77 research outputs found
Temporally and spectrally multiplexed single photon source using quantum feedback control for scalable photonic quantum technologies
Current proposals for scalable photonic quantum technologies require
on-demand sources of indistinguishable single photons with very high efficiency
(having unheralded loss below ). Even with recent progress in the field
there is still a significant gap between the requirements and state of the art
performance. Here, we propose an on-chip source of multiplexed, heralded
photons. Using quantum feedback control on a photon storage cavity with an
optimized driving protocol, we estimate an on-demand efficiency of and
unheralded loss of order , assuming high efficiency detectors and
intrinsic cavity quality factors of order . We further explain how
temporal- and frequency-multiplexing can be used in parallel to significantly
reduce device requirements if single photon frequency conversion is possible
with efficiency in the same range of
Photon-Photon Interactions in Dynamically Coupled Cavities
We study theoretically the interaction between two photons in a nonlinear
cavity. The photons are loaded into the cavity via a method we propose here, in
which the input/output coupling of the cavity is effectively controlled via a
tunable coupling to a second cavity mode that is itself strongly
output-coupled. Incoming photon wave packets can be loaded into the cavity with
high fidelity when the timescale of the control is smaller than the duration of
the wave packets. Dynamically coupled cavities can be used to avoid limitations
in the photon-photon interaction time set by the delay-bandwidth product of
passive cavities. Additionally, they enable the elimination of wave packet
distortions caused by dispersive cavity transmission and reflection. We
consider three kinds of nonlinearities, those arising from
and materials and
that due to an interaction with a two-level emitter. To analyze the input and
output of few-photon wave packets we use a Schr\"odinger-picture formalism in
which travelling-wave fields are discretized into infinitesimal time-bins. We
suggest that dynamically coupled cavities provide a very useful tool for
improving the performance of quantum devices relying on cavity-enhanced
light-matter interactions such as single-photon sources and atom-like quantum
memories with photon interfaces. As an example, we present simulation results
showing that high fidelity two-qubit entangling gates may be constructed using
any of the considered nonlinear interactions
Self-Similar Nanocavity Design with Ultrasmall Mode Volume for Single-Photon Nonlinearities
United States. Air Force Office of Scientific Research (FA8750-13-2-0120
On the theory of coupled modes in optical cavity-waveguide structures
Light propagation in systems of optical cavities coupled to waveguides can be
conveniently described by a general rate equation model known as (temporal)
coupled mode theory (CMT). We present an alternative derivation of the CMT for
optical cavity-waveguide structures, which explicitly relies on the treatment
of the cavity modes as quasinormal modes with properties that are distinctly
different from those of the modes in the waveguides. The two families of modes
are coupled via the field equivalence principle to provide a physically
appealing yet surprisingly accurate description of light propagation in the
coupled systems. Practical application of the theory is illustrated using
example calculations in one and two dimensions.Comment: 14 pages, 9 figure
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