33 research outputs found
Broadband Reconfiguration of OptoMechanical Filters
We demonstrate broad-band reconfiguration of coupled photonic crystal
nanobeam cavities by using optical gradient force induced mechanical actuation.
Propagating waveguide modes that exist over wide wavelength range are used to
actuate the structures and in that way control the resonance of localized
cavity mode. Using this all-optical approach, more than 18 linewidths of tuning
range is demonstrated. Using on-chip temperature self-referencing method that
we developed, we determined that 20 % of the total tuning was due to
optomechanical reconfiguration and the rest due to thermo-optic effects.
Independent control of mechanical and optical resonances of our structures, by
means of optical stiffening, is also demonstrated
Active dielectric antenna on chip for spatial light modulation
Integrated photonic resonators are widely used to manipulate light propagation in an evanescently-coupled
waveguide. While the evanescent coupling scheme works well for planar optical systems that are naturally
waveguide based, many optical applications are free-space based, such as imaging, display, holographics,
metrology and remote sensing. Here we demonstrate an active dielectric antenna as the interface device that
allows the large-scale integration capability of silicon photonics to serve the free-space applications. We
show a novel perturbation-base diffractive coupling scheme that allows a high-Q planer resonator to directly
interact with and manipulate free-space waves. Using a silicon-based photonic crystal cavity whose
resonance can be rapidly tuned with a p-i-n junction, a compact spatial light modulator with an extinction
ratio of 9.5 dB and a modulation speed of 150 MHz is demonstrated. Method to improve the modulation
speed is discussed.Air Force Office of Scientific Research (AFOSR grant FA9550-12-1-0261
Nano-Opto-Electro-Mechanical Systems
A new class of hybrid systems that couple optical, electrical and mechanical
degrees of freedom in nanoscale devices is under development in laboratories
worldwide. These nano-opto-electro-mechanical systems (NOEMS) offer
unprecedented opportunities to dynamically control the flow of light in
nanophotonic structures, at high speed and low power consumption. Drawing on
conceptual and technological advances from cavity optomechanics, they also bear
the potential for highly efficient, low-noise transducers between microwave and
optical signals, both in the classical and quantum domains. This Progress
Article discusses the fundamental physical limits of NOEMS, reviews the recent
progress in their implementation, and suggests potential avenues for further
developments in this field.Comment: 27 pages, 3 figures, 2 boxe