TRANSVERSE ELECTRIC/MAGNETIC WAVE SEVEN-CHANNEL SEPARATOR VIA TRAPEZOIDAL METASURFACE

This paper presents a high-efficiency, polarization-independent seven-port reflective grating featuring a dual-layer trapezoidal metasurface. The structural parameters, including incidence angle, period, duty cycle, and incident wavelength, were optimized using rigorous coupled-wave analysis (RCWA) combined with a simulated annealing algorithm (SAA) and subsequently validated by the finite element method (FEM). The device achieves diffraction efficiencies exceeding 13% for all seven channels (0th, ±1st, ±2nd, and ±3rd orders) under both transverse electric (TE) and transverse magnetic (TM) polarizations, yielding a total efficiency of no less than 98%. Crucially, the results demonstrate that the proposed grating exhibits exceptional stability and robust tolerance to manufacturing errors. The ability to achieve satisfactory performance in both polarization directions holds significant value for applications in advanced optical components and integrated optical systems.