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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 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.
Coherent THz pulses at 328.2 mum were generated by mixing two CO2 laser frequencies based on collinear phase-matched difference-frequency generation in GaSe crystals. The highest average output power was measured to be 260 muW.
By combining incoherent time gating (sum-frequency mixing) with coherent gating (optical coherence tomography), we process light backscattered from a sample in the optical domain to improve imaging contrast by 29 dB.
Tunable optical combs spanning the 6.5-8.5 mum range are obtained as a result of a difference-frequency-generation process between pulse-trains emitted by an amplified 100 MHz Er-fiber oscillator with unprecedented average power of tens of microwatts.
We present the first demonstration of ultra-low power four-wave-mixing in a high-index glass micro-ring resonator (47.5 mum radius). By using a mW-level CW pump power we obtained an appreciable wavelength conversion in the C-band.
We demonstrate widely tunable terahertz-wave generation using difference frequency generation (DFG) in an organic N-benzyl-2-methyl-4-nitroaniline (BNA) crystal. The frequency tuning of the BNA-DFG was obtained between 0.1 and 15 THz.
A fiber-coupled difference frequency generation laser spectrometer for measuring isotopic compositions of N2O at trace concentrations is presented. Using wavelength modulation 90/00 precision at 100 ppm is achieved. The accuracy is demonstrated with enriched samples.
Time-resolved mid-infrared upconversion based on sum-frequency generation was applied to measure the group-velocity dispersion in quantum cascade lasers; material, waveguide, and gain contributions were distinguished, and used to model the temporal pulse broadening.
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%.
The optical upconversion of infrared light to visible light has been achieved in infrared photosensitizer-doped organic light-emitting diodes. This work brought forth a prototype design for novel flexible organic optical upconversion device.
We propose a triply-resonant GaAs microdisk for difference-frequency generation in the 2.5-2.9 mum band. Its performances are first numerically studied, in terms of phase-matching condition, conversion efficiency and tolerances. Preliminary devices are then fabricated and characterized.
We demonstrate ultra-low-power parametric frequency conversion of 5-Gbit/s data in a silicon photonic structure via microcavity-enhanced four-wave mixing. Our modeling predicts high conversion efficiency up to 0-dB is possible through GVD-engineering and free-carrier lifetime reduction.
We present an Er:fiber laser generating two 11 fs pulse trains individually tunable between 1200 and 1300 nm. A relative timing jitter of 43 as is measured after frequency conversion and compression.
We report a novel mechanism of localization and frequency up-conversion of light pulses with spectra in the normal GVD range of optical fibres, due to the inertial force acting on pulses from the accelerating solitons.
We demonstrate difference frequency generation of backward THz waves from collinearly phase-matched, periodically poled lithium niobate. Coherent THz waves between 457~507 mum were generated by using kW pump power at a kHz repetition rate.
Millimeter-wave combs are synthesized using a novel time-multiplexed optical pulse shaping scheme by integrating fast wavelength switching, optical frequency comb generation, and spectral line-by-line pulse shaping.
We report an experiment on preparation and characterization of general four-dimensional quantum states using ultrafast-pumped frequency-nondegenerate spontaneous parametric down-conversion. We also discuss two additional experimental schemeswhich offermore complete control of the state purity and entropy.
We have experimentally implemented a differential phase shift quantum-key distribution system with up-conversion detectors operating at a 2.5 Gbps clock rate. A Michelson interferometer with Faraday mirrors is used to increase the system stability.
We demonstrate highly sensitive coherent detection of a monochromatic THz-wave pulse at room temperature using the frequency up-conversion in MgO:LiNbO3 combined with balanced homodyne detection. Both the intensity and phase of THz radiation are measured.
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