Intracavity dual-frequency power locking for a high-stable NPRO laser

Laser wavelength stabilization enables high-stable lasers to drive fundamental research and cutting-edge technologies. Advancements in such lasers now prioritize enhanced portability and reduced cost. In this Letter, we report a frequency-stability-enhanced, well-packaged non-planar ring oscillator laser at 1064 nm, by stabilizing its beat signal power of the dual-frequency laser inside the cavity. The locking mechanism perfectly utilizes the mapping relationship between the beat signal power and the laser frequency, without any external frequency reference. This approach experimentally demonstrates a 20-fold reduction in laser frequency noise and more than 10 dB reduction in beat signal phase noise within the 0.1 mHz-10 Hz range, compared to free-running condition of the laser. This work establishes a simplified and cost-effective approach for laser frequency stabilization while providing new insights for extending laboratory-grade optical metrology.