Development of diffraction binary grating using hot embossing processing with electroformed nickel mold for broadband IR optics

Abstract

In this paper we report on cost-effective fabrication of glass diffractive optical elements dedicated to work over a spectral range from the visible to the mid-infrared. As a test we have developed of checker-board diffraction grating using the hot embossing process. The nickel (Ni) shim fabricated using low-cost electroforming method was used as a mold. We synthesised in-house a new composition of lead-free bismuth-silicate glass, labelled SAB-1A, with good rheological properties and high transmittance up to 3.5 μm. Glass composition and parameters of hot embossing process were optimised to accurately replicate the grating and separate the glass replica from the mold. The quality of the fabricated elements was discussed and examined using a white light interferometer and in experimental setup for generation of diffractive pattern at different wavelengths.