TY - JOUR

T1 - Parity-time symmetry and coherent perfect absorption in a cooperative atom response

AU - Ballantine, Kyle

AU - Ruostekoski, Janne

PY - 2021/1/20

Y1 - 2021/1/20

N2 - Parity-Time (PT) symmetry has become an important concept in the design of synthetic optical materials, with exotic functionalities such as unidirectional transport and non-reciprocal reflection. At exceptional points, this symmetry is spontaneously broken, and solutions transition from those with conserved intensity to exponential growth or decay. Here we analyze a quantum-photonic surface formed by a single layer of atoms in an array with light mediating strong cooperative many-body interactions. We show how delocalized collective excitation eigenmodes can exhibit an effective PT symmetry and non-exponential decay. This effective symmetry is achieved in a passive system without gain by balancing the scattering of a bright mode with the loss from a subradiant dark mode. These modes coalesce at exceptional points, evidenced by the emergence of coherent perfect absorption where coherent incoming light is perfectly absorbed and scattered only incoherently. We also show how PT symmetry can be generated in total reflection and by balancing scattering and loss between different polarizations of collective modes.

AB - Parity-Time (PT) symmetry has become an important concept in the design of synthetic optical materials, with exotic functionalities such as unidirectional transport and non-reciprocal reflection. At exceptional points, this symmetry is spontaneously broken, and solutions transition from those with conserved intensity to exponential growth or decay. Here we analyze a quantum-photonic surface formed by a single layer of atoms in an array with light mediating strong cooperative many-body interactions. We show how delocalized collective excitation eigenmodes can exhibit an effective PT symmetry and non-exponential decay. This effective symmetry is achieved in a passive system without gain by balancing the scattering of a bright mode with the loss from a subradiant dark mode. These modes coalesce at exceptional points, evidenced by the emergence of coherent perfect absorption where coherent incoming light is perfectly absorbed and scattered only incoherently. We also show how PT symmetry can be generated in total reflection and by balancing scattering and loss between different polarizations of collective modes.

U2 - 10.1515/nanoph-2020-0635

DO - 10.1515/nanoph-2020-0635

M3 - Journal article

VL - 10

SP - 1357

EP - 1366

JO - Nanophotonics

JF - Nanophotonics

SN - 2192-8614

IS - 2

ER -