348 research outputs found
Ultra Fast Nonlinear Optical Tuning of Photonic Crystal Cavities
We demonstrate fast (up to 20 GHz), low power (5 ) modulation of
photonic crystal (PC) cavities in GaAs containing InAs quantum dots. Rapid
modulation through blue-shifting of the cavity resonance is achieved via free
carrier injection by an above-band picosecond laser pulse. Slow tuning by
several linewidths due to laser-induced heating is also demonstrated
Bichromatic Driving of a Solid State Cavity QED System
The bichromatic driving of a solid state cavity quantum electrodynamics
system is used to probe cavity dressed state transitions and observe coherent
interaction between the system and the light field. We theoretically
demonstrate the higher order cavity-dressed states, supersplitting, and AC
stark shift in a solid state system comprised of a quantum dot strongly coupled
to a photonic crystal cavity for on- and far off-resonant cases. For the
off-resonant case, phonons mediate off-resonant coupling between the quantum
dot and the photonic resonator, a phenomenon unique to solid state cavity
quantum electrodynamics.Comment: 8 pages 6 figure
Cell-to-cell variability of alternative RNA splicing
The role of mRNA processing in gene expression variability is poorly characterized. This study investigates the extent of cell-to-cell variability of alternative RNA splicing in mammalian cells using single-molecule imaging of CAPRIN1 and MKNK2 splice isoforms
Cavity-enhanced single photon emission from a single impurity-bound exciton
Impurity-bound excitons in ZnSe quantum wells are bright single photon
emitters--a crucial element in photonics-based quantum technology. But to
achieve the efficiencies required for practical applications, these emitters
must be integrated into optical cavities that enhance their radiative
properties and far-field emission pattern. In this work, we demonstrate
cavity-enhanced emission from a single impurity-bound exciton in a ZnSe quantum
well. We utilize a bullseye cavity structure optimized to feature a small mode
volume and a nearly Gaussian far-field transverse mode that can efficiently
couple to an optical fiber. The fabricated device displays emission that is
more than an order of magnitude brighter than bulk impurity-bound exciton
emitters in the ZnSe quantum well, as-well-as clear anti-bunching, which
verifies the single photon emission from the source. Time-resolved
photoluminescence spectroscopy reveals a Purcell-enhanced radiative decay
process with a Purcell factor of 1.43. This work paves the way towards high
efficiency spin-photon interfaces using an impurity-doped II-VI semiconductor
coupled to nanophotonics
Optical modes in oxide-apertured micropillar cavities
We present a detailed experimental characterization of the spectral and
spatial structure of the confined optical modes for oxide-apertured micropillar
cavities, showing good-quality Hermite-Gaussian profiles, easily mode-matched
to external fields. We further derive a relation between the frequency
splitting of the transverse modes and the expected Purcell factor. Finally, we
describe a technique to retrieve the profile of the confining refractive index
distribution from the spatial profiles of the modes.Comment: 4 pages, 3 figure
Spectroscopy by frequency entangled photon pairs
Quantum spectroscopy was performed using the frequency-entangled broadband
photon pairs generated by spontaneous parametric down-conversion. An absorptive
sample was placed in front of the idler photon detector, and the frequency of
signal photons was resolved by a diffraction grating. The absorption spectrum
of the sample was measured by counting the coincidences, and the result is in
agreement with the one measured by a conventional spectrophotometer with a
classical light source.Comment: 11 pages, 5 figures, to be published in Phys. Lett.
Superconducting nanowire photon number resolving detector at telecom wavelength
The optical-to-electrical conversion, which is the basis of optical
detectors, can be linear or nonlinear. When high sensitivities are needed
single-photon detectors (SPDs) are used, which operate in a strongly nonlinear
mode, their response being independent of the photon number. Nevertheless,
photon-number resolving (PNR) detectors are needed, particularly in quantum
optics, where n-photon states are routinely produced. In quantum communication,
the PNR functionality is key to many protocols for establishing, swapping and
measuring entanglement, and can be used to detect photon-number-splitting
attacks. A linear detector with single-photon sensitivity can also be used for
measuring a temporal waveform at extremely low light levels, e.g. in
long-distance optical communications, fluorescence spectroscopy, optical
time-domain reflectometry. We demonstrate here a PNR detector based on parallel
superconducting nanowires and capable of counting up to 4 photons at
telecommunication wavelengths, with ultralow dark count rate and high counting
frequency
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