Measurement of Wavelength-Dependent Complex Refractive Index of Transparent and Absorbing Liquids by a Multifunction Reflectometer

We have modified a recently developed reflectometer so that surface plasmon resonance (SPR) sensing is now possible. Thus, the complex refractive index of liquids can be obtained at a desired wavelength (the existing setup allows the use of the visible-NIR spectral range) using both the SPR and conventional measurement modes of the reflectometer. The multifunction operation of the present apparatus offers possibilities for off- and on-line industrial inspection of liquids.