Thermal noise and optomechanical features in the emission of a membrane-coupled compound cavity laser diode.

ABSTRACT: We demonstrate the use of a compound optical cavity as linear displacement detector, by measuring the thermal motion of a silicon nitride suspended membrane acting as the external mirror of a near-infrared Littrow laser diode. Fluctuations in the laser optical power induced by the membrane vibrations are collected by a photodiode integrated within the laser, and then measured with a spectrum analyzer. The dynamics of the membrane driven by a piezoelectric actuator is investigated as a function of air pressure and actuator displacement in a homodyne configuration. The high Q-factor (~3.4?·?10(4) at 8.3?·?10(-3)?mbar) of the fundamental mechanical mode at ~73?kHz guarantees a detection sensitivity high enough for direct measurement of thermal motion at room temperature (~87?pm RMS). The compound cavity system here introduced can be employed as a table-top, cost-effective linear displacement detector for cavity optomechanics. Furthermore, thanks to the strong optical nonlinearities of the laser compound cavity, these systems open new perspectives in the study of non-Markovian quantum properties at the mesoscale.

SUBMITTER: Baldacci L 

PROVIDER: S-EPMC4990904 | biostudies-other | 2016

REPOSITORIES: biostudies-other