We develop ultrastable lasers with linewidth ~1Hz for compact and deployable platforms.
At the heart of any stable laser is a reference cavity resonator. By locking a laser’s frequency to a reference cavity mode, the laser inherits the resonator’s stability. These stable lasers can then be used in various sensing and spectroscopy applications, including in optical atomic clocks and distributed fiber environmental sensors. Additionally, when used in conjunction with an optical frequency comb, the stability of these lasers can be transferred to the rf, microwave and millimeter-wave domains, aiding in position, navigation and timing applications. In order to realize ultrastable lasers outside the laboratory, we design, build and test extremely compact resonators and laser locking systems.
Attaining sub-1 Hz linewidth with an optical cavity requires careful attention to the fundamental limits of cavity length stability, the thermal and structural properties of cavity materials, and high-precision laser locking techniques. Moreover, these cavities are held in vacuum to remove airpath fluctuations from disturbing the stability. We investigate the optimal materials and methods to generate ultrastable laser frequencies in as compact volume as possible.