Open AccessUltrabroadband suppression of mid-infrared reflection losses of a layered semiconductor by nanopatterning with a focused ion beam
Author(s) -
Matthias Hagner,
Philipp Sulzer,
Andreas Liehl,
Moritz Cimander,
Hannes Kempf,
Annika Bitzer,
Alexa Herter,
Alfred Leitenstorfer
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.433703
Subject(s) - optics , materials science , focused ion beam , femtosecond , optoelectronics , fresnel equations , laser , infrared , optical rectification , reflection (computer programming) , refractive index , ion , nonlinear optics , physics , quantum mechanics , computer science , programming language
Moth-eye structures are patterned onto gallium selenide surfaces with sub-micrometer precision. In this way, Fresnel reflection losses are suppressed to below one percent within an ultrabroad optical bandwidth from 15 to 65 THz. We tune the geometry by rigorous coupled-wave analysis. Subsequently, ablation with a Ga + ion beam serves to write optimized structures in areas covering 30 by 30 μm. The benefits are demonstrated via optical rectification of femtosecond laser pulses under tight focusing, resulting in emission of phase-stable transients in the mid-infrared. We analyze the performance of antireflection coating directly in the time domain by ultrabroadband electro-optic sampling.