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Q: Fachverband Quantenoptik und Photonik
Q 41: Poster – Quantum Technologies II & Laser Technology
Q 41.25: Poster
Wednesday, March 4, 2026, 17:00–19:00, Philo 2. OG
Active Feedback for relative intensity noise reduction in solid-state lasers — •Thomas Konrad1, Tobias Steinle1, Roman Bek2, Michael Scharwaechter2, Matthias Seibold2, Andy Steinmann1, and Harald Giessen1 — 14th Physics Institute and Research Center SCoPE, University of Stuttgart — 2Twenty-One Semiconductors GmbH, Stuttgart
Fast and precise measurements are key for many challenging laser applications, such as biological and biomedical imaging. The precision is limited by the noise of the systems we use. Once the measurement precision reaches the laser noise level, the measurement time must be increased quadratically for further improvement. Especially with biological samples, a significant longer measurement time can alter the specimen and/or results. Therefore, exploiting the optimum noise characteristic of the driving source is superior to increasing measurement time. In this work, we investigate noise reduction of a solid-state laser in the spectroscopically relevant 1 kHz - 10 MHz frequency range. Our approach differs from traditional subsequent noise eaters, since we reduce the noise within the laser oscillator itself. In contrast to comparable commercial solutions with monolithic crystal oscillators, we use a free space cavity with two gain materials. To compensate the noise of our laser, we use a second high-speed gain medium in the cavity whose pump is modulated by a PID feedback loop, while the main medium remains constantly pumped. So far, we achieved a noise reduction of more than 18 dBc/Hz at the relaxation oscillation frequency.
Keywords: solid-state laser; laser noise; relative intensity noise