Diffraction efficiency

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

Multilevel-grating array generators: fabrication error analysis and experiments

Abstract: The effects of mask alignment and etch-depth errors in the array uniformity error U and diffraction efficiency η of multilevel-grating array illuminators are evaluated numerically. Also demonstrated are 16-level fan-out elements with array size up to 32 × 16, with U = 5%–10% and η = 83%–92%. These are fabricated with electron-beam-written binary masks, optical alignment and contact copying, and reactive ion etching. Good agreement between the predictions of the error analysis and the performance of the fabricated components is observed.

Efficiency of a grazing-incidence off-plane grating in the soft-x-ray region

Abstract: Efficiency measurements of a grazing-incidence diffraction grating in the off-plane mount were performed using polarized synchrotron radiation. The grating had 5000 grooves/mm, an effective blaze angle of 14 deg., and was gold coated. The efficiencies in the two polarization orientations (TM and TE) were measured in the 1.5-5.O nm wavelength range and were compared with the efficiencies calculated using the PCGrate-SX code. The TM and TE efficiencies differ, offering the possibility of performing unique science studies of astrophysical, solar, and laboratory sources by exploiting the polarization sensitivity of the off-plane grating.

Interference-term real-time measurement for self-stabilized two-wave mixing in photorefractive crystals.

Abstract: We report the real-time direct interference-term measurement for a two-wave-mixing experiment in photorefractive crystals. Knowledge of the interference term may provide information concerning diffraction efficiency, interference pattern-to-recorded hologram phase shift, and optical activity and anisotropic diffraction properties of these materials. This method comprises phase modulation of one of the interfering beams and synchronous detection of the first and second harmonics in the resulting output irradiance modulation. Simultaneous detection of both harmonics enables the measurement to be made even in strongly perturbed conditions, since one harmonic is used for measuring and the other is used for operating an active stabilization system. Experimental results for Bi12TiO20 are reported.

Single femtosecond pulse holography using polymethyl methacrylate.

Abstract: Holographic gratings have been written on the surface and inside transparent polymethyl methacrylate (PMMA) with individual 130 fs laser pulses at 800 nm. A surface-relief grating is fabricated by ablation and the diffraction efficiency is measured to be about 20%. A volume grating inside PMMA is formed by the change in the refractive index induced by the two-beam interference fringes. Holographic data storage on the surface is realized when one beam carries information. The stored information can be nondestructively reconstructed when the fluence of the read beam is reduced below the threshold.

Design, optical characterization, and operation of large transmission gratings for the laser integration line and laser megajoule facilities

Abstract: Within the framework of the laser integration line (LIL) and the laser megajoule, we describe the design, optical characterization, mounting, alignment, and operation on the LIL of large 420 mm × 470 mm transmission gratings. Two types of grating were manufactured. The first, operating at a wavelength of 1.053 µm, was used for deviation purposes. The second, operating at a wavelength of 0.351 µm, was used for both deviation and focusing purposes. We demonstrate that these large transmission gratings are suitable for nanosecond-regime operation on high-power laser facilities.