title: Experimental demonstration of the microscopic origin of circular dichroism in two-dimensional metamaterials.
abstract: Optical activity and circular dichroism are fascinating physical phenomena originating from the interaction of light with chiral molecules or other nano objects lacking mirror symmetries in three-dimensional (3D) space. While chiral optical properties are weak in most of naturally occurring materials, they can be engineered and significantly enhanced in synthetic optical media known as chiral metamaterials, where the spatial symmetry of their building blocks is broken on a nanoscale. Although originally discovered in 3D structures, circular dichroism can also emerge in a two-dimensional (2D) metasurface. The origin of the resulting circular dichroism is rather subtle, and is related to non-radiative (Ohmic) dissipation of the constituent metamolecules. Because such dissipation occurs on a nanoscale, this effect has never been experimentally probed and visualized. Using a suite of recently developed nanoscale-measurement tools, we establish that the circular dichroism in a nanostructured metasurface occurs due to handedness-dependent Ohmic heating.
authors.affiliation: Department of Physics, Queens College and Graduate Center of The City University of New York, Queens, New York 11367, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Khanikaev
authors.affiliation: Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: N
authors.initials: N
authors.lastname: Arju
authors.affiliation: Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Fan
authors.affiliation: Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: D
authors.initials: D
authors.lastname: Purtseladze
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA.
authors.forename: F
authors.initials: F
authors.lastname: Lu
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA.
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.affiliation: CIC nanoGUNE Consolider, Tolosa Hiribidea, 76, Donostia E-20018, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Sarriugarte
authors.affiliation: CIC nanoGUNE Consolider, Tolosa Hiribidea, 76, Donostia E-20018, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Schnell
authors.affiliation: CIC nanoGUNE Consolider, Tolosa Hiribidea, 76, Donostia E-20018, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Hillenbrand
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Belkin
authors.affiliation: Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: G
authors.initials: G
authors.lastname: Shvets