Izo Abram

Single-mode solid-state single photon source based on isolated quantum dots in pillar microcavities

We report the fabrication of a single-mode solid-state single photon source, based on an isolated InAs quantum dot (QD) on resonance with the fundamental mode of a pillar microcavity. Photon correlation experiments under pulsed excitation reveal a clear antibunching behavior. We show that a preparation of the single photons in a given quantum state (same spatial mode, same polarization) can be obtained by placing a QD in resonance with the nondegenerate fundamental mode of an elliptical micropillar.

Single photon emission from site-controlled pyramidal quantum dots

We demonstrate that a single photoexcited InGaAs semiconductor quantum dot (QD) grown by organo-metallic chemical vapor deposition on prepatterned substrates emits one photon at a time, with no uncontrolled background photon emission, making it an excellent single photon emitter. Moreover, our fabrication technique offers complete site control and small inhomogeneous broadening of QD arrays, which is essential for the practical implementation of QDs in efficient solid-state single photon emitting devices.

Indistinguishable single photons from a single-quantum dot in a two-dimensional photonic crystal cavity

We report on the spontaneous emission of a single-quantum dot embedded in a two-dimensional photonic crystal cavity. The resonant coupling between the dot and the strongly localized optical mode significantly shortens the spontaneous emission lifetime, so that the coherence time of the emitted photons is dominated by radiative effects: The emitted photons are indistinguishable, with a mean wave-packet overlap as high as 72%.

A single-mode solid-state source of single photons based on isolated quantum dots in a micropillar

Abstract In this paper we report the development of a single-mode single photon source based on a single InAs quantum dot placed in a micropillar. First, we study the photon statistics of our source by using a Hanbury Brown and Twiss setup. Second, we show as to how the coupling of the dot to the cavity mode permits a large extraction of the photons and their preparation into a given state (same spatial mode, same polarization). Finally, we estimate and discuss the external collection efficiency of our source.

Single photon emission from individual GaAs quantum dots

We report on photon correlation measurements on a single quantum dot formed at fluctuations of the interface of a GaAs/GaAlAs quantum well. We demonstrate that under pulsed nonresonant excitation, the quantum dot emits a single photon per pulse. This shows that after the photon emission, there is no refill of the quantum dot by the nearby two-dimensional reservoir of delocalized states. The possibility of delivering Fourier transform limited single photons makes this system a good candidate for exciton- and photon-based quantum information processing schemes.

Submicron-diameter semiconductor pillar microcavities with very high quality factors

Pillar microcavities are subject to two common fabrication artifacts: Bragg mirror corrugation and oxide deposit cladding. In this letter the authors investigate the impact of these features on the quality factor. A quasiperiodic variation of the quality factor as a function of the pillar diameter is experimentally observed and well described by theory. Moreover, observation of quality factors in excess of 1500, close to the theoretical limit, is reported for 600-nm-diameter GaAs micropillars bounded by AlGaAs∕GaAs Bragg mirrors.

Deformable two-dimensional photonic crystal slab for cavity optomechanics

We have designed photonic crystal suspended membranes with optimized optical and mechanical properties for cavity optomechanics. Such resonators sustain vibration modes in the megahertz range with quality factors of a few thousand. Thanks to a two-dimensional square lattice of holes, their reflectivity at normal incidence at 1064 nm reaches values as high as 95%. These two features, combined with the very low mass of the membrane, open the way to the use of such periodic structures as deformable end mirrors in Fabry-Perot cavities for the investigation of cavity optomechanical effects.

Reactive-ion etching of high-Q and submicron-diameter GaAs∕AlAs micropillar cavities

We present a fabrication process allowing the realization of high-Q and small-diameter micropillar cavities. The fabrication involves molecular beam epitaxy, electron-beam lithography, and reactive ion etching (RIE). The introduction of O2 to the SiCl4 RIE plasma and the dynamic adjustment of its flow rate enable the control of the etched profile throughout the process, through the deposition of silicon oxide on the vertical etched surfaces. The resulting cavities have very smooth, straight, and vertical sidewalls and remain optically and mechanically stable for long periods of time. The optical modes sustained by these cavities exhibit record quality factors in excess of 1200 for pillar diameters close to 400nm, which underscores the quality of our process.

Mode structure and ray dynamics of a parabolic dome microcavity.

We consider the wave and ray dynamics of an electromagnetic field in a parabolic dome microcavity. The structure of the fundamental s wave involves a main lobe in which the electromagnetic field is confined around the focal point in an effective volume of the order of a cubic wavelength, while modes with finite angular momentum have a structure that avoids the focal area and have correspondingly larger effective volumes. The ray dynamics indicate that the fundamental s wave is robust with respect to small geometrical deformations of the cavity, while the higher order modes are unstable, giving rise to optical chaos. We discuss the incidence of these results on the modification of the spontaneous emission dynamics of an emitter placed in such a parabolic dome microcavity.

Single InAs1−xPx/InP quantum dots as telecommunications-band photon sources

The optical properties of single InAsP/InP quantum dots are investigated by spectrally-resolved and time-resolved photoluminescence measurements as a function of excitation power. In the short-wavelength region (below 1.45