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Showing papers on "Diffraction efficiency published in 1983"


Journal ArticleDOI
TL;DR: The properties of optical elements fabricated by holographically recording an ultrahigh spatial-frequency pattern in a photoresist mask followed by reactive ion etching to transfer this pattern into the surface of a quartz substrate are discussed.
Abstract: In this paper we discuss the properties of optical elements fabricated by holographically recording an ultrahigh spatial-frequency pattern in a photoresist mask followed by reactive ion etching to transfer this pattern into the surface of a quartz substrate. Such optical elements are environmentally durable, potentially easy to replicate, and exhibit diffraction efficiencies in excess of 85%. In addition, two other properties are reported for the first time. Such elements at normal (0°) incidence are antireflective, with broadband reflection coefficients as low as 0.035%. Also, the elements exhibit artificially produced birefringence making them useful as wave plates. These results may be particularly significant in the UV and IR, where damage-resistant antireflection coatings and transparent birefringent materials may not exist.

237 citations


Journal ArticleDOI
TL;DR: In this article, the theory of diffraction by dielectric gratings is extended to cover E-mode polarization and losses, and it is shown that direct coupling exists between all diffracted orders rather than just between adjacent orders.
Abstract: Rigorous coupled-wave theory of diffraction by dielectric gratings is extended to cover E-mode polarization and losses. Unlike in the H-mode-polarization case, it is shown that, in the E-mode case, direct coupling exists between all diffracted orders rather than just between adjacent orders.

227 citations


Journal ArticleDOI
TL;DR: In this article, the propagation of electromagnetic waves in the periodic anisotropic media is described by coupled-wave equations in a unified matrix form expressing the coupling of the space harmonics in the grating region.
Abstract: A method for analyzing slanted anisotropic gratings is presented. The propagation of electromagnetic waves in the periodic anisotropic media is described by coupled-wave equations in a unified matrix form expressing the coupling of the space harmonics in the grating region. The solution of the equations is reduced to an eigenvalue problem of this coupling matrix. Through introduction of the concepts of transmission and boundary matrices, the diffraction properties of general slanted gratings are obtained rigorously by systematic matrix calculations that are easily implemented on a computer. The calculated results indicate that not only TE–TE or TM–TM but also TE–TM diffractions take place in general slanted gratings.

145 citations


Journal ArticleDOI
TL;DR: In this article, a deformable mirror device (DMD) is proposed for optical information processing applications, which consists of a 128x128 array of deformable mirrors addressed by an underlying array of metal-oxide-semiconductor (MOS) transistors.
Abstract: A new two-dimensional, fast, analog, electrically addressable, silicon-based membrane spatial light modulator (SLM) has been developed for optical information processing applications. This SLM, the deformable mirror device (DMD), consists of a 128x128 array of deformable mirror elements addressed by an underlying array of metal-oxide-semiconductor (MOS) transistors. Coherent light reflected from the mirror elements is phase modulated producing an optical Fourier transform of an analog signal input to the device. The DMD architecture and operating parameters related to this application are presented. A model is developed that describes the optical Fourier transform properties of the DMD. The calculated peak first-order diffraction efficiency of 8.2% is in good agreement with the value of 8.4% obtained from experimental optical Fourier transform measurements.

142 citations


Journal ArticleDOI
TL;DR: This research presents a novel probabilistic approach to estimating the response of the immune system to laser-spot assisted, 3D image analysis of central nervous system injury.
Abstract: Reference EPFL-ARTICLE-158578doi:10.1364/AO.22.003665View record in Web of Science Record created on 2010-11-25, modified on 2017-07-31

76 citations


Journal ArticleDOI
TL;DR: A high efficiency spectrograph design for the EUV and soft x rays is presented that uses a plane surface reflection grating with rulings that are radial, like the spokes of a wheel.
Abstract: A high efficiency spectrograph design for the EUV and soft X rays is presented. This grazing incidence system uses a plane surface reflection grating with rulings that are radial, like the spokes of a wheel. The grating is placed in a beam of light that is converging to a focus. The single reflection off the grating is in the conical diffraction mount ensuring maximum performance from the system. Aberrations and performance levels are discussed. The gratings can be manufactured with existing ruling engines. Sample applications to an X-ray monochromator and an EUV stellar spectrograph are discussed.

