Acousto-optic (AO) imaging is a promising technique that is able to reveal optical properties in the millimeter range inside scattering media by tagging the photon paths with an ultrasonic beam. To increase both the contrast and the resolution of the AO images, we have explored the possibility of using the nonlinear response of the speckle modulation. Variation of the second-harmonic signal as the square of the ultrasonic amplitude has been found, and strong reduction of the tagged zone size has been demonstrated.
© 2002 Optical Society of America
Juliette Selb, Lionel Pottier, and Albert Claude Boccara, "Nonlinear effects in acousto-optic imaging," Opt. Lett. 27, 918-920 (2002)