Figure 4.
Simulated transmission spectra for an Au NHA-hydrogel geometry that is (a) in contact with air (n0 = 1) and a collapsed hydrogel-like medium (ni = 1.48) as well as with water (n0 = 1.33) and a swollen hydrogel-like medium (ni = 1.36), with the optical beam normal to the surface θ = 0°. (b) Dispersion relation of excited SPPi and SPPo modes represented as absorption dependence on angle of incidence θ and wavelength λ (n0 = 1.33, ni = 1.45). Simulation of the near field distribution of the electric field intensity |E/E0|2 being normalized with that of the incident plane wave for a collapsed Au NHA-hydrogel structure (n0 = 1.33, ni = 1.45) at (c) wavelength of λ = 590 nm where the SPPo is excited and at (d) λ = 700 nm where the SPPi occurs.