Showing papers on "Diffraction efficiency published in 1975"
TL;DR: In this paper, holograms were recorded and fixed simultaneously in heated (∼160°C) crystals of Fe−doped LiNbO3, with the erase/write asymmetry required for multiple storage of high−diffraction−efficiency holograms.
Abstract: Holograms were recorded and fixed simultaneously in heated (∼160°C) crystals of Fe−doped LiNbO3. With this procedure the crystals have the erase/write asymmetry required for multiple storage of high−diffraction−efficiency holograms. Five hundred fixed holograms, each with more than 2.5% diffraction efficiency, were recorded.
265 citations
TL;DR: In this article, a theory is presented that describes the time evolution of the diffraction properties of holographically formed thick phase gratings in ferroelectrics, particularly in iron-doped lithium niobate, based upon a model that relates the instantaneous electromagnetic fields in a grating to the refractive index in a manner consistent with the work of Young et al.
Abstract: A theory is presented that describes the time evolution of the diffraction properties of holographically formed thick phase gratings in ferroelectrics, particularly in iron‐doped lithium niobate. The theory is based upon a model that relates the instantaneous electromagnetic fields in a grating to the refractive index in a manner consistent with the work of Young et al.; that is, the index modulation amplitude is proportional to the product of the amplitudes of the writing fields, while index maxima and intensity maxima are spatially shifted by some fraction of a fringe. The model leads to coupled nonlinear equations for the writing fields that are analogous to the linear equations of Kogelnik, and in certain limits, yield identical results. Closed‐form solutions of the coupled nonlinear equations are found to describe the interaction between writing beams observed by Staebler and Amodei, as well as the time evolution of diffraction efficiency observed by Amodei et al. In conjunction with the latter exper...
110 citations
TL;DR: In this paper, a coupled-wave analysis is given for Bragg-angle diffraction of light within a thick holographic emulsion containing two incoherently superimposed phase gratings with a common Bragg angle.
Abstract: A coupled-wave analysis is given for Bragg-angle diffraction of light within a thick holographic emulsion containing two incoherently superimposed phase gratings with a common Bragg angle. Algebraic formulas are given for the amplitude of the coupled diffracted waves. Applications to holographic multi-beam splitters and beam combiners are given and experimental verification is discussed.
107 citations
TL;DR: In this paper, the development of interference (or 'holographic') techniques for manufacturing spectroscopic diffraction gratings, and the relationship between ruled gratings and those made interferometrically, are discussed.
Abstract: Recent progress in the techniques of manufacture of spectroscopic diffraction gratings is described. Three main topics are discussed in detail; (i) the mechanical ruling of gratings, and the way in which the mechanical aspects of the ruling process affect the spectroscopic performance of the grating; (ii) the development of interference (or 'holographic') techniques for manufacturing gratings, and the relationship between ruled gratings and those made interferometrically; (iii) X-ray gratings for use at grazing incidence, and the different criteria that arise through the use of gratings in this way. The review was completed in April 1975.
86 citations
TL;DR: In this paper, the angular selectivity curves for the diffracted waves were computed for varying relative strengths of the two gratings and also for varying degrees of coupling, determined by the relative fringe slants of the 2D gratings.
Abstract: The coupling between two gratings of arbitrary spatial frequency and relative fringe orientation, recorded in the same thick emulsion, is examined. Both direct coupling of the incident energy into the diffracted waves of each grating and the cross coupling of energy through diffracted waves are considered. The analysis is for a read-out wave at arbitrary angle of incidence. The angular-selectivity curves for the diffracted waves are computed for varying relative strengths of the two gratings and also for varying degrees of coupling, determined by the relative fringe slants of the two gratings. The necessary Bragg-angle difference to decouple the effects of the two gratings is considered. Experimental results for double gratings recorded in dichromated gelatin are given to support the theory.
63 citations
TL;DR: In this article, the authors describe the fabrication of diffraction gratings in the {100} surfaces of silicon by preferential etching and the importance of utilizing this technique in integrated optics is also discussed.
Abstract: Here, we describe the fabrication of diffraction gratings in the {100} surfaces of silicon by preferential etching. The gratings thus made have grooves with well‐defined geometric shape and bounded by nearly perfect reflecting walls. Meanwhile, the importance of utilizing this technique in integrated optics is also discussed.
