Yu P, Peng L, Nolte D D, Melloch M R
Department of Physics, Purdue University, West Lafayette, Indiana 47907-1398, USA.
Opt Lett. 2003 May 15;28(10):819-21. doi: 10.1364/ol.28.000819.
Optical coherence-domain reflectometry and laser-based ultrasound detection have been combined with the use of adaptive optics to detect ultrasound through turbid media. The dynamic hologram in a photorefractive quantum-well device performs as a coherence gate that eliminates multiply scattered background. Quadrature homodyne detection conditions are selected by the choice of center wavelength of the pulse spectrum, requiring no active stabilization or feedback. A depth resolution of 30 microm was achieved, with a pulse duration of nominally 120 fs for ultrasound detection through turbid media up to optical thicknesses of 11 mean free scattering lengths.
