Direct imaging of tunable photonic nanojets from a self-assembled liquid crystal microdroplet.

We report the direct experimental observation of electrically tunable photonic nanojets (PNJs) generated from self-assembled liquid crystal (LC) microdroplets formed by dispersing nematic LCs in polymer matrix. Optical measurements were performed with a home-built laser-scanning confocal microscope system. PNJs with subwavelength beam waists were successfully obtained from LC microdroplets of 5 μm diameter, similar to those from SiO microspheres of the same size. By applying external voltage of a few volts, some of major properties of PNJs, such as beam length and brightness, are tuned. Electro-tunable PNJs from self-assembled LC microdroplets may open the way for the development of novel micro-optical devices.