61 citations
TL;DR: In this paper, an acousto-optic guided light beam device utilizing two surface acoustic wave interdigital transducers, which are staggered in their center frequency and tilted in their propagation direction, on an essentially single−mode optical guiding layer of a Y−cut LiNbO3 substrate has been shown to be capable of providing a very wide bandwidth.
Abstract: An acousto−optic guided−light−beam device utilizing two surface acoustic wave interdigital transducers, which are staggered in their center frequency and tilted in their propagation direction, on an essentially single−mode optical guiding layer of a Y−cut LiNbO3 substrate has been shown to be capable of providing a very wide bandwidth. Deatiled measurements on the diffraction efficiency and the deflection angle of the light beam versus the frequency of the driving signal, usign a 6328−A He−Ne laser light, are presented. The measured −3 dB bandwidth of the device is close to 200 MHz, which is more than an order of magnitude larger than that obtained in previous devices, with the measured electric driving power of 200 mW at 50% diffraction efficiency. The new device configuration introduced here should be very useful for wide−band applications such as a guided−wave acousto−optic rf spectrum analyzer and high−speed multiport switches for fiber/integrated optics.
44 citations
TL;DR: In this paper, the integral reflection coefficient (IRC) was measured using a single crystal spectrometer, as a function of wavelength, for a number of crystals commonly used.
Abstract: Analyzing crystals used in x-ray spectrometers have widely varying diffraction efficiencies. When employed in x-ray fluorescence analysis, the parameter which defines the efficiency is the integral reflection coefficient. This parameter has been measured using a single crystal spectrometer, as a function of wavelength, for a number of crystals commonly used. A recent adaptation of an existing diffraction theory is shown to make possible the calculation of integral reflection coefficients which agree with measured values.
44 citations
TL;DR: In this paper, a method for calculating arbitrary-order diffraction efficiencies of thick, lossless transmission gratings with arbitrary periodic grating shapes has been developed, along with a coupled-mode theory of diffraction.
Abstract: A method for calculating arbitrary-order diffraction efficiencies of thick, lossless transmission gratings with arbitrary periodic grating shapes has been developed. A Fourier-series representation of the grating is employed, along with a coupled-mode theory of diffraction. For illustration, numerical values of the diffraction efficiencies at the first three Bragg angles are calculated for sinusoidal, square-wave, triangular, and saw-tooth gratings. Numerical results for the same grating shapes with the same parameters are also calculated for comparison, by extending Burckhardt's numerical method for analyzing thick sinusoidal gratings. The comparison shows that the coupled-mode theory provides results with relative computational ease and results that are in agreement with calculations obtained by extending the more-rigorous Burckhardt theory to nonsinusoidal grating shapes and to higher-order Bragg angles.
43 citations
Patent•
03 Feb 1975TL;DR: A subtractive color filtering technique, suitable for the projection of color pictures, employs diffraction, rather than color dyes, for discriminatingly subtracting unwanted spectral wavelength portions of polychromatic illuminating light as discussed by the authors.
Abstract: A subtractive color filtering technique, suitable for the projection of color pictures, employs diffraction, rather than color dyes, for discriminatingly subtracting unwanted spectral wavelength portions of polychromatic illuminating light. The useful output light may consist of solely the zero-order diffraction output light or, alternatively, one or a certain combination of diffraction orders other than the zero diffraction order (such as the aggregate of all diffraction orders other than the zero diffraction order which corresponds to the complement of the zero-order diffraction output light).
40 citations
TL;DR: In this paper, a scalar diffraction theory has been developed which demonstrates that grating diffraction efficiency varies periodically with wavelength, pitch, groove depth and incidence angle, and can be used to optimize grating parameters for most efficient use in any selected region of the spectrum.
Abstract: X-ray gratings have been developed for use in the wavelength region of 0.01-20 nm, where it is required to employ a grazing incidence configuration. The gratings have a rectangular profile and radiation is diffracted both from the tops and bottoms of the grooves. They therefore differ from blazed gratings, used at grazing incidence, in that a substantial portion of the grating participates in the diffraction process. A scalar diffraction theory has been developed which demonstrates that grating diffraction efficiency varies periodically with wavelength, pitch, groove depth and incidence angle. The theory can be used to optimize grating parameters for most efficient use in any selected region of the spectrum. The gratings are produced by processing a ruled 300 lines per millimetre master grating, so that surface profile defects introduced by ruling are eliminated. Grating performance has been assessed by means of a specially designed grating analyser in addition to spectrometers and a spectrograph. The experimental results are in qualitative agreement with theory. At very short wavelengths of 0.05 nm and grazing incidence angles of about 59, the diffraction efficiency in the first order is below 1 %. The efficiency rises rapidly to between 5 and 10 % at 0.15 nm and to 20 % in the 1 nm region where the incidence angles are typically a few degrees.
