Kelley Rivoire

Deterministic Coupling of a Single Nitrogen Vacancy Center to a Photonic Crystal Cavity

We describe and experimentally demonstrate a technique for deterministic, large coupling between a photonic crystal (PC) nanocavity and single photon emitters. The technique is based on in situ scanning of a PC cavity over a sample and allows the precise positioning of the cavity over a desired emitter with nanoscale resolution. The power of the technique is demonstrated by coupling the PC nanocavity to a single nitrogen vacancy (NV) center in diamond, an emitter system that provides optically accessible electron and nuclear spin qubits.

Engineered quantum dot single-photon sources

Fast, high efficiency and low error single-photon sources are required for the implementation of a number of quantum information processing applications. The fastest triggered single-photon sources to date have been demonstrated using epitaxially grown semiconductor quantum dots (QDs), which can be conveniently integrated with optical microcavities. Recent advances in QD technology, including demonstrations of high temperature and telecommunications wavelength single-photon emission, have made QD single-photon sources more practical. Here we discuss the applications of single-photon sources and their various requirements, before reviewing the progress made on a QD platform in meeting these requirements.

Second harmonic generation in gallium phosphide photonic crystal nanocavities with ultralow continuous wave pump power

We demonstrate second harmonic generation in photonic crystal nanocavities fabricated in the semiconductor gallium phosphide. We observe second harmonic radiation at 750 nm with input powers of only nanowatts coupled to the cavity and conversion effciency P(out)/P(2)(in,coupled)=430%/W. The large electronic band gap of GaP minimizes absorption loss, allowing effcient conversion. Our results are promising for integrated, low-power light sources and on-chip reduction of input power in other nonlinear processes.

Multiply resonant photonic crystal nanocavities for nonlinear frequency conversion

We describe a photonic crystal nanocavity with multiple spatially overlapping resonances that can serve as a platform for nonlinear frequency conversion. We show nonlinear characterization of structures with two resonances nearly degenerate in frequency. We also demonstrate structures with resonances separated by up to 592 nm.

Optical fiber tips functionalized with semiconductor photonic crystal cavities

We develop a new method to transfer photonic crystal resonators to the tips of optical fibers. High Q (2000-4000) cavities are coupled via transmission or PL emission to the fibers in both Si and GaAs.

Fast quantum dot single photon source triggered at telecommunications wavelength

We demonstrate a 300 MHz quantum dot single photon source at 900 nm triggered by a telecommunications wavelength laser. The quantum dot is excited by on-chip-generated second harmonic radiation, resonantly enhanced by a photonic nanocavity.

Lithographic positioning of fluorescent molecules on high-Q photonic crystal cavities

Photoluminescent molecules are coupled to high quality photonic crystal nanocavities. The cavities are fabricated in a gallium phosphide membrane and show resonances from 735 to 860 nm with quality factors up to 12 000. The molecules, which are dispersed in a thin polymer film deposited on top of the cavities, can be selectively positioned onto the location of the cavity by using a lithographic technique, which is easily scalable to arrays of cavities.

Multiply resonant high quality photonic crystal nanocavities

We propose and experimentally demonstrate a photonic crystal nanocavity with multiple resonances that can be tuned nearly independently. The design is composed of two orthogonal intersecting nanobeam cavities. Experimentally, we measure cavity quality factors of 6600 and 1000 for resonances separated by 382 nm; we measure a maximum separation between resonances of 506 nm. These structures are promising for enhancing efficiency in nonlinear optical processes such as sum/difference frequency and stimulated Raman scattering.

Sum-frequency generation in doubly resonant GaP photonic crystal nanocavities

We demonstrate and characterize continuous wave χ(2) sum-frequency generation in gallium phosphide photonic crystal nanocavities. We use two confined modes of the nanocavity in the wavelength range 1500–1600 nm to enhance conversion efficiency. Our results show that these nanocavities can serve as integrated light sources across a range of wavelengths, and are promising for on-chip upconversion of weak intensity telecommunication wavelengths signals to visible wavelengths.

Tunable-wavelength second harmonic generation from GaP photonic crystal cavities coupled to fiber tapers

We demonstrate up to 30 nm tuning of gallium phosphide photonic crystal cavities resonances at aproximately 1.5 microm using a tapered optical fiber. The tuning is achieved through a combination of near-field perturbations and mechanical deformation of the membrane, both induced by the fiber probe. By exploiting this effect, we show fiber-coupled second harmonic generation with a tuning range of nearly 10 nm at the second harmonic wavelength of approximately 750 nm. By scaling cavity parameters, the signal could easily be shifted into other parts of the visible spectrum.