HOLOGRAM MEMORY CONSISTING OF LITHIUM NIOBATE SINGLE CRYSTAL WITH IMPROVED PHOTOINDUCED REFRACTIVE INDEX CHARACTERISTICS AND PHOTOMULTIPLYING DEVICE USING THE MEMORY

摘要

PROBLEM TO BE SOLVED: To provide an LN single crystal hologram memory having high diffraction efficiency, no scattering of light and extremely excellent transmission characteristics. ;SOLUTION: The hologram memory consisting of a lithium niobate single crystal has 0.495 to 0.50 molar ratio of Li2O/(Nb2O5+Li2O), ≤1 cm-1 absorbance in 400 to 600 nm visible ray region and 20 to 27 cm-1 coupling coefft. without addition of a transition metal Fe, and has high hologram diffraction efficiency. After the lithium niobate single crystal is grown, the crystal may be subjected to heat treatment to control the writing rate and recording time of the hologram. In a device to write a hologram diffraction grating in a single crystal by using visible ray laser light to amplify the light, the above lithium niobate single crystal memory having high hologram diffraction efficiency is used as the single crystal.;COPYRIGHT: (C)2000,JPO