Nanowire-based ultra-wideband absorber for visible and ultraviolet light

We present an ultra-wideband and polarization-insensitive absorber for ultraviolet and visible light, which is made of gold nanowires embedded in a truncated pyramid silica host. Through rigorous full-wave simulations, we show that the nanowire-based absorber can remain over 90% absorptivity in an ultra-wideband range from 200 nm to 600 nm with moderate changes of geometrical parameters. It is also demonstrated that the geometry of the nanowire pays little influence on the absorption performance, which provide unique flexibility in design and fabrication. The proposed absorber is of high practical feasibility and able to be integrated with semiconductor technologies for potentially high efficient photothermal applications.