Experimental verification of a tunable optical negative refraction in nematic liquid crystals

The authors experimentally demonstrate a magnetically tunable optical negative refraction (NR) in nematic liquid crystals (NLCs), arising from the variation of optical anisotropy in the NLCs induced by external magnetic field. By measuring the refraction angle of the transmitted beam through the prism-shaped NLC device, the tunable extraordinary refractions for different molecular directions using magnetic field are observed. It shows that NR in NLCs occurs at certain inclination angle and can be tuned by changing the direction of the magnetic field, which is in good agreement with the established theory. (C) 2007 American Institute of Physics.