All-Fiber 770 nm Laser Stabilized With Bichromatic Absorption Spectroscopy

A high-power, coherent, and frequency-stable 770 nm laser is vital for experiments in atom physics. This letter presents an all-fiber 770 nm laser based on second harmonic generation (SHG) and frequency-stabilized using the R2 absorption line of H
¹³
C
¹⁴
N. This stabilization technique utilizes the acoustic effect to generate a dispersion-like error signal with a steep slope. Moreover, a cascaded gas cell configuration is utilized to double the frequency locking range. After frequency stabilization, the frequency offset has been effectively shifted to close zero. The laser provides an output power of 192 mW with a side mode suppression ratio (SMSR) larger than 35 dB, and a significant frequency noise suppression over 30 dB in the range of 10 to 10
³
Hz. The integral linewidth of the 770 nm laser is 28.1 kHz, which outperforms most semiconductor lasers. The proposed all-fiber configuration offers a new compact laser source potentially useful for quantum measurement.