Nanoscale All-Solid-State Plasmochromic Waveguide Nonresonant Modulator

Abstract

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 WO 3 and ion conducting LiNbO 3 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 WO 3 /Au interface, where the Li + ions are intercalated into a thin WO 3 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.

Advanced developments in nonstoichiometric tungsten oxides for electrochromic applications

“…8,67 Other recent approaches attempted based on energy savings EC materials and technologies for novel multifunction are published elsewhere. 67,68,[70][71][72][73][74][75][76][77][78] Modern commercial buildings in European countries have installed EC smart windows functioning instead of the active air conditioning, and approximately 4.5% of energy can be saved annually in the USA and Australia. 79 Similarly, the auto-dimming smart glass and automotive rear-view mirrors have been commercialized.…”

On-chip high ion sensitivity electrochromic nanophotonic light modulator

“…When functioning as a light modulator, this versatile device platform exhibits a light modulation depth of ΔT = 10 6 , which is 2 orders of magnitude higher than previously reported for EC waveguides (Table S3 †). 21,26,27 The high on-state optical transmission of the nanophotonic EC waveguide makes it possible to further enhance the modulation depth by increasing the length of the EC modulation layers according to ΔT = 1.7 × 10 3 μm −1 V −1 , since optical loss from electric contacts is avoided. Furthermore, when employed for ion detection, the nanophotonic waveguide offers high sensitivity to ion concentrations between 1 mM and 1 M in a few µl of specimen.…”

“…[23][24][25] To achieve higher modulation depth and to increase switching speeds, various EC photonic devices have been introduced. 21,26,27 Recently, the optical transmission modulation of EC infrared photonic waveguides were shown to mimic synaptic behavior and could replace resistive switching devices for optical on-chip addressability. 21 When compared to traditional electrochromic device architectures, this platform exhibited improved switching speeds of t < 1 s and an enhanced optical contrast modulation of ∼90%.…”

“…Recently, a dynamic, plasmonic metal-insulator-metal solid-state modulator having an integrated WO 3 waveguide core and greater penetration of the EC material was shown to exhibit a light transmission contrast modulation as high as 10 4 . 26 In this configuration, however, the maximum length of the waveguide as well as the overall achievable modulation depth are limited to several dB µm −1 due to the inherent and unavoidable plasmonic propagation loss of the gold electrodes.…”

Nanoscale Manipulating Silver Adatoms for Aqueous Plasmonic Electrochromic Devices

“…[34][35][36] Recently, Ag nanoparticles, having tunable nano structures, along with their localized surface plasmon resonance (LSPR), have been investigated for multicolor electrochromic films. [17][18]37] Compared to the nonmetallic-based electrochromic materials, whose optical indices are altered through ions intercalation or redox reactions, [38][39][40] various LSPR color bands are tuned by manipulating the size and shape of the Ag nanoparticles. [19,41] However, to realize stable and reversible Ag nanoparticles electrodeposition, these LSPR-based electrochromic displays are administered in nonaqueous electrolyte environments that require high electrodeposition voltage.…”