Coherence-restored pulse interferometry (CRPI) is a recently developed method for optical detection of ultrasound that achieves shot-noise-limited sensitivity and high dynamic range. In principle, the wideband source employed in CRPI may enable the interrogation of multiple detectors by using wavelength multiplexing. However, the noisereduction scheme in CRPI has not been shown to be compatible with wideband operation. In this work, we introduce a new scheme for CRPI that relies on a free-space Fabry-Perot filter for noise reduction and a pulse stretcher for reducing nonlinear effects. Using our scheme, we demonstrate that shot-noise-limited detection may be achieved for a spectral band of 80 nm and powers of up to 5 mW.

Date Published: 19 July 2019
PDF: 3 pages
Proc. SPIE 11077, Opto-Acoustic Methods and Applications in Biophotonics IV, 1107714 (19 July 2019); doi: 10.1117/12.2526277

Published in SPIE Proceedings Vol. 11077:
Opto-Acoustic Methods and Applications in Biophotonics IV
Vasilis Ntziachristos; Roger Zemp, Editor(s)