57 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used the extended boundary condition method to solve the wave scattering and guidance by a stratified medium with a periodic surface, and derived the transition matrix for two sets of Flocquet waves incident from above and below a periodic boundary separating the two media.
Abstract: The extended-boundary-condition method is used to solve the wave scattering and guidance by a stratified medium with a periodic surface. First, the transition matrix for two sets of Flocquet waves incident from above and below a periodic surface separating the two media is derived. The results are applied to the diffraction of an incident plane wave by a multilayered medium having a periodic surface. The theoretical results can easily be applied to the guidance problem for which the complex guiding constant of the periodic structure is obtained. Numerical results for both the scattering and the guidance problems are obtained. The theory is compared with experiment for metallic gratings with surface-plasmon excitations. The calculated guiding constants of a thin film with a periodic sinusoidal surface are also compared with other numerical methods.

50 citations


Journal ArticleDOI
TL;DR: In this paper, the diffraction properties of high-spatial-frequency gratings recorded in relatively thin photoresist layers are investigated, and it is shown that optical elements with efficiencies greater than 88% can be recorded in media less than one wavelength.
Abstract: This paper describes an experimental study of the diffraction properties of high-spatial-frequency gratings recorded in relatively thin photoresist layers. Angular selectivity, wavelength selectivity, and peak efficiencies are investigated. Details on grating fabrication are given. The study shows that optical elements with efficiencies greater than 88% can be recorded in media less than one wavelength thick (~0.5 μm for our visible-light experiments). The results are important in that such diffractive structures could be replicated by embossing, chemical-vapor deposition, or other means.

49 citations


Journal ArticleDOI
TL;DR: Volume phase holograms are formed by a standard process in commercially available photographic emulsion and an improved model is formulated, capable of analytic solution, taking into account phase and absorption modulation, a second harmonic in the grating profile and the appearance of some higher diffraction orders.
Abstract: Volume phase holograms are formed by a standard process in commercially available photographic emulsion. The material is characterized before recording, and initial experimental results are presented for reconstruction under index-matched conditions. An initial comparison is made using two-wave coupled-wave theory and a technique of curve fitting with experimental measurements of transmission and diffraction efficiency. The model works well close to the Bragg condition, but several differences are noted between theory and experiment away from the Bragg condition. An anomalous absorptive effect is noted in transmission. An improved model is then formulated, again using coupled-wave theory, and capable of analytic solution, taking into account phase and absorption modulation, a second harmonic in the grating profile and the appearance of some higher diffraction orders. Using this model, all the initial experimental results are satisfactorily explained, and the effect of spurious gratings in the hologram response is noted. The model is then used with an extensive set of experimental results to deduce the major characteristics of the material, including saturation of the modulation with exposure. The formulation of a mixed grating and possible dispersion of the modulation are also investigated. Suggestions are made for the design of more complicated components using this material and for material improvement.

43 citations


Journal ArticleDOI
TL;DR: In this article, a new method was proposed for the study of lamellar gratings in electromagnetic theory, which is related to a method recently proposed by Australian authors for the case of Littrow mounts, and the present authors first recall the principle of this method and make some theoretical comments.
Abstract: This paper is related to a new method recently proposed by Australian authors for the study of lamellar gratings in electromagnetic theory. The present authors first recall the principle of this method and make some theoretical comments. Then they describe how numerical difficulties which appear in normal incidence and in Littrow mounts can be overcome.

42 citations


Proceedings ArticleDOI
26 Oct 1983
TL;DR: In this article, the authors have produced highly efficient binary diffraction gratings -94% first order diffraction efficiency measured in the infrared (10.6 μm) on straight binary gratings and on binary holographic off-axis lenses.
Abstract: We have produced highly efficient binary diffraction gratings -- 94% first order diffraction efficiency measured in the infrared (10.6 μm) on straight binary gratings and on binary holographic off-axis lenses. The observed point-spread functions of these lenses (F/10, f = 25 cm) were limited only by diffraction. To fabricate gratings we adapted IC production techniques. Our work brings together three independent developments: (1) theories on binary diffraction gratings operating in the EM domain, (2) large-scale integration (LSI) advances in pattern generation and substrate depositions, and (3) improvements in reactive ion-beam etching techniques.

