Hartman N F, Gaylord T K
Appl Opt. 1990 Oct 10;29(29):4372-83. doi: 10.1364/AO.29.004372.
A precision optical system, developed for characterizing the amplitude and phase properties of spatial light modulators, was used to characterize a 48 x 48 pixel magnetooptic spatial light modulator (MOSLM). Considerable variations in the amplitude (+/-25%) and phase transmittance (+/-50%) over the area of a given pixel were observed with coherent light illumination. The pixel-to-pixel variations in the average amplitude (+/-5%) and average phase (+/-6%) were considerably less. The contrast ratio and the polarization rotation for full frame monochromatic illumination were ~10:1 and 11.25 degrees , respectively. For illumination within a single pixel, the contrast ratio and polarization rotation were ~100:1 and 14.0 degrees , respectively. A theoretical model is presented showing that the reduced values for full frame illumination may be described by the coherent addition of light of unrotated polarization (transmitted between pixels and around the edges) with the polarization rotated light. The amplitude and phase characteristics of the MOSLM were found to be a very stable with repeated switching of the pixel and with switching of neighboring pixels. This stability is a central requirement in coherent optical information processing.
一种为表征空间光调制器的幅度和相位特性而开发的精密光学系统，被用于表征一个48×48像素的磁光空间光调制器（MOSLM）。在相干光照明下，观察到给定像素区域内的幅度（±25%）和相位透过率（±50%）有相当大的变化。像素间平均幅度（±5%）和平均相位（±6%）的变化则小得多。全帧单色照明下的对比度和偏振旋转分别约为10:1和11.25度。对于单个像素内的照明，对比度和偏振旋转分别约为100:1和14.0度。提出了一个理论模型，表明全帧照明的降低值可以通过未旋转偏振光（在像素之间和边缘周围传输）与偏振旋转光的相干叠加来描述。发现MOSLM的幅度和相位特性在像素重复切换以及相邻像素切换时非常稳定。这种稳定性是相干光学信息处理的核心要求。
