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Optomécanique en cavité cryogénique avec un micro-pilier pour l'observation du régime quantique d'un résonateur mécanique macroscopique

Abstract : We present the operation of an experimental setup designed to optically measure the quantum position fluctuations of a macroscopic mechanical resonator. The resonator is kept in a cryogenic environment and its movement is monitored with a high-finesse Fabry-Perot cavity. We have designed and realized an optimized resonator for the observation of its quantum position fluctuations. It consists in a quartz micropillar vibrating on a compression mode and clamped at its center by a thin membrane. We have demonstrated a fundamental vibration mode oscillating at 4 MHz with a mechanical quality factor close to two millions. We have implemented this resonator in a high-finesse Fabry-Perot cavity. A high-reflectivity mirror is coated only on top of the pillar in order to avoid any altering of its mechanical quality factor. We have developed a laser photoablation technique in order to realize the coupling mirror of the cavity with a very small radius of curvature as well as a high reflectivity. This allows us to build a cavity with a finesse of 50 000 and an optical beam waist, smaller than 10 μm, fitting the transverse size of the resonator. We had make a dilution refrigerator especially designed and optimized for ultrasensitive position measurement, in which we have operated the optomechanical device. The whole optical setup, made of an ultra-stable laser source and a resonator motion detection device, allows us to observe thermal position fluctuations of the resonator down to about 1 K.
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https://tel.archives-ouvertes.fr/tel-00842915
Contributor : Aurélien Kuhn <>
Submitted on : Tuesday, July 9, 2013 - 4:47:06 PM
Last modification on : Thursday, November 19, 2020 - 1:01:09 PM
Long-term archiving on: : Thursday, October 10, 2013 - 4:12:51 AM

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  • HAL Id : tel-00842915, version 1

Citation

Aurélien Kuhn. Optomécanique en cavité cryogénique avec un micro-pilier pour l'observation du régime quantique d'un résonateur mécanique macroscopique. Physique Quantique [quant-ph]. Université Pierre et Marie Curie - Paris VI, 2013. Français. ⟨tel-00842915⟩

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