A displacement sensor that uses a vertical cavity surface emitting laser (VCSEL), which is superior in terms of remediation of the mode-hop issue and modulation efficiency, is proposed. The interference signal in the sensor is processed with the phase-locked technique. This device allows real-time measurement of displacement. No unstable signals due to mode-hop were observed in the experiments. Displacement measurements recorded with this device indicated that it has an rms measurement accuracy of 0.3 μm and 50 nm for displacements of 150 μm and 1.2 μm, respectively.

Date Published: 20 November 2012
PDF: 6 pages
Proc. SPIE 8563, Optical Metrology and Inspection for Industrial Applications II, 85630K (20 November 2012); doi: 10.1117/12.999720

Published in SPIE Proceedings Vol. 8563:
Optical Metrology and Inspection for Industrial Applications II
Kevin G. Harding; Peisen S. Huang; Toru Yoshizawa, Editor(s)