitted by the single-mode optical fiber is split into two beams by a beam splitting device, one of which is incident on the coupling prism 5 at a fixed angle, is reflected by the SPR device, is received by the PIN detector, and converts the optical signal into The electrical signal, that is, the first time domain signal, another beam that has not undergone SPR reflection but passes through the chirped pulsed coherent broad spectrum light is received by the second PIN detector to obtain a second time domain signal -; remaining signal processing
  • the mode is the same as that of the first structure.
  • the first and second time domain signals can be measured simultaneously, thereby achieving faster measurement, and at the same time, overcoming the influence of the time-varying noise in the optical path on the measurement result, and in the case where the light source output is unstable, Overcoming the influence of the pulse change of the light source, in addition, because the detection system is concerned with the relative reflectivity of the SPR device and its variation law rather than its absolute value, the two beams of light obtained by splitting the beam splitting device may not be equal, Personnel should understand that the beam splitting device can also split the incident light into three or more beams, depending on the needs of the specific application, without affecting the detection.

Description

一种表面等离子共振的测量方法及其测量系统 技术领域
本发明涉及传感器及传感技术领域。 本发明具体涉及表面等离子共振 检测方法， 以及实现该方法的检测系统。 背景技术
在目前的市场上表面等离子（Surface Plasmon, 简称为 SP) 是沿着金属 和电介质间界面传播的由金属表面电荷的集体振荡形成的振动模式；表面等 离子波存在于两种介电常数符号相反 (一般为金属与介质）的材料交界面上。 这种模式的场强在界面处达到最大， 并且在界面两侧都沿着垂直于界面的方 向呈指数式衰减， 从而模场被限制在界面附近。 表面等离子波色散关系可表 达为：
V/2 r
ε\ε2 ω ε\ε2 ( 1 )
c
为金属表面等离子波的传播系数， ^, c分别为波长， 角频率和光速。 和 分別为金属层、 介质层的介电系数。
表面等离子共振（Surface Plasmon Resonance, 简称为 SPR)是一种物理 光学现象，可以利用光在棱鏡界面处发生全内反射时的倏逝波等方式与金属 表面等离子共振模式的耦合， 将能量从光波鵜合到等离子波， 引发金属表面 的自由电子产生表面等离子振荡。 当电场分量平行于入射平面的线偏振平面 光波以特定角度入射在介质 /金属界面上时， 表面等离子的波矢与倏逝波的 波矢匹配， 入射光能量耦合到表面等离子波， 达到表面等离子共振， 从而导 致反射光能量显著减少。 SPR的相位匹配关系可表达为：
