A method of tomographic imaging is proposed in which two-wave mixing in a p
hotorefractive crystal is used with wavelength scanning of a laser diode an
d phase modulation of the pump beam. This method provides full optical proc
essing and is effective for weak light from objects because of the use of t
wo-wave mixing. The depth resolution of the method was similar to 1 cm when
the wavelength-scanning width was similar to 0.02 nm. (C) 2000 Optical Soc
iety of America OCIS codes: 170.4500, 170.1650, 190.7070.