Single domain structure and two-color holographic recording in LiNbO 3:Cu:Ce crystals grown by the vertical Bridgman method

Abstract

Single domain LiNbO 3:Cu:Ce crystal was grown for the first time by the vertical Bridgman (VB) method without applying any external electric field on the crystal during and after the growth process. The mechanism of single domain formation is discussed qualitatively. The Li ion diffusion in the crystal, low segregation coefficients of Cu and Ce and low radial temperature gradient could be the main reasons that caused the single domain structure of the as-grown crystal. The single domain structure was checked by etching with HF:HNO 3 (1:2) mixture and performing two-color holographic recording experiments on the as-grown crystal samples. The two-color recording performance of the crystal was studied by using an ordinary polarization He–Ne laser (632.8 nm) as recording light and an UV lamp (300–400 nm) as gating light. Nonvolatile readout was realized in the VB-grown LiNbO 3:Cu:Ce crystal with a sensitivity of 0.0042 cm/J. A high diffraction efficiency of 12% was achieved.