Electrically Tunable Metasurface
Members of the CPDS group have recently co-authored a paper on a liquid crystal based dynamically tunable metasurface for amplitude modulation.
The metasurface consists of coupled subwavelength grating fingers, which provide alignment for the liquid crystal without the need for an additional alignment material or process.
The coupled grating fingers exhibit a resonance quality factor of 27 at telecommunication wavelength and an amplitude modulation depth of 8 times of the minimum at 1630 nm.
This work highlights the potential of liquid crystal-based tunable metasurface, combining polarization control via liquid crystal and spectrum control via metasurface. it also shows a way in which the interaction between liquid crystal and metasurface is used for an alignment layer-free cell assembly process.
The work was performed in collaboration with Lark Optics, a spin-off company created by CPDS alumni.
The paper is published in Optics Letters Vol. 49, No. 19 page 5551 (October 2024) and is available online at https://doi.org/10.1364/OL.537839
Fig. 1. Device illustration and simulation. (a) Schematic illustration of TN LC-based dynamic metasurface. (b) Simulated reflection spectrum at different LC director angles. The inset shows the reflection spectrum when θ = 45°. (c) Calculated band structure of TN LC-based metasurface. (d) Electric mode profile of mode A and mode B.