Analysis of Refractive-Index Sensitivity of Nanoporous Waveguide Based Leaky Mode Resonance Sensor

Nanoporous waveguide based leaky mode resonance(LMR) sensors with Kretschmann configuration and spectral interrogation were prepared using a nanoporous TiO2 thin film of about 320 nm in thickness dip-coated on a 50 nm gold layer sputtered on the glass substrate.Surface and cross-section morphologies of the TiO2 film were examined by scanning electron microscope(SEM).The resonance wavelength and the refractive-index sensitivity for a given leaky mode in the nanoporous waveguide were investigated as a function of the incident angle.As the incident angle increases,the resonance wavelength blueshifts and the refractive-index sensitivity decreases.The experimental results also indicate that at the same resonance wavelength the refractive-index sensitivity of the LMR sensor is higher than that of a conventional surface plasmon resonance(SPR) device.