posted on 2021-02-18, 19:56authored byEric Hopmann, Brett N. Carnio, Curtis J. Firby, Basem Y. Shahriar, Abdulhakem Y. Elezzabi
Plasmochromics, the interaction of
plasmons with an electrochromic
material, have spawned a new class of active plasmonic devices. By
introducing electrochromic materials into the plasmon’s dielectric
environment, plasmons can be actively manipulated. We introduce inorganic
WO3 and ion conducting LiNbO3 layers as the
core materials in a solid-state plasmochromic waveguide (PCWG) to
demonstrate light modulation in a nanoplasmonic waveguide. The PCWG
takes advantage of the high plasmonic loss at the high field located
at the WO3/Au interface, where the Li+ ions
are intercalated into a thin WO3 plasmon modulating layer.
Through careful PCWG design, the direction for ion diffusion and plasmon
propagation are decoupled, leading to enhanced modulation depth and
fast EC switching times. We show that at a bias voltage of 2.5 V,
the fabricated PCWG modulator achieves modulation depths as high as
20 and 38 dB for 10 and 20 μm long devices, respectively.