kx = ksinQ = ksp ( 2 ) 由方程（1 )和（2 ) 可以看出， 对于同种待测介质， SPR的产生条件是 由入射光波长和入射角度表征的函数。 因此， 目前应用的 SPR检测扫描方法 均是基于改变入射光条件的。这些扫描方法目前主要有角度扫描、波长扫描、 强度扫描和相位扫描四种， 其中前两种方法最为常见：
1. 角度扫描方法（Angular Interrogat ion) : 这是传统表面等离子共振 传感器最常用的扫描方式。该法使用固定波长的光源，通过机械装置旋转 SPR 检测结构或入射光源， 从而改变入射光在 SPR检测结构界面上的入射角度， 来寻找 SPR共振角。 角度扫描虽然直观、 简单， 在目前扫描方法中能达到的 精度最高， 但其所依赖的精密机械旋转台的运行速度十分有限， 因此系统扫 描速度很慢， 难以实现高时间分辨率的快速实时测量。
2、 波长扫描方法（Wavelength Interrogat ion)： 该方法是在近平面光束 的入射角度固定的情况下， 以宽谱光源入射， 采用光倕仪或单色仪等测量反 射光的光谱， 从而得到不同入射波长下的光强响应， 来寻找能产生 SPR共振 的对应光波长。这种方法工作在较长波段时的系统精度能达到甚至超过角度 扫描方法的精度。 但目前光谱仪等的测量速度都非常緩慢， 而该方法的系统 中扫描速度又受限于光语仪等的速度， 因而扫描频率十分低， 无法实现对快 速变化的信号进行实时检测。
从上面介绍的几种 SPR信号扫描方法可以看出，现有利用 SPR效应的传感 检测系统在信号扫描技术上还存在着扫描速度慢、 设备体积大、 不能进行高 密度的多通道并行检测等缺陷。 发明内容
因此， 本发明的任务是提供一种表面等离子共振的测量方法； 本发明的另一任务是提供一种使用上述测量方法的测量系统。
一方面， 本发明提供了一种表面等离子共振的测量方法， 包括以下步 驟：
( 1 )将具有线偏振的相干宽谱脉冲光入射到待测 SPR样品表面， 发 生反射；
( 2 )对所述入射相干宽谱脉冲光或所述 SPR反射光在时域上进行单 调啁啾；
( 3 )对具有时域单调啁啾的 SPR反射光进行检测得到第一时域信号， 检测未经过所述待测 SPR样品反射、 但经过所述啁啾的脉冲相干宽谱光得 到第二时域信号 ,才艮据笫一时域信号和第二时域信号得到 S PR效应的信息。
上述方法中， 将第一时域信号与第二时域信号相比较， 获得时域信号 变化所对应的时间位置， 然后根据脉冲频率经过在时域上进行单调啁啾后 的分布，得到所述时间位置对应的频域波长，从而获得 SPR共振波长信息。
上述方法中， 还可以同时对所述入射相干宽谱脉冲光和所述 SPR反射 光在时域上进行单调啁啾。
进一步地， 还包括步骤（4 ) 利用波长扫描的数据处理方法确定 SPR 被测样品的折射率变化等信息。
上述方法中， 所述时域单调啁啾优选线性的时域单调啁啾。
上述方法中， 所述相干宽谱脉冲光以固定角度入射到待测 SPR样品表 面。
另一方面， 本发明还提供了一种表面等离子共振的测量系统， 包括能 够产生线性偏振光的相干宽谱脉冲光源、 能够产生时域单调啁啾的色散器 件、 待测 SPR器件、 用于接收 SPR反射光的第一检测器和用于处理所述第 一检测器检测结果的数据处理系统， 所述色散器件设置于所述第一检测器 之前的光路上， 即所述色散器件设置于所述相干宽谱脉冲光源与所述待测 SPR器件之间的光路上， 或者所述色散器件设置于所述 SPR器件与所述第 一检测器之间的光路上。
上述测量系统中， 还可以包括第二检测器， 所述色散器件设置于所述 相干宽谱脉冲光源与所述待测 SPR器件之间的光路上， 所述色散器件与所 述 SPR器件之间的光路上还设有将入射光分成多束的分束装置， 经过分束 后， 至少一束分束光入射到所述待测 SPR器件上， 且至少另一束分束光直 接被所述第二检测器接收， 并由所述数据处理系统来处理所述第一和第二 检测器的检测结果。
上述测量系统中， 所述相干宽谱脉冲光源可以选择超连续谱光源、 锁 模激光器等。
所述色散器件可以选择能够产生时域单调线性啁啾的色散器件。 所述色散器件可以选择光纤、 啁啾光纤光栅、 光栅对、 棱镜对或超短 脉冲波形控制器等； 所述光纤可以为普通单模光纤或色散补偿光纤等。
所述检测器可以使用高速光电检测器， 包括 PIN检测器和 APD检测器 等。
所述分束装置可以采用光学分束片或光纤定向分路耦合器等。
本发明的表面等离子共振传感的测量方法及其测量系统具有以下优 点：
