CN102393380A - Surface plasma resonance sensor - Google Patents

Abstract

Translated fromChinese

本发明公开了一种基于平面介质栅耦合的表面等离子共振传感器，包括平面介质栅，纳米厚度金属膜和玻璃基底，所述的平面介质栅的上表面与环境介质接触，环境中被探测物质的折射率改变导致入射波矢量的改变，导致平面正弦栅的衍射谱的改变；所述的平面介质栅的下表面与纳米厚度金属膜相连，平面介质栅引入的额外波矢量，能在界面处激发表面等离子共振效应。平面介质栅由光折变材料组成，其介电常数在空间上正弦分布；所述平面介质栅光栅矢量K可以倾斜。此传感器具有制备简单，由于每层都是平面结构易于光学集成，可以向低成本，集成化，阵列化发展，且工作稳定和灵敏度高的优点，在矿井安全，空气污染等领域提供了有效的研究手段。

The invention discloses a surface plasmon resonance sensor based on the coupling of a planar dielectric grid, which comprises a planar dielectric grid, a metal film with a nanometer thickness and a glass substrate. The upper surface of the planar dielectric grid is in contact with the environmental medium, and The change of the refractive index leads to the change of the incident wave vector, which leads to the change of the diffraction spectrum of the planar sinusoidal grating; the lower surface of the planar dielectric grating is connected with the nano-thickness metal film, and the extra wave vector introduced by the planar dielectric grating can be excited at the interface Surface plasmon resonance effect. The planar dielectric grating is composed of photorefractive materials, and its permittivity is sinusoidally distributed in space; the grating vector K of the planar dielectric grating can be inclined. This sensor has the advantages of simple preparation, easy optical integration because each layer is a planar structure, and can be developed towards low cost, integration, and array, and has the advantages of stable operation and high sensitivity. research tools.

Description

Translated fromChinese

一种表面等离子共振传感器A Surface Plasmon Resonance Sensor

技术领域technical field

 本发明涉及表面等离子共振传感器领域，特别是一种基于平面介质栅耦合的表面等离子共振传感器。The invention relates to the field of surface plasmon resonance sensors, in particular to a surface plasmon resonance sensor based on planar dielectric grid coupling.

背景技术Background technique

表面等离子共振（SPR）是一种物理现象，当入射光以临界角入射到两种不同折射率的介质界面（比如玻璃表面的金或银镀层）时，可引起金属自由电子的共振，由于电子吸收了光能量，从而在反射光强的响应曲线看到一个最小的尖峰，此时对应的入射光波长为共振波长，对应的入射角为共振角。根据这一原理研制的表面等离子体传感器在检测、 分析生物分子间的相互作用等方面得到广泛的应用。由于其具有体积小、 测量准确度高、 抗电磁干扰能力强，因此表面等离子共振传感器在生物医学、 环境保护、 食品及化学等领域具有广泛的应用前景。Surface plasmon resonance (SPR) is a physical phenomenon. When the incident light hits the interface of two media with different refractive indices (such as gold or silver coating on the glass surface) at a critical angle, it can cause the resonance of metal free electrons. The light energy is absorbed, so that a minimum peak can be seen in the response curve of the reflected light intensity. At this time, the corresponding incident light wavelength is the resonance wavelength, and the corresponding incident angle is the resonance angle. The surface plasmon sensor developed according to this principle has been widely used in the detection and analysis of the interaction between biomolecules. Due to its small size, high measurement accuracy, and strong anti-electromagnetic interference ability, surface plasmon resonance sensors have broad application prospects in the fields of biomedicine, environmental protection, food, and chemistry.

