Observation of coherent perfect absorption at an exceptional point
Abstract
The past few years have witnessed growing interests in exceptional points (EPs) in various domains, including photonics, acoustics and electronics. However, EPs have mainly been realized based on the degeneracy of resonances of physical systems; distinct degeneracies occur relating to the absorption properties of waves, with distinct physical manifestations. Here we demonstrate this physically different kind of exceptional point, by engineering degeneracies in the absorption spectrum of optical microcavities with dissipation. We experimentally distinguish the conditions to realize a resonant EP and an absorbing EP. Furthermore, when the optical loss is optimized to achieve perfect absorption at such an EP, we observe an anomalously broadened lineshape in the absorption spectra, as predicted by theory. The distinct scattering properties enabled by this type of EP creates new opportunities for both the fundamental study and applications of non-Hermitian singularities.
Keywords
Cite
@article{arxiv.2109.08353,
title = {Observation of coherent perfect absorption at an exceptional point},
author = {Changqing Wang and William R. Sweeney and A. Douglas Stone and Lan Yang},
journal= {arXiv preprint arXiv:2109.08353},
year = {2021}
}
Comments
41 pages (19 pages Main Text, 22 pages Supplementary Materials), 11 figures (4 figures Main Text, 7 figures Supplementary Materials), 88 references (51 references Main Text + 37 references Supplementary Materials)