Fig. 2
From: Anti-Hermitian photodetector facilitating efficient subwavelength photon sorting
Effectiveness of anti-Hermitian coupling in a semiconductor nanobeam array with two beam widths. a, b Absorption spectrums of arrays that feature a supra- and b sub-diffraction limit pitches of 350 and 160 nm, respectively, between adjacent beams. c, d Maps of the spectral absorption in just c the narrow or d the wide nanobeams versus array pitch. The black dashed line indicates the boundary below which first-order diffraction is precluded and a metafilm description becomes valuable. In this regime, pronounced spectral enhancements and suppressions in the absorption are observed. The blue dotted lines indicate the locations at which spectrums shown a, b were taken. e, f Vertical cross sections of the maps in c and d taken at the wavelengths of e 595 nm and f 625 nm, respectively. Blue line shows the absorption in the narrow beams (Pnarrow) and the red line shows the absorption in wide beams (Pwide). Black circled curve depicts the sorting efficiency defined as the ratio of the absorbed power in the target beam of the total absorbed power ηs (%) = [Ptarget/Ptotal] × 100, Although the efficiency is over 50% for most periods, it reaches near 100% in metamaterial regime with Ptotal also being close to unity
