Thin film optical coatings have a
wide range of industrial applications
from displays and lighting to photovoltaic cells. The realization
of electrically tunable thin film optical coatings in the visible
wavelength range is particularly important to develop energy efficient
and dynamic color filters. Here, we experimentally demonstrate dynamic
color generation using electrically tunable thin film optical coatings
that consist of two different phase change materials (PCMs). The proposed
active thin film nanocavity excites the Fano resonance that results
from the coupling of a broadband and a narrowband absorber made up
of phase change materials. The Fano resonance is then electrically
tuned by structural phase switching of PCM layers to demonstrate active
color filters covering the entire visible spectrum. In contrast to
existing thin film optical coatings, the developed electrically tunable
PCM based Fano resonant thin optical coatings have several advantages
in tunable displays and active nanophotonic applications.