1. 本发明将检测手段由缓慢的传统波长扫描的频语检测转换为高速、 可实时进行的时域脉冲信号检测， 可实现高速 SPR扫描检测， 比起现有的 SPR检测方式， 其扫描速度可提高几个数量级。 本发明基于相干宽谱光源， 对于具有一定重复频率的短脉冲， 每个脉冲可进行一次 SPR检测， 扫描速 度与展宽后的脉冲的重复频率相同。 现有的相干宽谱光源产生的重复频率 一般在几十 MHz以上， 并可达到 10GHz以上。
2. 本发明可用于细致监测 SPR反应的过程， 得到时间分辨率极高的 动力学曲线。 由于扫描速度非常高， 对于一个 SPR反应过程， 进行一次扫 描的时间为一个啁啾后脉冲的宽度， 这一时间可以极短 （可达到 ns , ps 量级）， 从而可实现连续扫描， 即可在精细的时间轴上监测整个 SPR反应 过程， 得到精确的动力学曲线。
3. 本发明可用于监测快速生化反应过程。 SPR传感器件多用于生化检 测， 对生化反应过程进行动态监测， 进而获得生物动力学信息是其中一项 很有意义的内容。 而现有 SPR传感系统由于扫描速度的限制， 对于一些反 应时间较短 （在秒或以下量级） 的生化反应， ^[艮难动态监测到反应过程。 本发明在大大提高扫描速度的同时， 可在动力学曲线的时间轴上大大提高 时间分辨率， 对于快速生化反应， 连续的高速扫描一样能对其反应过程进 行动态监测。
4. 按本发明的方法实现的传感系统中的扫描部分的光源、 检测结构、 光检测器等都可以固定不动， 便于实现集成化、 小型化和便携化。
5. 按本发明的方法实现的传感系统中的扫描部分中对一路信号只需 要一个高速光检测器， 而不需要高速度的检测器阵列， 实现较简单、 成本 较低。
6. 按本发明的方法与包括传统单层金属 SPR结构、 长程表面等离子 共振（LRSPR)、 耦合等离子波导共振（CP ）、 波导耦合表面等离子共振 (WCSPR)等各种 SPR检测器件和组件兼容， 可方便地应用于对这些器件的 检测。 附图说明
以下， 结合附图来详细说明本发明的实施例， 其中：
图 1 是一种高速 SPR实时检测系统装置及工作原理示意图。
图 2 是输入啁啾脉冲的时域波形与瞬时频率分布。
图 3 是不同被检测层折射率情况下的经 SPR效应调制后的啁啾脉冲的 时域波形。
图 4 是由图 3结果获得的不同被检测层折射率情况下的经 SPR效应调 制后的脉冲的频谱波形。
图 5 是由图 2和图 4结果获得的不同被检测层折射率情况下的 SPR频 傳响应。
图面说明
1-相干宽谱脉冲光源 2-色散器件 3-SPR器件 4-检测器
5 -耦合棱镜 6-传感层 7-样品池 8-第一脉冲
9 -第二脉冲 10-第三脉冲 11-数据处理系统 具体实施方式
下面， 结合说明书附图对本发明做进一步的解释和说明。
随着光纤和光学技术的发展，新型光源技术和光信号处理技术得到了巨 大发展。 目前常见的具有较宽的输出光谱范围的相干宽诸光源主要包括： 锁 模脉冲激光源和超连续谱光源。 其中， 锁模技术包括主动锁模和被动锁模： 主动锁模技术中一般利用强度或相位调制器，对腔内振荡的光场的振幅或频 率（相位）进行反复调制， 从而不断产生新的调制边频， 使输出光信号具有 是一种全光非线性技术，在腔内不使用调制器之类的有源器件实现短脉冲输 出， 其原理在于利用非线性光学器件对输出脉冲的强度依赖性， 实现对脉冲 的压缩， 获得脉冲宽度很窄的光脉冲。 锁模技术是一种已经相当成熟且易于 实现的技术， 并有固体锁模激光器、 光纤锁模激光器、 半导体锁模激光器等 多种实现方法。 目前利用锁模技术可以实现脉宽小于几十 f s、 峰值功率大 于 1 kW、 重复频率大于 10 GHz、 时间抖动小于几个 f s的具有 f艮大占空比的高 重复频率的脉冲光源。 根据激光器增益介质的不同， 产生的输出光的中心波 长可以是可见光或红外波段。 目前各波段的各类锁模激光器都已有众多的成 熟的商用产品可选用。
超连续侮产生是指高功率的短光脉冲通过非线性介质时， 在自相位调 制、 交叉相位调制、 受激喇曼散射或四波混频等非线性效应和材料群速度色 散的共同作用下脉冲频语展宽的一种现象。超连续谱光源就是利用该物理现 象实现频谱宽度达到几十 nm以上， 乃至几百、 上千 nm的光源技术。 其输出光 谱的宽度可以进一步超过锁模脉冲激光器的谱宽，可覆盖可见光或近红外等 SPR系统常用的波长范围。其中的短光脉冲一般由锁模激光器或 Q开关激光器 产生并经光放大器放大得到。 非线性介质一般采用非线性光子晶体光纤、 色 散渐减光纤、 色散平坦光纤或色散位移光纤。 由于超连续谱可以在很宽的波 长范围内提供超短光脉冲， 因而已被应用于全光采样、 全光转换、 光波分复 用 （0WDM)和光时分复用（0TDM)等光通信技术中。 同时， Koheras和 Fianium 等公司都相继推出了相关产品。
