Second-harmonic generation of Er:YAG 2.94-micron laser radiation using an organic vinylidene cyanide/vinyl acetate thin film

An SHG of Er:YAG 2.94-micron laser line radiation was observed using a vinylidene cyanide/vinyl acetate copolymer. Using experimental data, the coherence length and the effective nonlinear susceptibility were evaluated. The nonlinear susceptibility of this laser was found to be 5.6 x 10 to the -7th esu (i.e., 2.8 times larger than that of LiNbO3 crystal. It is shown that the SHG power is greatly enhanced by the poling and stretching processes. It was found that the SHG power monotonically increased with increasing poling field, for a field strength of less than 70 kV/mm; the threefold stretching resulted in an increase of the SHG power by about 20 percent. (I.S.)