We have experimentally demonstrated a decoy-state quantum key distribution scheme (QKD) with a heralded single-photon source based on parametric down-conversion. What we used is a one-way BB84 protocol with a four-state and one-detector phase-coding scheme.
We report the generation of time-energy entangled paired photons with subnatural linewidths and controllable temporal lengths. The photons are generated using EIT and slow light in a high optical depth two-dimensional MOT.
We demonstrate a new technique of efficient, time-resolved, infrared single-photon detection using non collinearly phase-matched frequency upconversion by an ultrafast pump, allowing nearly background-free sub-picosecond characterization of 1582-nm time anti-correlated entangled photons.
We experimentally studied the effect of standing wave pulses on an atom interferometer. Despite the external field perturbations the coherence is perfectly preserved for the conditions similar to quantum resonances of a quantum kicked rotor.
We describe a scalable nanocavity array, with single quantum dots, for universal single-operation N-qubit quantum gate. A single two-level system controls the lineshapes, departing from optical-analog of electromagnetically-induced-transparency, with high fidelity and low photon loss.
We generate a highly-controlled, optically-dense, and repeatable Rb vapor inside of a hollow-core photonic bandgap fiber using light-induced atomic desorption. Here we present its generation dynamics and use for nonlinear quantum optical applications.
We present experimental results of the use of continuous adaptive feedback in quantum optical measurement of phase of the sidebands on continuous-wave (cw) coherent light, consistent with theoretical predictions (Berry and Wiseman, 2002).
We investigate the manipulation of nanoscopic particles, which contain few or single quantum emitters, on photonic crystal cavities using scanning probe techniques, thereby aiming at the precise control of light-matter coupling in these cavities.
Ultrafast upconversion is employed to investigate pulse propagation in quantum cascade lasers. The authors have observed advances of the pulse peak to early times, pulse re-shaping, and evidence of a coherent contribution to pulse propagation.
A novel polarization-frequency-multiplexing scheme is implemented to suppress noise in a fiber-based Gaussian-modulated coherent-state quantum key distribution system. The achievable secrete key rate is 0.30 bit/pulse with a 5 km-fiber and 0.05 bit/pulse with a 20 km-fiber.
We combined high resolution laser spectroscopy and microscopy to identify individual molecules in two independent microscopes. Then the Stark effect was exploited to tune the transition frequencies of the molecules and thus obtain indistinguishable single photons.
Photon statistics in the cooperative spontaneous emission (Dickepsilas superradiance) is investigated by Monte-Carlo simulations. Giant photon bunching due to generation of superradiant photon pairs is predicted.
The nonlinear dynamics of a classical photon pulse occurring at a two-sided cavity QED system in the weak-coupling regime is investigated theoretically. It is shown that this system functions as a single-photon filter.
We describe the first electrically-driven single-photon source which can demonstrate Hong-Ou-Mandel type interference. Experiments were performed under both pulsed and CW excitation, and we discuss the factors limiting visibility in both cases.
We report the temporal shaping and nonlocal control of a heralded single-photon wave packet, conditionally prepared by detecting the idler trigger photon of the signal-idler photon pair born in the process of spontaneous parametric down-conversion.
We are developing an experimental setup to deterministically create single photons using spontaneous downconversion. We expect our source to output a single photon with a probability of 70%, and two photons with less than 3%.
A photonic crystal slab nanocavity with a single InAs quantum dot in a field antinode is a promising system for cavity QED because of the cavitypsilas small volume and the dotpsilas stationary position.
We present a new scheme for trapping single atoms in separate dipole-traps and manipulating them individually. It relies on a spatial light-modulator to create the traps and will find applications in cavity-QED.
We coherently probe a quantum dot, strongly coupled to a photonic crystal nano-cavity, using a resonant laser beam. At higher pump power, the coupled systempsilas response becomes highly nonlinear. This coherent probing method has applications for classical and quantum information processing.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.