Aaron C. Hryciw

The microstructure of SiO thin films: from nanoclusters to nanocrystals

The microstructure and electronic structure of silicon-rich oxide (SRO) films were investigated using transmission electron microscopy and electron energy loss spectroscopy as the main analytical techniques. The as-deposited SRO film was found to be a single phase SiO1.0, as suggested by its electronic structure characteristics determined by the valence electron energy loss spectrum. This single phase undergoes a continuous but incomplete phase decomposition to Si and SiO2 for films annealed between 300 and 1100°C. The resulting Si phase first appears as ∼2 nm-diameter amorphous clusters which grow to larger sizes at higher annealing temperatures, but only crystallize at a critical temperature between 800 and 900°C. This cluster/matrix configuration of the SRO films is consistent with the appearance of the interface plasmon and its oscillator strength as a function of the nanoparticle size. Three separate stages were identified in the sequence of annealed films that were characterized by the presence of single-phase SiO, amorphous silicon nanoclusters, and silicon nanocrystals, respectively. The presence of amorphous silicon nanoclusters in the intermediate stage, the mean size of which can be controlled via annealing, may offer an alternative to silicon nanocrystal composites for optical applications.

Dissipative and Dispersive Optomechanics in a Nanocavity Torque Sensor

Sensors in optical cavities can be used for measuring acceleration, fields, and particles. New research reveals a record sensitivity for detecting small amounts of torque within optical cavities, useful for detecting magnetic fields.

High-Q/V Monolithic Diamond Microdisks Fabricated with Quasi-isotropic Etching.

Optical microcavities enhance light-matter interactions and are essential for many experiments in solid state quantum optics, optomechanics, and nonlinear optics. Single crystal diamond microcavities are particularly sought after for applications involving diamond quantum emitters, such as nitrogen vacancy centers, and for experiments that benefit from diamonds excellent optical and mechanical properties. Light-matter coupling rates in experiments involving microcavities typically scale with Q/V, where Q and V are the microcavity quality-factor and mode-volume, respectively. Here we demonstrate that microdisk whispering gallery mode cavities with high Q/V can be fabricated directly from bulk single crystal diamond. By using a quasi-isotropic oxygen plasma to etch along diamond crystal planes and undercut passivated diamond structures, we create monolithic diamond microdisks. Fiber taper based measurements show that these devices support TE- and TM-like optical modes with Q > 1.1 × 10(5) and V < 11(λ/n) (3) at a wavelength of 1.5 μm.

Photoluminescence in the silicon-oxygen system

The luminescent properties of SiOx ranging in composition between x=0 and x=2 are presented. Luminescence in the SiOx system is found to be tunable across the full visible spectrum and into the near infrared. The data are used to generate an emission color map for the complete SiOx system. At the lower annealing temperatures, several lines of evidence suggest that the luminescence is due to the presence of amorphous silicon nanoclusters, whereas for higher annealing temperatures the emission is dominated by silicon nanocrystals.

Nonresonant carrier tunneling in arrays of silicon nanocrystals

Silicon nanocrystals are of interest in the nascent field of silicon microphotonics, with potential applications as waveguide amplifiers, light-emitting diodes, and silicon-based lasers. Comparing computational simulations and experiment, it is shown that nonresonant carrier tunneling in ensembles of silicon nanocrystals is a controlling factor in the luminescence. In thin film silicon nanocrystal composites, only the larger particles can be luminescent as a result of rapid carrier tunneling, suggesting that these applications may only be achieved for well-isolated nanocrystals or for arrays with a narrow distribution of sizes.

Single-Crystal Diamond Nanobeam Waveguide Optomechanics

Optomechanical devices sensitively transduce and actuate motion of nanomechanical structures using light. Single--crystal diamond promises to improve the performance of optomechanical devices, while also providing opportunities to interface nanomechanics with diamond color center spins and related quantum technologies. Here we demonstrate dissipative waveguide--optomechanical coupling exceeding 35 GHz/nm to diamond nanobeams supporting both optical waveguide modes and mechanical resonances, and use this optomechanical coupling to measure nanobeam displacement with a sensitivity of

Cavity optomechanics in gallium phosphide microdisks

9.5

Interaction between amorphous silicon nanoclusters and neodymium ions

fm/

Nanocluster sensitized erbium-doped silicon monoxide waveguides

\sqrt{\text{Hz}}

Nonlinear optomechanical paddle nanocavities

and optical bandwidth