Realization of a Tunable 455.5-nm Laser With Low Intensity Noise by Intracavity Frequency-Doubled Ti:Sapphire Laser

A tunable single-frequency 455.5-nm laser with low intensity noise by means of intracavity frequency-doubled Ti:sapphire (Ti:S) laser is presented. By optimizing the curvature radii of the resonator mirrors, the beam waist of the fundamental wave at the Ti:S crystal is focused, and the threshold pump power is decreased, which can overcome the disadvantage of the upper threshold pump power due to the smaller gain at oscillating a wavelength of 911 nm than that of 795 nm. Based on the numerical calculation, a single-frequency 455.5-nm laser with an output power of 421 mW and an optical conversion efficiency of 3.95% is obtained from 10.65-W all-solid-state 532-nm pump laser, and the intensity noise of the 455.5 nm laser reaches the quantum noise limit at 1.8 MHz. With the obtained laser resource, the saturation absorption spectrum of the higher state excitation transition of
¹³³
Cs is successfully measured when its frequency is continuously scanned over 3.4 GHz.