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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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Journal ArticleDOI
TL;DR: In certain conditions, the diffraction efficiency is shown to be exactly proportional to the inverse of the object beam intensity, and the dependence of the range of beam ratios over which inversion occurs on the experimental parameters of total writing beam intensity and applied electric field is investigated.
Abstract: In this paper, we consider a two-wave mixing system using a photorefractive medium and compute the diffraction efficiency as a function of the writing beam ratios. In certain conditions, the diffraction efficiency is shown to be exactly proportional to the inverse of the object beam intensity. Experimental results, obtained using a Bi12GeO20 crystal, are compared to the theoretical expression. In particular, we investigate the dependence of the range of beam ratios over which inversion occurs on the experimental parameters of total writing beam intensity and applied electric field. Results of performing inversion of gray-scale objects using a degenerate four-wave mixing setup are shown.

46 citations

Journal ArticleDOI
TL;DR: In this paper, a diffraction grating recorded by two opposite circularly polarized beams is proposed for polarimetric applications, which is based on a Langmuir-Blodgett film of an azo-compound material.
Abstract: The study of a diffractive device for polarimetric applications is reported. The device consists of a diffraction grating recorded by two interfering opposite circularly polarized beams and is based on a Langmuir–Blodgett film of an azo-compound material. This material provides long-time stability and high photoinduced birefringence that makes the grating highly diffraction efficient. We show how polarization gratings permanently stored in these films are suitable for applications as photopolarimeter components.

46 citations

Journal ArticleDOI
TL;DR: In this article, a comprehensive analysis of the evolution of a grating envelope, in both transmission and reflection geometry, during the erasure process in various readout configurations in bulk photorefractive media is presented.
Abstract: We present a comprehensive analysis of the evolution of a grating envelope, in both transmission and reflection geometry, during the erasure process in various readout configurations in bulk photorefractive media. We derive a single partial differential equation that describes grating evolution. This equation shows that under certain conditions the grating envelope propagates and shares several features with either bright or dark solitons. Details of the grating envelopes directly relate to the dynamics of the observed diffraction efficiency. We derive analytical expressions for diffraction during nondestructive readout. Finally, we discuss the effects of nonzero absorption, finite dark conductivity, fringe bending, fanning, and nonlinear responses on the propagating envelope.

46 citations

Journal ArticleDOI
TL;DR: The diffraction properties at wavelengths of 632.8 and 1550 nm for volume transmission gratings made of a sequence of continuously aligned nematic liquid-crystal layers separated by isotropic polymer slices are reported.
Abstract: We report the diffraction properties at wavelengths of 632.8 and 1550 nm for volume transmission gratings made of a sequence of continuously aligned nematic liquid-crystal layers separated by isotropic polymer slices. The gratings are generated by holographically curing a solution of liquid crystal diluted in an isotropic prepolymer by means of a laser beam at a wavelength of 352 nm with a total intensity of approximately 10 mW/cm2. A diffraction efficiency of 98% was measured, and an electric field as low as 5 V/µm switches off the phase grating. Measured angular spectra are fitted by use of the modified coupled-mode theory including the effects of grating birefringence.

46 citations

Proceedings ArticleDOI
22 Aug 2001
TL;DR: In this article, the authors proposed a method that relies on the diffraction of a probing laser beam at a periodic reference pattern in order to obtain a strong diffraction signal and thus a sufficient signal to noise ratio optimum grating designs have been computed by means of rigorous diffraction modeling.
Abstract: Optical overlay measurement methods are very effective since they are rapid and non-destructive. Imaging techniques need sophisticated image processing and suffer from the wave-optical resolution drawback. Presently, leading edge devices are offered with 5 through 10 nm measuring accuracy. In this paper a method is proposed that relies on the diffraction of a probing laser beam at a periodic reference pattern. This special pattern is implemented in the circuit layout. After the resist patterning of the second of two consecutive layers, the diffraction at the resulting net grating is measured. If an appropriate grating design is chosen, the misalignment error can be directly extracted from the diffraction efficiency. In order to obtain a strong diffraction signal and thus a sufficient signal-to-noise ratio optimum grating designs have been computed by means of rigorous diffraction modeling. Experimental results supported by rigorous modeling suggest that this technique could have the potential to meet next generation overlay accuracy requirements.

46 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202391
2022188
2021167
2020223
2019259
2018259