Absolutely Stabilized, Sub-kHz Linewidth Comb with Automated Locking and Unified user Interface

Low phase-noise laser sources with robust performance are crucial for numerous applications, including ultraprecision spectroscopy, optical clocks, and trapped-atom quantum computers, where high-fidelity quantum control of atomic qubits is often limited by technical noise in laser systems [1]. Femtosecond frequency combs have proven to be precise optical frequency rulers, capable of transferring the ultra-narrow linewidth of high-finesse-cavity stabilized lasers across the comb spectrum [2]. However, such systems require cost-intensive and complex setups, including a high-finesse cavity within a vacuum chamber, and are prone to long-term drift due to the lack of absolute referencing. As a compelling alternative, we demonstrate a cost-effective locking scheme for the simultaneous short-term and absolute long-term stabilization of a broadband frequency comb, serving as a universal locking reference [3].