为了满足光偏振态分振幅测量模块(DOAP)对分光棱镜复杂且严格的加工要求,采用在经典DOAP透射光路及反射光路各引入一块波片的方法,组成改进后的光偏振态测量模块.推导了新的仪器矩阵表达式,通过分析波片参量对仪器矩阵条件数的影响,得到了最佳波片的参量及其关系.结果表明,优化后的斯托克斯椭偏仪测量薄膜样品的厚度和折射率的标准差分别为0.1nm和0.001.通过选择波片的最佳方位角或相位延迟量可以实现斯托克斯椭偏仪仪器矩阵的优化,从而提高系统的测量稳定性及可靠性.%Division-of-amplitude photopolarimeter( DOAP) was the key part of Stokes ellipsometer. To reach the complex and strict processing demands of beam splitter in DOAP, two waveplates are inserted respectively in the reflection light path and transmittion light path of classic DOAP to form an improved DOAP. The instrument matrix of new DOAP was derived and influence of waveplate parameters on the condition number of instrument matrix was also analyzed. From theoretical analysis and experimental verification, the optimal parameters and their relationships of waveplates were gotten. The results show that, measurement standard errors of film thickness and refractive index of the optimized Stokes ellipsometer are 0. 1nm and 0. 001 respectively. By choosing the optimal azimuthal angles or phase retardations of waveplates, the instrument matrix can be optimized to improve the accuracy and stability of measurement.
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