Spectral radiative properties of a nickel porous microstructure and magnetic polariton resonance for light trapping

In this work, we investigated theoretically the spectral radiative properties of a nickel porous microstructure, including wavelength-selective transmission, reflection, and absorption. The structure can be described briefly like that the arrays of uniformly sized spherical pores are ordered closely inside the structure and nickel is filled in the whole void spaces between the pores. The finite-difference time-domain (FDTD) method for electromagnetics was used to calculate the spectral radiative properties of the nickel porous microstructure. It is found that the absorption spectra of the nickel porous microstructure will generate two peaks within the wavelength range of 0.2-2.0 μm at normal incidence of light. Furthermore, the value, position and shape of the absorption peaks have tightly coupled relationships with the pore diameter, the filling height of nickel, the incident angle and polarization of light. Then magnetic polariton (MP) resonance can be observed clearly in the obtained results of this work, which is the crucial mechanism to elucidate for the power absorption enhancement. Additionally, it is revealed that the power absorption predominantly focuses on the top surface of the structure, especially on the region near the orifice. In practical application, we can enhance the efficiency of power absorption in the target wavelength by modulating the pore size, the filling height of nickel, the incident angle and polarization of light, which has great potential in many fields such as thermophotovoltaic (TPV) systems and impact energy absorption applications.