Topic
Diffraction efficiency
About: Diffraction efficiency is a research topic. Over the lifetime, 10320 publications have been published within this topic receiving 158298 citations.
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TL;DR: In this paper, the surface relief, optical parameters, and diffraction efficiency dependence on the recording mechanism and film structure were examined, taking into account the possible effects of mutually additive or exclusive components of light modulation in reflection or transmission measurement modes.
Abstract: Photoinduced structural transformations in nanolayered, compositionally modulated films of light-sensitive chalcogenide vitreous semiconductors (ChVS), were investigated by holographic diffraction gratings (HDG) recording. The essential role of surface deformation (expansion up to 5% in illuminated regions) at hologram recording in such structures is established. The surface relief, optical parameters, and diffraction-efficiency dependence on the recording mechanism and film structure are examined, taking into account the possible effects of mutually additive or exclusive components of light modulation in reflection or transmission measurement modes.
38 citations
TL;DR: In this article, the mass transport effect in amorphous selenium thin films induced by band-gap irradiation was studied in situ by real-time atomic force microscopy and diffraction efficiency measurements.
Abstract: Surface relief gratings formation in amorphous selenium thin films in two recording configurations with light intensity modulation were studied in situ by real-time atomic force microscopy and diffraction efficiency measurements. We report observation of mass transport effect in films induced by band-gap irradiation when the light polarization of the recording beams has a component along the light intensity gradient (“p-p” scheme of recording) that allows obtaining giant stable gratings in this versatile chalcogenide material. On the contrary, only a pure scalar weak grating caused by photoinduced volume shrinkage is obtained in the “s-s” recording configuration, even for long-term irradiation.
38 citations
TL;DR: In this article, a model based on a shadow concept was used to predict the diffraction efficiency with high accuracy. But as the period-to-wavelength ratio is reduced, the approximation becomes inaccurate.
38 citations
Patent•
02 Aug 1989
TL;DR: In this article, the authors characterized an optical head device for reading information stored in a recording medium, where a light beam from a light source is converged on an optical disk and a reflected beam from the optical disk is received by a light receiving element.
Abstract: An optical head device for reading information stored in a recording medium (16) wherein a light beam from a light source is converged on an optical disk and a reflected beam from the optical disk is received by a light receiving element (17) thereby to read out information stored in the optical disk is characterized in comprising a diffraction element (13) including: first diffraction gratings (13e, f) for dividing the light beam from the light source into a 0th order diffracted beam utilized for reading out the information stored in the optical disk and a pair of first order diffracted beams utilized for reading tracking errors; and second diffraction gratings (13a-d) for guiding the reflected beam from the optical disk to the light receiving element. The transmission factors of 0th order diffracted beam of the first and/or second diffraction gratings in the regions located in the vicinity of both ends of the diffraction element are lower than those of the first and/or second diffraction gratings in the regions located in the vicinity of the center of the diffraction element, the ends and center being set in a corresponding direction to the radial direction of the optical disk.
38 citations
TL;DR: It is shown that it is possible to determine the ellipticity, the direction of rotation, and the azimuth of the polarization ellipse of light by the measurement of the intensity of the diffraction orders by the obtained formulas.
Abstract: We consider the possibility of a complete real-time analysis of the polarization state of light using two types of polarization-holographic grating that decompose the light analyzed into orthogonal circular and orthogonal linear bases. It is shown that it is possible to determine the ellipticity, the direction of rotation, and the azimuth of the polarization ellipse of light by the measurement of the intensity of the diffraction orders by the obtained formulas. The possibility of creating gratings that give an orthogonal linear basis on actual polarization-sensitive materials is shown. A comparison of the experimental results with the theory is given.
38 citations