Circular dichroism analysis of half-roll plasmonic chiral nanostructures

Chiro-plasmon responses of x-shaped titanium nitride (TiN) nanoarrays by numerical simulations

“…It reveals that when W 1 = 470 nm, H 2 = 0 nm, with W 2 increasing from 180 nm to 340 nm, the maximum g-factor still gets ∼0.03, obtained by the metamaterial with W 2 = 250 nm. With W 1 and W 2 increasing, the surface area and volume of the two composing rods of the X-shaped TiN unit cell increase, and the effective resonant length of the electric dipole/ quadruple increases, hence further result into their red shift of λ 1 , λ 2 , and λ 3 [38]. Moreover, to further improve the chiral optical response of the metamaterial, we lifted the tilted nanorod of each X structure along z-direction vertically by a height H 2 as illustrated by figure 1(d).…”

“…Comparatively, under RCP incidence, the maximum E-field enhancement is revealed to ∼4 at z = 0 nm and it slightly improves to ∼5 at z = 100/200 nm. The different E-field enhancements directly reflect their different charge distributions [38]. It is taken to be resulted from the difference by -y-polarized light and y-polarized light as the RCP and LCP incidences get the same x-polarized component.…”

“…This is also confirmed by the E-field enhancement distribution of figure S2 that the E-field enhancement excited by LCP light is stronger than that excited by RCP case. When -y/y-polarized light is combined with x-polarized light, there will be differences in charge distribution between out-of phase and in-phase, resulting in different LSPR resonance intensities [38], which further contribute to the obtained different extinction cross-section, thereby CD and g-factor responses. For reference, figures S3-S4 of the supporting information presents the snap shots of the Efield enhancement and charge distributions at λ 1 ' and λ 3 ' as well.…”