光纤中的超连续谱产生的主要方案， 一种是在采用具有反常色散的光 纤， 利用孤子效应压缩脉冲获得光谱的展宽， 另一种是采用具有正常色散的 光纤， 利用其中的光克尔效应引起的频率啁啾， 实现脉冲展宽。 后者可以较 方便地产生具有线性啁啾的短光脉冲。
本实施例中下面所述的时域单调啁啾是指对脉冲频率在时域上单调展 开， 所述单调展开是指经过时域展宽后的脉冲中， 一个频率分量只对应一个 时间位置； 所述线性啁啾是指经过啁啾后的脉冲中， 各频率分量出现的时间 位置与其相对频率偏移成线性关系。
在光信号处理技术方面，本实施例主要利用的是色散效应和光脉冲的啁 嗽技术。
当一束光波与电介质的束缚电子相互作用时，介盾的响应通常与光波频 率有关， 这种特性称为色散。 当脉冲经过色散介盾或色散元件后， 不同波长 的频率分量经历不同的传输时延。 实现这样的色散效应的材料和器件很多， 例如： 光纤、 啁啾光纤光栅、 光栅对、 棱镜对、 超短脉冲波形控制器等。
以光纤为例： 当一个无啁啾的高斯脉冲 （其归一化光场振幅 由式（3) 给出）入射光场入射到光纤中时， 其在光纤中传输距离 z之后的光场振幅如 式（4) 。
[/(0,t) = exp(--^) ( 3)
U{∑' = (To2 - i 2z)m (- 2(T0 2― ιβ^ ( 4 ) 上式中， Τ。为输入脉冲的半宽参数（在光强度峰值的 1/e处）， 为群速 度色散参数， z为沿光纤的传播距离。 可见， 高斯脉冲在传输过程中仍具有 高斯波形， 但脉冲的半宽参数 T,随着 z增加， 如式（5)所示。
7ί(ζ) = Γ0[1 + ( / ο)2]1/2 (5) 其中， LD =T。VI 为色散长度。 (4)式可写作:
Figure imgf000009_0001
(7) l + O/ 。） T0 2 LD
δω(ί) = _l 2SgnQg2)( / 。） t (8)
d l + (z/LD)2 T0 2
由式（8)可见， 经过光纤传输的光场的瞬时频率 ， 即偏离中心频率 的频率差， 与时间 ί成正比， 这说明整个脉冲时间位置上各点的频率已经不 同， 且与时间位置成正比关系， 这被称为线性频率啁啾。
随着自 80年代末以来光脉冲技术的发展，光脉冲波形的控制技术已经非 常成熟。 采用上述光学色散技术和脉冲相位控制技术， 可以将相干脉冲光源 输出的短光脉冲， 经过色散器件， 得到展宽的具有线性啁啾的光脉冲波形。 对于采用波长扫描的 SPR系统来说，均采用非相干宽谱光源为光源，通过 检测出射光频傅分析 SPR响应， 采用单色仪、 光讲仪等为检测设备， 检测速 度非常有限。 若采用相干宽谱光源为光源， 经过色散元件展宽成具有啁啾的 脉冲波形， 使得在一个脉冲内， 频率位置与时间位置有对应关系， 则只需通 过检测时域波形分布来判断频域 SPR响应。 而时域波形分布通过高速光电探 测器能做到高速、 实时检测。
图 1给出了一种高速 SPR实时检测系统的实施例。 该系统包括在光路 上顺序设置的能够输出线性偏振光的相干宽谱脉冲光源 1、 色散器件 2、 SPR器件 3、 检测器 4和数据处理系统 11, 由相干宽谱脉冲光源 1输出的 第一脉冲 8经过色散器件 2后， 成为具有啁啾的第二脉冲 9, 第二脉冲 9 以固定角度入射到 SPR器件 3上，经过 SPR器件 3的反射得到第三脉冲 10, 检测器 4接收第三脉冲 10, 并将获得的数据传送给数据处理系统 11进行 处理。
其中所述相干宽谱脉冲光源 1采用飞秒脉冲激光器， 其输出脉冲的中 心波长为 1550nm, 脉冲重复频率 50MHz, 脉冲形状为高斯型， 脉冲宽度为 200fs, 频谱宽度为 26nm (均定义在强度峰值的 1/e处的宽度）；
所述色散器件采用普通单模光纤构成， 其群速度色散参数 ^为- 20 psVkm, 光纤长度为 25km, 将脉冲展宽到 10ns, 其脉冲波形和啁啾分布如图 2所示，从图中可以看到， 瞬时角频率的变化量与时间成正比， =2 x l022 rad/s2; 本领域技术人员应当理解， 色散器件也可以使用色散补偿光纤 (DCF)、 啁啾光纤光栅、 光栅对、 棱镜对或超短脉冲波形控制器等。
SPR传感器件中， 采用传统的棱镜耦合 Kretschmann结构， 耦合棱镜 5的 材料为 ZF-4, 其折射率为 1.69855 (在 1550nm波长上）， 传感层 6为厚度 50nra 的金膜；
样品池 7中的被测溶液为 1%的酒精水溶液， 折射率约为 1.3303, 其緩冲 溶液为水溶液， 折射率为 1.33;
