Fig. 1. Schematic diagram of the proposed PWG-coupled LRSPR biosensor based on Au film.

Fig. 2. (a) Effective refractive indices of LRSPP and PWG modes; (b) variation of reflectance with respect to the incident angle for the LRSPR and PWG-coupled LRSPR configurations.

Fig. 3. Schematic diagram of the electric field distributions for the configuration of single (a) PWG and (b) LRSPR; electric field distributions at (c) θ=34.7337° and (d) θ=34.7928° when the PWG is coupled with LRSPR.

Fig. 4. Variation of peak sensitivity with respect to the thickness of cytop layer for the proposed sensor.

Fig. 5. Variation of reflectance and sensitivity with the incident angle for the sensors based on (a) PWG-coupled LRSPR, (b) LRSPR, and (c) conventional SPR when ns=1.34.

Fig. 6. Schematic diagram of the electric field distributions for the proposed PWG-coupled LRSPR sensor at θ=34.7337° and θ=34.7928°.

Fig. 7. Variation of peak sensitivity with respect to refractive index of sensing medium in the vicinity of 1.34.

Fig. 8. Variation of reflectance and sensitivity with respect to the incident angle when the thicknesses of cytop and Al are 2350 and 12.4 nm.