Lin JY, Liao YC. Small-angle measurement with highly sensitive total-internal-reflection heterodyne interferometer.
APPLIED OPTICS 2014;
53:1903-1908. [PMID:
24663469 DOI:
10.1364/ao.53.001903]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 02/05/2014] [Indexed: 06/03/2023]
Abstract
In this paper, a high-sensitivity total-internal-reflection (TIR) heterodyne interferometer is proposed for measuring small angles. In the proposed interferometer, a half-wave plate and two quarter-wave plates that exhibit specific optic-axis azimuths are combined to form a phase shifter. When a rhomboid prism is placed between the phase shifter and an analyzer that exhibits suitable transmission-axis azimuth, it shifts and enhances the phase difference of the s- and p-polarization states at double TIR. The enhanced phase difference is dependent on the incident angle; thus small angles can be easily and accurately measured by estimating the phase difference. The experimental results demonstrate the feasibility of this method. Angular resolution and sensitivity levels superior to 1.2×10⁻⁴ deg (2.1×10⁻⁶ rad) and 100 (deg/deg), respectively, were attainable in a dynamic range of 0.5 deg.
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