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.
The fluorescence quenching of a single molecule can be controlled using a plasmonic device made of a metallic or negative-index slab and a metallic nanoparticle. The concept of dark near-field fluorescence imaging is introduced.
We present direct experimental measurements of localized eigenmodes in disordered one-dimensional waveguide arrays. In the nonlinear regime we observe delocalization of localized states, exhibiting different features in the limits of weak and strong disorder.
We propose complex networks constructed from interacting vector solitons. Within soliton-based networks, we demonstrate memory effects that are greatly enhanced by noise, as well as spontaneous entire network self-synchronization effects.
We predict a lateral shift of the reflected beam when an electromagnetic beam is normally incident on an antiferromagnet in the presence of an external field. This shift is confirmed using simulations for Gaussian beams.
Thermoreflectance and coherent spin dynamics in Fe films are measured using asynchronous optical sampling at kilohertz rates. We observe ultrafast laser-induced time dependence of spin precession frequencies that is attributed to thermal relaxation.
We report on the dramatic ultrafast photo-enhancement of ferromagnetism on a 100 picosecond timescale in ion-implanted semiconductor GaMnAs via photoexcited transient carriers. This non-thermal, transient cooperative magnetic process surprisingly quenches at low temperatures, significantly bellow the Curie temperature.
We study the extended modes of a nonlinear quasi-periodic system and show that the nonlinear spectra are deformed versions of the Hofstadter butterfly. An optical realization of the Hofstadter butterfly is proposed.
We present experimental and numerical results of wavepacket expansion in one-dimensional disordered nonlinear waveguide arrays. We show that in 1D there is a direct transition from ballistic expansion to localization, which is accelerated by nonlinearity.
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 report on the observation of collapse and revival of a spatial light grating stored into the Zeeman coherences of cold cesium atoms. Bragg diffraction is employed to probe the dynamic of the stored grating.
Electromagnetically induced transparency is observed in rubidium-filled kagome structure hollow-core PCF with polymer-coated core. We show that the 6 MHz transparency linewidth is below that expected from a bare fiber.
Propagation of a quantized optical field through a thick sample of two-level atoms, considering the complete Zeeman sublevel structure, is theoretically investigated. Squeezing and entanglement between orthogonal polarization components is predicted for the transmitted field.
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 have measured the polarization dependence of the detection efficiency of NbN superconducting single photon detectors. This behavior is explained by the calculated absorption efficiency of a parallel set of metal lines.
The capability of 2D IR spectroscopy for elucidating time-evolving structures is enhanced by a programmable mid-IR pulse shaper that greatly improves the ease, speed and accuracy of data collection. We demonstrate our technique on a model metal carbonyl compound and then apply it to study the structural disorder of amyloid fibers composed of aggregated human islet amyloid polypeptide (hIAPP).
A novel all-electronic scheme for real-time measurement and stabilization of the carrier-envelope phase of kHz pulse trains is demonstrated, revealing new insight into the pulse-to-pulse phase fluctuations of such lasers.
No broadband lasing medium like Ti:Saph has been demonstrated yet for terahertz radiation. We show that laser-aligned molecules can amplify broadband terahertz radiation, allowing high-energy chirped-pulse amplification at terahertz frequencies.
The terahertz dielectric properties of several heterostructures based on epitaxial SrTiO3 and DyScO3 thin films were characterized without and under applied static or low-frequency electric field. We demonstrate up to 65% variation of the permittivity of SrTiO3 films and up to 35 % modulation of the power transmission of terahertz waves at 500 GHz and 112 V (75 kV/cm) bias.
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”.