Switchable Induced-Transmission Filters Enabled by Vanadium Dioxide

Abstract

An induced-transmission filter (ITF) uses an ultrathin layer of metal positioned at an electricfield node within a dielectric thin-film bandpass filter to select one transmission band while suppressing other transmission bands that would have been present without the metal layer. Here, we introduce a switchable mid-infrared ITF where the metal film can be "switched on and off", enabling the modulation of the filter response from single-band to multiband. The switching is enabled by a deeply subwavelength film of vanadium dioxide (VO 2 ), which undergoes a reversible insulator-to-metal phase transition. We designed and experimentally demonstrated an ITF that can switch between two states: one broad passband across the long-wave infrared (LWIR, 8 -12 µm) and one narrow passband at ~8.8 µm. Our work generalizes the ITF-previously a niche type of bandpass filter-into a new class of tunable devices. Furthermore, our unique fabrication process-which begins with thin-film VO 2 on a suspended membrane-enables the integration of VO 2 into any thin-film assembly that is compatible with physical vapor deposition (PVD) processes, and is thus a new platform for realizing tunable thin-film filters.

Exceptional points in parity-time symmetric plasmonic Huygens’ metasurfaces

“…To sum up, the reflectionless transmission obtained at the EP will enable the use of the proposed active core-shell array metasurface to be employed as a compact nanophotonic optical filter with perfect transmission. Compared to other conventional multilayer optical filter designs [36][37][38][39], the proposed metasurface is extremely thin, making its fabrication and implementation much simpler and cost effective.…”

“…We further analyze the EP singularity by demonstrating the eigenvalue switching behavior when encircling the EP in the complex frequency space. The proposed non-Hermitian PTsymmetric ultrathin metasurface design is expected to have applications in compact perfect transmission optical filtering, since its thickness is extremely smaller compared to conventional multilayer filters based on low loss dielectric materials [36][37][38][39].…”

Tunable directional filter for mid-infrared optical transmission switching

“…For each time step, the temperature of the filter is first determined using Eqs. (6)(7)(8) and then the optical constants of VO2 are calculated using Eq. ( 4).…”

“…A VO2 filled double cavity was designed for operation in the near IR that could act as band-pass filter or optical switch [6]. More recently, switchable transmission in the mid-IR range was demonstrated using a thin VO2 layer in a multilayer filter design [7]. However, most of the previously works demonstrate switching and reconfigurability only by varying the bulk temperature of the obtained device and not by dynamically changing the incident laser power in a pump-probe laser experimental configuration setup.…”

High-Strain-Induced Local Modification of the Electronic Properties of VO2 Thin Films

“…Electronic phase transitions play a key role in the study of quantum materials and promise versatile applications in the next generation of low-power electronic devices for information processing and storage, 1 fast optoelectronic switches, 2 actuators, 3 filters, 4 hydrogen storage, 5 and smart windows. 6 With a phase transition temperature close to room temperature and an electrical resistance change of several orders of magnitude, 7 vanadium dioxide (VO 2 ) is one of the best-studied candidates from the class of transition metal oxides.…”