Infrared holographic recording in a two-step process is demonstrated in stoichiometric iron-doped lithium tantalate crystals. Through absorption of two intersecting infrared pulses (λ = 1064 nm) a temperature grating and thus a modulated pyroelectric field build up. Free electrons, excited by homogeneous light of a shorter wavelength (λ = 532 nm) drift in this field, and a phase hologram is stored that can be read nondestructively. The change in refractive index depends mainly on the absorption coefficient at the wavelength of the recording light and on the intensity of the infrared light. The proposed method may be extended to telecommunication wavelengths by choice of suitable dopants.
© 2003 Optical Society of America
(090.2900) Holography : Optical storage materials
(090.7330) Holography : Volume gratings
(160.5320) Materials : Photorefractive materials
(210.2860) Optical data storage : Holographic and volume memories
Helge A. Eggert, Jörg Imbrock, Christoph Bäumer, Hartmut Hesse, and Eckhard Krätzig, "Infrared holographic recording in lithium tantalate crystals by means of the pyroelectric effect," Opt. Lett. 28, 1975-1977 (2003)