Observation of Nonvanishing Optical Helicity in Thermal Radiation from Symmetry-Broken Metasurfaces

Abstract

We experimentally demonstrate magnetic-field-free circular-polarized thermal radiation based on a symmetry-broken metasurface. A nonvanishing optical helicity in the radiation excited by thermal fluctuations is observed in a dispersionless energy band.

Symmetry breaking in thermal photonics

“…Generating such chiral thermal emission in a symmetry-broken system is of both fundamental and applied interest. It can enable a compact circular-polarized light source in the mid-infrared spectral range that is desired in numerous scientific and industrial applications 5 . While laser light has been used to study chirality, spin angular momentum and orbital angular momentum of coherent radiation extensively, exploiting thermal agitation in metasurfaces to shape such properties in completely incoherent light is an unexplored frontier.…”