Ks. Johnston et al., NEW ANALYTICAL TECHNIQUE FOR CHARACTERIZATION OF THIN-FILMS USING SURFACE-PLASMON RESONANCE, Materials chemistry and physics, 42(4), 1995, pp. 242-246
A theoretical technique is presented for simultaneously determining th
e thickness and dispersive refractive index of a homogeneous thin film
applied to a surface plasmon resonance sensor. The technique has the
potential for real-time characterization of film parameters while imme
rsed in air, vacuum or liquid media. Experimental realization requires
a calibrated wavelength-modulated surface plasmon resonance sensor th
at is measured at several angles of illumination. A fine-tuned numeric
al model is used to generate general solutions that describe the senso
r response for each angle of illumination. A differential technique an
d an assumption of a linear dispersion are used to produce a unique so
lution for the thickness and dispersive refractive index of the film.
For a simulated 183 nm thick glass film, results shows 1% thickness pr
ediction error and refractive index prediction error on the order of 3
X 10(-3).