ABSTRACT
Despite appealing high-symmetry properties that enable strong spatial confinement and ultrahigh-Q, optical whispering-gallery modes of spherical and circular resonators have been absent from the field of quantum-well exciton polaritons. Here we observe whispering-gallery exciton polaritons in a gallium arsenide microdisk cavity filled with indium gallium arsenide quantum wells, the test bed materials of polaritonics. Strong coupling is evidenced in photoluminescence and resonant spectroscopy accessed through concomitant confocal microscopy and near-field optical techniques. Excitonic and optical resonances are tuned by varying temperature and disk radius, revealing Rabi splittings between 5 and 10 meV. A dedicated analytical quantum model for such circular whispering-gallery polaritons is developed, which reproduces the measured values. At high power, lasing is observed and accompanied by a blueshift of the emission consistent with the regime of polariton lasing. With experimental methods and theory now established, whispering-gallery-mode polaritons in round dielectric resonators appear as a new viable platform toward low loss polaritonics.
ABSTRACT
Nanoelectro-opto-mechanical systems enable the synergistic coexistence of electrical, mechanical, and optical signals on a chip to realize new functions. Most of the technology platforms proposed for the fabrication of these systems so far are not fully compatible with the mainstream CMOS technology, thus, hindering the mass-scale utilization. We have developed a CMOS technology platform for nanoelectro-opto-mechanical systems that includes piezoelectric interdigitated transducers for electronic driving of mechanical signals and nanocrystalline silicon nanobeams for an enhanced optomechanical interaction. Room-temperature operation of devices at 2 GHz and with peak sensitivity down to 2.6 cavity phonons is demonstrated. Our proof-of-principle technology platform can be integrated and interfaced with silicon photonics, electronics, and MEMS devices and may enable multiple functions for coherent signal processing in the classical and quantum domains.
ABSTRACT
Optical nonlinearities, such as thermo-optic mechanisms and free-carrier dispersion, are often considered unwelcome effects in silicon-based resonators and, more specifically, optomechanical cavities, since they affect, for instance, the relative detuning between an optical resonance and the excitation laser. Here, we exploit these nonlinearities and their intercoupling with the mechanical degrees of freedom of a silicon optomechanical nanobeam to unveil a rich set of fundamentally different complex dynamics. By smoothly changing the parameters of the excitation laser we demonstrate accurate control to activate two- and four-dimensional limit cycles, a period-doubling route and a six-dimensional chaos. In addition, by scanning the laser parameters in opposite senses we demonstrate bistability and hysteresis between two- and four-dimensional limit cycles, between different coherent mechanical states and between four-dimensional limit cycles and chaos. Our findings open new routes towards exploiting silicon-based optomechanical photonic crystals as a versatile building block to be used in neurocomputational networks and for chaos-based applications.
