Enhancing sideband cooling by feedback-controlled light.

Rossi M., Kralj N., Zippilli S., Natali R., Borrielli A., Pandraud G., Serra E., Di Giuseppe G., Vitali D.
  Mercoledì 13/09   09:00 - 13:00   Aula A107   II - Fisica della materia
We realize a phase-sensitive closed-loop control scheme to engineer the fluctuations of the pump field which drives an optomechanical system, and show that the corresponding cooling dynamics can be significantly improved. In particular, operating in the unusual "anti-squashing" regime of positive feedback and increased field fluctuations, sideband cooling of a nanomechanical membrane within an optical cavity can be improved by 7.5 dB with respect to the case without feedback. Close to the quantum regime of reduced thermal noise, such feedback-controlled light would allow going well below the quantum backaction cooling limit.