MEMS Tunable 795 nm VCSEL for Chip Scale Atomic Clock

Compact laser sources have become an indispensable and ideal component to incorporate a coherent population tapping (CPT) based chip scale atomic clock (CSAC). The implementation of CPT resonance is effective to generate a signal as a frequency reference, as the emission wavelength of the laser should be same as the characteristic absorption wavelength of alkali atoms. Vertical Cavity Surface Emitting Laser (VCSEL) is used mostly in the atomic clock for CPT excitation as an optical source due to various advantages such as reliability, cost effectiveness, and wide tunability. In this work, we established a 795 nm wavelength range tunable VCSEL utilizing micro electro-mechanical system (MEMS) as a movable reflector, which confirmed the emission wavelength at 795 nm and wavelength tuning range of 35 nm. The results indicate that 795 nm VCSEL is suitable for Rb transition and CPT resonance effect in CSAC applications.