Journal Article•
TL;DR: In this paper, a relief-type diffraction grating of the amorphous film was obtained (the pitch between grating lines, 0.86 μm), which achieved a high diffraction efficiency of 15.8%, which was about 10 times greater than before chemical etching.
Abstract: In As‐Se‐ (S) ‐Ge amorphous films, a remarkable difference of chemical etching rate between the heat‐treated state and the light‐irradiated state has been observed. Utilizing this characteristic, a relief‐type diffraction grating of the amorphous film was obtained (the pitch between grating lines, 0.86 μm). This grating has achieved a high diffraction efficiency of 15.8%, which was about 10 times greater than before chemical etching.
TL;DR: In this paper, a study of the spectroscopic properties of blazed interference diffraction gratings for wavelengths between 121.6 and 351 nm was performed and it was found that they combine the high efficiency of ruled gratings with the spectral purity of gratings produced interferometrically.
Abstract: The results are presented of a study of the spectroscopic properties of blazed interference diffraction gratings for wavelengths between 121.6 and 351 nm. It is found that they combine the high efficiency of ruled gratings with the spectral purity of gratings produced interferometrically.
TL;DR: In this article, the thickness dependence of the efficiency of the Bragg diffraction between the same optical modes (TE0→TE0, TM0→TM0) by acoustic surface waves in ZnO−film optical waveguides is investigated at an acoustic frequency of 130 MHz and a film thickness from 0.6 to 8.0 μm.
Abstract: The thickness dependence of the efficiency of the Bragg diffraction between the same optical modes (TE0→TE0, TM0→TM0) by acoustic surface waves in ZnO−film optical waveguides is investigated at an acoustic frequency of 130 MHz and a film thickness from 0.6 to 8.0 μm. It is observed that the efficiencies for both the TE0 and the TM0 modes vary more than 2 orders of magnitude with the film thickness.
TL;DR: In this paper, three algorithms for computer-generating binary holograms with differing aperture distributions are discussed and compared for image detail and diffraction efficiency, and the authors conclude that the form of modular-overflow-corrected yields the highest image detail, while 3 2 |order yields the best image detail.
TL;DR: In this paper, an exact solution of the coupled differential equation system as developed by Kogelnik for the case of symmetrical recording without neglecting the second differentials is given for dielectric, absorption and mixed volume holograms.
Abstract: In this paper we give an exact solution of the coupled differential equation system as developed by Kogelnik [1] for the case of symmetrical recording without neglecting the second differentials. This generalized solution is applicable to dielectric, absorption and so-called mixed volume holograms. It is shown that under special assumptions and approximations we get the same equations for the diffraction efficiency as derived by Kogelnik. In this first part of the paper transmission holograms are only investigated and in the second part we will give the solution for reflection holograms.
TL;DR: In this article, the scanning of a transparency is done by letting a collimated light wave front illuminate it and be diffracted by very short pulses of ultrasonic surface waves, which give a potential number of resolved spots per second almost equal to 107.
Abstract: The scanning of a transparency is done by letting a collimated light wave front illuminate it and be diffracted by very short pulses of ultrasonic surface waves. Detection of diffracted light follows a time dependence that equals the transparency brightness along each line that is successively scanned. 94−MHz wave trains, about 10 wavelengths long, give a potential number of resolved spots per second almost equal to 107. Interaction geometry by back−surface reflection has been used, which greatly enhances the diffraction efficiency and yet retains the large acousto−optical bandwidth proper to surface waves.
TL;DR: The diffraction efficiency of synthetic amplitude and phase holo grams has been studied as a function of the ratio of the line width to the grating period (s/d) as mentioned in this paper.
Abstract: The diffraction efficiency of synthetic amplitude and phase holo grams has been studied as a function of the ratio of the line-width to the grating period (s/d). A strong dependence of the diffraction efficiency on s/d results in a reconstructed wave with non-uniform amplitude. This behaviour will restrict the applications of synthetic holograms as optical components.
TL;DR: Diffraction efficiency of a hologram stored in an U-doped LiNbO(3) crystal was scarcely reduced from its initial value when the crystal was held at room temperature for 150 days.
