Liquid crystal electric tuning of a photonic crystal laser

We demonstrate an electrically-tuned nematic liquid crystal (LC) infiltrated photonic crystal (PC) laser. The PC laser is encased between two transparent indium tin oxide (ITO) glass plates which serve as the modulating electrodes and also define the LC cell. Applying a voltage across the cell realigns the LC, modifies the laser cavity's optical path length, and blue-shifts the lasing wavelength. The measured tuning threshold voltage agrees well with the experimentally determined LC threshold voltage which confirms the tuning is due to the LC realignment at the onset of the LC's Freedericksz transition. Furthermore, the electrically-tuned PC laser also demonstrates the successful integration of nonlinear optical materials, electronics, and fluidics with PCs and suggests further integration with other materials will lead to photonic devices with increased functionality and utility.