SAMOP 2021 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 7: Precision Measurements
Q 7.11: Poster
Dienstag, 21. September 2021, 16:30–18:30, P
Frequency stability of a cryogenic silicon resonator with crystalline mirror coatings — •Jialiang Yu1, Thomas Legero1, Fritz Riehle1, Daniele Nicolodi1, Dhruv Kedar2, John Robinson2, Eric Oelker3, Jun Ye2, and Uwe Sterr1 — 1Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany — 2JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado, USA — 3University of Glasgow, UK
The performance of ultra-stable lasers is ultimately limited by various types of thermal noise, with Brownian thermal noise of the optical coatings as the largest contribution.
We have set up a 21 cm long optical resonator made from single-crystal silicon with Al0.92Ga0.08As/GaAs crystalline mirror coatings, which is operated at a cryogenic temperature of 124 K. Compared to usual dielectric coatings, the crystalline coatings are expected to have a lower mechanical loss, thus improving the frequency stability to 1× 10−17. The most important technical noise sources affecting the frequency stability are suppressed to a level below this predicted thermal noise floor for averaging times between 5 s and 1000 s. However, the lowest measured frequency instability of 4.5 × 10−17 is significantly higher than predicted. Compared to dielectric coatings we observe a much more complex behavior of the crystalline semiconductor coatings on e.g. fluctuations of the intracavity power. The influence on cavity frequency stability is investigated by locking simultaneously two lasers to different cavity modes.