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 monolithic laser structure was proposed and demonstrated in which the tuning range Δλ/λ can be more than an order of magnitude larger than the fractional index change in one section.
Abstract: We propose and demonstrate a new monolithic laser structure in which the fractional tuning range Δλ/λ can be more than an order of magnitude larger than the fractional index change Δμ/μ in one section. The key idea involves using grating mirrors with grating elements removed in a periodic fashion. These ‘‘sampled gratings’’ have reflection spectra with periodic maxima. By using two such mirrors with identical grating pitch but mismatched sampling periods, it is possible to tune among the various reflectivity maxima. Our initial experimental results show 29.3 nm of tuning in an InGaAsP laser.
92 citations
TL;DR: A bioinspired photonic material is presented that mimics the reverse color-order diffraction found in the butterfly Pierella luna and could provide a basis for novel developments in biosensing, anticounterfeiting, and efficient light management in photovoltaic systems and light-emitting diodes.
Abstract: Recently, diffraction elements that reverse the color sequence normally observed in planar diffraction gratings have been found in the wing scales of the butterfly Pierella luna. Here, we describe the creation of an artificial photonic material mimicking this reverse color-order diffraction effect. The bioinspired system consists of ordered arrays of vertically oriented microdiffraction gratings. We present a detailed analysis and modeling of the coupling of diffraction resulting from individual structural components and demonstrate its strong dependence on the orientation of the individual miniature gratings. This photonic material could provide a basis for novel developments in biosensing, anticounterfeiting, and efficient light management in photovoltaic systems and light-emitting diodes.
92 citations
TL;DR: In this paper, a Bragg-grating-based acoustooptic superlattice modulator is presented, whose diameter is reduced by HF etching, and the acoustically induced reflections appear on both sides of the Bragg stopband.
Abstract: This paper reports a 100% efficient Bragg-grating-based acoustooptic superlattice modulator in a fiber whose diameter is reduced by HF etching. The acoustically induced reflections, which appear on both sides of the Bragg stop-band, are tunable by altering the acoustic frequency, and have bandwidths corresponding to weak versions of the permanent Bragg grating. These unique properties may lead to important applications in, e.g., reconfigurable wavelength division multiplexing, Q-switching, amplitude modulation, and frequency shifting.
92 citations
TL;DR: A neutron phase contrast imaging method based on a grating interferometer setup that characterized the produced diffraction gratings by locally evaluating the produced contrast in each detector pixel, resulting in a visibility map over the whole grating size.
Abstract: We have developed a neutron phase contrast imaging method based on a grating interferometer setup. The principal constituents are two absorption gratings made of gadolinium and a phase modulating grating made of silicon. The design parameters of the setup, such as periodicity, structure heights of the gratings, and the distances between the gratings, are calculated. The fabrication of each grating is described in detail. The produced diffraction gratings were finally characterized within the setup, by locally evaluating the produced contrast (visibility) in each detector pixel, resulting in a visibility map over the whole grating size. An averaged value of 23% is achieved.
92 citations
22 May 2011
TL;DR: This work introduces a different mechanism to achieve total transmission through an otherwise opaque screen, based on an inherently ultra-broadband tunneling mechanism that can span from DC to the visible range.
Abstract: Extraordinary optical transmission through metallic gratings is a well established effect based on the collective resonance of corrugated screens [1]. Being based on plasmonic resonances, its bandwidth is usually narrow, in particular for thick screens and small apertures. Here we introduce a different mechanism to achieve total transmission through an otherwise opaque screen, based on an inherently ultra-broadband tunneling mechanism that can span from DC to the visible range. This phenomenon may effectively represent the equivalent of Brewster transmission for plasmonic and opaque screens. As long as only the dominant TM mode is supported inside the slit and only the zero diffraction order can propagate, i.e., w << d < λ0 = 2π/k 0 , where d is the grating period, w the slit aperture and λ0 the incident wavelength, it is possible to define a plasmonic Brewster angle as [2] : cos(ϑ B ) = (β S w)/(k 0 d), where β s is the wave-number of the fundamental TM mode guided inside each slit. In Fig. 1, we show the calculated TM power transmission spectra for a grating with thickness l=400nm and period d=192nm varying the incidence angle, frequency and the slit width, as indicated in each panel. The left column shows full-wave simulations based on the Fourier modal method [3], compared in the right to our analytical model based on a transmission line approach [2].
92 citations