High-refractive-index gratings for spectroscopic and Laser applications

Fabrication of high performance gratings may significantly benefit from the use of high index materials such as Ta2O5, TiO2 or Al2O3. However, these materials can typically not be patterned with the required quality by common etching processes. To overcome this limitation we developed novel grating fabrication technologies based on a combination of conventional lithography with Atomic-Layer-Deposition. For that the basic structure of the grating is first realized in a fused-silica substrate or a SiO2-layer. This template is then functionalized by an ALD-coating in a specific pre-defined manner. The new approach opens up a huge variety of new options for the realization of gratings whose fabrication would otherwise not be possible.