Laser frequency stabilization based on Fano resonance in a microcylinder cavity

Abstract

We investigate the application of Fano resonance in microcylinder cavities for laser frequency stabilization. By combining Fano resonance and the differential subtraction method, we successfully reproduce the error signal of the traditional Pound–Drever–Hall (PDH) technique. The frequency noise of the laser, when locked to both microsphere and microcylinder cavities, approaches the thermal noise limit. The microcylinder cavity, with a high Q factor of ∼108, benefiting from its large mode volume, exhibits a significant reduction in frequency noise by one order of magnitude compared with a microsphere in the frequency range of 0.1 to 10 kHz, achieving a minimum noise of ∼2.25 Hz2/Hz at 10 kHz. As this approach eliminates the need for additional electronic circuits typically used in the PDH technique, it holds promise as a cost-effective and reliable solution for laser frequency stabilization.