Search results for "Wavelength"
showing 10 items of 741 documents
Target localization in the three-dimensional space by wavelength multiplexing.
2002
A method to localize a target in the three-dimensional space is presented. Each different position of the target on the depth axis produces, when captured with a CCD camera, an image of a different size on its sensor plane. The size of this image depends only on the distance between the target and the camera. The use of a white light optical correlator that gives us a different response depending on the scale of the input image permits us to know the depth position of the particular target. The obtained results demonstrate the utility of the newly proposed method.
Buildup of terahertz vector dark-soliton trains from induced modulation instability in highly birefringent optical fiber.
2007
We present the experimental observation of generation of vector dark-soliton pulse trains with terahertz repetition rates in the normal dispersion regime of an optical fiber. The polarization solitons build up from induced cross-phase modulation instability of two orthogonal pumps in a highly birefringent fiber.
High performance configuration of all-raman N &#x000D7; 40 Gbit/s RZ-DPSK systems over ultrawave<sup>TM</sup> maps
2007
In order to explore the impact of the DPSK format on best system configuration, and to cross-check the simulation tools, transmission experiments involving 16 × 40 Gbit/s WDM channels on a recirculating loop including a symmetric UltrawaveTM fiber dispersion map are performed. In these experiments the RZ-DPSK format is used, and each 100 km span is brought to optical transparency with 75%(25%) of backward (forward) Raman gain. The pre-compensation is experimentally varied, and a significant transmission improvement after 4000 km for the pre-compensation of -350 ps/nm is observed.
Compact dielectric reflective elements II Multichannel filter of closely spaced spectral bands
1994
The optical design of an interference wedge filter providing the simultaneous separation of a number of closely spaced spectral bands is studied. Multiple reflections of the incident collimated beam within the wedge are initiated, each of them characterized by a different angle of incidence and consequently by specific spectral parameters of the transmitted band. Model calculations based on the measured angular dependences of filter transmission parameters have been performed. The design is proposed for applications in optical communications (wavelength division demultiplexing), analytical spectroscopy (minipolychromators), color analysis, and similar areas.
Crumpling of a stiff tethered membrane.
2003
first-principles numerical simulation model for crumpling of a stiff tethered membrane is introduced. In our model membranes, wrinkles, ridge formation, ridge collapse, as well as the initiation of stiffness divergence, are observed. The ratio of the amplitude and wave length of the wrinkles, and the scaling exponent of the stiffness divergence, are consistent with both theory and experiment. We observe that close to the stiffness divergence there appears a crossover beyond which the elastic behavior of a tethered membrane becomes similar to that of dry granular media. This suggests that ridge formation in membranes and force-chain network formation in granular packings are different manife…
Spectral imaging system for money counterfeit detection
2019
A prototype with three different wavelength lasers (448nm, 532nm and 659nm) for money counterfeit illumination, analyzation and detection using RGB crosstalk correction and comparing spectral image ration for different banknote elements will be presented.
Acoustic dynamics of network-forming glasses at mesoscopic wavelengths
2013
The lack of long-range structural order in amorphous solids induces well known thermodynamic anomalies, which are the manifestation of distinct peculiarities in the vibrational spectrum. Although the impact of such anomalies vanishes in the long wavelength, elastic continuum limit, it dominates at length scales comparable to interatomic distances, implying an intermediate transition regime still poorly understood. Here we report a study of such mesoscopic domains by means of a broadband version of picosecond photo-acoustics, developed to coherently generate and detect hypersonic sound waves in the sub-THz region with unprecedented sampling efficiency. We identify a temperature-dependent fra…
Integrated optic surface plasmon resonance measurements in a borosilicate glass substrate
2008
The surface plasmon resonance (SPR) technique is a well-known optical method that can be used to measure the refractive index of organic nano-layers adsorbed on a thin metal film. Although there are many configurations for measuring biomolecular interactions, SPR-based techniques play a central role in many current biosensing experiments, since they are the most suited for sensitive and quantitative kinetic measurements. Here we give some results from the analysis and numerical elaboration of SPR data from integrated optics experiments in a particular borosilicate glass, chosen for its composition offering the rather low refractive index of 1.4701 at 633 nm wavelength. These data regard the…
Axial apodization in 4Pi-confocal microscopy by annular binary filters
2002
We present a novel technique for considerably decreasing the sidelobe height of the axial point-spread function of one-photon 4Pi-confocal microscopes. By means of a numerical example, in which the ratio between the excitation and the fluorescence wavelengths was set to epsilon = lambdaexc/lambdadet = 0.8, we show that simply inserting a pair of properly designed two-ring binary masks in the illumination set allows the height of the axial sidelobes to be reduced from 20% to 5% of the height of the central peak. This allows one to receive the full benefit of the strong narrowness of the central lobe provided by the 4Pi-confocal technique.
Director orientation in chevron surface-stabilized ferroelectric liquid crystal cells. Verification of orientational binding at the chevron interface…
1990
Abstract We present results of theoretical modelling and experimental study of director distributions and the associated optical properties of chevron surface stabilized ferroelectric liquid crystal (SSFLC) cells. Chevron cells are modelled as being two stacked FLC slabs, described by distinct orientation distributions of the director [ncirc]-polarization P([ncirc] – P) couple. In each slab the [ncirc] – P distribution is governed by bulk Frank elastic and electric field-induced torques and by surface torques at the FLC-solid interface and at the chevron interface, where the two distributions are coupled. The optical properties of such structures are calculated numerically and the results t…