Abstract

Optical storage and laser printer applications require a compact solid-state blue source to achieve greater versatility. One method to obtain this blue light is via Quasi phase matched (QPM) second harmonic generation (SHG).¹,² With QPM we are able to fabricate a high-efficiency blue light source. By inverting the spontaneous polarization with an appropriate period it is possible to phase match any arbitrary wavelength. Several methods have been used to fabricate periodic domain inversion in LiNbO₃ and LiTaO₃. Ti indiffusion³ or Li outdiffusion⁴ near the Curie temperature are well-known techniques to reverse the polarization in LiNbO₃. Electron beam bombardment⁵,⁶,⁷ has also been employed to make "well"-shaped inverted domains. Periodically poled structures in LiTaO₃ can be realized through selective proton exchange (PE) followed by heat treatment near the Curie temperature⁸. A few micron deep semi-circular shaped domains with a first-order period has been fabricated using proton exchange and a quick heat treatment near the Curie temperature, generating 15mW of blue light⁹.

© 1993 Optical Society of America