No abstract

The 1064 nm optimal spatial phase matching (PM) direction for LaCa 4 O(BO 3 ) 3 (LaCOB) crystals was found to be (113.5°, 43.8°) with d eff of 1.34 pm V −1 , angular acceptance of 0.9 mrad cm and walk-off angle of 14.9 mrad, and more than a 56% second-harmonic generation (SHG) conversion efficiency was realized on a sample (4 × 4 × 6 mm 3 ) cut in this direction, by using a 1064 nm Nd : YAG pico-second laser. The angular noncritical phase-matching (A-NCPM) wavelengths along the y and z axes for La x Gd 1−x COB (x = 0.09, 0.13) crystals were measured. Using a nanosecond laser, the type-I single-pass A-NCPM SHG conversion efficiency along y axis reached 30.2% by taking advantage of the longer crystal sample (4 × 4 × 27 mm 3 ).