Observation of parity-time symmetry in optics

    Authors

    C. E. Ruter; K. G. Makris; R. El-Ganainy; D. N. Christodoulides; M. Segev;D. Kip

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    Abbreviated Journal Title

    Nat. Phys.

    Keywords

    NON-HERMITIAN HAMILTONIANS; WAVE-GUIDES; REAL; EIGENVALUES; SPECTRA; Physics, Multidisciplinary

    Abstract

    One of the fundamental axioms of quantum mechanics is associated with the Hermiticity of physical observables(1). In the case of the Hamiltonian operator, this requirement not only implies real eigenenergies but also guarantees probability conservation. Interestingly, a wide class of non-Hermitian Hamiltonians can still show entirely real spectra. Among these are Hamiltonians respecting parity-time (PT) symmetry(2-7). Even though the Hermiticity of quantum observables was never in doubt, such concepts have motivated discussions on several fronts in physics, including quantum field theories(8), non-Hermitian Anderson models(9) and open quantum systems(10,11), to mention a few. Although the impact of PT symmetry in these fields is still debated, it has been recently realized that optics can provide a fertile ground where PT-related notions can be implemented and experimentally investigated(12-15). In this letter we report the first observation of the behaviour of a PT optical coupled system that judiciously involves a complex index potential. We observe both spontaneous PT symmetry breaking and power oscillations violating left-right symmetry. Our results may pave the way towards a new class of PT-synthetic materials with intriguing and unexpected properties that rely on non-reciprocal light propagation and tailored transverse energy flow.

    Journal Title

    Nature Physics

    Volume

    6

    Issue/Number

    3

    Publication Date

    1-1-2010

    Document Type

    Article

    Language

    English

    First Page

    192

    Last Page

    195

    WOS Identifier

    WOS:000275024000019

    ISSN

    1745-2473

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