Slanted Etching of High RI Materials

Current polymer-based Augmented Reality (AR) glasses are reaching an upper threshold of field of view, due to their refractive index (RI). Current resins used have n ≤ 1.9 and it seems a significant hurdle to further improve this. Glass substrates and coatings are already easily available that have n > 2, such as ZrO₂ and TiO₂ and are therefore viable replacements for the current technologies.

Etching these materials in a binary or slanted waveguide requires the development of new processes and the use of more novel technologies. In this webinar, Dr William Frost will demonstrate that nanoimprint lithography based on resin with a thin sacrificial layer can be used as a mask for slanted etching of TiO₂ waveguides, using reactive ion beam etching (RIBE). Furthermore, we demonstrate that this process can be transferred to other high RI materials, such as glasses. This work is based on the work performed in collaboration with EV Group¹.

1) M. Eibelhuber et al, "Towards AR waveguides with refractive index 2.0 utilizing nanoimprint lithogrpahy," Proc. SPIE 11765, Optical Architectures for Displays and Sensing in Augmented, Virtual, and Mixed Reality (AR, VR, MR) II, 117650H (29 March 2021); doi: 10.1117/12.2579505