Chu Shu-Chun, Chern Jyh-Long
Department of Photonics, Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
J Opt Soc Am A Opt Image Sci Vis. 2005 Feb;22(2):335-41. doi: 10.1364/josaa.22.000335.
The dynamic signature of the subwavelength variation of a rectangular aperture has recently been shown to be determinable from far-field irradiance with a precision better than 1 nm [Opt. Lett. 29, 1045 (2004)]. We have proposed, and have theoretically shown, that detection sensitivity can be greatly enhanced with an embedded-aperture Mach-Zehnder interferometer configuration, after parameter optimization. The sensitivity, in terms of derivative intensity of observed subwavelength variations, could be enhanced approximately 2.7 times, compared with the directly detected method. Another method of detection of subwavelength variation from pattern measurement of far-field diffraction has also been proposed. The associated shifting of the dark line of the diffraction pattern had a good linear correlation to subwavelength variation, which was magnified approximately 150 times, and gave good contrast for measurement.
最近研究表明，矩形孔径亚波长变化的动态特征可通过远场辐照度来确定，精度优于1nm [《光学快报》29, 1045 (2004)]。我们已经提出并从理论上证明，在优化参数后，采用嵌入式孔径马赫 - 曾德尔干涉仪配置可大大提高检测灵敏度。与直接检测方法相比，就观察到的亚波长变化的导数强度而言，灵敏度可提高约2.7倍。还提出了另一种通过远场衍射图案测量来检测亚波长变化的方法。衍射图案暗线的相关位移与亚波长变化具有良好的线性相关性，该变化被放大了约150倍，并且为测量提供了良好的对比度。
