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arXiv · 2205.11336

CPA-lasing associated with the quasibound states in the continuum in asymmetric non-Hermitian structures

Denis V. Novitsky·Adia Canos Valero·Alexander Krotov·Toms Salgals·Alexander S. Shalin·Andrey V. Novitsky
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Abstract

Non-Hermitian photonic systems with loss and gain attract much attention due to their exceptional abilities in molding the flow of light. Introducing asymmetry to the $\mathcal{PT}$-symmetric system with perfectly balanced loss and gain, we reveal the mechanism of transition from the quasibound state in the continuum (quasi-BIC) to the simultaneous coherent perfect absorption (CPA) and lasing in a layered structure comprising epsilon-near-zero (ENZ) media. Two types of asymmetry (geometric and non-Hermitian) are analyzed with the scattering matrix technique. The effect of the CPA-lasing associated with the quasi-BIC is characterized with the unusual linear dependence of the quality factor on the inverse of asymmetry parameter. Moreover, the counter-intuitive loss-induced-lasing-like behavior is found at the CPA-lasing point under the non-Hermitian asymmetry. The reported features of non-Hermitian structures are perspective for sensing and lasing applications.

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Denis V. Novitsky, Adia Canos Valero, Alexander Krotov, Toms Salgals, Alexander S. Shalin, Andrey V. Novitsky. 2022-05-23. CPA-lasing associated with the quasibound states in the continuum in asymmetric non-Hermitian structures. https://doi.org/10.1021/acsphotonics.2c00790

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