Surface plasmon excitation and emitted light characteristics of polystyrene sphere films

Polystyrene submicron and micron sphere films were fabricated and the optical properties were investigated using surface plasmon resonance (SPR) and reverse irradiation utilizing the SPR Kretschmann configuration. BK-7 (n=1.515) and S-TIH53 (n=1.805) prisms were used for the measurements. The diameters of thee spheres were 0.1 and 1.0 μm. For the 0.1-μm-sphere films, some SPR dips were observed and were considered to be due to the existence of defects in the film. For the highly packed 1.0-μm-sphere films, SPR dip was observed only in the curves obtained using S-TIH53 prism and it was considered to be due to the size and the large dielectric constant of the sphere. Emitted light due to reverse irradiation was observed as a function of the emitted angle in the Kretschmann configuration. The peak angles of the emitted light almost corresponded to the dip angles of the SPR curves and the emitted light was considered to be due to surface plasmon excitation.