High-efficiency wide-band metal-dielectric resonant grating for 20 fs pulse compression

Abstract

More than 95% average efficiency TE-polarisation diffraction over a 200 nm wavelength range centred at 800 nm is obtained by a metaldielectric grating structure with non-corrugated mirror. 98% maximum -1 st order diffraction efficiency and a wide band top-hat spectrum are demonstrated experimentally opening the way to high-efficiency Chirped Pulse Amplification of femtosecond pulses as short as 20 fs.

Innovations in structured thin film design and fabrication for optical applications

“…This has triggered many research activities in the recent years, covering both design and fabrication. Gratings with highefficiency over 200 nm bandwidth based on metal-dielectric structure have been reported [18][19]. However, the use of metallic materials reduces the efficiency and LIDT of these components.…”

“…Due to the low absorption, multilayer dielectric gratings (MDG) provide high-efficiency, high laser-induced damage threshold (LIDT) [15][16][17]. To meet the bandwidth requirements in ultrashort laser systems, the research on broadband MDG draws increasing attention [18][19][20][21]. Pulse compression gratings and broadband polarizers can be realized with a single material based on a 2D photonic crystal structure.…”

Diffraction gratings: from principles to applications in high-intensity lasers

“…Consequently, the widening of the tolerance of dielectric gratings has gained most of the efforts over the last 10 years. It was suggested in 2007 to etch the grating on the high refractive index to improve the spectral tolerance [130,131]. One of the nicest achievement in the design and fabrication of diffraction gratings was obtained by Martz et al who increased the contrast between the different materials of the multilayer and by etching the grating in different materials [127] (see Fig.…”

“…The etching in the high refractive index material offers the possibility to design shallow gratings (≈ 70 nm in depth) [133,135]. Rapidly, these gratings were showed to feature particularly high spectral tolerance in TE polarization and were proposed as an alternative solution for ultrashort pulse compression [131,132]. This technology requires an etching of the grating in a high refractive index material but it leads to reflected efficiencies in the -1 st order around 95% in average.…”

Optimization design of an ultrabroadband, high-efficiency, all-dielectric grating

“…However, as the reflection bandwidth of dielectric high-reflectivity (HR) mirror is much narrower than that of a metal HR mirror, it is a challenge to design a broadband, high-efficiency MDG. In recent years, Flury et al have reported their works about broadband gratings and have obtained some fruitful results [6,8,9], including an all-dielectric grating with a DE close to 100% over a range of 40 nm wide and metal-dielectric grating with an average DE of 95% over a 200 nm wavelength bandwidth centered at 800 nm. Although the bandwidth has been widened in metal-dielectric gratings, the use of metal material would more or less lead to the light absorption.…”