检测器 4为高速光电检测器， 采用带宽为 40GHz的 P I N光电二极管检测器， W 响应时间为 9ps， 其对应波长约为 0. 2nm, 本领域技术人员应当理解， 也可以 使用雪崩光电二极管 PD )等其他高速光电检测器。
在整个测量系统中，所述相干宽谱脉冲光源还可以采用其他超连续谱光 源、 锁模激光器等， 相干宽谱光源的作用主要有： （i)其输出光谱中包含具 有能激发 SPR器件中的表面等离子共振效应相应的频谱分量， （i i)其输出光 谱具有一定谱宽， 包含丰富的频率分量， （i i i)其输出频谱具有相干性， 在 时域体现为其输出光的波形为脉冲形式， （i V)其输出光是具有较高重复频率 的脉冲序列，重复频率达到匪 z乃至 GHz量级，每个脉冲可完成一次测量扫描， 则检测速度可相应达到廳 z乃至 GHz量级， （V)其产生的输出脉冲序列具有高 稳定性， 即脉冲重复频率稳定， 序列中的各脉冲的启始时间位置具有严格的 周期性、 稳定准确， 脉冲序列中的各个脉冲的时域波形与频域频谱均相同， (vi)其输出傳宽决定了检测范围， （vi i)输出光具有 TM线偏振特性。 如果相 干宽谱光源的输出光不具有所需的线偏振性 , 还需要在输出光入射到 SPR器 件之前增加偏振器件。
所述色散器件还可以使用啁啾光纤光栅、 光栅对、 棱镜对或超短脉冲 波形控制器等， 色散器件的主要作用有： （i)使到达检测器之前的检测光具 有时域啁啾， 脉冲波形内的时域位置可对应于频域的波长， 如果使用时域线 性啁啾， 则脉冲波形内的时域位置可线性对应于频域的波长； （i i)使到达检 测器之前的检测光发生时域展宽， 提高信号波形的时间分辨率（即波长分辨 色散器件可以放置于 SPR器件之前， 将入射光展宽、 啁啾后用来激发 SPR 效应， 或可将色散器件放置于 SPR器件之后， 将 SPR效应作用后的信号光进行 展宽、 啁啾， 或者在 SPR器件的前后分别设置一个或多个色散器件， 共同实 现对被检测光的展宽、 啁啾。 另外， 如果选用的相干宽谱光源的输出已具有 满足检测系统的分辨率的要求的、 较大线性啁啾和脉冲展宽的情况下， 色散 器件也可省略。
所述 SPR器件主要为各种可产生 SPR效应的 SPR结构系统， 对待测物盾进 行检测。 本实施例所涉及的检测方法适用于各种 SPR结构， 传统单层金属 SPR 结构、 长程表面等离子共振 (LRSPR)、 耦合等离子波导共振 (CPWR)、 波导耦 合表面等离子共振 (WCSPR)等均可直接应用于上述测量系统当中。 SPR器件中 还包括将入射光束与反射光束耦合进出 SPR结构的光学装置， 当入射光不是 偏振光时， 还包括设置在 SPR器件之前的偏振控制器件， 用于以特定角度、 将检测光以 TM偏振态入射到 SPR组件上以激发相应的 SPR效应。
所述检测器的主要作用有： （i)将光信号转换为电信号， 以便进行信号 存储和处理； （i i)优选具有较高的响应速度， 这样才能够测量输入时域波形 的快速变化， 由此可分辨敖小的频率间隔上面的响应变化。
所述数据采集和处理单元的主要作用可以有： （i)将检测器输出的电信 号按照相干宽傅脉冲光源的输出频率分别对每个电脉冲信号的时域幅度信 息进行采集， （i i)对每个脉冲的釆集需要与脉冲频率严格同步， 即保证采集 后的各个脉冲的时间位置相同， （i i i)根据光源和色散器件所实现的脉冲的 啁啾特性，将每个脉冲波形的时间位置信息与其相对应的光频率信息一一对 应， （iv)将检测到的脉冲波形与无 SPR效应时的脉冲波形进行比较计算， 从 而将时域的幅度数据转化为波长与 SPR频谱响应的关系，从而获得 SPR效应的 息。
上述高速 SPR实时检测系统的检测方法如下：
首先， 将 SPR器件移出光路， 将所述飞秒脉冲激光器输出的激光耦合进 所述单模光纤中， 经过单模光纤的色散后， 激光脉冲的宽度由 200fs被展宽 到 10ns , 并且获得了线性啁啾特性， 未经过待测 SPR样品反射但经过所述啁 啾的脉冲相干宽谱光被所述 PIN检测器接收， 得到第二时域信号 ； 然后， 将注有待测样品的 SPR器件移入光路， 由所述单模光纤出射的激 光以固定角度入射到耦合棱镜 5上， 经过反射后的激光束被 PIN检测器接收， 并将光信号转换为电信号， 即第一时域信号 ( 0；
上述检测系统中， 另一种得到第一和第二时域信号的方法是： 首先， 根据待测样品的不同调整所述单模光纤出射的激光的入射角度， 激光以该固定的入射角度入射到耦合棱镜 5和 SPR器件上， 但所述 SPR器件中 注入与待测样品性质显著不同的其它样品， 如： 空气， 使得入射光在相应波 长范围内不满足 SPR条件从而不出现 SPR效应。 这时， 反射光经过单模光纤的 色散后， 激光脉冲的宽度由 200f s被展宽到 10ns , 获得了线性啁啾特性且不 具有 SPR响应信号， 经过反射后的激光束被 PIN检测器接收， 并将光信号转换 为电信号， 即得到第二时域信号
