Quantitative determination of photorefraction in Mg doped congruent and stoichiometric LiNbO/sub 3/

Summary form only given. New interest on LiNbO/sub 3/ (LN) is on raise since the demonstration of quasi-phase matched (QPM) optical frequency conversion processes in periodically poled LN. The newly developed stoichiometric LN (sLN) has two orders of magnitude smaller coercitive field strength than the congruent LN (cLN) making the poling process easier and more accurate. Unfortunately, both sLN and cLN shows strong photorefraction (PR) what is very disturbing in frequency conversion devices. It was demonstrated that Mg doping could significantly reduce PR. To optimize the stoichiometry and the Mg doping it is essential to measure the PR damage in a real quantitative way at light intensity typical in frequency conversion applications.