非扫描衰减全反射探测法监控光漂白过程

Real-Time Measurement for the Refractive Index and Depth Change of a Polymer During Photobleaching Process by Non-Scanning ATR Method

提出了一种基于衰减全反射原理的实时探测方法。其实验框架由半导体激光器、空间滤波器、聚焦透镜、耦合棱镜、CCD接受装置等组成。激光束先经空间滤波器扩束 ,再由透镜聚焦 ,以一定角宽度的光束聚焦于耦合棱镜底面 ,由于棱镜底面的波导结构 ,在反射光斑中会出现若干条吸收峰 ,即显示出标志波导模式的一组黑线 ,若外界条件变化时 (如紫外光照射、电极化等 ) ,波导薄膜某些参量会受外界条件的变化而变化 ,表现为黑线的移动 ,可根据黑线的移动量 ,精确测量每一时刻波导薄膜的折射率和膜厚等参量。利用这种技术 ,可以广泛地用于条波导制作、镀膜监控、薄膜极化监控。

A real-time measuring method based on the ATR technique is proposed. The experimental setup consists of a laser diode as the optical source, a spatial filter as a beam expander, a CCD detector as a camera and a coupling prism. When a converged light beam which is transmitted through the spatial filter incidents upon the hypotenuse face of the prism, the reflected divergence spot imaged by the CCD camera will embody a black line in the case of the angular width of the light beam contains a coupling angle corresponding to guided wave resonance. Several dark lines corresponding to the guided-wave modes are demonstrated on the computer screen. The dark lines move when some parameters of guide wave change. According to the shift of the dark lines, the refractive index and the film thickness of the polymer can be determined. This experimental setting can be used widely such as the waveguide fabricating, detecting the poling process etc.