Journal ArticleDOI
TL;DR: In this article, the analysis is extended to take into account an arbitrary phase of the sinusoidal modulation of the pure reflection grating's dielectric constant, and the correct method of computing the diffraction efficiencies is presented, and results obtained with the extended and corrected analysis are given.
Abstract: Rigorous coupled-wave analysis is shown to be valid for a pure reflection grating The analysis is extended to take into consideration an arbitrary phase of the sinusoidal modulation of the pure reflection grating’s dielectric constant The correct method of computing the diffraction efficiencies is presented, and results obtained with the extended and corrected analysis are given

Journal ArticleDOI
TL;DR: In this paper, the first high-resolution phase lens for use at x-ray wavelengths was fabricated and the lens is a Fresnel phase plate made of silver approximately 5500 A thick.
Abstract: We have fabricated the first high resolution phase lens for use at x‐ray wavelengths. The lens is a Fresnel phase plate made of silver approximately 5500 A thick. The structure has 100 zones with a minimum zone width of 3200 A. The lens is designed for use at the Al Kα line (approximately 1.5 keV) with an anticipated first order diffraction efficiency of ≂25%, and a spatial resolution of 4000 A. Details of phase lens design and fabrication are presented.

Journal ArticleDOI
TL;DR: The five-channel demultiplexer was assembled with this grating as well as with a multimode slab waveguide and a fiber array and its branching loss was in the 1.4-1.8-dB range.
Abstract: A demultiplexer composed of a concave diffraction grating and a multimode slab waveguide is attractive since it has many advantageous features. However, this type of demultiplexer has had high demultiplexing losses until now, because the concave diffraction gratings used had poor diffraction efficiency. A silicon concave diffraction grating has been developed to overcome this problem, manufactured by cylindrically bending a thin silicon plane diffraction grating. The diffraction efficiency of this grating was 82% at a blaze wavelength. The five-channel demultiplexer was assembled with this grating as well as with a multimode slab waveguide and a fiber array. Its branching loss was in the 1.4-1.8-dB range.

Journal ArticleDOI
Toshiaki Kita1, Tatsuo Harada1
TL;DR: An aberration-corrected concave grating for a demultiplexer has been designed and fabricated for use in a six-channel multiplex system in the 800-nm wavelength region.
Abstract: A method of designing aberration-corrected concave gratings and their mounting for optical demultiplexers is described. An aberration-corrected concave grating for a demultiplexer has been designed and fabricated for use in a six-channel multiplex system in the 800-nm wavelength region. A coupling efficiency of 55% and signal cross talk of less than ~3 × 10−4 have been achieved experimentally.

Journal ArticleDOI
TL;DR: In this paper, the first-order and higher-order diffraction efficiencies are determined over the entire range of possible conductivities and Bragg angles of incidence (or equivalently, grating periods) for H-mode polarization incident plane waves.
Abstract: Planar (co)sinusoidal conductivity (absorption) transmission gratings are analyzed using rigorous coupled-wave theory. The first-order and higher-order diffraction efficiencies are determined over the entire range of possible conductivities and Bragg angles of incidence (or equivalently, grating periods) for H-mode polarization incident plane waves. The maximum possible first diffracted order efficiency is found to be 5.26%. Rigorous results are compared to approximate results from the Raman-Nath theory and the two-wave first-order coupled-wave (Kogelnik) theory. A regime parameter, ϱσ, is defined which delineates the regions of Raman-Nath diffraction behavior (ϱσ 1). Likewise, the angular selectivity characteristics of conductivity gratings are determined from rigorous theory and are compared with corresponding results from approximate theory.

Journal ArticleDOI
TL;DR: In this paper, the time dependence and diffraction efficiency of optically induced phase gratings in thin films of the nematic liquid crystals 5CB and 6CB were investigated and the experimental results were in quantitative agreement with a three-dimensional model for the induced grating.
Abstract: The time dependence and diffraction efficiency of optically‐induced phase gratings in thin films of the nematic liquid crystals 5CB and 6CB are reported. The experimental results are in quantitative agreement with a three‐dimensional model for the induced grating. This analysis provides an independent determination of the elastic constants K2 and K3 as well as a vicosity coefficient ν.

