Fig. 5: Optimization of the transmittance (over a spectral window of 580–700 nm averaged over all permitted incident angles (below the critical angle) and its sensitivity to the NP meta-grid parameters.

a Dots with different fill colors depicting the deviation from the maximum transmittance (T_max) for a fixed height of h_opt = 33 nm but various radius R and gap g, where both these parameters are assumed to be larger/smaller than their optimal values by up to 3 nm. T_max (of 96.2%) is achieved at the optimal height h_opt = 33 nm, for the optimal radius of 13 nm and gap of 13 nm [highlighted in cyan]. b–g Same as in (a), but for different heights of (h_opt − 1), (h_opt + 1), (h_opt − 2), (h_opt + 2), (h_opt − 3), (h_opt + 3), respectively. Note that, for the calculations the spectral window between 580 and 700 nm was considered at a step of 1 nm and angles between 0° and 26° were taken at a step of 1°. Here, AlGaInP (n = 3.49) is the semiconductor material and epoxy (n = 1.58) is the encapsulating material