Search results for "photonics"

Quantum Optics and Photonics 2021: Book of Abstracts : The 4th International Conference, Riga, 22-23 April 2021

2021

The conference was supported by ERDF project No. 1.1.1.5/19/A/003 “The Development of Quantum Optics and Photonics at the University of Latvia”

Oblique surface waves at an interface between a metal–dielectric superlattice and an isotropic dielectric

2012

We investigate the existence and dispersion characteristics of surface waves that propagate at an interface between a metal–dielectric superlattice and an isotropic dielectric. Within the long-wavelength limit, when the effective-medium (EM) approximation is valid, the superlattice behaves like a uniaxial plasmonic crystal with the main optical axes perpendicular to the metal–dielectric interfaces. We demonstrate that if such a semi-infinite plasmonic crystal is cut normally to the layer interfaces and brought into contact with a semi-infinite dielectric, a new type of surface mode can appear. Such modes can propagate obliquely to the optical axes if favorable conditions regarding the thick…

Optical Characterization Method for Tilted or Decentered Intraocular Lenses

2016

Purpose To test and validate a method for measuring the optical quality and optical power of monofocal intraocular lenses (IOLs) in the presence of a tilt or a decentration as well as its optical power. Methods The experimental system consists of an artificial eye (wet-cell) and a commercial aberrometer with a Shack-Hartmann sensor. Optical image quality parameters such as point spread function (PSF), modulation transfer function (MTF), and the simulations of the retinal image of an extended object are computed from the in vitro wavefront data of an IOL. Repeatability and reproducibility of the system are tested. Mathematical and ray-tracing simulations are used to ascertain the precision a…

All-optical regeneration of polarization of a 40 Gbit/s return-to-zero telecommunication signal

2013

International audience; We report all-optical regeneration of the state of polarization of a 40 Gbit/s return-to-zero telecommunication signal. The device discussed here consists of a 6.2-km-long nonzero dispersion-shifted fiber, with low polarization mode dispersion, pumped from the output end by a backward propagating wave coming from either an external continuous source or a reflection of the signal. An initially scrambled signal acquires a degree of polarization close to 100% toward the polarization generator output. All-optical regeneration is confirmed by means of polarization and bit-error-rate measurements as well as real-time observation of the eye diagrams. We show that the physic…

Precision tests of QED and non-standard models by searching photon-photon scattering in vacuum with high power lasers

2009

We study how to search for photon-photon scattering in vacuum at present petawatt laser facilities such as HERCULES, and test Quantum Electrodynamics and non-standard models like Born-Infeld theory or scenarios involving minicharged particles or axion-like bosons. First, we compute the phase shift that is produced when an ultra-intense laser beam crosses a low power beam, in the case of arbitrary polarisations. This result is then used in order to design a complete test of all the parameters appearing in the low energy effective photonic Lagrangian. In fact, we propose a set of experiments that can be performed at HERCULES, eventually allowing either to detect photon-photon scattering as du…

Step-along power vector method for astigmatic wavefront propagation

2013

Purpose To propose both a new algebraic solution and a graphical monitoring method for astigmatic wavefront propagation in the framework provided by power vectors. Methods The generalised propagation equation describing the propagation of astigmatic wavefronts from one plane to another is adapted to the power vectors formalism using a novel algorithm based on a step-along method. The step-along procedure is directly applied to the tuple of power vectors [M, J0, J45] representing an arbitrary astigmatic wavefront and it permits the calculation of the tuple of power vectors [M′, J′0, J′45] after a given propagation distance. This is achieved mathematically first by temporarily rotating the as…

Sub-200-kHz single soliton generation in a long ring Er-fiber laser with strict polarization control by using twisted fiber

2020

Abstract In the present work we demonstrate a novel single-soliton ultra-low pulse repetition frequency passively mode-locked erbium-doped fiber laser. We mitigate the residual linear birefringence of fiber by fiber twist to achieve a strict control of polarization. For mode-locking the nonlinear polarization rotation (NPR) was used. Special technique was applied to reduce the overdriving of NPR that allows the generation of single soliton in ultra-long cavity. The strict control of polarization yields a stable relation between the polarization state of the pulses propagating in the cavity and the regimes of generation. A 192.12-kHz train of soliton pulses was obtained with pulse duration o…

Reply to 'The super-quadratic growth of high-harmonic signal as a function of pressure'

2010

Quality control in the optical industry: From a work analysis of lens inspection to a training programme, an experimental case study

2007

A cognitive work analysis of quality inspection in the optical industry has been carried out in order to devise a training programme. The task concerned the inspection of high quality human eyeglass lenses. We conducted an experimental investigation of defect detection and acceptability decision-making tasks in 18 experts and novice inspectors. Detection and decision-making were investigated together and separately in two experimental sessions. We showed the effect of expertise on reaction times and errors, and we described the cognitive processes of novice inspectors. On the basis of the processing differences between the two groups, a training programme for new inspectors was devised and …

Proof-of-Principle Direct Measurement of Particle Statistical Phase

2022

The symmetrization postulate in quantum mechanics is formally reflected in the appearance of an exchange phase governing the symmetry of identical-particle global states under particle swapping. Many indirect measurements of this fundamental phase have been reported thus far, but a direct observation has been achieved only recently for photons. Here, we propose a general scheme capable of directly measuring the exchange phase of any type of particle (bosons, fermions, or anyons), exploiting the operational framework of spatially localized operations and classical communication. We experimentally implement it on an all-optical platform, providing a proof of principle for different simulated …