Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 13: Quantum Technologies
Q 13.4: Talk
Monday, March 11, 2024, 17:45–18:00, HS 3219
Ultra-low frequency noise diode-laser systems for quantum applications — •Niklas Kolodzie1,2, Ivan Mirgorodskiy1, Kai Dietze2, Christian Nölleke1, and Piet O. Schmidt2,3 — 1TOPTICA Photonics AG, Gräfelfing, Germany — 2Physikalisch-Technische Bundesanstalt, Braunschweig, Germany — 3Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany
Narrow-linewidth lasers are essential in many quantum applications which exploit ultra-cold atoms. Tasks like optical trapping or coherent qubit manipulation have high requirements on the laser frequency noise (FN). In many experiments it is crucial to keep FN at a minimum level: slow FN is responsible for the long-term stability, while fast FN ultimately limits the fidelity of qubit operations.
External-cavity diode lasers (ECDL) are the tool of choice for such applications due to their versatility and robustness: A wide range of atomic transitions in the visible and infrared frequency ranges can be addressed. However, ECDLs typically have a high level of FN due to relatively high cavity losses compared to other laser concepts.
We demonstrate an ultra-low noise laser (ULNL) by applying weak optical feedback from an additional external cavity to an ECDL. This method reduces fast FN i.e. reducing the Lorentzian part of the linewidth. We investigate the characteristics of the ULNL in detail: FN reduction with respect to different feedback power-levels, mode-stability and frequency stabilization to an optical reference. Finally, we integrate the ULNL into a calcium ion experiment and compare the performance to a state-of-the-art laser.
Keywords: low-noise laser; ECDL; frequency noise density; calcium ion