11 research outputs found
A Correlation between the Emission Intensity of Self-Assembled Germanium Islands and the Quality Factor of Silicon Photonic Crystal Nanocavities
We present a comparative micro-photoluminescence study of the emission
intensity of self-assembled germanium islands coupled to the resonator mode of
two-dimensional silicon photonic crystal defect nanocavities. The emission
intensity is investigated for cavity modes of L3 and Hexapole cavities with
different cavity quality factors. For each of these cavities many nominally
identical samples are probed to obtain reliable statistics. As the quality
factor increases we observe a clear decrease in the average mode emission
intensity recorded under comparable optical pumping conditions. This clear
experimentally observed trend is compared with simulations based on a
dissipative master equation approach that describes a cavity weakly coupled to
an ensemble of emitters. We obtain evidence that reabsorption of photons
emitted into the cavity mode is responsible for the observed trend. In
combination with the observation of cavity linewidth broadening in power
dependent measurements, we conclude that free carrier absorption is the
limiting effect for the cavity mediated light enhancement under conditions of
strong pumping.Comment: 8 pages, 5 figure
Emitters of -photon bundles
We propose a scheme based on the coherent excitation of a two-level system in
a cavity to generate an ultrabright CW and focused source of quantum light that
comes in groups (bundles) of photons, for an integer tunable with the
frequency of the exciting laser. We define a new quantity, the \emph{purity} of
-photon emission, to describe the percentage of photons emitted in bundles,
thus bypassing the limitations of Glauber correlation functions. We focus on
the case and show that close to 100% of two-photon emission and
90% of three-photon emission is within reach of state of the art cavity QED
samples. The statistics of the bundles emission shows that various
regimes---from -photon lasing to -photon guns---can be realized. This is
evidenced through generalized correlation functions that extend the standard
definitions to the multi-photon level.Comment: Introduce the n-th order N-photon correlation functions. Reorganized
to emphasize the N-photon emitter, now extended to the antibunching regime,
rather than only coherent emission as previsoul
Correlation between emission intensity of self-assembled germanium islands and quality factor of silicon photonic crystal nanocavities
A carrier relaxation bottleneck probed in single InGaAs quantum dots using integrated superconducting single photon detectors
Highly directed emission from self-assembled quantum dots into guided modes in disordered photonic-crystal waveguides
On-Chip Generation, Routing, and Detection of Resonance Fluorescence
Quantum optical circuits can be used
to generate, manipulate, and exploit nonclassical states of light
to push semiconductor based photonic information technologies to the
quantum limit. Here, we report the on-chip generation of quantum light
from individual, resonantly excited self-assembled InGaAs quantum
dots, efficient routing over length scales â„1 mm via GaAs ridge
waveguides, and in situ detection using evanescently coupled integrated
NbN superconducting single photon detectors fabricated on the same
chip. By temporally filtering the time-resolved luminescence signal
stemming from single quantum dots we use the quantum optical circuit
to perform time-resolved excitation spectroscopy on single dots and
demonstrate resonance fluorescence with a line-width of 10 ±
1 ÎŒeV; key elements needed for the use of single photons in
prototypical quantum photonic circuits
Monolithically Integrated HighâÎČ Nanowire Lasers on Silicon
Reliable technologies for the monolithic
integration of lasers onto silicon represent the holy grail for chip-level
optical interconnects. In this context, nanowires (NWs) fabricated
using IIIâV semiconductors are of strong interest since they
can be grown site-selectively on silicon using conventional epitaxial
approaches. Their unique one-dimensional structure and high refractive
index naturally facilitate low loss optical waveguiding and optical
recirculation in the active NW-core region. However, lasing from NWs
on silicon has not been achieved to date, due to the poor modal reflectivity
at the NW-silicon interface. We demonstrate how, by inserting a tailored
dielectric interlayer at the NW-Si interface, low-threshold single
mode lasing can be achieved in vertical-cavity GaAsâAlGaAs
coreâshell NW lasers on silicon as measured at low temperature.
By exploring the output characteristics along a detection direction
parallel to the NW-axis, we measure very high spontaneous emission
factors comparable to nanocavity lasers (ÎČ = 0.2) and achieve
ultralow threshold pump energies â€11 pJ/pulse. Analysis of
the inputâoutput characteristics of the NW lasers and the power
dependence of the lasing emission line width demonstrate the potential
for high pulsation rates â„250 GHz. Such highly efficient nanolasers
grown monolithically on silicon are highly promising for the realization
of chip-level optical interconnects