Noncritical quasiphase-matched second harmonic generation in LiB3O5 crystal at room temperature

Noncritical quasiphase-matched (NQPM) second harmonic generation (SHG) in LBO crystal at room temperature is reported. It is observed that the SHG conversion efficiency increases approximately as the square of the number of LBO sheets. The dependence of SHG conversion efficiency on incident angle and the intensity of the fundamental wave at 1064 nm were also measured. Using a 4 mm thick NQPM LBO frequency doubler, a maximum conversion efficiency of 12% is obtained at a pump intensity of 0.254 GW/cm2.