Results 151 to 160 of about 626 (184)
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The Production of Diffraction Gratings: II The Design of Echelle Gratings and Spectrographs1
Journal of the Optical Society of America, 1949In seeking to circumvent the difficulties that have limited production of ruled gratings having resolving powers in excess of 400,000, it is observed that resolving power at a given wave-length depends only on the ruled width of the grating and the angles of illumination and observation, and not specifically on the number of ruled grooves.
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Echelle and holographic gratings compared for scattering and spectral resolution
Applied Optics, 1981An echelle grating with 316 grooves/mm and a 63 degrees blaze angle is compared with a 3600-groove/mm holographic grating. The scattered light and resolution of the 10- x 20-cm gratings are photoelectricaly evaluated in a 3-m spectrometer optimized to eliminate coma and baffled to minimize instrumental scattered light. Both gratings are ghost-free, but
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A large mosaic echelle grating for ESPRESSO spectrograph
Optical and Infrared Interferometry and Imaging VI, 2018ESPRESSO, The Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations, is a super-stable Optical, fiber feed High Resolution Spectrograph for the combined coude focus of the VLT. The instrument has been successfully commissioned end of 2017.
Marco Riva +5 more
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Effect of particle defects on an Echelle grating demultiplexer
Optics Communications, 2006The impact of particle defects in the free propagation region on the performance of an etched diffraction grating demultiplexer is analyzed in the present paper. Numerical simulations using a method of moment and a Green function method show that particle defects with some special sizes can result in a strong resonance with the incident wavelength and ...
Xiaohua Cao, Dongyan Wang, Kang Li
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Perfect blazing with echelle gratings in TE and TM polarization
Optics Letters, 2012Perfect blazing with echelle gratings in a high-order Littrow mount exists not only with TM polarization, as can perhaps be assumed, but also with TE and TM polarizations simultaneously. This finding contradicts with a heuristic explanation as to why perfect blazing is not possible simultaneously in TE and TM polarizations given by Loewen and Popov ...
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Examination of the Spectral Efficiency of an Echelle Grating Monochromator
Applied Spectroscopy, 1979The spectral efficiency of an echelle grating monochromator has been examined. The frequently cited advantage that “echelles are blazed at all wavelengths” is observed to be a result of the periodic character of the echelle efficiency as compared with the continually decreasing efficiency from the blaze wavelength for conventional gratings.
Andrew T. Zander, Peter N. Keliher
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On-Chip Spectrometer using Cascaded Echelle Gratings and Arrayed Waveguide Gratings
2019 IEEE Research and Applications of Photonics in Defense Conference (RAPID), 2019A novel, compact, on-chip spectrometer based on cascaded EG, multiple AWGs as well as PIC foundry compatible components was designed and analyzed. The proposed device operates in the spectral range of 1050 nm −1250 nm, 0.5 nm resolution, −30dB cross talk and 400 output channels.
Mustafa Karabiyik +2 more
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Photoelectrochemical Etching of Blazed Echelle Gratings in n ‐ GaAs
Journal of The Electrochemical Society, 1988Photoelectrochemical etching can be a technique for producing microstructures in semiconductors with high aspect ratios and lateral uniformities. As an example of this application, the authors have reported recently on producing sawtooth Echelle diffraction gratings in (100) oriented crystals on n-GaAs using this method.
J. Li +4 more
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The performance of a large echelle grating in a solar spectrometer
Solar Physics, 1967A number of tests of a large diffraction grating are described. It is shown that useful information about the performance of the grating in a spectrometer can be obtained from an analysis of the diffracted wavefront by the method of Stroke. Comparison of the instrumental profile at three wavelengths strongly suggests that the influence of changes in ...
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The Multi-Echelle Grating Arrangement (Mega) Spectrometer
SPIE Proceedings, 1984A spectrometer system, based on the Multi-Echelle Grating Arrangement (MEGA) (1) has been developed. Through series diffraction in an even number of echelle gratings, high dispersion and spectral resolutions are obtained. It can be shown (1) that with n gratings of width W, utilized in a MEGA-spectrometer of focal length f, the same resolution and ...
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