We demonstrate that a laser can be directly locked to a cavity when the laser linewidth is much greater than the cavity linewidth. We lock an external-cavity diode laser with more than 1 MHz of added frequency noise to a 3.5 kHz wide cavity resonance. Our analog servo acquires lock even though the laser frequency sweeps through the cavity resonance in less than the cavity buildup time. Our theoretical analysis fully describes our measurements and explains why lock can be acquired.
© 2005 Optical Society of America
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.3930) Instrumentation, measurement, and metrology : Metrological instrumentation
(140.4780) Lasers and laser optics : Optical resonators
Instrumentation, Measurement, and Metrology
Lingze Duan and Kurt Gibble, "Locking lasers with large FM noise to high-Q cavities," Opt. Lett. 30, 3317-3319 (2005)