高功率单频LBO 腔内倍频461 nm 钛宝石激光器

Abstract

A high-power single-frequency 461 nm light by intracavity doubling of Ti:sapphire laser is designed and built. An astigmatically compensated double-folded resonator with six mirrors is employed to give two tight-focus regions, where Ti:sapphire and doubling crystals are located respectively. A type-I critical phase-matched LBO, an optical diode composed with a TGG crystal and a broadband half wave plate (HWP) are placed inside the resonator for the intracavity frequency doubler and forcing the laser to operate unidirectionally. Three birefringent filters with different thicknesses of 1, 2, 4 mm and a temperature controlled etalon with thickness of 0.25 mm are inserted in the cavity to tune the fundamental wavelength of 461 nm Ti∶sapphire laser. With the pump power of 14 W and an optimized LBO crystal with the length of 7.3 mm, the tunable single-frequency second harmonic output of 1.02 W at 460.86 nm is obtained. The peak-to-peak fluctuation of the power is less than ±1.3% within 3 h. The measured beam quality of M 2 and the tuning range of blue laser are better than 1.59 and 20 nm, respectively.