Wtra Sensitive PhaseRecovery Microscope Based on Fourier Iterative Method

对薄膜厚度大于前一年的90 nm的模型位相物体传输的光波进行了位相恢复实验。薄膜厚度与633 nm处的相位延迟约为1/14相对应。通过在熔融石英衬底上涂覆SiO_2薄膜来获得线宽为10 mm的线条和空间线条的位相分布，并对位相分布的基本参数，即线条的幅度和周期进行了精确的估计。由于测量的夫琅和费衍射图受到噪声的污染，相位恢复的准确性受到很大的限制，提出了一种估计和消除测量衍射图中的附加噪声的算法，并通过计算机模拟成功地验证了该算法的可行性。

Phase recovery experiments were conducted for the light waves transmitted through the model phase object whose film thickness is 90nm and greater than the one used in the previous year. The film thickness correspods to a phase delay of about lambda/14 at the wavelength of 633nm. The model object was fabricated by coating SiO2 film on a fused silica substrate in order to obtain a phase distribution of a line and space pattern whose linewidth was 10 mum.The fundamental parameters of the phase distribution, i.e., the amplitude and period of the pattern was estimated with good accuracy.Since the accuracy of phase recovery is greatly restricted if the measured Frauhofer diffraction pattern is contaminated with noise, an algorithm for estimating and eliminating the additive noise contained in the measured diffraction pattern was proposed, and its feasibility was successfully confirmed with computer simulation.