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Coherent perfect absorption at an exceptional point
Changqing Wang1, William R Sweeney2,3, A Douglas Stone2,3
1Department of Electrical and Systems Engineering, Washington University, St. Louis, MO 63130, USA.
Science (New York, N.Y.)
|September 13, 2021
Summary
Researchers demonstrate a novel absorbing exceptional point in optical microcavities. This degeneracy in wave absorption, distinct from resonance, offers new avenues for studying non-Hermitian physics and developing advanced optical devices.
Area of Science:
- * Physics, Optics, and Photonics
- * Non-Hermitian physics and wave phenomena
Background:
- * Exceptional points (EPs) are degeneracies in open wave systems, observed in photonics, acoustics, and electronics.
- * Previous research primarily focused on EPs as a degeneracy of resonances.
- * Degeneracies associated with wave absorption offer unique physical characteristics.
Purpose of the Study:
- * To demonstrate an absorbing exceptional point (AEP) by engineering degeneracies in the absorption spectrum.
- * To experimentally differentiate between AEPs and resonant exceptional points (REPs).
- * To investigate the physical signatures and potential applications of AEPs.
Main Methods:
- * Fabrication and characterization of dissipative optical microcavities.
- * Engineering of spectral degeneracies to achieve wave absorption.
- * Experimental distinction between AEP and REP conditions through spectral analysis.
Main Results:
- * Successful demonstration of an AEP in optical microcavities.
- * Experimental differentiation of conditions for realizing AEPs versus REPs.
- * Observation of an anomalously broadened line shape in the absorption spectrum at perfect absorption, a signature of AEPs.
Conclusions:
- * Absorbing exceptional points represent a distinct class of non-Hermitian degeneracies.
- * The unique scattering properties of AEPs open opportunities for fundamental research.
- * AEPs hold promise for novel applications in wave absorption and control.
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