然后， 再向 SPR器件中注入待测样品， 由所述单模光纤出射的激光以固 定角度入射到耦合棱镜 5上， 经过反射后的激光束被 PIN检测器接收， 并将光 信号转换为电信号， 即得到第一时域信号 。 根据上面提及的激光器和光纤的参数可知， 在每一个激光脉冲内， 有^ ω=2 1022 ^i rad/s2, 又因为 λ Ι λ0 = 1 ωΙ ωϋ , 本领域技术人员应当理解， 可 将时域脉冲波形转换到频域， 有频域反射率 ?( L) = . ( ) , 由此进行分析。 或者， 由于时域反射率 ?(t) = . a¾ ， 该式中， 为经过 SPR器件反 射后的脉冲波形， 即第一时域信号； 为未经过 SPR器件反射， 但经过 单模光纤啁，秋的脉冲波形， 即第二时域信号， 也称背景波形。 两者相除， 即 可获得消除背景影响后， 时域脉冲反射率函数在对应 SPR位置上具有相对的 凹陷， 再由时域与频域的对应关系转换到频域， 获得的频域反射率函数具有 在对应 SPR波长位置上的相对凹陷， 如图 5所示。 具体如何由时域转换到频域 如前所示， 并进行相应的分析。 对频域 SPR信号的分析是本领域的常用技术 和手段， 在此不再赘述。
本例中将固定的入射角度选定为 52. 411度， 这是 I 550nm波长上产生 SPR 响应的角度， 本领域技术人员根据不同的入射波长， 应当能够选择合适的入 射角度， 图 3中为脉冲波形经 SPR效应调制后的形状， 图中分别对应使用金膜 的传感层 6对酒精水溶液和緩冲溶液水的 SPR响应。 由该波形可获得对应的有 SPR效应时脉冲的频谱强度， 如图 4所示。 通过与背景波形的对比， 可得对应 的 SPR波长响应， 如图 5所示。 由此， 本领域普通技术人员可根据波长扫描方 式中的数据处理方式提取被测介 的折射率等信息。
另外， 在上述检测系统实施例的基础上， 还可以设计出另一种结构的检 测系统， 该系统还包括第二 PIN检测器， 将单模光纤设置于所述飞秒脉冲激 光器与所述待测 SPR器件之间的光路上， 并在所述单模光纤与所述 SPR器件 之间增加分束装置， 由单模光纤出射的相干宽谱脉冲光被所述分束装置分成 两束， 其中一束经过分束后的相干宽谱脉冲光入射到所述待测 SPR器件上， 且另外一束经过分束后的相干宽谱脉冲光直接入射到所述第二 PIN检测器 上， 并由所述数据处理系统来分析和处理第二 PIN检测器的检测结果。
第二 PIN检测器同样可以用雪崩光电二极管检测器（ADP )等光电检测器 替代， 所述分束装置可以选择光学分束片、 光纤定向分路耦合器等。
相应地， 上述第二种检测系统的测量方法如下：
首先， 将所述飞秒脉冲激光器输出的激光耦合进所述单模光纤中， 经过 单模光纤的色散后， 激光脉冲的宽度由 200fs 宽到 10ns , 并且获得了线 性时域单调啁啾特性，
然后， 由所述单模光纤出射的激光被分束装置分成两束， 其中的一束以 固定角度入射到耦合棱镜 5上， 经过 SPR器件反射后被 PIN检测器接收， 并将 光信号转换为电信号， 即第一时域信号 另一束未经过 SPR反射但经 过所述啁啾的脉冲相干宽谱光被所述第二 PIN检测器接收， 得到第二时域 信号 — ； 其余的信号处理方式与第一种结构的检测装置相同。
第二种结构的检测系统与第一种检测系统相比， 在光路中， 所有用于产 生时域单调啁啾的色散器件必须设置在 SPR器件之前； 但是， 每次检测不必 再对 SPR器件进行移动， 可以同时测量第一和第二时域信号， 从而实现更加 快速的测量， 同时可克服光路中随时间变化的噪声对测量结果带来的影响， 在光源输出不稳定的情况下， 还可以克服光源脉冲变化造成的影响， 另外， 因为检测系统关心的是 SPR器件相对反射率和其变化规律而非其绝对值， 经分束装置分束得到的两束光强度可以不相等， 本领域技术人员应当理解， 根据具体应用的需要， 在不影响检测的情况下， 分束装置也可以将入射光分 成三束或更多束。
最后应说明的是， 以上各附图中的实施例仅用以说明本发明的表面等 离子共振传感的测量方法及其测量系统的结构和技术方案， 但非限制。 尽 管参照实施例对本发明进行了详细说明， 本领域的普通技术人员应当理 解， 对本发明的技术方案进行修改或者等同替换， 都不脱离本发明技术方 案的精神和范围， 其均应涵盖在本发明的权利要求范围当中。

