Effect of refractive index of dielectric on transmission properties for metal/dielectric/metal photonic crystal

The effect of refractive index of dielectric on transmission properties for metal/dielectric/metal photonic crystal (M/D/MPhC) by changing a thin dielectric layer was studied experimentally. We measured zero-order transmission spectra of three different M/D/MPhC samples in the middle-infrared region and found that the transmission peaks shifted regularly along with the refractive index change, owing to the role of surface plasmon polaritons (SPP) coupling in the M/D/MPhC. The position of transmission peak for M/D/MPhC is not only determined by the periodic structure on top Au film but is also affected by the refractive index of intermediate dielectric. By analyzing the relationship between transmission peaks and effective refractive index of a thin dielectric layer sandwiched by two gold layers, we find that the transmission properties for M/D/MPhC depend strongly on both the material property and the refractive index of dielectric being sandwiched by two metal films. The transmission peak sensitive nature to the refractive index of a thin dielectric layer in M/D/MPhC is promising in applications of biochemical sensing and tunable integrated plasmonic devices.