A compact mode-locked diode laser system for high precision frequency comparison experiments

Viac o knihe

Optical frequency combs (OFC) have transformed various scientific applications that depend on precise optical frequencies and their differences. This process requires stabilizing the spectral distance between individual comb lines, simplifying the OFC generator (OFCG) system. One significant application is the quantum test of free fall universality in the QUANTUS experimental series, which compares the free fall rates of Rb and K atoms in microgravity. This thesis focuses on developing a compact, robust, and space-compatible diode laser-based OFCG with a mode-locked optical spectrum around 780 nm. The resulting OFCG surpasses requirements with a spectral bandwidth exceeding 16 nm at 20 dBc, comb line optical power over 650 nW (at 20 dBc), a pulse repetition rate of 3.4 GHz, and an RF linewidth of the free-running pulse repetition rate below 10 kHz. A proof-of-concept demonstrator module was created by hybrid-integrating the OFCG into a space-suitable technology platform for future QUANTUS experiments. The RF stability of the OFCG was validated by stabilizing the pulse repetition rate to an external RF reference, achieving a linewidth smaller than 1.4 Hz (resolution limited). This diode laser-based OFCG marks a significant advancement for comparing the free fall rates of Rb and K quantum gases in microgravity during QUANTUS experiments.