## 3 Results and Discussion
### Passive Simulations  
In our previous numerical work, we showed that chiral absorption in ENHA arises due to the different coupling of LCP- and RCP- excited SPPs with elliptical nanoholes tilted from the lines of the 2D array symmetry [26]. We optimized the ENHA with \(a=500\) nm in terms of D\({}_{\rm X}\), D\({}_{\rm Y}\), and the tilt angle \(\phi\); we found that the optimum CD\({}_{\rm A}\) (reaching almost 84%) was around 745 nm for \(\phi=15^{\circ}\), D\({}_{\rm X}=280\) nm, and D\({}_{\rm y}=500\) nm. These ENHA were standing upon glass substrates in air; therefore, their spectral features and CD\({}_{\rm A}\) were expected to red-shift with an increase of the refractive index of the surrounding medium. Here, we started from the previously optimized ENHA geometry, and embedded it in the refractive index-matching layer, which served as a dielectric matrix for the emitters in the active simulations. In a hexagonal lattice, the ENHA tilt angle of \(\phi=15^{\circ}\) always provides the highest CD\({}_{\rm A}\), so we kept this parameter constant. We investigated CD\({}_{\rm A}\) dependence on various separate geometric parameters (not shown here), and conclude that its spectral features mainly depend on lattice periodicity, which defines the light coupling to the SPP modes. Therefore, here we show the results of the parameter sweep over the periodicity range of \(a=350\)-\(550\) nm, while we scale the nanohole surface in the unit cell according to the previous optimization, i.e., \(\text{D}_{\text{x}}=280^{\circ}a/500\), and \(\text{D}_{\text{y}}=a\). We investigate this range as it is of interest for future fabrication; namely, the starting diameter of commercial polystyrene nanospheres determines the hexagonal array periodicity in the NSL [32]. Figure 2a,b show spectral maps of Au-ENHA absorption dependence for the LCP and RCP excitations, respectively. Spectral features linearly shift with \(a\), as is expected for the linearity of the phase matching condition of SPPs. Below \(540\) nm, absorption for both excitations increases in the same manner due to the intraband absorption in Au. For LCP excitation and lattices around \(a=500\) nm and larger, there is one main plasmonic maximum in the near-infrared. Changing the excitation to RCP, the quality factor of this maximum increases, and other plasmonic features at larger wavelengths appear. This different spectral behavior leads to a high \(\text{CD}_{\text{A}}\) in the near-infrared range, with two prominent branches in the opposite \(\text{CD}_{\text{A}}\) signs, as seen in Figure 2c. Specifically, for \(a=500\) nm, \(\text{CD}_{\text{A}}\) reaches around \(50\%\) at \(740\) nm, and inverts the behavior at \(940\) nm. This peculiar behavior of ENHA absorption influences the coupling with the emitting layer; therefore, these two wavelengths will be considered for dipole emission further in the manuscript. Moreover, we note that under \(600\) nm \(\text{CD}_{\text{A}}\) vanishes because of the absence of the plasmonic coupling, and, eventually, Au intraband absorption. Finally, one can note that the maximum \(\text{CD}_{\text{A}}\) branches red-shifted because of the superstrate, while their absolute value decreased with respect to the design previously optimized in [26]. In this manuscript, we focus on the investigation of the chiral absorption and emission phenomena which take place in the previously designed ENHA, embedded in glass. However, this design is scalable and can be easily re-optimized for specific emission and excitation wavelengths. Once the wavelength of maximum \(\text{CD}_{\text{A}}\) is defined, one can perform multiparameter optimization of parameters \(a\), \(\text{D}_{\text{x}}\), \(\text{D}_{\text{y}}\), and \(\text{t}\), to get the highest contrast of RCP and LCP absorption at those wavelengths by means of particle-swarm algorithm [39]. In Figure 2d-f, we repeat the same \(a\) sweep when the plasmonic materials is Ag, by keeping all the geometric features equal as before.