Controllable Circularly Polarized Chiral Metasurface Laser

Figures that support information in the highlight.
Design & spectrogram of an ultra-thin, cavity-free metasurface laser emitting circularly polarized light when pumped by a linearly polarized pump beam. Direct stimulated emission from the quantum gain into the chiral resonant plasmonic mode of tightly-coupled twisted-cross meta-atoms, which then radiate a purely circularly polarized coherent far-field.

Scientific Achievement:

Numerical simulations demonstrate a cavity-free metasurface laser capable of controllable, purely circularly polarized output via direct lasing from chiral resonant modes of plasmonic meta-atoms strongly coupled to quantum gain. 

Significance and Impact:

This represents a chiral analog to plasmon lasers ("Spasers"), achieving direct lasing into, and coherent feedback from, just the resonant plasmonic eigenmode of sub-wavelength chiral meta-atoms with circularly polarized far-field radiation instead of relying on a conventional propagating waves cavity.

Research Details:

  • This enables ultra-thin, deeply sub-wavelength functionalized circularly polarized metasurface lasers. The layered, planar design is well suited for optical implementation.
  • Right- and left-circular output can be tuned via either the geometrical twist-angle of the metallic crosses or the pump-beam polarization, enabling dynamic polarization control.

This work was supported by the U.S. Department of Energy (Basic Energy Sciences, Division of Materials Sciences and Engineering) under Contact No DE-AC02-07CH11358. Work at FORTH was supported by Horizon 2020 RISE (CHARTIST, 101007896) & EU National Recovery and Resilience Plan Greece 2.0 (14830, PhoToCon). 

I. Katsantonis, A.C. Tasolamprou, E.N. Economou, Th. Koschny, M. Kafesaki, “Ultrathin, Dynamically Controllable Circularly Polarized Emission Laser Enabled by Resonant Chiral Metasurfaces,”  ACS Photonics 12, 71 (2025). https://doi.org/10.1021/acsphotonics.4c01005