Journal ArticleDOI
TL;DR: In this article, it was shown that the periodic structures (gratings) formed at the surface of a solid exposed to high-power laser irradiation are due to interference between the SEW and the incident wave.
Abstract: An analysis is made of the transformation of a surface electromagnetic wave (SEW) into a bulk wave and of the converse process at the corrugated interface of two media. It is shown that the periodic structures (gratings) formed at the surface of a solid exposed to high-power laser irradiation are due to interference between the SEW and the incident wave. Dependences of the diffraction efficiency of the gratings on the average power of the incident radiation were obtained experimentally for bulk samples and thin germanium films. It was found that the complex diffraction pattern observed during irradiation of a surface may be due to resonant interaction between the SEW and the grating. It was demonstrated experimentally that SEW's may be excited and periodic structures may be formed on the surfaces of thin germanium films.

Patent
11 Oct 1983
TL;DR: In this article, a method of copying a thick hologram, recorded at wavelength λ 1, so that the copy can be efficiently read out with a beam λ 3 at the same incident angle as used to efficiently read the original was proposed.
Abstract: A method of copying a thick hologram, recorded at wavelength λ1, so that the copy can be efficiently read out with a beam λ3 at the same incident angle as used to efficiently read out the original. The method involves copying the hologram using wavelength λ2 at a predetermined incident angle, which incident angle provides fringe angles in the copy to yield maximum diffraction efficiency of the read-out beam λ3.

Journal ArticleDOI
TL;DR: In this article, the authors compare the results of the rigorous coupled-wave analysis, the chain-matrix analysis, and the new method presented by Zylberberg and Marom.
Abstract: The descriptions of diffraction by pure reflection gratings (fringes parallel to surfaces) and by reflection gratings with slanted fringes are clarified. The rigorous coupled-wave analysis, the chain-matrix analysis, and the new method presented by Zylberberg and Marom [ J. Opt. Soc. Am.73, 392 ( 1983)] are compared and their regions of applicability determined. Zylberberg and Marom refer to their method as a coupled-wave analysis, a description that is inconsistent with previous use of this terminology.

Journal ArticleDOI
TL;DR: In this article, the authors study classes of plane uncrossed diffraction gratings which have the common property that their Fourier transform patterns consist of sharp-line caustics.
Abstract: This paper is the third in a series of papers on the diffraction and imaging properties of generalized curvilinear diffraction gratings. Here we study classes of plane uncrossed diffraction gratings which have the common property that their Fourier transform patterns consist of sharp-line caustics. These types of generalized gratings are referred to as ‘Euclidian diffraction gratings’, because the condition for the formation of line caustics is equivalent to the global vanishing of the gaussian curvature of the grating line pattern function. The analysis is applied to the laser material processing system discussed in our last paper [1].

Journal ArticleDOI
TL;DR: In this paper, the diffraction efficiency of blazed holographic gratings for the visible region was measured as a function of wavelength and angle of incidence for S and P polarization, and it was shown that blazed gratings have better diffraction than traditional gratings.

Proceedings ArticleDOI
H. Dammann1
26 Oct 1983
TL;DR: Digital-phase gratings are synthetic optical elements operating in-line as direct-vision components as mentioned in this paper, where only a few discrete values are allowed for the phase structure within each grating period.
Abstract: Digital-phase gratings are synthetic optical elements operating in-line as direct-vision components. They are called digital because only a few discrete values are allowed for the phase-structure within each grating period. Digital-phase gratings can be used for different applications. Three examples are described: star-couplers using binary-phase gratings for generating a central block of diffraction orders with equal intensity; color-splitters using gratings with more than two phase-levels; alterable gratings the blaze of which can be switched between the 3 central diffraction orders. Surface-relief digital-phase gratings are made by reactive ion etching in glass, and cheap plastic copies are obtained by a simple replication technique.

Journal ArticleDOI
TL;DR: In this paper, the authors theoretically investigated the efficiency of thick photochromic absorption gratings and derived analytic solutions for dynamic diffraction characteristics, which showed that the maximum diffraction efficiency may exceed 10% in some cases.