Abstract: A single LiNbO3 crystal doped with U ions is a new sensitive phase holographic material with high diffraction efficiency and with long thermal decay time of a hologram. The energy density of a 4880-A beam from an Ar-ion laser required to reach 40% diffraction efficiency is about 1 J/cm2 for a 1.2-mm thick crystal. Diffraction efficiency of a hologram stored in an U-doped LiNbO3 crystal was scarcely reduced from its initial value when the crystal was held at room temperature for 150 days.
TL;DR: In this paper, a birefringent phase matched TeO2 deflector with doubled resolution was demonstrated using the second optical diffraction order, which maintained high diffraction efficiency with doubled resolutions.
Abstract: We have demonstrated operation of birefringent phase‐matched TeO2 deflectors, utilizing the second optical diffraction order, which maintain high diffraction efficiency with doubled resolution. 1200‐spot resolution was achieved with 25‐μsec access time.
Patent•
04 Dec 1975TL;DR: In this article, a light deflector utilizing Bragg diffraction in an anisotropic medium in which the directions of the wave front normal and the energy propagation of ultrasonic waves are arranged to be different and the frequency range of the ultrasonic wave for causing re-diffraction of light diffracted once by said ultrasonic was set outside the driving frequency range.
Abstract: A light deflector utilizing the anisotropic Bragg diffraction in an anisotropic medium in which the directions of the wave front normal and the energy propagation of ultrasonic waves are arranged to be different and the frequency range of the ultrasonic wave for causing re-diffraction of light diffracted once by said ultrasonic wave is set outside the driving frequency range. The diffraction efficiency does not fall near the central frequency of the driving ultrasonic frequency range due to the prevention of rediffraction. Further, the driving frequency can be selected over a remarkably wide range compared to that of the conventional light deflector.
TL;DR: In this paper, a holographic process is used to produce triangular groove profiles for the extraction of diamond-like gratings with diameter between 150 and 3050 gr/mm, which are then coated with metal films of Al, Au, Ag, Al by vacuum evaporation.
TL;DR: In this article, the authors used computers to form generalized diffractive elements, and three unique features can be incorporated in the elements: convenient selection of their geometrical shape, changes in speed and direction of the deflected light beam, and variations in focal power.
TL;DR: In this article, photoinduced refractive index changes in these ceramics by deflected and modulated argon laser beams, the behaviour of the diffraction efficiency versus light power density and applied field, the possibility of image selection and optical selective erasure are explained phenomenologically in terms of a photoinduced field model.
Abstract: After defining the properties of transparent lead-lanthanum zirconate-titanate ceramics (PLZT) we report the results of holographic and digital recording in quadratic electrooptic ceramics Pb0.91La0.09(Zr0.65Ti0.35)0.9775O3. Photoinduced refractive index changes in these ceramics by deflected and modulated argon laser beams, the behaviour of the diffraction efficiency versus light power density and applied field, the possibility of image selection and optical selective erasure are explained phenomenologically in terms of a photoinduced field model.
TL;DR: In this paper, the diffraction efficiency of holograms stored in lithium niobate and similar materials by exposure to known amounts of light was evaluated by taking into account multiple internal reflections from the surfaces.
Abstract: In experimentally determining the diffraction efficiency of holograms stored in lithium niobate and similar materials by exposure to known amounts of light, it is necessary to take into account multiple internal reflections from the surfaces. In particular, the effective diffraction efficiency is very sensitive to small changes in temperature (∼ 1 °C) such as those which are easily produced by exposure to medium−intensity laser beams.
TL;DR: In this paper, numerical solutions for rectangular and echelette gratings are presented for the case of E-polarized wave diffraction, which are compared with a number of similar results reported in the literature.
TL;DR: The blurring effect in printing fine grating patterns on photoresist films can be minimized by using the Fourier image effect, which involves the image-forming nature of periodic patterns in the Fresnel region.
Abstract: The blurring effect in printing fine grating patterns on photoresist films can be minimized by using the Fourier image effect, which involves the image-forming nature of periodic patterns in the Fresnel region. Experiments using gratings having lattice constants of 3.8 μm and 10 μm are reported. The effectiveness of the Fourier image was confirmed by the evaluation of constructed phase gratings using diffraction efficiency measurements and SEM observations of sectional views. Effects of partial spatial coherence on the quality of gratings are discussed.