Nonlinear enhancement of the efficiency of the second harmonic generation

Abstract

Birefringent ND:YVO4 pumped by diode laser with fundamental wavelength of 1064 nm was used to pump nonlinear KTP crystal. Quartz crystals having natural birefringent property namely quarter and half waveplates were conducted in conjunction with the bulk of KTP to enhance the nonlinear beam. The result showed that half waveplate have electrical to optical conversion efficiency of 15.6 mW/A as compared to quarter waveplate is only 8.74 mW/A. The threshold current for SHG is found 5.3 A with half waveplate and 5.9 A with quarter waveplate. The high performance shown by half waveplate is realized due to the good mode matching after converting the polarization state.