摘要
表面等离子体共振(surface plasmon resonance,SPR)在生物传感中有极大的应用价值,基于棱镜结构的共振角的相位传感比反射率传感具有更高的灵敏度.多通道实时相移探测是SPR生物传感的研究热点和难点.本文提出了一种基于Kretschmann棱镜结构的衰减全反射(attenuated total reflection,ATR)单光路的SPR相位检测系统.通过液晶可变延迟器(liquid crystal variable re-tarder,LCVR)调控可激发表面等离子体激元(surface plasmon plaritons,SPPs)的P-偏振光和作为参考光的S-偏振光的相位差,实现单光路干涉.通过可寻址的微镜阵列(micro-mirror array,MMA)实现棱镜二维表面的定点相位探测.该系统能够以接近单个MMA像素的空间分辨率(水平/垂直为7.64μm或对角线为10.8 μm)探测相移信息,从而实现单光路、高精度、多通道的二维等离子共振相移探测,为原位生物传感器和突破衍射极限的相位成像提供新的实验思路.
Abstract
Surface plasmon resonance(SPR)has tremendous application value in biosensing.The phase sensing of the resonant angle based on a prism structure exhibits higher sensitivity compared with the reflectivity sensing.Multi-channel real-time phase shift detection is a research highlight in SPR biosens-ing.An SPR phase detection system based on Kretschmann prism structure attenuated total reflection(ATR)single-path is proposed.The phase difference between P-polarized signal light and S-polarized reference light is controlled by a liquid crystal variable retarder(LCVR)to realize single-path interfer-ence.Fixed-point phase detection of two-dimensional surfaces is realized by an addressable micro-mirror array(MMA).The system can detect the phase shift information with a spatial resolution close to a sin-gle MMA pixel(7.64 μm horizontally/vertically or 10.8 μm diagonally).It is capable of realizing single-path,high-precision,multi-channel two-dimensional plasmon resonance phase shift detection,providing new experimental ideas for in-situ biosensors and phase imaging beyond diffraction limits.
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