An augmented reality display based on a planar waveguide made in photo-thermo-refractive glass had been demonstrated. The monolithic integration of multiplexed volume Bragg gratings with the ...waveguide platform provided in/out-coupling and image transmission from a portable projector. Design and calculation of the grating configuration was performed. The optical replication method was simulated and implemented for manufacturing the multiplexed coupling elements. Resulted field of view was limited by the projection system of the prototype, however can be expanded beyond 50 o .
This paper examines the feasibility of producing multiplexed Bragg gratings for use as diffractive optical elements (DOEs) by coherent optical replication of a surface-relief phase grating into ...thick-film photosensitive materials. The use of such DOEs in light guide plates (LGPs) for optical imaging systems ensures energy-efficient light input into and output from LGPs and allows one to minimise their weight and size. We present simulation results for the interference structure fabrication process and recording of a series of multiplexed diffraction gratings in photosensitive materials.
The recording process of multiplex Bragg diffraction gratings for lightguide displays by the method of optical copying with use of a phase mask is described. In this experiment, the lightguides are ...made of photothermorefractive glass. A photoresistive relief phase diffraction grating unattached to the light guide plate is used as a phase mask. A compact augmented reality display is created on the basis of studying the angular multiplexing of such Bragg gratings.
The Flp recombinase of yeast and the Cre recombinase of bacteriophage P1 both belong to the λ-integrase (Int) family of site-specific recombinases. These recombination systems recognize ...recombination-target sequences that consist of two 13
bp inverted repeats flanking a 6 or 8
bp spacer sequence. Recombination reactions involve particular geometric and topological relationships between DNA target sites at synapsis, which we investigate using nicked-circular DNA molecules. Examination of the tertiary structure of synaptic complexes formed on nicked plasmid DNAs by atomic-force microscopy, in conjunction with detailed topological analysis using the mathematics of tangles, shows that only a limited number of recombination-site topologies are consistent with the global structures of plasmids bearing directly and inversely repeated sites. The tangle solutions imply that there is significant distortion of the Holliday-junction intermediate relative to the planar structure of the four-way DNA junction present in the Flp and Cre co-crystal structures. Based on simulations of nucleoprotein structures that connect the two-dimensional tangle solutions with three-dimensional models of the complexes, we propose a recombination mechanism in which the synaptic intermediate is characterized by a non-planar, possibly near-tetrahedral, Holliday-junction intermediate. Only modest conformational changes within this structure are needed to form the symmetric, planar DNA junction, which may be characteristic of shorter-lived intermediates along the recombination pathway.
Optical sensors of linear displacements with diffraction gratings serving as the measurement scales are investigated. A method of stabilization of the phase difference of quadrature measurement ...signals, consisting in the use of an analyzing scale with a special structure, is proposed. A design of an optical encoder based on the method is proposed. Mathematical simulation of the phase shift of the measurement signals as a function of the parameters of the diffraction grating is performed, and the results of the simulation are presented. The RCWA method is used to simulate the passage of radiation through the optical system. The optimal parameters of the structure of the analyzing scale are calculated. Experimental investigations of a mock-up of the encoder are performed and results of measurements of the phase difference of the measurement signals are presented.
A method of computer generation and projection recording of microholograms for holographic memory systems is presented; the results of mathematical modelling and experimental implementation of the ...method are demonstrated.
Linear displacement encoders are necessary in field of machine tools, metrology and electronic industry. Those devices provide nanometric resolution when constructed according to the interferometric ...scheme. Mathematical modeling of signal transfer process into its optical system to analyze an interference field is described. Signal intensity depending on a small displacement of moving grating phase shift correlations is considered. A sample model of the linear optical encoder is developed based on the optical scheme under research.
Using aquatic worms (Oligochaeta: Tubificidae) for oil decontamination of bottom sediments has been first considered. In a set of experiments on
Limnodrilus hoffmeisteri
Claparede, 1862, worms ...survived the exposure to oil content as high as 16.72 g/kg; they died of natural causes. Vigorous silt agitation by worms (bioturbation) was observed: the silt layer thickened as compared with that in reference aquaria without worms. Besides, it tended to thicken with increasing oil content of sediments. Within 30 days
Limnodrilus hoffmeisteri
reduced oil content by 1.20 to 1.72 times, or by 16.67 to 41.90% (a<0.05), compared with that in reference aquaria.
In this paper, dependencies of the angular and spectral selectivity on the incidence angle of the reference beam in a scheme for obtaining reflection and transmission holograms are obtained and ...analyzed. It is shown that for obtaining color holographic stereograms a scheme for obtaining transmission holograms is more suitable. While the angular selectivity of reflection and transmission color holograms is the same, the spectral selectivity of the reflection hologram is much higher at all wavelengths of recording. A method and equipment for one-step digital recording of color full-parallax holographic stereograms with rasterless image are developed. Samples of color full-parallax security holographic stereograms with a “flip-flop” effect in the image were obtained. The quality of the reconstructed image verifies high spectral selectivity for this type of holograms.
One aspect of recent research to control Stimulated Raman Scattering (SRS) in hohlraum plasmas is the investigation of risk mitigation strategies for indirect drive inertial confinement fusion. ...Experimental tests of these strategies, based on prior theoretical and experimental knowledge of SRS, are performed in hohlraum experiments. In the last year, two strategies have been investigated. The first is the use of high Z dopants to reduce SRS backscatter. Forward stimulated Brillouin scattering (FSBS) could lead to beam spray reducing SRS. Since FSBS depends on the electron temperature and thermal effects depend strongly on Z2, a small amount of a high Z dopant, 1-2%, can have a large effect. Experiments have been conducted at the Omega laser to test this theory by varying the amount of Xe dopant in neo-pentane gas filled hohlraums. The experimental measurements do show a decrease in SRS backscatter as Xe dopant is added. However, there are still uncertainties regarding the responsible mechanism since increases inverse-Bremsstrahlung absorption of the SRS light may play a role. The second strategy investigated is using high kλD plasmas to reduce SRS backscatter. Experiments conducted at the Omega laser facility in hohlraum plasmas determined the critical onset intensity for a range of kλD. A scaling of the critical onset intensity as a function of kλD has been determined.
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