Liquid-Crystal alignment by a nanoimprinted grating for wafer-scale fabrication of tunable devices

International audienceA simple technology is demonstrated for wafer-scale fabrication of liquid-crystal (LC) microcells that can be integrated in active optoelectronic devices. Fabrication of 1.55µm tunable Fabry-Perot optical micro-filter arrays is achieved owing to the insertion of a single nanoimprinted polymer grating dedicated to LC alignment and to the soft thermal transfer of a dry thick resist film between two highly reflective mirrors. The filter exhibits a spectral tuning range of 102nm with only 18V applied, as well as negligible internal loss, which makes it suitable for being inserted in a laser cavity. This constitutes a key step toward large-scale integration of widely-tunable photonic devices such as VCSELs using LC technology