We report a demonstration of phase-resolved vibrometry, in which out-of-plane sinusoidal motion is assessed by heterodyne holography. In heterodyne holography, the beam in the reference channel is an optical local oscillator (LO). It is frequency-shifted with respect to the illumination beam to enable frequency conversion within the sensor bandwidth. The proposed scheme introduces a strobe LO, where the reference beam is frequency-shifted and modulated in amplitude, to alleviate the issue of phase retrieval. The strobe LO is both tuned around the first optical modulation sideband at the vibration frequency, and modulated in amplitude to freeze selected mechanical vibration states sequentially. The phase map of the vibration can then be derived from the demodulation of successive vibration states.
© 2013 Optical Society of America
Original Manuscript: November 26, 2012
Revised Manuscript: December 19, 2012
Manuscript Accepted: January 3, 2013
Published: January 31, 2013
Nicolas Verrier, Michel Gross, and Michael Atlan, "Phase-resolved heterodyne holographic vibrometry with a strobe local oscillator," Opt. Lett. 38, 377-379 (2013)