Kretschmann利用衰减全反射棱镜藕合方法, 实现光激发表面等离子波, 为SPR传感器的商用化奠定了基础。表面等离子共振传感技术作为一种新型的光电检测技术近年来己经在国外得到了迅速的发展和应用。瑞典的BIAcore AB、美国的Affinity Sensors、Texas Instrument，日本的Nippon Laser Electronics等公司相继有产品投入商用。在我国，对此类SPR生化分析仪的需求也日趋迫切，对其研制和开发也是非常必要和紧迫的。值得一提的是中科院电子所开发的SPR-2000型产品是我国自主研发的SPR传感仪,最近又获得新的进展。此外国内开展此项研究的科研院校还有清华大学精密仪器与机械学系余兴龙课题组，吉林大学宋大千课题组，浙江大学王晓萍课题组以及南京航空航天大学梁大开课题组在这方面取得了不错的进展。从目前产品的结构原理来看，无论是国外的BIAcore AB，还是中科院SPR-2000型表面等离子共振生化分析仪均属于棱镜结构，而且几乎都是采用角度调制模型建立起来的SPR生化分析仪器。尽管这些仪器采用了先进的虚拟仪器技术以及嵌入式微控制器为主体的仪器系统，由于系统中需要一套精确测角机构和角度调整装置，增加了仪器的构建难度和成本。Kretschmann used the attenuated total reflection prism coupling method to realize light-excited surface plasmon waves, which laid the foundation for the commercialization of SPR sensors. As a new type of photoelectric detection technology, surface plasmon resonance sensing technology has been rapidly developed and applied abroad in recent years. Companies such as BIAcore AB in Sweden, Affinity Sensors and Texas Instrument in the United States, and Nippon Laser Electronics in Japan have successively put their products into commercial use. In our country, the demand for this kind of SPR biochemical analyzer is becoming more and more urgent, and its research and development is also very necessary and urgent. It is worth mentioning that the SPR-2000 product developed by the Institute of Electronics, Chinese Academy of Sciences is an SPR sensor independently developed by my country, and has recently made new progress. In addition, domestic scientific research institutions that have carried out this research include Yu Xinglong’s research group from the Department of Precision Instruments and Mechanics of Tsinghua University, Song Daqian’s research group from Jilin University, Wang Xiaoping’s research group from Zhejiang University, and Liang Dakai’s research group from Nanjing University of Aeronautics and Astronautics. Nice progress. Judging from the structural principle of the current products, both the foreign BIAcore AB and the SPR-2000 surface plasmon resonance biochemical analyzer of the Chinese Academy of Sciences belong to the prism structure, and almost all of them are SPR biochemical analysis instruments established by using the angle modulation model. Although these instruments use advanced virtual instrument technology and embedded microcontroller as the main instrument system, because the system needs a set of precise angle measuring mechanism and angle adjustment device, the difficulty and cost of instrument construction are increased.

提高传感器性能, 实现阵列化、集成化, 采用新型传感装置和检测技术, 以及拓展新的应用领域已成为当前及未来传感器发展的主要方向。其中结合光栅、光波导，光纤技术的SPR传感器在降低成本, 实现小型化、集成化及高稳定性等方面有独特优势, 可推动传感器的普及和拓展新的应用领域。Improving sensor performance, realizing arraying and integration, adopting new sensing devices and detection technologies, and expanding new application fields have become the main directions of current and future sensor development. Among them, the SPR sensor combined with grating, optical waveguide and fiber optic technology has unique advantages in reducing cost, realizing miniaturization, integration and high stability, which can promote the popularization of sensors and expand new application fields.

发明内容Contents of the invention

本发明所要解决的技术问题是提供一种表面等离子共振传感器，具有低成本，微型化，阵列化的特点。The technical problem to be solved by the present invention is to provide a surface plasmon resonance sensor, which has the characteristics of low cost, miniaturization and array formation.

为解决上述技术问题，本发明的技术方案是：一种表面等离子共振传感器，包括纳米厚度金属膜和玻璃基底，其特征在于，还包括平面介质栅,所述的平面介质栅的上表面与环境介质接触，下表面与所述纳米厚度金属膜相连；所述平面介质栅的厚度为60nm-200nm，可调度为0.05-0.15，所述纳米厚度金属膜的厚度为50nm-200nm。环境中被探测物质的折射率改变导致入射波矢量的改变，导致平面正弦栅的衍射谱的改变；平面介质栅引入的额外波矢量，能在界面处激发表面等离子共振效应。所述的平面介质栅由常见的重铬酸盐明胶材料组成。所述平面介质栅的光栅矢量方位角为大于0°小于180°。所述纳米厚度金属膜为表面连续的金属膜。In order to solve the above technical problems, the technical solution of the present invention is: a surface plasmon resonance sensor, comprising a nanometer-thick metal film and a glass substrate, characterized in that it also includes a planar dielectric grid, the upper surface of the planar dielectric grid is in contact with the environment In contact with the medium, the lower surface is connected with the nano-thick metal film; the thickness of the planar dielectric gate is 60nm-200nm, which can be adjusted to 0.05-0.15, and the thickness of the nano-thick metal film is 50nm-200nm. The change of the refractive index of the detected substance in the environment leads to the change of the incident wave vector, resulting in the change of the diffraction spectrum of the planar sinusoidal grating; the extra wave vector introduced by the planar dielectric grating can excite the surface plasmon resonance effect at the interface. The planar dielectric grid is composed of common dichromate gelatin material. The azimuth angle of the grating vector of the planar dielectric grating is larger than 0° and smaller than 180°. The nanometer-thick metal film is a metal film with a continuous surface.

