Advances and prospects of frequency doublers based on periodically poled silica fibres

Record high efficient frequency doublers in periodically poled silica fibres are demonstrated for light generation at 532 nm and 775 nm. The onset of nonlinear conductivity is shown to limit the maximum χ(2) in glass

Second-harmonic vortex generation with a poled glass

A Simple method for nonlinear vortex generation is presented. Spin-to-Orbital transfer with total angular momentum conservation between photons at the fundamental and at the second-harmonic frequency is demonstrated

Advances in single-mode poled fibres

Integration of optical functions in fibre is a subject of constant investigation. If most of the basic functions like splitting, wavelength combining, filtering, amplification, dispersion management, etc, are already solved in fibres, others like isolation, pulse gating or frequency conversion are still subject of research. This is part of the current investigation performed in the frame of the EU project CHARMING (FP7-288786) and presented here

Derivation of Motion Vectors from Sequential Satellite Images Using Vague Contouring

A relaxation-contour method for retrieving motion vectors from sequential satellite images is presented. The contour part explores image contours (level set) to extract targets (extreme points on these contours). Motion vectors are derived by examining the correspondence between targets extracted from symmetrical pairs of images. The basic criterion is geometrical similarity of contours taken at the same level (contour matching), while gradient information is used to sustain robustness of search. Vague contouring generates much more motion vectors than by the current template matching methodology. Naturally, many invalid vectors are generated in this way, yet their abundance gives preferentiality to a relaxation labeling approach aimed at selection of correct vectors from several candidates to be consistent (in space and time) with others. Estimates of water vapor motion vectors obtained using relaxationcontour and maximum cross-correlation (with and without relaxation labeling) methods have been compared to those derived manually. Results show advantages of the relaxation-contour method both in density and quality. We contemplate future integration of this scheme with assimilation models

Freezing ultrashort light pulses by exciton-polariton interference in glass

Self-assembled nanostructures with two characteristic periods, sub-wavelength along polarization and close to wavelength along propagation direction, are revealed in silica glass after femtosecond laser writing. The phenomenon is interpreted in terms of exciton-polariton crystal formation

High-purity, broadband, entangled photon pairs generated in poled silica fibers

We discuss direct polarization-entangled photon pair generation in poled fibers, including the role that fiber birefringence and dispersion play. The broadband nature of the fiber source is demonstrated, and the downconversion spectrum is measured

Multi-party agile QKD network with a fiber-based entangled source

A multi-party quantum key distribution scheme is experimentally demonstrated by utilizing a poled fiber-based broadband polarization-entangled source and dense wavelength-division multiplexing. Entangled photon pairs are delivered over 40-km of fiber, with secure key rates of more than 20 bits/s observed

Quantum interferometry through cascading broadband entanglement sources

We demonstrate broadband (~100nm) quantum interference in telecom frequencies in an all-fiber system with cascaded SPDC sources. Its applications in dispersion metrology and quantum state engineering are also demonstrated.</p