OPTICAL-FIELD CORRECTION WITH DEFORMABLE MIRRORS

Optical-field correction with deformable mirrors can be accomplished b y correction of both amplitude and phase. As a result of developments over the past 20 years, phase correction with deformable mirrors has b ecome a mature technology. We discuss simply the phase correction when it is concerned with field correction. The basic principle of amplitu de correction with deformable mirrors is that if a certain phase distr ibution is constructed at the deformable mirror, after a vacuum diffra ction, a certain amplitude distribution can be obtained. Some algorith ms for implementing the principle have been put forward by several res earchers [T. T. Karr, Proc. Soc. Photo-Opt. Instrum. Eng. 1221, 26 (19 90); Wang Yai-yun et al., Proc. Soc. Photo-Opt. Instrum. Eng. 1628, 24 4 (1992)]. But there are two problems that need to be solved. The firs t is that the vacuum path is too long. The second is that the precisio ns of these algorithms are relatively low. We describe a new algorithm , which not only yields a 1-2 order-of-magnitude reduction in the vacu um distance but also improves the amplitude correction precision.