Claims

权 利 要 求
1. 一种表面等离子共振的测量方法， 包括以下步驟：
( 1 )将具有线偏振的相干宽谱脉冲光入射到待测 SPR样品表面， 发 生反射；
( 2 )对所述入射相干宽谱脉冲光或所述 SPR反射光在时域上进行单 调啁啾；
( 3 )对具有时域单调啁啾的 SPR反射光进行检测得到第一时域信号， 检测未经过所述待测 SPR样品反射但经过所述啁啾的脉冲相干宽谱光得到 第二时域信号， 根据第一时域信号和第二时域信号， 获得 SPR共振波长信 息。
2. 根据权利要求 1所述的测量方法， 其特征在于， 步骤（3 )所述获 得 SPR共振波长信息的方法为： 根据第一时域信号与第二时域信号的比较 结果， 获得时域信号变化所对应的时间位置， 然后根据脉沖频率经过在时 域上进行单调啁啾后的分布， 得到所述时间位置对应的频域波长， 从而获 得 SPR共振波长信息。
3. 根据权利要求 1或 2所述的测量方法， 其特征在于， 同时对所述
Figure imgf000016_0001
（ 4 ) 利用波长扫描的数据处理方法确定 SPR被测样品的折射率变化等信息。
5. 根据权利要求 1-4任一项所述的测量方法， 其特征在于， 所述时 域单调啁啾为时域单调线性啁啾。
6. 根据权利要求 1-5任一项所述的测量方法， 其特征在于， 所述脉 冲相干宽谱光以固定角度入射到待测 SPR样品表面。
7. 一种表面等离子共振的测量系统， 包括能够产生线性偏振光的相 干宽谱脉冲光源、 能够产生时域单调啁啾的色散器件、 待测 SPR器件、 用 于接收 SPR反射光的检测器和用于处理所述第一检测器检测结果的数据处 理系统， 所述色散器件设置于所述检测器之前的光路上。
8. 根据权利要求 7 所述的测量系统， 其特征在于， 还包括第二检测 器和将入射光分成多束的分束装置， 所述色散器件设置于所述相干宽谱脉 冲光源与所述待测 SPR器件之间的光路上， 所述分束装置设置于所述色散 器件与所述 SPR器件之间的光路上， 经过分束后的分束光中， 至少一束分 束光入射到所述待测 SPR器件上， 且至少另外一束分束光直接被所述第二 检测器接收， 并由所述数据处理系统来处理所述第一和第二检测器的检测 结果。
9. 根据权利要求 8 所述的测量系统， 其特征在于， 所述分束装置为 光学分束片或光纤定向分路耦合器。
10. 根据权利要求 7或 8所述的测量系统， 其特征在于， 所述相干宽 谱脉冲光源为超连续谱光源或锁模激光器。
11. 根据权利要求 7或 8所述的测量系统， 其特征在于， 所述色散器 件为能够产生时域展宽的线性啁啾的色散器件。
12. 根据权利要求 7或 8所述的测量系统， 其特征在于， 所述色散器 件为光纤、 啁啾光纤光栅、 光栅对、 棱镜对或超短脉冲波形控制器。
13. 根据权利要求 7或 8所述的测量系统， 其特征在于， 所述第一检 测器和第二检测器为光电检测器。
14. 根据权利要求 13 所述的测量系统， 其特征在于， 所述光电检测 器为 PIN检测器或 APD检测器。
PCT/CN2007/003369 2007-11-29 2007-11-29 Procédé et système de mesure spr WO2009070913A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US12/745,444 US8416416B2 (en) 2007-11-29 2007-11-29 Measuring method for SPR and system thereof
PCT/CN2007/003369 WO2009070913A1 (fr) 2007-11-29 2007-11-29 Procédé et système de mesure spr

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2007/003369 WO2009070913A1 (fr) 2007-11-29 2007-11-29 Procédé et système de mesure spr

Publications (1)

Publication Number Publication Date
WO2009070913A1 true WO2009070913A1 (fr) 2009-06-11

Family

ID=40717246

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2007/003369 WO2009070913A1 (fr) 2007-11-29 2007-11-29 Procédé et système de mesure spr

Country Status (2)

Country Link
US (1) US8416416B2 (zh)
WO (1) WO2009070913A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108981584A (zh) * 2018-09-06 2018-12-11 中国工程物理研究院流体物理研究所 一种全光纤动态绝对距离测量装置及方法
WO2020169026A1 (zh) * 2019-02-23 2020-08-27 华为技术有限公司 在多显示驱动电路系统中显示图像的方法和电子设备

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10531859B2 (en) 2008-01-02 2020-01-14 Arcscan, Inc. Components for a precision ultrasonic scanning apparatus for body parts
JP2011508651A (ja) 2008-01-02 2011-03-17 アークスキャン インコーポレイテッド 撮像装置、超音波アーク走査装置、及び超音波走査装置
US9597059B2 (en) 2012-05-17 2017-03-21 Arcscan, Inc. Correcting for unintended motion for ultrasonic eye scans
US9320427B2 (en) 2012-07-09 2016-04-26 Arcscan, Inc. Combination optical and ultrasonic imaging of an eye
WO2015127417A1 (en) 2014-02-24 2015-08-27 Arcscan, Inc. Disposable eyepiece system for an ultrasonic eye scanning apparatus
US9459205B1 (en) * 2015-04-27 2016-10-04 Empire Technology Development Llc Refractive index measurement of liquids over a broad spectral range
WO2017066460A1 (en) 2015-10-13 2017-04-20 Arcscan, Inc Ultrasonic scanning apparatus
US11426611B2 (en) 2015-10-13 2022-08-30 Arcscan, Inc. Ultrasound therapeutic and scanning apparatus
CN111352144A (zh) * 2020-03-27 2020-06-30 中国科学院西安光学精密机械研究所 一种x射线超快检测装置及方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0517930A1 (en) * 1991-06-08 1992-12-16 Hewlett-Packard GmbH Method and apparatus for detecting the presence and/or concentration of biomolecules
US5229833A (en) * 1990-09-26 1993-07-20 Gec-Marconi Limited Optical sensor
CN1342885A (zh) * 2001-10-26 2002-04-03 清华大学 角度调制偏振型表面等离子体波传感器
US20070031154A1 (en) * 2005-08-05 2007-02-08 Vanwiggeren Gregory D Measurement system having modulated laser source

