Pulsed digital holography for deformation measurements on biological tissues

Digital holograms are recorded of biological tissues by use of a Q-switched double-pulsed ruby laser. An image-plane digital holography setup is used with a CCD camera for capturing two holograms with a short time separation (20-800 mu s). Subtraction of the phase distribution in two digital hologra ms yield a fringe phase map that shows the change in deformation of the tis sue surface between the recordings. Experiments are pet-formed on tissue fr om a pig that was excited by a short-shock pulse and on a human hand that w as excited by sinusoidal stimulation. Results when the object is imaged thr ough an endoscope are also presented. The technique could be an approach fo r measuring parameters like elasticity on biological tissues. (C) 2000 Opti cal Society of America OCIS codes: 090.2880, 170.4580.