本发明的主要优点有：Main advantage of the present invention has:

由于平面正弦栅结构不需刻蚀复杂形状的几何结构，易于制备且结构简单，利用该结构进行表面等离子耦合，最直接的优点就是可以向低成本，微型化，阵列化发展。Since the planar sinusoidal grid structure does not need to etch a geometric structure with complex shapes, it is easy to prepare and has a simple structure. The most direct advantage of using this structure for surface plasmon coupling is that it can be developed towards low cost, miniaturization, and array.

与金属光栅或其他面型介质栅比，平面正弦栅除了光栅周期，厚度可以控制外，还增加了光栅矢量K可控，设计更加灵活。通过调光栅矢量K，就可以间接的调制界面沿X方向的光栅周期，从而调制表面等离子的共振波长，消除了制备不同周期的光栅需要不同波长激光制备的弱点。Compared with metal gratings or other surface dielectric gratings, in addition to the controllable period and thickness of the grating, the planar sinusoidal grating also increases the controllability of the grating vector K, making the design more flexible. By adjusting the grating vector K, the grating period of the interface along the X direction can be indirectly modulated, thereby modulating the resonance wavelength of the surface plasmon, eliminating the weakness that different wavelength lasers are required to prepare gratings with different periods.

附图说明Description of drawings

下面结合附图和具体实施方式对本发明的技术方案作进一步具体说明。The technical solutions of the present invention will be further specifically described below in conjunction with the accompanying drawings and specific embodiments.

图1为本发明表面等离子共振传感器的截面示意图，Fig. 1 is a schematic cross-sectional view of a surface plasmon resonance sensor of the present invention,

图2为实施例1的反射谱。Fig. 2 is the reflection spectrum ofembodiment 1.

图3为实施例2的反射谱。Fig. 3 is the reflection spectrum ofembodiment 2.

图4为实施例3的反射谱。Fig. 4 is the reflection spectrum ofembodiment 3.

图5为实施例4的反射谱。Figure 5 is the reflectance spectrum of Example 4.

图6为实施例5的反射谱。Figure 6 is the reflectance spectrum of Example 5.

具体实施方式Detailed ways

如图1所示的本发明表面等离子共振传感器截面示意图，包括平面介质栅1、纳米厚度金属膜2和玻璃基底3，平面介质栅1的厚度为60nm-200nm，折射率调制度为0.05-0.15，平面介质栅的上表面与环境介质接触，下表面与纳米厚度金属膜2相连,环境介质折射率在图2~图6中用n1表示；纳米厚度金属膜的下表面与玻璃基底的上平面连接。纳米厚度金属膜的厚度为50nm-200nm。光栅矢量K方位角在大于0°小于180°的范围内可调。The cross-sectional schematic view of the surface plasmon resonance sensor of the present invention as shown in Figure 1 includes a planardielectric grid 1, a nanometer-thick metal film 2 and aglass substrate 3, the thickness of the planardielectric grid 1 is 60nm-200nm, and the refractive index modulation is 0.05-0.15 , the upper surface of the planar dielectric grid is in contact with the environmental medium, and the lower surface is connected with the nanometer-thick metal film 2, and the refractive index of the environmental medium is represented by n1 in Figures 2 to 6; the lower surface of the nanometer-thick metal film is in contact with the upper plane of the glass substrate connect. The thickness of the nano-thickness metal film is 50nm-200nm. The azimuth angle of the grating vector K is adjustable within a range greater than 0° and less than 180°.

下面给出几个具体实施例，在下列实施例中，选择平面介质栅的光栅周期比相应光源的波长小，即为亚波长光栅，比如白光光源，周期可选400~600nm，如果是光通信波段（1300-1600nm）,周期可选1000-1200 nm较好。 另外光栅材料可选重铬酸盐明胶，未调制时的折射率对应为1.50，可获得较大折射率调制度，是理想的制备平面正弦光栅材料。Several specific examples are given below. In the following examples, the grating period of the planar dielectric grating is selected to be smaller than the wavelength of the corresponding light source, that is, a sub-wavelength grating, such as a white light source, and the period can be 400~600nm. If it is an optical communication Band (1300-1600nm), the period can be selected from 1000-1200nm is better. In addition, dichromate gelatin can be selected as the grating material, and the unmodulated refractive index corresponds to 1.50, which can obtain a large refractive index modulation degree, and is an ideal material for preparing planar sinusoidal gratings.

