$\mathcal{P}\mathcal{T}$-symmetric microring laser-absorber

Abstract

The lasing and coherent perfect absorption (CPA) properties of $\mathcal{P}\mathcal{T}$-symmetric microrings with mixed index and gain gratings, externally coupled to a bus waveguide, are theoretically investigated. For a complex grating at the $\mathcal{P}\mathcal{T}$ symmetry breaking point, perfect unidirectional (either clockwise or counterclockwise) laser emission can be realized, however the grating does not discriminate longitudinal modes and CPA can not be simultaneously achieved. Above the grating $\mathcal{P}\mathcal{T}$ symmetry breaking point, single mode emission and simultaneous CPA can be obtained, with unbalanced and controllable excitation of clockwise and counterclockwise modes in the ring.

5 pages, 3 figures, to appear in Optics Letters

References in corpus (4)

• Making Sense of Non-Hermitian Hamiltonians
• PT-symmetry breaking and laser-absorber modes in optical scattering systems
• Reversing the Pump-Dependence of a Laser at an Exceptional Point
• Parity-Time Synthetic Laser

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• Parity-Time Symmetry and Exceptional points: A Tutorial
• Spectral singularities of a potential created by two coupled microring resonators
• Electromagnetic Eigenvalue Problems and Nonhermitian Effects in Linear and Saturable Scattering
• Bidirectional acoustic negative refraction based on a pair of metasurfaces with both local and global PT-symmetries