نتایج جستجو برای: diffraction grating
تعداد نتایج: 76208 فیلتر نتایج به سال:
A Dammann grating can generate an array of uniform intensity and equally spaced spots for an incoming monochromatic light beam. But chromatic dispersion will occur when a beam of femtosecond laser pulse, which contains a broad spectral bandwidth, is split by a Dammann grating. Furthermore, the quantity of chromatic dispersion is different in each diffraction order. As a result, diffraction spot...
We have developed a new type of soft x-ray diffraction grating. This critical-angle transmission (CAT) grating combines the advantages of traditional transmission gratings (low mass, extremely relaxed alignment and flatness tolerances) with those of x-ray reflection gratings (high efficiency due to blazing in the direction of grazing-incidence reflection, increased resolution due to the use of ...
A method for a compact lens-less image encoding system using diffraction grating and random phase masks is presented. Lensless double phase encoding is implemented using diffraction grating. The Beam Propagation Method (BPM) is used to analyze optical waveguide grating. The phase keys functions and grating parameters are the encryption keys. Simulation results are presented in support of the pr...
Programmable diffraction gratings are relevant in optical data processing. One of the adequate device candidates is the in-plane switching liquid crystal cell. This technology, developed initially for liquid crystal screens, has also been studied with two inter-digital electrodes as a diffraction grating. Recently, the apparition of programmable zigzag wall lattices in an in-plane switching con...
The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed. This diffraction takes place when the refractive index for diffracted light is different from the refractive index for incident light. It is found that in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mism...
A new type of diffraction range finder is disclosed that places the primary grating at an angle of grazing incidence relative to the receiver. The new design offers improvements over earlier prototypes in reduced package size, reduced chirp depth and a highly anamorphic behavior that provides a high profile to depth ratio. Demonstrations with transmission and reflection types of diffraction gra...
Recently, a novel holographic diffraction grating made of polymer slices alternated to homogeneous films of nematic liquid crystal (POLICRYPS) was realized. We study the optical performance of the POLICRYPS gratings by both numerical simulations and experiments. Characterization of the grating at normal and conical reading mount are performed. The diffraction efficiency depends strongly on the ...
The main conditions and parameters for obtaining surface relief total internal reflection diffraction gratings in conical mounting are presented. Calculated and experimental investigations reveal that there are ranges of grating periods, incidence angles, diffraction angles and gratings depths for which such gratings could be obtained, both for TE and TM polarizations. With optimized grating pa...
Diffraction gratings are used inmany fields in physics, especially astronomy. In astronomy, diffraction gratings are used in spectrographs to analyze the light of astronomical objects that is gathered by telescopes. These gratings use the principles of constructive and destructive interference of light to spread the different wavelengths out based on the wave nature of light and the diffraction...
We report an experimental demonstration of diffraction of He* atoms from a magneto-optical grating. The grating was produced by the interaction of three-level atoms with a light field of spatially varying polarization and a magnetic field. For a light shift matched to the Zeeman shift. a two-peaked diffraction pattern was observed. corresponding to a momentum splitting of 42hk. The effect of ch...
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