Singularities of open systems, known as exceptional points (EPs), have been shown to exhibit increased sensitivities, but the observation of EPs has so far been limited to wavelength-scaled systems subject to the diffraction limit. Plasmons, the collective oscillations of free electrons coupled to photons, shrink the wavelength of light to electronic and molecular length scales. We propose a novel approach to EPs based on spatial symmetry breaking and report their observation in plasmonics at room temperature. The plasmonic EPs are based on the hybridization of detuned resonances in multilayered plasmonic structures to reach a critical complex coupling rate between nanoantenna arrays, resulting in the simultaneous coalescence of the resonances and loss rates. Their utility as sensors of anti-immunoglobulin G, the most abundant immunoglobulin isotype in human serum, is evaluated. Our work opens the way to a new class of nanoscale devices, sensors and imagers based on topological polaritonic effects.
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The computer codes that support the plots within this paper and other findings of this study are available from the corresponding author on reasonable request.
Degen, C. L., Reinhard, F. & Cappellaro, P. Quantum sensing. Rev. Mod. Phys. 89, 035002 (2017).
Heiss, W. D. Exceptional points of non-Hermitian operators. J. Phys. Math. Gen. 37, 2455–2464 (2004).
Berry, M. V. Physics of nonhermitian degeneracies. Czech. J. Phys. 54, 1039–1047 (2004).
Bender, C. M., Brody, D. C. & Jones, H. F. Complex extension of quantum mechanics. Phys. Rev. Lett. 89, 270401 (2002).
Carusotto, I. & Ciuti, C. Quantum fluids of light. Rev. Mod. Phys. 85, 299–366 (2013).
Dembowski, C. et al. Experimental observation of the topological structure of exceptional points. Phys. Rev. Lett. 86, 787–790 (2001).
Choi, Y. et al. Quasieigenstate coalescence in an atom-cavity quantum composite. Phys. Rev. Lett. 104, 153601 (2010).
Ding, K., Ma, G., Xiao, M., Zhang, Z. Q. & Chan, C. T. Emergence, coalescence, and topological properties of multiple exceptional points and their experimental realization. Phys. Rev. X 6, 021007 (2016).
Makris, K. G., Ge, L. & Türeci, H. E. Anomalous transient amplification of waves in non-normal photonic media. Phys. Rev. X 4, 041044 (2014).
Cui, H. X. et al. Exceptional points in extraordinary optical transmission through dual subwavelength metallic gratings. Opt. Express 21, 13368–13379 (2013).
Kodigala, A., Lepetit, T. & Kanté, B. Exceptional points in three-dimensional plasmonic nanostructures. Phys. Rev. B 94, 201103(R) (2016).
Lourenco-Martins, H., Das, P., Tizei, L. H. G., Weil, R. & Kociak, M. Self-hybridization within non-Hermitian localized plasmonic system. Nat. Phys. 14, 360–364 (2018).
Wiersig, J. Enhancing the sensitivity of frequency and energy splitting detection by using exceptional points: application to microcavity sensors for single particle detection. Phys. Rev. Lett. 112, 203901 (2014).
Gao, T. et al. Observation of non-Hermitian degeneracies in a chaotic exciton-polariton billiard. Nature 526, 554–558 (2015).
Doppler, J. et al. Dynamically encircling an exceptional point for asymmetric mode switching. Nature 537, 76–79 (2016).
Xu, H., Mason, D., Jiang, L. & Harris, J. G. E. Topological energy transfer in an optomechanical system with exceptional points. Nature 537, 80–83 (2016).
Miao, P. et al. Orbital angular momentum microlaser. Science 353, 464–467 (2016).
Hodaei, H. et al. Enhanced sensitivity at higher-order exceptional points. Nature 548, 187–191 (2017).
Chen, W., Özdemir, S. K., Zhao, G., Wiersig, J. & Yang, L. Exceptional points enhance sensing in an optical microcavity. Nature 548, 192–196 (2017).
Zhen, B. et al. Spawning rings of exceptional points out of Dirac cones. Nature 525, 354–358 (2015).