实施例1Example 1

本实施例的表面等离子共振传感器的平面介质栅的周期为500nm,厚度为60nm，光栅矢量K方位角为120o，折射率为1.5，调制度为0.15。纳米厚度金属膜选用贵金属银膜，厚度为100nm。所述的玻璃基底折射率为1.46。在环境折射率为1或1.1，垂直入射的条件下，得到如图2所示的检测图谱。The period of the planar dielectric grating of the surface plasmon resonance sensor in this embodiment is 500 nm, the thickness is 60 nm, the azimuth angle of the grating vector K is 120°, the refractive index is 1.5, and the modulation degree is 0.15. The nano-thickness metal film is selected from precious metal silver film with a thickness of 100nm. The refractive index of the glass substrate is 1.46. Under the conditions of the ambient refractive index of 1 or 1.1 and normal incidence, the detection spectrum shown in Figure 2 is obtained.

图中表明该实例参数下表面等离子共振吸收峰尖锐，全宽半高（FWHH）为4nm；另一方面环境折射率改变0.1，共振波长改变了42nm，灵敏度为420nm每折射率单位。该实例具有良好的环境折射率传感性能，品质因子（灵敏度/全宽半高）为105。The figure shows that the surface plasmon resonance absorption peak is sharp under the parameters of this example, and the full width half maximum (FWHH) is 4nm; on the other hand, the ambient refractive index changes by 0.1, the resonance wavelength changes by 42nm, and the sensitivity is 420nm per refractive index unit. This example has good ambient refractive index sensing performance with a figure of merit (sensitivity/full width half maximum) of 105.

实施例2Example 2

本实施例的表面等离子共振传感器的平面介质栅的周期为500nm,厚度为60nm，光栅矢量K方位角为120o，折射率为1.5，调制度为0.05。纳米厚度金属膜选用贵金属银膜，厚度为100nm。所述的玻璃基底折射率为1.46。在环境折射率为1或1.1，入射角为0°的条件下，得到如图3所示的检测图谱。与实例1参数相比，仅折射率调制度减小，由图3可知，反射共振吸收峰的位置没变，只是深度稍变浅，而灵敏度，全宽半高及品质因子都没变。The period of the planar dielectric grating of the surface plasmon resonance sensor in this embodiment is 500 nm, the thickness is 60 nm, the azimuth angle of the grating vector K is 120°, the refractive index is 1.5, and the modulation degree is 0.05. The nano-thickness metal film is selected from precious metal silver film with a thickness of 100nm. The refractive index of the glass substrate is 1.46. Under the condition that the refractive index of the environment is 1 or 1.1 and the incident angle is 0°, the detection spectrum shown in Figure 3 is obtained. Compared with the parameters in Example 1, only the modulation degree of the refractive index is reduced. It can be seen from Figure 3 that the position of the reflection resonance absorption peak has not changed, but the depth has become slightly shallower, while the sensitivity, full width at half maximum and quality factor have not changed.

实施例3 Example 3

本实施例的表面等离子共振传感器的平面介质栅的周期为500nm，厚度为60nm，光栅矢量K方位角为120o，折射率为1.52，调制度为0.1。纳米厚度金属膜选用贵金属银膜，厚度为100nm。所述的玻璃基底折射率为1.72。在环境折射率为1或1.1，垂直入射的条件下，得到如图4所示的检测图谱。与图3接近，说明在配备重铬酸盐明胶的溶液时引起的误差导致光栅折射率的微小变化对传感性能的影响不大，。The period of the planar dielectric grating of the surface plasmon resonance sensor in this embodiment is 500 nm, the thickness is 60 nm, the azimuth angle of the grating vector K is 120°, the refractive index is 1.52, and the modulation degree is 0.1. The nano-thickness metal film is selected from precious metal silver film with a thickness of 100nm. The glass substrate has a refractive index of 1.72. Under the condition of the ambient refractive index of 1 or 1.1 and normal incidence, the detection spectrum shown in Figure 4 is obtained. It is close to Fig. 3, which shows that the error caused when the dichromate gelatin solution is prepared causes a small change in the refractive index of the grating to have little effect on the sensing performance.

