RETRACTED: A continuous-wave alexandrite laser and its degenerated optical parametric generator

Abstract

• To the best of our knowledge, this is the first report of the CW degenerated optical parametric generator at 1503.4 nm for the alexandrite crystal, which is both used as laser gain and DOPG nonlinear medium. At present, there are no papers about a degenerated optical parametric generator of the alexandrite laser. • The spectral width of DOPG is about 7.16 nm and the frequency spacing between adjacent longitudinal modes at 1503.4 nm reduces to 1.72 × 10 11 Hz. • The DOPG central wavelength tunes from 1502.77 to 1505.08 nm when the crystal temperature increases from 20 to 70 °C. • Our investigation provides further insight into studying the complex nonlinear effects of the biaxial alexandrite crystal. We present a continuous-wave (CW) alexandrite laser at 751.7 nm end-pumped by a red laser diode (LD) at 636 nm. A laser output power of 1160 mW with an optical-to-optical efficiency of 11.9% and a slope efficiency of 16.7% is obtained at the pump power of 9.72 W. The spectral width of the alexandrite laser is about 3.58 nm, and the frequency spacing between adjacent longitudinal modes is 3.44 × 10 11 Hz. The first CW degenerated optical parametric generator (DOPG) at 1503.4 nm of the alexandrite crystal is reported. The spectral width of DOPG is about 7.16 nm, and the frequency spacing between adjacent longitudinal modes at 1503.4 nm reduces to 1.72 × 10 11 Hz. The DOPG central wavelength tunes from 1502.77 to 1505.08 nm when the crystal temperature increases from 20 to 70 °C.