Patent
15 Dec 1983
TL;DR: In this paper, the authors proposed to compensate the intensity variation of diffracted light to be used for scanning even when the diffraction efficiency is high, by introducing outputs of the 1st light detecting means which detects the optical intensity of a illuminating flux and the 2nd light detecting signals which detect the optical intensities of the zero-dimensional reflected light of the illuminating flux from a transmission type diffraction grating to an arithmetic circuit.
Abstract: PURPOSE:To compensate the intensity variation of diffracted light to be used for scanning even when the diffraction efficiency is high, by introducing outputs of the 1st light detecting means which detects the optical intensity of a illuminating flux and the 2nd light detecting means which detects the optical intensity of the zero-dimensional reflected light of the illuminating flux from a transmission type diffraction grating to an arithmetic circuit. CONSTITUTION:While laser light is made incident to one of transmission type diffraction gratings of a spinner 3 after it is modulated into a video signal by a modulator 5 and becomes an illuminating flux L, a part of the flux L0 is made incident to a photodetector 10 and converted photoelectrically and the zero-dimensional reflected light LR of light made incident to the transmission type diffraction grating is made incident to a photodetector 11 and converted photoelectrically, and then, the primary diffracted light Lalpha is converged in a spotlike form upon a surface 8 to be scanned. Photoelectrical conversion signals from the photodetectors 10 and 11 are inputted into an arithmetic circuit 14 and the output of the circuit 14 is introduced to a correcting circuit 15 and the diffraction efficiency of the primary diffracted light is judged. Based on the judged result, a signal corresponding to a modulation amount to be modulated in intensity is sent to a multiplier 17 and the video signal is corrected.

Journal ArticleDOI
TL;DR: In this article, the diffraction efficiency of Ag coated holographic gratings was measured as a function of the grating amplitude, H, for a He-Ne laser incident at 30° and 70° in the plane perpendicular to grating grooves.

Journal ArticleDOI
TL;DR: In this article, light deflection is achieved by optically changing the characteristics of a transient index modulation generated in an optical material by two interfering beams using a novel technique to maintain the Bragg condition, which is kept constant during the whole deflection process.
Abstract: Light deflection is achieved by optically changing the characteristics of a transient index modulation generated in an optical material by two interfering beams. Using a novel technique to maintain the Bragg condition, diffraction efficiency is kept constant during the whole deflection process.

Journal ArticleDOI
TL;DR: In this article, a design of a reflection holographic lens with nonspherical wavefront is described, which is based on a ray-tracing program and a simple search algorithm suitable for a microcomputer.

Patent
18 Jul 1983
TL;DR: In this article, a diffraction grating is constructed by constituting the grating so that the refractive index of a medium forming the diffraction grid, the depth of the grid, and the intervals of the grids satisfy prescribed conditions for a used wavelength.
Abstract: PURPOSE:To obtain >=34% logical diffraction efficiency, by constituting the diffraction grating so that the refractive index of a medium forming the diffraction grating, the depth of the grating, and intervals of the grating satisfy prescribed conditions for a used wavelength. CONSTITUTION:The laser luminous flux emitted from a laser light source 2 becomes a parallel luminous flux through a lens 3, an object lens 4, a pinhole 5, and a lens 6. The parallel luminous flux has a uniform intensity distribution through a filter 7 having a reverse Gaussian transmittance distribution and is divided into two by a beam splitter 8 to irradiate a recording material 10 through mirrors 91 and 92. Processings such as development are performed to obtain a diffraction grating 1 where a relief is formed on a light transmittive resin 1B on a transparent substrate 1A. h/lambda>0.4 and D/lambda>1/(no+1) are satisfied when the refractive index of the meidum 1B, the wavelength of the incident light, the depth of the diffraction grating 1, and intervals of the grating are denoted as no, lambda, (h), and D respectively, thereby obtaining >=34% diffraction efficiency.

Journal ArticleDOI
TL;DR: A new type of polygonal holographic scanner that combines a reflection volume hologram with a computer-generated hologram (CGH) is described that is free from the aberration of field curvature and can allow for a compact folded version of the scanner and Bragg diffraction into only a single order.
Abstract: A new type of polygonal holographic scanner that combines a reflection volume hologram with a computer-generated hologram (CGH) is described. The scanner is free from the aberration of field curvature. Such a scanning system can allow for a compact folded version of the scanner and Bragg diffraction into only a single order. The equations expressing the spatial-variable image distance are derived and are fit to the phase function designated by polynomials incorporated into a CGH in terms of the least-squares method. A reflection scanner with field-curvature correction is made by interfering a diffracted wave front from this CGH with a spherical wave front having scanning focal power through a second plane hologram. Experiments demonstrating the feasibility of this scanner are presented. Raster-scan patterns using a multifaceted scanner are shown. Helpful data on the diffraction efficiency and the spectrally diffracted intensity of reflection holograms are also presented.