High-dispersion TIR-GRISMs with flattened angular dispersion profile

Abstract

Modern grating imaging spectrographs typically show aberrations due to the nonlinear dependence of angular dispersion on wavelength. This error can be reduced by a combination of diffracting and refracting components (grating and prism). Here, we present a dispersive optical component, namely, total internal reflection (TIR) grating + prism, with a grating attached to one facet of a prism. The elements work within the limit of TIR and exhibit three advantages compared to standard diffraction gratings: first, high diffraction efficiency up to 98%; second, enormous angular dispersion up to 0.75 ∘ n m − 1 ; and third, a nearly constant angular dispersion profile. As an example, the fabrication of such a disperser designed for the short-wave infrared2 spectral range is demonstrated. We report on details of the manufacturing process, which relies on a dedicated combination of technologies, i.e., electron beam lithography, atomic layer deposition, and hydrophilic direct bonding.