نتایج جستجو برای: diffraction gratings

تعداد نتایج: 71674  

2010
K. Nygård S. Gorelick J. Vila-Comamala E. Färm A. Bergamaschi A. Cervellino F. Gozzo B. D. Patterson M. Ritala C. David

The issue of beam-induced damage on diffractive hard X-ray optics is addressed. For this purpose a systematic study on the radiation damage induced by a high-power X-ray beam is carried out in both ambient and inert atmospheres. Diffraction gratings fabricated by three different techniques are considered: electroplated Au gratings both with and without the polymer mold, and Ir-coated Si grating...

2012
T. Kohoutek M. A. Hughes H. Kawashima M. Mastumoto T. Misumi T. Suzuki Y. Ohishi

Direct laser writing has been already demonstrated for the fabrication of under surface “buried” 3D mid-IR waveguides in chalcogenide glasses by employing a large photo-induced refractive index change in the features formed in the path of the focused beam from a short pulse laser. In this paper, we report on direct laser writing of relief diffraction gratings with periods of 6, 14 and 24 μm int...

Journal: :Applied optics 2002
Celia Garcia Inmaculada Pascual Angel Costela Inmaculada Garcia-Moreno Clara Gomez Antonio Fimia Roberto Sastre

The variation in transmittance produced when a photopolymer is irradiated with a pulsed laser is analyzed and experimental results obtained when diffraction gratings are stored using pulsed exposure are presented. In either case, the influence of the energy of the irradiation pulse, the number of pulses, and the pulse repetition rate were studied. The photopolymer used was an acrylamide/polyvin...

Journal: :Optics letters 1994
A Fimia R Fuentes A Beléndez

Noise gratings in diffuse-object holograms recorded as volume phase holograms in bleached silver halide emulsion are experimentally analyzed. Measurements of the diffraction efficiency and the noise of the holograms are taken. The experimental results obtained show that there is a drop not only in the diffraction efficiency but also in the noise that is due to the presence of noise gratings.

2006
V. G. Baryshevsky A. A. Gurinovich

The equations providing to describe generation process in FEL with varied parameters of diffraction grating (photonic crystal) are obtained. It is shown that applying diffraction gratings (photonic crystal) with the variable period one can significantly increase radiation output. It is mentioned that diffraction gratings (photonic crystal) can be used for creation of the dynamical wiggler with ...

1999
S. Honkanen S. B. Mendes N. Peyghambarian

We report on the fabrication of diffraction gratings in photosensitive sol–gel thin films by direct contact printing using a UV-mercury lamp. Titanium amplitude masks were used to replicate diffraction gratings into photosensitive sol–gel films by contact printing with an incoherent UV-light source. Gratings with 1-mm period were fabricated in sol–gel films. The diffraction efficiencies of each...

2012
R. Güther

We present a simple model for understanding the perfect blaze for diffraction with echelle gratings. Littrow diffraction at grating profiles with rectangular apexangles implicates two pairs of counterpropagating light waves. The four waves show a rectangular pattern of interference fringes. Integer numbers of such fringes along both facets of a groove ensure perfect blazing with echelle gratings.

2001
Malgosia Kaczmarek Min-Yi Shih Roger S. Cudney

We report on further experimental studies of the ac field response of transient and permanent gratings written with visible light in both planar and homeotropic, dye-doped liquid crystal cells. It is found that the diffraction efficiency of these gratings can be controlled by the applied ac field. High ac frequencies can switch off diffraction completely in both permanent and transient gratings...

2008
M. Fally M. Bichler M. A. Ellabban

We discuss the applicability of holographically recorded gratings in photopolymers and holographic polymer-dispersed liquid crystals as neutron optical elements. An experimental investigation of their properties for light and neutrons with different grating spacings and grating thicknesses is performed. The angular dependencies of the diffraction efficiencies for those gratings are interpreted ...

Journal: :Optics letters 2004
John R Marciante Daniel H Raguin

We report a new class of high-dispersion immersed diffraction gratings for which the reflective nature of the diffraction is provided by the phenomenon of total internal reflection (TIR) regardless of grating tooth shape. Thus, the component can be fabricated from a single dielectric material and requires no metallic or dielectric film layers for high reflection diffraction efficiency. With the...

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