Development of glass microoptics for MidIR with hot embossing technology

In this paper we report on the development of diffractive and refractive micro optical components devoted to MidIR applications. As a material we use a customized heavy metal oxide glasses with high transmission in the range 0.6 divided by 6.0 mu m. Optimization of the glass composition in four- and five-component oxide systems for a broadband transmission window is difficult due to their excessive crystallization susceptibility. Several metals and alloys were tested for their suitability as a stamping medium. Optimal performance was obtained for selected brass and steel stamps, as well as for pure silica stamps. As a technology testboard we have developed 1D and 2D diffractive gratings with a minimum feature size of 5 mu m as well as Fresnel microlenses with a diameter of 200 mu m. The quality of the embossed elements was verified by comparison of the master and replicated elements using a non-contact white light interferometer.