Fig. 2: Field distribution and optical dispersion relation of Pd nanoparticles arranged in a periodic array.
From: Inverse designed plasmonic metasurface with parts per billion optical hydrogen detection
a Extinction spectrum of an array sample with d = 180 nm, h = 45 nm, a = 550 nm, and tPMMA = 200 nm. b 2D maps of the normalized total field amplitude |E|2 of the array at the mid-height of the nanoparticles and at different excitation wavelengths, as marked in panel (a). Excitation at wavelengths λ1 and λ2 generate field maxima far away from the nanodisks—a prominent characteristic in a RA mode. In contrast, excitation at λ3 features field maxima surrounding the nanodisks. Dashed lines outline the base of the nanodisks. c Experimental and simulated wavelength-resolved optical dispersion represented as the extinction spectra of the array for different angles of incidence. The dashed lines indicate the different RA orders of the array. The LSPR wavelength of the corresponding single-particle counterpart is also plotted which crosses two lower RA orders.
