Design of a wideband metamaterial absorber for optical wavelength applications based on the quantum-inspired Hadamard matrix

Attaining broadband absorption with a simple-designed photonic absorber is still considered a complex and daunting task. The Hadamard matrix has been a well-known concept for designing quantum gates in quantum mechanics and computing. Despite a series of noteworthy works being done with regard to the design of metamaterial absorbers, very few works exist in literature where a quantum-inspired design has been employed to design a metamaterial-based photonic absorber. In this work, we have demonstrated a polarization-insensitive ultrathin and wideband metamaterial (MM) absorber based on the pattern distribution of the Hadamard matrix. Within the optical domain, the demonstrated MM absorber showcases absorption of over 91% for both transverse electric (TE) mode and transverse magnetic (TM) mode. To explore the angular dependence on absorption features of our Hadamard matrix meta-absorber (HMMA), both TE and TM modes have been used at numerous incident-angles. Finite integration technique has been utilized to simulate the demonstrated MM absorber design and validated using the interference theory model to assure the simulated data. Moreover, electric and magnetic field characteristics, current distributions, and a plethora of parametric sweeps have also been investigated in order to better understand the suggested HMMA absorption mechanism. Because of its wideband absorption and polarization-insensitive characteristic, this MM absorber based on the Hadamard matrix arrangement permits a variety of applications such as light detectors, optical-sensors, magnetic resonance imaging, plasmonic-sensors, and thermal imaging applications.