Effect of probe on surface plasmon resonance

In order to get the best lithography conditions, the effect of the probe on surface plasmon resonance (SPR), which is utilized in probe induced surface plasmon resonance coupling nanolithography (PSPRN), has been investigated by using finite difference time domain (FDTD) method. The results show that SPR field enhancement effect is small with a small waist radius of fundamental mode Gaussian beam. When working in contact mode, Si probe with a tip radius of curvature of 10 nm, and 35 nm and 100 nm for Au prodes, make the SPR resonance angle change 0, 0.8°, 1° respectively. For Au prodes, smaller tip radius of curvature can get stronger local field enhancement effect. Analysis showed that with a Si probe of 10 nm tip radius of curvature or a Au probe of 35 nm tip radius of curvature probe, by adjusting the incident angle, it is likely to realize experimentally a 50 nm recording spot with a suitable SPR film structure.