The paper presents an experimental study of the possibility of constructing a near-infrared atmospheric optical communication system based on a pair of 100Base-TX / 1000BASE-T signal format media converters in the 1000BASESX / LX format with DEM-310GT SFP transceivers. To ensure better stability of the input of radiation coming from the receiving collimator into the fiber cable, the FTB900 SN-Y4 BRANCHED TUBE cable was used. Its cable connector has been modified to match the DEM-310GT transceiver. The collimator of the transmitting radiation is supplemented by a spiral phase plate forming a vortex beam. The influence of atmospheric influence on the data transfer rate is analyzed.
The paper considers photo-induced microrelief formation using Gaussian paraxial vortex laser beams with different polarizations and their characteristics, such as the Poynting vector, gradient force and force density, which are important for assessing the effect of radiation on matter. It is shown that the characteristics, which depend only on the intensity gradient, do not allow to correctly describe dependence of the distribution of optical forces and the formed relief. A model taking into account non-gradient forces is presented. Theoretical and experimental results are compared.
We report the experimental studies on the thermal deposition of CdTe films. The deposition of thin CdTe films is performed onto the substrate of varying temperature. The characteristics of the deposited CdTe films are studied using Raman spectroscopy, scanning profilometry, and scanning electron microscopy. According to the measurements, thin CdTe films deposited on substrates with temperatures of 300 °C and 450 °C demonstrate the best stoichiometry. The processes of changing the stoichiometric composition of CdTe films were studied by exposing the films to plasma at a high-voltage gas discharge. The optimal regimes were obtained to achieve 5 % excess and 12% deficiency of Te in the fabricated CdTe films. The optical properties of CdTe films in the visible and infrared ranges were studied. We experimentally demonstrate the resonances in spectra of CdTe-based metal-dielectric structures including layers of water, isopropanol, and ethanol, which can be used to determine the concentration of these solvents.
The propagation of vortex beams of wavelength 1530 nm through an aerosol and turbulent atmosphere was experimentally investigated. The stability of a vortex phase under the beam wandering caused by a flow of warm air was experimentally showed. The results obtained can be used for optical atmospheric communication.
In this paper, we study the possibility of forming beams with a scalable wavefront. To multiply the wavefront with a scale factor, it is proposed to use a combination of the wavefront distribution generator and a diffractive grating with binarization operation. It is shown numerically and experimentally using spatial light modulator that such beams as the Zernike basis functions and Airy beams are suitable for testing optical systems.
An interference polarizer for forming a radially-polarized zero-order vortex Bessel beam with the wavelength of 1530 nm has been developed. The polarizer contains 33 layers of SiO2 / Nb2O5 evaporated on a glass substrate using the vacuum electron beam method. The measurement of polarizer characteristics showed the ratio of transmittance of radially- and azimuthally-polarized beams to be 80:1 – 90:1 with the angle of incidence equal to 24.5 – 25°. The transmittance of radially-polarized light was not less than 75%. A radially-polarized zero-order vortex Bessel beam of high optical quality was formed with the help of the developed polarizer and a diffractive axicon.
This paper describes synthesis, characteristics and experimental observation a new nonlinear optical characteristics new azopolymer based on poly-n-epoxypropyl carbazole (PEPC) and Disperse Orange 3 under the influence of a highintensity laser beam. The regularities in the formation of surface microstructures by the action of a focused Gaussian beam on the film of the synthesized polymer are shown. The dependence of the formation of the microstructure with increasing beam power density is studied. Nonlinear topographic effects arising in the formation of microstructures by beams with linear and circular polarization are described. The anisotropic nanoscale polymer movements were demonstrated for linearly polarized laser beam irradiation.
A new approach is proposed to implement diffractive optical elements (DOEs) for the conversion of the polarization state of beams. The fabricated four-sector polarization converter is experimentally investigated. The orthogonal polarization state of beams in opposite sectors is achieved by selecting a wavelength with a tunable laser. The experimental results of focusing the converted beams are presented.
An approach is proposed to implement diffractive optical elements for the conversion of the polarization state of beams. Calcite crystal etching technology is developed and applied to manufacture a four-sector polarization converter. The fabricated four-sector polarization converter is experimentally investigated. The orthogonal polarization state of beams in opposite sectors is achieved by selecting a wavelength with a tunable laser. The experimental results of focusing the converted beams are consistent with the numerical simulation.
A hyperspectrometer based on the Offner scheme was investigated. Spectral characteristics were studied and calibrated using a standard spectrometer. As a result of estimating the deviations of the spectra of the imaging hyperspectrometer and the reference spectrometer, calibration coefficients were obtained. The reflectance spectra of beets, onions and potatoes under natural solar illumination were experimentally obtained. Based on the analysis of hyperspectral imaging data, an analysis of the distribution of vegetative indices and, in particular, moisture content, was carried out. Analysis of histograms of moisture content index distribution was carried out.
In the present work, on-chip dielectric diffraction gratings for steering the propagation of surface plasmon polaritons (SPP) are theoretically, numerically and experimentally studied. The investigated plasmonic gratings consist of dielectric ridges located on the SPP propagation surface (on the metal surface). In contrast to Bragg gratings, at normal incidence the periodicity direction of the grating is perpendicular to the SPP propagation direction. The studied gratings are designed using a simple plane-wave grating model and rigorously simulated using the aperiodic Fourier modal method for numerical solution of Maxwell’s equations. In particular, plasmonic grating-based beam splitter with subwavelength footprint in the propagation direction is presented. Along with the theoretical and numerical results, proof-of-concept experimental results are presented. The investigated grating-based plasmonic gratings were fabricated from resist on a silver film using electron beam lithography and characterized using the leakage radiation microscopy technique. The obtained experimental results are in good agreement with the performed numerical simulations. The proposed on-chip gratings may find application in the design of systems for optical information transmission and processing at the nanoscale.
Experimental research in deposition of thin CdTe films was carried out using the resistive dynamic vacuum evaporation method. While forming thin CdTe films, temperature parameters of a substrate varied. Parameters of obtained CdTe films were investigated using Raman spectroscopy, scanning profilometry and scanning electron microscopy. The measured results showed high quality of thin CdTe films deposited on the substrate at temperature of 300°C and 450°C.
In this paper we provide 3d full-vector static electromagnetic simulation of silicon micro-ring resonator operating. We show that geometrical and scalar approaches are not sufficiently accurate for calculating resonator parameters. Quite strong dependence of ring resonator radius on waveguide width is revealed.
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