Diffraction efficiency

About: Diffraction efficiency is a research topic. Over the lifetime, 10320 publications have been published within this topic receiving 158298 citations.

Polymeric, electrically tunable diffraction grating based on artificial muscles.

Abstract: We demonstrate a low-cost, electrically tunable diffraction grating that is driven by a dielectric elastomer actuator. The angular tuning range of the polymer-based device is up to 118 mrad for the first diffracted order. The achievable grating period change of 32% is an improvement by more than a factor of 150 compared with existing analog tunable diffraction gratings based on hard materials. We show that in combination with a white light source, the presented diffraction grating can be used as a wavelength-adjustable luminous source. Such an illuminant has a potential application in inexpensive color displays that could reproduce all perceivable colors.

High efficiency optical diffraction device

Abstract: Lightwave diffraction device formed of a dielectric layer (4), a mirror (12) arranged at the lower face (10) of said layer, a semi­reflective structure (13) arranged at the upper face (100) of said layer, and a diffractive structure (8) arranged in said layer or on its faces. The height (H) of the layer is chosen so as to substantially satisfy the resonance condition for at least one leaky mode propagating in said layer for at least one given incident wave having a determined wavelength λ and a determined incidence angle θc. Next, the diffractive structure is arranged so that there is no propagating positive diffracted order, and so that all negative orders other than the -1st propagating order have zero or a relatively small diffraction efficiency, the reflected -1st order propagating in a direction non-parallel to the incident wave. This diffraction device allows a high diffraction efficiency of up to 100% for the -1st order.

Fe-Doped LiNbO(3) for Read-Write Applications.

Abstract: High erase sensitivity is observed in heavily reduced crystals of Fe-doped LiNbO3. Only 12 mJ/cm2 of incident 4880-A radiation erases a hologram, nearly 3 orders of magnitude less energy than previously required. However, the maximum diffraction efficiency that can be reached in these crystals is substantially reduced. These results are shown to be consistent with an extremely low density of Fe3+ ions. The crystals are resistant to optical scattering effects usually observed in Fe-doped LiNbO3.

Effect of electric field on laser induced damage threshold of multilayer dielectric gratings

Abstract: This paper studies gratings engraved in multilayer dielectric stacks for ultra high intensity laser compressors application. We design various grating profiles with high reflected efficiencies for 1780 l/mm multilayer dielectric gratings (MLD). Each grating is defined to exhibit a different electric field maximum value in the pillars of the grating. A damage testing facility operating at 1.053 μm, 500 fs pulse duration is used to damage test the parts manufactured from these designs. It is evidenced that for fixed incident angle and materials the damage of the grating is directly related to the electric field intensity maximum in the material, which depends on the groove profile. Laser induced damage thresholds of 5 J/ cm2 are experimentally reached with very high and uniform efficiencies.

High efficiency volume diffractive elements in photo-thermo-refractive glass

Abstract: Novel volume holographic elements were made from Bragg diffractive gratings in photo-thermo-refractive (PTR) glass with absolute diffraction efficiency ranging from greater than approximately 50% up to greater than approximately 93% and total losses below 5%. Both transmitting and reflecting volume diffractive elements were done from PTR glasses because of high spatial resolution enabling recording spatial frequencies up to 10000 mm−1. The use of such diffractive elements as angular selector, spatial filter, attenuator, switcher, modulator, beam splitter, beam sampler, beam deflectors controlled by positioning of grating matrix, by a small-angle master deflector or by spectral scanning, selector of particular wavelengths (notch filter, add/drop element, spectral shape former (gain equalizer), spectral sensor (wavelength meter/wavelocker), angular sensor (pointing locker), Bragg spectrometer (spectral analyzer), transversal and longitudinal mode selector in laser resonator were described. Combinations of those elements in the same volume are available too.