Topic
Diffraction grating
About: Diffraction grating is a research topic. Over the lifetime, 24884 publications have been published within this topic receiving 372437 citations. The topic is also known as: grating.
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TL;DR: In this paper, a technique for multiplexing Bragg gratings in a fiber laser arrangement is described, which has successfully been used to multiplex two and three Bragg grating gratings with very little crosstalk.
Abstract: A technique for multiplexing Bragg gratings in a fiber laser arrangement is described. This technique has successfully been used to multiplex two and three Bragg gratings with very little crosstalk. The Bragg grating laser sensors were used to measure both strain and temperature. Independent strain and temperature tuning of the gratings shows no crosstalk. >
80 citations
TL;DR: Tests of fully completed devices in immersion show that the gratings have reached the level where they compete with and, in some cases, exceed the performance of commercially available conventional diffraction gratings (relative efficiencies up to 71%).
Abstract: Immersion gratings, diffraction gratings where the incident radiation strikes the grooves
while immersed in a dielectric medium, offer significant compactness and performance
advantages over front-surface gratings. These advantages become particularly large for
high-resolution spectroscopy in the near-IR. The production and
evaluation of immersion gratings produced by fabricating grooves in silicon substrates
using photolithographic patterning and anisotropic etching is described. The gratings produced under
this program accommodate beams up to
25 mm in diameter (grating areas to
55 mm×75 mm).
Several devices are complete with appropriate reflective and antireflection coatings.
All gratings were tested as front-surface devices as well as immersed gratings. The results of the
testing show that the echelles behave according to the predictions of the scalar
efficiency model and that tests done on front surfaces are in good agreement with tests
done in immersion. The relative efficiencies range from 59% to 75% at
632.8 nm. Tests of
fully completed devices in immersion show that the gratings have reached the level where
they compete with and, in some cases, exceed the performance of commercially available
conventional diffraction gratings (relative efficiencies up to 71%).
Several diffraction gratings on silicon substrates up to
75 mm in diameter having been produced, the
current state of the silicon grating technology is evaluated.
80 citations
TL;DR: In this article, the spectral shift of the Bragg wavelength was measured for a hydrogen gas sensor based on a palladium thin-film transducer, which is caused by the decreasing complex refractive index of Pd with increasing absorption of hydrogen.
80 citations
TL;DR: The aim of this study is the selection without dispersion of one or more high-order laser harmonics produced by a pulse lasting a few femtoseconds and interacting with a gas jet.
Abstract: The extraction of the spectrum corresponding to a single extreme-ultraviolet ultrashort pulse embedded in an extended spectrum may alter the duration of the pulse itself. This is due to the spectral filtering of optics and the differences in the optical path of the rays caused by ordinary diffraction when a grating is used. The basic mechanism that leads to the latter effect is the difference of one wavelength of the path length of two rays diffracted at the first order by nearby grating grooves. A study of these effects and some possible solutions obtained from using a pair of diffraction gratings is presented. The aim of this study is the selection without dispersion of one or more high-order laser harmonics produced by a pulse lasting a few femtoseconds and interacting with a gas jet.
80 citations
TL;DR: In this paper, a simplified model which assumes that the UV-induced periodic corrugations result from both permanent and elastic strains is presented, which accounts not only for a large part of the measured refractive index change but also for the localization of the UVinduced birefringence along the grating wavevector.
Abstract: Bragg gratings have been written within MCVD germanosilicate preform slices using CW laser light at 244 nm. Afterwards, scanning light interferometry was used to perform a 3D imaging analysis of the sample surface topography. The results show that the same process (namely densification) pointed out in a previous work in which we used UV pulsed exposure of preform slices is also active here. A simplified model which assumes that the UV-induced periodic corrugations result from both permanent and elastic strains, is presented. This model accounts not only for a large part of the measured refractive index change but also for the localization of the UV-induced birefringence along the grating wavevector. It also gives a satisfactory interpretation of the observations made by Fonjallaz et al, according to whom grating inscription within a germanosilicate fibre increased the axial tensile core stress.
80 citations