Experimental study of laser recording and heterodyne detecting of microstructures in volume media

Results of an experimental study of a two-beam laser method of recording and heterodyne detection of elementary microstructures (microgratings) in “thick” recording media are described. The study is performed on iron-doped lithium niobate crystals and on thick photopolymer materials in the single-photon absorption mode. The size of the volume micrograting is demonstrated to depend on the operating wavelength, numerical aperture of the focusing microobjective, and refractive index of the medium. The experiments are performed with microgratings 1.0 × 1.4 × 5.7 μm in the X, Y, and Z directions, respectively. Characteristics of individual microgratings and matrices of microgratings recorded at different depths of recording media are given.