Yoon, J. W. et al. Time-asymmetric loop around an exceptional point over the full optical communications band. Nature 562, 86–90 (2018).
Pick, A. et al. General theory of spontaneous emission near exceptional points. Opt. Express 25, 12325–12348 (2017).
Lai, Y.-H., Lu, Y.-K., Suh, M.-G. & Vahala, K. Observation of the exceptional-point-enhanced Sagnac effect. Nature 576, 65–69 (2019).
Dong, Z., Li, Z., Yang, F., Qiu, C.-W. & Ho, J. S. Sensitive readout of implantable microsensors using a wireless system locked to an exceptional point. Nat. Electron. 2, 335–342 (2019).
Kazemi, H., Nada, M. Y., Maddaleno, F. & Capolino, F. Experimental demonstration of exceptional points of degeneracy in linear time periodic systems and exceptional sensitivity. Preprint at https://arxiv.org/abs/1908.08516 (2019).
Zhao, H., Chen, Z., Zhao, R. & Feng, L. Exceptional point engineered glass slide for microscopic thermal mapping. Nat. Commun. 9, 1764 (2018).
Alaeian, H. & Dionne, J. A. Parity-time-symmetric plasmonic metamaterials. Phys. Rev. A 89, 033829 (2014).
Vidarsson, G., Dekkers, G. & Rispens, T. IgG subclasses and allotypes: from structure to effector functions. Front. Immunol. 5, 520 (2014).
Prodan, E., Radloff, C., Halas, N. J. & Nordlander, P. A hybridization model for the plasmon response of complex nanostructures. Science 302, 419–422 (2003).
Liu, N., Hentschel, M., Weiss, T., Alivisatos, A. P. & Giessen, H. Three-dimensional plasmon rulers. Science 332, 1407–1410 (2011).
Kanté, B. et al. Symmetry breaking and optical negative index of closed nanorings. Nat. Commun. 3, 1180 (2012).
Wu, C. et al. Fano-resonant asymmetric metamaterials for ultrasensitive spectroscopy and identification of molecular monolayers. Nat. Mater. 11, 69–75 (2012).
Brongersma, M. L. & Shalaev, V. M. The case for plasmonics. Science 328, 440–441 (2010).
Meinzer, N., Barnes, W. L. & Hooper, I. R. Plasmonic meta-atoms and metasurfaces. Nat. Photon. 8, 889–898 (2014).
Kabashin, A. V. et al. Plasmonic nanorod metamaterials for biosensing. Nat. Mater. 8, 867–871 (2009).
Glover, F. A. & Goulden, J. D. S. Relationship between refractive index and concentration of solutions. Nature 200, 1165–1166 (1963).
Cetin, A. E. et al. Plasmonic nanohole arrays on a robust hybrid substrate for highly sensitive label-free biosensing. ACS Photon. 8, 1167–1174 (2015).
Sreekanth, K. V. et al. Extreme sensitivity biosensing platform based on hyperbolic metamaterials. Nat. Mater. 15, 621–627 (2016).
This research was supported by the National Science Foundation Career Award (ECCS-1554021) and the Office of Naval Research Young Investigator Award (N00014-17-1-2671) and the ONR JTO MRI Award (N00014-17-1-2442). The work was partially supported by the DARPA DSO-NLM Program no. HR00111820038 and the US Department of Energy (DOE) (grant no. DE-EE0007341). The work was performed in part at the San Diego Nanotechnology Infrastructure, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the National Science Foundation (grant no. ECCS-1542148). We thank M. Montero for technical assistance regarding the fabrication.
The Regents of the University of California have filed a patent application (US Prov. App. 62/823,158) on technology related to the processes described in this article.
Peer review information Nature Physics thanks Christos Argyropoulos, Jan Wiersig and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
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Park, JH., Ndao, A., Cai, W. et al. Symmetry-breaking-induced plasmonic exceptional points and nanoscale sensing. Nat. Phys. 16, 462–468 (2020). https://doi.org/10.1038/s41567-020-0796-x
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