The plasmonic Raman sensor using periodic nanofocusing arrays

Numerical optimization of periodic hole arrays for plasmonic Raman sensor

“…Our analysis and investigation demonstrated the potential for combining plasmonic effects with nanofluidics in a flow-through type of SERS sensor (similar to the sensor presented in [21,22]). The results of optical characterization of the fabricated membranes with nanoholes agreed with most of the calculation results (for a cylindrical hole array) obtained using the finite-difference time-domain (FDTD) method [20]. However, the resonance peak at a long wavelength in the transmittance spectra could not be fitted with the experimental results.…”

“…The local electric field enhancement was observed at the observation point near the hole side, as shown by the black dot in Fig. 2(a), where we had already determined that the electric field enhancement was largest [20].…”

“…We calculated the wavelength dependence of the local electric field enhancement at the observation point shown by the black dot in Fig. 2(b), which again was close to the Au-Si 3 N 4 interface where we had already confirmed the enhancement to be largest [20]. At the same time, the characteristics of transmittance and reflectance spectra from the hole array were calculated in the observation plane (far field), as shown in Fig.…”

“…The hole diameters on the Au surface, Au-Si 3 N 4 interface, and rear side of Si 3 N 4 were denoted D U , D M , and D L , respectively. Hole period P for the simulations was chosen to be the same as in the hole arrays used to produce the experimental results shown in [20]. TE polarized light illuminated the hole array from either the Si 3 N 4 side to the Au side or vice versa.…”

“…In the cylindrical hole array, the hole diameter D and hole period P for the simulations were chosen to be the same as in the hole arrays used in the experiment, as determined from the SEM images shown in [20]. Transverse electric (TE) polarized light (x-direction) illuminated the plasmonic cylindrical hole array from the Si 3 N 4 side to the Au side.…”