Low-coherence interferometric detection of photo-thermal and photo-acoustic effects in tissue

We have developed a low-coherence optical sensor for detection of laser-induced thermoelastic deformations in biological materials. The presented optical sensor utilizes a birefringent fiber-based dual channel low-coherence Michelson interferometer capable of differential phase measurements. We demonstrate that the low-coherence sensor can be used for spatially-resolved measurements of laser-induced thermoelastic deformations in biological materials with high axial resolution. Experimental studies were carried out using gelatin-based tissue phantoms.