Highly absorbing black Mg and rare-earth-Mg switchable mirrors

摘要: Apart from a reflecting and transparent state, rare-earth-Mg alloys (RE-Mg) exhibit also highly absorbing, black state during loading with hydrogen. The occurrence of such is due to the disproportionation into subwavelength size ${\mathrm{REH}}_{2+\ensuremath{\epsilon}}$ Mg grains first hydrogen loading. While optical properties ${\mathrm{REH}}_{x}$ change continuously further increase in concentration x, changes abruptly good reflector insulator $({\mathrm{MgH}}_{2}).$ Thin pure films show this when (un)loaded carefully at elevated temperatures. By using Bruggeman effective medium approximation combination transfer matrix method it shown that coexistence ${\mathrm{MgH}}_{2}$ cause high absorption. Furthermore, we compare phenomenon absorption light observed metal-dielectric composites.