Wavelength-scanning Talbot effect and its application for arbitrary three-dimensional step-height measurement
- 作者：Satish Kumar Dubey ; Dalip Singh Mehta ; Amitava Roy ; Ch ; ra Shakher
- 关键词：Spectral shift ; Partially coherent flattened multi-Gaussian beam with an axial shadow ; ABCD optical system
- 刊名：Optics Communications
- 出版年：2007
- 期刊代码：50_00304018
- 类别：ph
- 出版时间：1 November 2007
- 卷：279
- 期：1
- 页码：13-19
- 文件大小：534 K
摘要
We demonstrate the phenomenon of Talbot self-image plane shift by tuning the wavelength of the broadband light source. A superluminescent diode (SLD) is used as a broad-band light source and an acousto-optic tunable filter (AOTF) as wavelength-scanning device. A periodic grating is illuminated by the wavelength tuned light of SLD using AOTF and Talbot self-image plane is shifted continuously in the longitudinal direction without mechanically moving the grating. The wavelength-scanning Talbot effect is then implemented for the measurement of arbitrary step-height of discontinuous objects with extended range. The main advantages of the proposed system are non-mechanical scanning, high stability because of it’s common-path geometry and compactness. Since the measurement of the phase is not required the system is free from phase ambiguity problem and therefore, the range of measurement is large as compare to interferometric techniques.