A nanometer-resolution displacement measurement instrument based on tunable cavity frequency-splitting method is presented. One beam is split into two orthogonally polarized beams when anisotropic element inserted in the cavity. The two beams with fixed frequency difference are modulated by the movement of the reflection mirror. The changing law of the power tuning curves between the total output and the two orthogonally polarized beams is researched, and a method splitting one tuning cycle to four equal parts is proposed based on the changing law, each part corresponds to one-eighth wavelength of displacement. A laser feedback interferometer (LFI) and piezoelectric ceramic are series connected to the sensor head to calibrate the displacement that less than one-eighth wavelength. The displacement sensor achieves to afford measurement range of 20mm with resolution of 6.93nm.

Date Published: 12 January 2018
PDF: 6 pages
Proc. SPIE 10621, 2017 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems, 1062113 (12 January 2018); doi: 10.1117/12.2291990

Published in SPIE Proceedings Vol. 10621:
2017 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems
Jigui Zhu; Hwa-Yaw Tam; Kexin Xu; Hai Xiao; Liquan Dong, Editor(s)