Photothermal effects in ultra-precisely stabilized tunable microcavities

Brachmann, Johannes F. S.; Kaupp, Hanno; Hänsch, Theodor W. and Hunger, David (2016): Photothermal effects in ultra-precisely stabilized tunable microcavities. In: Optics Express, Vol. 24, No. 18: pp. 21205-21215

Abstract

We study the mechanical stability of a tunable high-finesse microcavity under ambient conditions and investigate light-induced effects that can both suppress and excite mechanical fluctuations. As an enabling step, we demonstrate the ultra-precise electronic stabilization of a microcavity. We then show that photothermal mirror expansion can provide high-bandwidth feedback and improve cavity stability by almost two orders of magnitude. At high intracavity power, we observe self-oscillations of mechanical resonances of the cavity. We explain the observations by a dynamic photothermal instability, leading to parametric driving of mechanical motion. For an optimized combination of electronic and photothermal stabilization, we achieve a feedback bandwidth of 500 kHz and a noise level of 1.1 x 10(-13) m rms. (C) 2016 Optical Society of America

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 1094-4087
• Language: English