实施例4Example 4

本实施例的表面等离子共振传感器的平面介质栅的周期为600nm，厚度为100nm，光栅矢量K方位角为90o，折射率为1.50，调制度为0.08。纳米厚度金属膜选用贵金属银膜，厚度为200nm。所述的玻璃基底折射率为1.72。在环境折射率为1或1.1，入射角为10°的条件下，得到如图5所示的检测图谱。灵敏度为290nm每折射率单位，全宽半高也相应变小为3，这样品质因子为96.7。The period of the planar dielectric grating of the surface plasmon resonance sensor in this embodiment is 600 nm, the thickness is 100 nm, the azimuth angle of the grating vector K is 90°, the refractive index is 1.50, and the modulation degree is 0.08. The metal film with nanometer thickness is selected from precious metal silver film, and the thickness is 200nm. The glass substrate has a refractive index of 1.72. Under the condition that the ambient refractive index is 1 or 1.1 and the incident angle is 10°, the detection spectrum shown in Figure 5 is obtained. The sensitivity is 290nm per refractive index unit, and the full width and half maximum is correspondingly reduced to 3, so the quality factor is 96.7.

实施例5Example 5

本实施例的表面等离子共振传感器的平面介质栅的周期为1000nm，厚度为200nm，光栅矢量K方位角为90o，折射率为1.5，调制度为0.15。纳米厚度金属膜选用贵金属银膜，厚度为100nm。所述的玻璃基底折射率为1.46。在环境折射率为1.3或1.4，入射角为0°的条件下，得到如图6所示的检测图谱。该实例适用光通信波段，传感性能与可见光波段相似，灵敏度为540纳米每单位折射率，全宽半高为5nm，品质因子为108。The period of the planar dielectric grating of the surface plasmon resonance sensor in this embodiment is 1000 nm, the thickness is 200 nm, the azimuth angle of the grating vector K is 90°, the refractive index is 1.5, and the modulation degree is 0.15. The nano-thickness metal film is selected from precious metal silver film with a thickness of 100nm. The refractive index of the glass substrate is 1.46. Under the condition that the ambient refractive index is 1.3 or 1.4 and the incident angle is 0°, the detection spectrum shown in Figure 6 is obtained. This example is suitable for the optical communication band, the sensing performance is similar to that of the visible light band, the sensitivity is 540 nanometers per unit refractive index, the full width and half maximum is 5nm, and the quality factor is 108.

最后所应说明的是，以上具体实施方式仅用以说明本发明的技术方案而非限制，尽管参照较佳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，可以对本发明的技术方案进行修改或者等同替换，而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。Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the present invention can be Modifications or equivalent replacements of the technical solutions without departing from the spirit and scope of the technical solutions of the present invention shall fall within the scope of the claims of the present invention.

Claims (3)

Translated fromChinese

1.一种表面等离子共振传感器，包括纳米厚度金属膜和玻璃基底，其特征在于，还包括平面介质栅,所述的平面介质栅的上表面与环境介质接触，下表面与所述纳米厚度金属膜相连；所述平面介质栅的厚度为60nm-200nm，可调度为0.05-0.15，所述纳米厚度金属膜的厚度为50nm-200nm。1. A surface plasmon resonance sensor, comprising a nano-thick metal film and a glass substrate, characterized in that it also includes a planar dielectric grid, the upper surface of the planar dielectric grid is in contact with the environmental medium, and the lower surface is in contact with the nano-thickness metal The films are connected; the thickness of the planar dielectric gate is 60nm-200nm, which can be adjusted to 0.05-0.15, and the thickness of the nanometer-thick metal film is 50nm-200nm.2.根据权利要求1所述的一种表面等离子共振吸收传感器，其特征在于，所述平面介质栅的光栅矢量方位角为大于0°小于180°。2. A surface plasmon resonance absorption sensor according to claim 1, characterized in that the azimuth angle of the grating vector of the planar dielectric grating is greater than 0° and less than 180°.3.根据权利要求1或2所述的一种表面等离子共振吸收传感器，其特征在于，所述纳米厚度金属膜为表面连续的金属膜。3. A surface plasmon resonance absorption sensor according to claim 1 or 2, characterized in that the nanometer-thick metal film is a continuous metal film on the surface.

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