Krishna C. Balram

Coherent coupling between radiofrequency, optical and acoustic waves in piezo-optomechanical circuits

Optomechanical cavities have been studied for applications ranging from sensing to quantum information science. Here, we develop a platform for nanoscale cavity optomechanical circuits in which optomechanical cavities supporting co-localized 1550 nm photons and 2.4 GHz phonons are combined with photonic and phononic waveguides. Working in GaAs facilitates manipulation of the localized mechanical mode either with a radio frequency (RF) field through the piezo-electric effect, which produces acoustic waves that are routed and coupled to the optomechanical cavity by phononic crystal waveguides, or optically through the strong photoelastic effect. Along with mechanical state preparation and sensitive readout, we use this to demonstrate an acoustic wave interference effect, similar to atomic coherent population trapping, in which RF-driven coherent mechanical motion is cancelled by optically-driven motion. Manipulating cavity optomechanical systems with equal facility through both photonic and phononic channels enables new architectures for signal transduction between the optical, electrical, and mechanical domains.

Moving boundary and photoelastic coupling in GaAs optomechanical resonators

Chip-based cavity optomechanical systems are being considered for applications in sensing, metrology, and quantum information science. Critical to their development is an understanding of how the optical and mechanical modes interact, quantified by the coupling rate

Efficient fiber-coupled single-photon source based on quantum dots in a photonic-crystal waveguide

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Acousto-optic modulation and opto-acoustic gating in piezo-optomechanical circuits

. Here, we develop GaAs optomechanical resonators and investigate the moving dielectric boundary and photoelastic contributions to

The Nanolithography Toolbox

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Tuning and Stabilization of Optomechanical Crystal Cavities Through NEMS Integration.

. First, we consider coupling between the fundamental radial breathing mechanical mode and a 1550 nm band optical whispering gallery mode in microdisks. For decreasing disk radius from

Nanolithography toolbox: Device design at the nanoscale

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Piezo-optomechanical circuits

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GaAs nanobeam piezo-optomechanical crystals

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