Abstract
The surface plasmon technique is employed to measure the refractive indices and to probe the nematic-isotropic phase transition of 4-cyano-4′-n-pentylbiphenyl. Coexistence of isotropic and nematic phases in a 60 mK range and a hysteresis effect of the phase transition have been observed. A diffuse droplet model is used to estimate the supercooling and superheating range.