Passive Laser Power Stabilization via an Optical Spring

Metrology experiments can be limited by the noise produced by the laser involved via small fluctuations in the laser’s power or frequency. Typically, active power stabilization schemes consisting of an in-loop sensor and a feedback control loop are employed. Those schemes are fundamentally limited by shot noise coupling at the in-loop sensor. In this letter we propose a passive power stabilization scheme via the optical spring effect. In a proof of principle experiment, we show that the free running relative power noise of the laser is stabilized from approximately 2 × 10⁻⁵ Hz^−1/2 to a minimum value of 1.6 × 10⁻⁷ Hz^−1/2 , corresponding to the power noise reduction by a factor of 125. The bandwidth at which stabilization occurs ranges from 400 Hz to 100 kHz. The work reported in this letter further paves the way for high power laser stability techniques which could be implemented in optomechanical experiments and in gravitational wave detectors.