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Electromagnetically induced transparency provides a powerful mechanism for controlling light propagation in a dielectric medium, and for producing slow and fast light. Electromagnetically induced transparency traditionally arises from destructive interference induced by a non-radiative coherence in an atomic system. Stimulated Brillouin scattering of light from propagating hypersonic acoustic waves has also been used successfully for the generation of slow and fast light. However, Electromagnetically induced transparency-type processes based on stimulated Brillouin scattering were considered infeasible because of the short coherence lifetime of hypersonic phonons. Here, we report a new Brillouin scattering induced transparency phenomenon generated by acousto-optic interaction of light with long-lived propagating phonons in a silica resonator. We demonstrate that Brillouin scattering induced transparency is uniquely non-reciprocal owing to the propagating acoustic wave and accompanying momentum conservation requirement. We also show that Brillouin scattering induced transparency enables ultralow-power ultralow-footprint slow-light generation with delay-bandwidth product comparable to state-of-the-art stimulated Brillouin scattering systems. [ABSTRACT FROM AUTHOR]

In an optomechanical resonator, an optically active mechanical mode can couple to any of the optical resonances via radiation pressure. This unique property can enable a remarkable phenomenon: conversion of optical fields via optomechanical coupling between vastly different wavelengths. Here we expand an earlier experimental study [Science 338, 1609 (2012)] on classical wavelength conversion of coherent optical fields by coupling two optical modes to a mechanical breathing mode in a silica resonator. Heterodyne detection of the converted optical fields shows that the wavelength conversion process is coherent and bidirectional. The conversion efficiency obtained features a distinct saturation behavior that arises from optomechanical impedance matching. A measurement of the coherent mechanical excitation involved in the wavelength conversion process also provides additional insight on the underlying optomechanical interactions. [ABSTRACT FROM AUTHOR]

Thermal mechanical motion hinders the use of a mechanical system in applications such as quantum information processing. Whereas the thermal motion can be overcome by cooling a mechanical oscillator to its motional ground state, an alternative approach is to exploit the use of a mechanically dark mode that can protect the system from mechanical dissipation. We have realized such a dark mode by coupling two optical modes in a silica resonator to one of its mechanical breathing modes in the regime of weak optomechanical coupling. The dark mode, which is a superposition of the two optical modes and is decoupled from the mechanical oscillator, can still mediate an effective optomechanical coupling between the two optical modes. We show that the formation of the dark mode enables the transfer of optical fields between the two optical modes. Optomechanical dark mode opens the possibility of using mechanically mediated coupling in quantum applications without cooling the mechanical oscillator to its motional ground state. [ABSTRACT FROM AUTHOR]

We report the experimental demonstration of storing optical information as a mechanical excitation in a silica optomechanical resonator. We use writing and readout laser pulses tuned to one mechanical frequency below an optical cavity resonance to control the coupling between the mechanical displacement and the optical field at the cavity resonance. The writing pulse maps a signal pulse at the cavity resonance to a mechanical excitation. The readout pulse later converts the mechanical excitation back to an optical pulse. The storage lifetime is determined by the relatively long damping time of the mechanical excitation. [ABSTRACT FROM AUTHOR]

We have experimentally realized on-chip silica microspheres that feature excellent thermal coupling to the silicon wafer. The chip-based microspheres significantly reduce laser-induced heating and correspondingly exhibit much lower threshold optical power for heating-induced optical bistability. We also show that the chip-based microspheres have optical and especially optomechanical properties that are similar to those of traditional fiber-stem-attached silica microspheres, making the chip-based microspheres suitable for optomechanical studies in a vacuum environment.