Broadband pyramid antireflective structure on chalcogenide glasses by the hot embossing method for infrared photonics

Pyramidal antireflective structures were produced by hot embossing single- and double-sides of an amorphous GeSe₄ optical element. The optical performances were measured across the wavelength range from 2 µm to 15 µm. The transmittance at normal incident angle was increased up to 75.6% and 79.8% for single and double-side embossing respectively. The experimental results were in close agreement with simulation performed using the rigorous coupled-wave analysis (RCWA). Theoretical models also predicted well the transmittance changes as a function of incident angle from 0 ° to 50 ° at a fixed laser wavelength of 5.1 µm. A Fabry-Perot interferometer consisting of two single surface embossed samples is proposed.