Figure 12.

(a) Enantiomeric multilayer nanoapertures (forms A and B) are depicted. The total Au film thickness is $H=180$ nm. Top and bottom building layers have aperture thicknesses of $h1=80$ nm and $h2=100$ nm. Other geometrical parameters are taken as $p=360$ nm, $r=140$ nm, $b=120$ nm, $\alpha ={60}^{\circ }$, $g1=20$ nm, and $g2=40$ nm. Light is considered to be vertically impinging onto the top layer and transmitted out of the bottom layer. (b) and (c) are the sideview (${52}^{\circ }$) and top view SEM images of the multilayer nanoapertures fabricated using the FIB milling method. The scale bar is 100 nm. (d) Experimental values of the transmission, CDT and CPR spectra of the nanoapertures in Form A for different incident/output handedness combinations. Reproduced with permission from ref. [59]. Copyright 2018 Springer Nature.