Fig. 1: Optical properties of Si nanostructures.
From: Giant photothermal nonlinearity in a single silicon nanostructure
a We used Si nanoblocks on a quartz substrate, whose lateral dimensions (wx and wy) vary from 60 to 220 nm, with a 10-nm step, and a fixed height (h) of 150 nm. b Focused ion-beam image of a typical Si nanoblock (wx = wy = 200 nm). Resolution is compromised because of the charging effect of the non-conductive quartz substrate. c Halogen lamp illuminated dark-field image of the isolated Si nanoblocks, showing colorful resonance among different sizes. d 561-nm scattering intensity along the array diagonal (w = wx = wy), presenting the characteristic multipole resonance of silicon nanostructures. The excitation intensity is 1.3 mW μm−2. e Simulated single-particle forward scattering (CscaF) and f absorption cross section (Cabs) spectra versus different nanoblock widths. The white dashed line marks the 561-nm laser, which excites multiple resonances. g Simulation of size-dependent 561-nm scattering, which agrees well with experiment results. MD magnetic dipole, ED electric dipole, EQ electric quadrupole, MQ magnetic quadrupole.