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5375011A (en) * 1993-08-18 1994-12-20 National Research Council Of Canada Non-linear, real-time, micrometer resolution optical time domain reflectometers for optoelectronic circuits diagnostic and sensing applications
US6915040B2 (en) * 1997-12-15 2005-07-05 University Of Southern California Devices and applications based on tunable wave-guiding bragg gratings with nonlinear group delays
EP0872721B1 (en) * 1998-02-14 2001-05-30 Agilent Technologies, Inc. Remote measurement of wavelength dependent information about optical components
US6459479B1 (en) * 1999-12-02 2002-10-01 University Of Southern California Optical detection of a fiber span with high polarization-mode dispersion in a fiber system
AU2003276870A1 (en) * 2002-09-07 2004-03-29 Lightwave Bioapplications Bioanalysis systems including optical integrated circuit
US7330301B2 (en) * 2003-05-14 2008-02-12 Imra America, Inc. Inexpensive variable rep-rate source for high-energy, ultrafast lasers
JP2005315858A (ja) * 2004-03-31 2005-11-10 Sun Tec Kk 光パルス評価装置およびインサービス光パルス評価装置
AU2005248797A1 (en) * 2004-05-15 2005-12-08 The Board Of Trustees Of The Leland Stanford Junior University Method of characterizing fiber Bragg gratings using iterative processing
US7586618B2 (en) * 2005-02-28 2009-09-08 The Board Of Trustees Of The University Of Illinois Distinguishing non-resonant four-wave-mixing noise in coherent stokes and anti-stokes Raman scattering
US7473916B2 (en) * 2005-12-16 2009-01-06 Asml Netherlands B.V. Apparatus and method for detecting contamination within a lithographic apparatus
US7407817B2 (en) * 2006-01-19 2008-08-05 The Chinese University Of Hong Kong Surface plasmon resonance sensors and method for detecting samples using the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5229833A (en) * 1990-09-26 1993-07-20 Gec-Marconi Limited Optical sensor
EP0517930A1 (en) * 1991-06-08 1992-12-16 Hewlett-Packard GmbH Method and apparatus for detecting the presence and/or concentration of biomolecules
CN1342885A (zh) * 2001-10-26 2002-04-03 清华大学 角度调制偏振型表面等离子体波传感器
US20070031154A1 (en) * 2005-08-05 2007-02-08 Vanwiggeren Gregory D Measurement system having modulated laser source

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108981584A (zh) * 2018-09-06 2018-12-11 中国工程物理研究院流体物理研究所 一种全光纤动态绝对距离测量装置及方法
CN108981584B (zh) * 2018-09-06 2023-07-18 中国工程物理研究院流体物理研究所 一种全光纤动态绝对距离测量装置及方法
WO2020169026A1 (zh) * 2019-02-23 2020-08-27 华为技术有限公司 在多显示驱动电路系统中显示图像的方法和电子设备
US11749171B2 (en) 2019-02-23 2023-09-05 Huawei Technologies Co., Ltd. Method for displaying image in multi display drive circuit system and electronic device

Also Published As

Publication number Publication date
US20100321697A1 (en) 2010-12-23
US8416416B2 (en) 2013-04-09

Similar Documents

Publication Publication Date Title
WO2009070913A1 (fr) Procédé et système de mesure spr
US9863815B2 (en) Method and apparatus for multifrequency optical comb generation
JP4883806B2 (ja) 分光方法及び分光装置
US6479822B1 (en) System and Method for terahertz frequency measurements
US9207121B2 (en) Cavity-enhanced frequency comb spectroscopy system employing a prism cavity
US11300452B2 (en) Spectral measurement method, spectral measurement system, and broadband pulsed light source unit
JP3498141B2 (ja) 光パルス評価方法、光パルス評価装置、及び光通信システム
KR20110036945A (ko) 주파수 빗 광원을 갖는 푸리에 변환 분광기
EP2994741A1 (en) A system and method for stimulated raman spectroscopy
Zarifi et al. Highly localized distributed Brillouin scattering response in a photonic integrated circuit
CN110646805A (zh) 一种基于虚拟扫频光源的调频连续波激光测距系统
WO2020075441A1 (ja) 分光分析用光源、分光分析装置及び分光分析方法
CN109060150B (zh) 基于光谱干涉的超短脉冲时间宽度测量装置和方法
Wan et al. Review on speckle-based spectrum analyzer
CN110274880A (zh) 一种高精度空间分辨的光谱探测方法和系统
CN209590271U (zh) 一种空间长度的测量装置
CN102636337A (zh) 一种测量光纤色散的方法
US6266145B1 (en) Apparatus for measurement of an optical pulse shape
JP2001272279A (ja) 光パルス評価装置
JP2000321134A (ja) テラヘルツ分光光度計
Nissim et al. Free-surface velocity measurements of opaque materials in laser-driven shock-wave experiments using photonic Doppler velocimetry
US10921290B2 (en) Laser ultrasonic testing
CN115165762B (zh) 一种具有光谱分辨功能的芯片
Hao et al. Time-delay fourier transform spectrometer for high-speed spectral measurement
Cherniak et al. Laser Diode based THz-TDS System with 133 dB peak Signal-to-Noise Ratio

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07845734

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 12745444

Country of ref document: US

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07845734

Country of ref document: EP

Kind code of ref document: A1