Optical absorbers with NPs-based lossy metasurfaces

In this contribution, we show how it is possible to exploit the exotic response of arrays of plasmonic nanoparticles (NPs) to design ultra-thin optical absorbers and color filters. First, it is shown that an array of electrically small spheroidal NPs may be effectively characterized using a complex-valued surface impedance tensor. Then, the model is exploited to design optical Salisbury-like screens able to absorb all the impinging light within a desired frequencies range. Finally, an innovative nanoscale color filter able to selectively absorb the light in a narrow frequencies band while being transparent in the rest of the IR and optical spectrum is proposed.