Fig. 3: Far-field and near-field of radiation through the metallic aperture.
From: Ultra-low threshold lasing through phase front engineering via a metallic circular aperture
a–i Measured (a–c) and simulated (d–i) far-field patterns of the beam emitted through the circular aperture in the front metallic coating. a, d, g Unpolarized far-field beam patterns, b, e, h vertically polarized and c, f, i horizontally polarized. a–c Measured at room temperature with a bias voltage of 13.6 V. Plotted in (a–i) are the patterns of the energy (∣E∣2). j, k Simulated near-field patterns near the circular aperture in the front view (j) and the side view (k). The colormap shows the vertical component of the electric field (Ez) and the vectors represent the electric field vectors. Upper right insets indicate the direction of the view in each plot. The plane of (j) is selected as the outer interface of the metallic coating and the plane of (k) is the cut-plane through the middle of the device. The color bar ranges in (a–i) are [3.2, 8.6], [2.5, 7.0], [0, 11], [0.3, 0.9], [0.3, 0.9], [0, 0.2], [0, 0.9], [0, 0.9], [0, 0.2] (arbitrary units), respectively.
