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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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TL;DR: In this article, the fullerene molecule C60 is shown to act as a useful sensitizer of a recently discovered photorefractive polymer, and the sensitization appears to result from a small increase in the carrier generation efficiency and a larger increase in useful optical absorption at the operating wavelength, 647 nm.
Abstract: The fullerene molecule C60 is shown to act as a useful sensitizer of a recently discovered photorefractive polymer. Measurements of the steady‐state diffraction efficiency, grating growth rate, and other photorefractive properties are presented as a function of C60 concentration, writing intensity, and applied electric field. The dc photoconductivity, grating growth rate, and steady‐state diffraction efficiency all increase by as much as a factor of 20 upon doping with up to 0.2 wt % C60. The sensitization appears to result from a small increase in the carrier generation efficiency and a larger increase in the useful optical absorption at the operating wavelength, 647 nm.
81 citations
TL;DR: In this paper, a review on electron-beam lithography and accompanying technologies for high performance gratings can be found, which can be realized by different approaches, such as the one described in this paper, for the Radial Velocity Spectrometer of the GAIA-mission of the ESA.
Abstract: Gratings are essential components in different high performance optical set-ups such as spectrometers in space missions or ultrashort-pulse laser compression arrangements. Often such kinds of applications require gratings operating close to the technological accessible limits of today’s fabrication technology. Typical critical parameters are the diffraction efficiency and its polarization dependency, the wave-front error introduced by the grating, and the stray-light performance. Additionally, space applications have specific environmental requirements and laser application typically demand a high damage threshold. All these properties need to be controlled precisely on rather large grating areas. Grating sizes of 200 mm or even above are not unusual anymore. The paper provides a review on how such high performance gratings can be realized by electron-beam lithography and accompanying technologies. The approaches are demonstrated by different examples. The first example is the design and fabrication of the grating for the Radial-Velocity-Spectrometer of the GAIA-mission of the ESA. The second grating is a reflective pulse compression element with no wavelength resonances due to an optimized design. The last example shows a three level blazed grating in resonance domain with a diffraction efficiency of approximately 86 %.
81 citations
TL;DR: The effects of F NP holographic gratings on their diffraction performance are found to be comparable to their counterparts of FNP surface-relief gratings.
Abstract: The effects of finite number of periods (FNP) and finite incident beams on the diffraction efficiencies of holographic gratings are investigated by the finite-difference frequency-domain (FDFD) method. Gratings comprising 20, 15, 10, 5, and 3 periods illuminated by TE and TM incident light with various beam sizes are analyzed with the FDFD method and compared with the rigorous coupled-wave analysis (RCWA). Both unslanted and slanted gratings are treated in transmission as well as in reflection configurations. In general, the effect of the FNP is a decrease in the diffraction efficiency with a decrease in the number of periods of the grating. Similarly, a decrease in incident-beam width causes a decrease in the diffraction efficiency. Exceptions appear in off-Bragg incidence in which a smaller beam width could result in higher diffraction efficiency. For beam widths greater than 10 grating periods and for gratings with more than 20 periods in width, the diffraction efficiencies slowly converge to the values predicted by the RCWA (infinite incident beam and infinite-number-of-periods grating) for both TE and TM polarizations. Furthermore, the effects of FNP holographic gratings on their diffraction performance are found to be comparable to their counterparts of FNP surface-relief gratings.
81 citations
TL;DR: A Ti:Sapphire femtosecond laser with a pulse energy of 1.3 nJ at a 93 MHz repetition rate has been used to micro-machine optical gratings inside several silicone-based and non-silicone-based hydrogel polymers to measure the diffraction efficiency of the gratings.
Abstract: A Ti:Sapphire femtosecond laser with a pulse energy of 1.3 nJ at a 93 MHz repetition rate has been used to micro-machine optical gratings inside several silicone-based and non-silicone-based hydrogel polymers. By measuring the diffraction efficiency of the gratings at 632.8 nm, we find as large as 0.06+/- 0.005 average refractive index change within the irradiated area.
81 citations
TL;DR: This work solved for the zero-order diffraction efficiency and the phase of each polarization component for arbitrary incident angles and illustrated the phase shift between polarizations associated with the diffraction process as a function of the incident angles.
Abstract: A complete solution of plane-wave scattering from a groove-corrugated surface of infinite extent for arbitrary incidence is presented. The electromagnetic wave is decomposed into fast and slow modal representation, and the solution is accomplished through the use of the mode-matching method. We solved for the zero-order diffraction efficiency and the phase of each polarization component for arbitrary incident angles. Our results have verified special cases previously published by others and have illustrated the phase shift between polarizations associated with the diffraction process as a function of the incident angles.
81 citations