Abstract
Abstract This dissertation demonstrates a novel nano-gap sensing technique based on the four-layer Kretschmann-Raether (K-R) configuration of Surface Plasmon Resonance (SPR) effect. Using this new measuring method, an air gap width of 126 nm, beyond the optical diffraction limit, has been achieved. We believe that the SPR gap measuring technique will produce many new applications, such as a position detector of a pickup head flying of a near-field disk drive, or as a position detector used in advanced lithography and stepper system. In addition, an advanced application for the SPR gap width measuring technique used in a parallel metal-layer structure had been verified. A five-layer K-R configuration including the double-deck metal layers, i.e., prism/metal-1/air gap/metal-2/glass slide, for the air gap width measurement, had been developed. The results indeed indicate that the SPR effect would occur as the prediction of Fresnel’s equations for the five-layer structure in a specific condition. It is similar to the SPR effect in the four-layer K-R configuration. The SPR gap measuring method is still suitable for the metal-dielectric-metal structure. Otherwise, because the Fabry-Perot (F-P) resonance and the surface plasmon wave (SPW) tunnel-coupled effects could occur in double-deck structure, it would affect the SPR angle shift effect in this five-layer structure, which is very different to the four-layer K-R configuration, and arises some limitation of the gap measurement used in double-deck metal layers structure.