Exceptional points and lasing self-termination in photonic molecules

Abstract

We investigate the rich physics of photonic molecule lasers using a non-Hermitian dimer model. We show that several interesting features, predicted recently using a rigorous steady state ab-initio laser theory (SALT), can be captured by this toy model. In particular, we demonstrate the central role played by exceptional points in both pump-selective lasing and laser self-terminations phenomena. Due to its transparent mathematical structure, our model provides a lucid understanding for how different physical parameters (optical loss, modal coupling between microcavities and pump profiles) affect the lasing action. Interestingly, our analysis also confirms that, for frequency mismatched cavities, operation in the proximity of exceptional points (without actually crossing the square root singularities) can still lead to laser self-termination. We confirm this latter prediction for two coupled slab cavities using scattering matrix analysis and SALT technique. In addition, we employ our model to investigate the pump-controlled lasing action and we show that emission patterns are governed by the locations of exceptional points in the gain parameter space. Finally we extend these results to multi-cavity photonic molecules, where we found the existence of higher-order EPs and pump-induced localization.

21 pages, 8 figures

References in corpus (5)

• PT-symmetry breaking and laser-absorber modes in optical scattering systems
• Reversing the Pump-Dependence of a Laser at an Exceptional Point
• Strong Interactions in Multimode Random Lasers
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Cited by in corpus (9)

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• Dynamical Phonon Laser in Coupled Active-Passive Microresonators
• Contrasting Spectral Signatures and Sensitivities of CPA-Lasing in a $\mathcal{P}\mathcal{T}$-Symmetric Periodic Structure
• Exceptional points of degeneracy and $\mathcal{P}\mathcal{T}$-symmetry in photonic coupled chains of scatterers
• Cyclic permutation-time symmetric structure with coupled gain-loss microcavities
• Spectral Signatures of Exceptional Points and Bifurcations in the Fundamental Active Photonic Dimer
• Condensation of Thresholds in Multimode Microlasers
• Origin of robust exceptional points: a restricted bulk zero mode