  Large dynamic index measurement range (n = 1 to n = 1.7) using surface
plasmon resonance (SPR) shifts is demonstrated with a ZnSe prism at 632.8 nm,
limited by the available high index liquid hosts. In contrast to borosilicate
based SPR measurements where angular limitations restrict solvent use to water
and requires considerable care dealing with Fresnel reflections, the ZnSe
approach allows SPR spectroscopies to be applied to a varied range of solvents
An uncertainty in angular resolution between 1.5 and 6 deg, depending on the
solvent and SPR angle, was estimated. The refractive index change for a given
glucose concentration in water was measured to be n = (0.114 to 0.007) per
precentage C6H12O6 conc. Given the transmission properties of ZnSe the
processes can be readily extended into the mid infrared.
