Long GAO^1*, Chunhui WANG¹, Yiqin JI², Yanchao LI¹, and Yang QU¹

¹National Key Laboratory of Science and Technology on Tunable laser, Harbin Institute of Technology, Harbin 150001, China
²Tianjin Key Laboratory of Optical Thin Films, Tianjin Jinhang Institute of Technical Physics, Tianjin 300192, China

(Received June 11, 2011; Accepted September 3, 2011)

This paper describes a novel fiber-coupled heterodyne interferometer using a micro-electro-mechanical system (MEMS) mirror and an f-theta lens. In this interferometer system, the cross-polarized laser beams operating at 2 μm with the frequency difference of 100 kHz are introduced by means of the two acousto-optic modulators (AOM). The sample with diameter of 300 mm is uniformly scanned by the 1 mm laser beam with the help of the combined optical scanning configuration, a MEMS mirror and an f-theta lens. The output intermediate signal from the two channels, reference channel and the measurement channel, are processed in the 12 bit analog-to-digital (A/D) process system. Details of our interferometer scheme are discussed.

Key words: heterodyne interferometer, MEMS mirror, f-theta lens, optical scanning

^*E-mail address: gaolong526@yahoo.cn