Pt-Symmetric Micro-Resonators: High Sensitivity At Exceptional Points

Abstract

Enhanced sensitivity is demonstrated in PT-symmetric coupled micro-resonator arrangements biased at an exceptional point. The spectral response of such a system is shown to follow a square root dependence on externally introduced perturbations. OCIS codes: 140.3948 (Microcavity devices), 280.3420 (Laser sensors), 140.3560 (Lasers, ring) Exceptional points (EPs) represent degeneracies in parameter space, where both eigenvalues and eigenvectors of a non-Hermitian operator tend to coalesce [1]. Recently, the properties associated with such singularities have been utilized in optics to introduce a number of new functionalities that are not readily attainable in conventional Hermitian systems [2,3]. Among various optical structures, parity-Time (PT) symmetric arrangements provide an excellent platform for the experimental realization of exceptional points [4]. Along these lines, single mode lasing in PTsymmetric coupled microring lasers has been demonstrated by exploiting the abrupt phase transitions at EPs [5,6]. An important feature of this class of non-Hermitian arrangements is an extreme sensitivity to external perturbations when operated close to their exceptional points. While this behavior has been proposed as a means to increase the responsivity of optical micro-resonator [7,8], this enhancement is yet to be experimentally demonstrated. In this study, we report on the observation of enhanced sensitivity associated with a PT-symmetric coupled cavity configuration biased at an EP. We show that the system response has a square root dependence on the applied perturbation that can be further boosted by increasing the coupling strength between the resonators.

Publication Date

10-25-2017

Publication Title

2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings

Volume

2017-January

Number of Pages

1-2

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1364/CLEO_AT.2017.FTh3D.2

Socpus ID

85044227965 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85044227965

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