为了研究反射式256 pixel×256 pixel纯相位液晶空间光调制器(LC-SLM)的性能,并最大程度地发挥其波前校正能力,建立了泰曼格林(Twyman-Green)干涉仪与移相点衍射干涉仪分别对SLM的相移特性以及静态畸变进行测量,同时使用该空间光调制器对其自身的波前畸变进行补偿。实验结果表明,当应用一个正确的相位灰度值映射并且增加静态畸变补偿后,这个空间光调制器的波前像差的峰谷(PV)值由0.39λ减小到0.23λ,均方根(RMS)值由0.08λ减小到0.03λ(λ=632.8 nm),远场点扩展函数的斯特雷尔比由0.82提高到0.98。因此经畸变补偿后的液晶空间光调制器能够被更好地应用在动态衍射光学元件、波前产生和高分辨、高精度的波前校正中。

To investigate the performance of a reflecting 256 pixel×256 pixels phase-only liquid crystal spatial light modulator (LC-SLM) and to improve the ability of wavefront correction,the Twyman-Green interferometer and the phase-shift point-diffraction interferometer are set-up to measure the phase-shift characteristic and the static distortion of this SLM individually,and then use the SLM to compensate the distortion from itself. Experimental results show that the peak-to-valley (PV) value and the root mean square (RMS) values of the wavefront are reduced from 0.39λ and 0.08λ to 0.23λ and 0.03λ (λ=632.8 nm) respectively after applying an appropriate mapping of phase to grayscale and adding static distortion compensation. In addition,the Strehl ratios of far-field point spread functions are increased from 0.82 to 0.98. Therefore,this SLM with compensation is an excellent candidate for applications,such as dynamic diffractive optical elements,wavefront generation,high-resolution and high-precision wavefront correction.