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Engineered non-Hermitian systems featuring exceptional points (EPs) can lead to a host of extraordinary phenomena in diverse fields ranging from photonics, acoustics, opto-mechanics, and electronics to atomic physics. In optics, non-Hermitian dynamics are typically realized using dissipation and phase-insensitive gain accompanied by unavoidable fluctuations. Here, we introduce non-Hermitian dynamics of coupled optical parametric oscillators (OPOs) arising from phase-sensitive amplification and de-amplification, and show their distinct advantages over conventional non-Hermitian systems relying on laser gain and loss. OPO-based non-Hermitian systems can benefit from the instantaneous nature of the parametric gain, noiseless phase-sensitive amplification, and rich quantum and classical nonlinear dynamics. We show that two coupled OPOs can exhibit spectral anti-parity-time (anti-PT) symmetry and a EP between its degenerate and nondegenerate operation regimes. To demonstrate the distinct potentials of the coupled OPO system compared to conventional non-Hermitian systems, we present higher-order EPs with two OPOs, tunable Floquet EPs in a reconfigurable dynamic non-Hermitian system, and the generation of a squeezed vacuum around EPs, all of which are not easy to realize in other non-Hermitian platforms. We believe our results show that coupled OPOs are an outstanding non-Hermitian setting with unprecedented opportunities to realize nonlinear dynamical systems for enhanced sensing and quantum information processing.
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Emulating exceptional-point encirclements using imperfect (leaky) photonic components: asymmetric mode-switching and omni-polarizer action
Non-Hermitian systems have recently attracted significant attention in photonics. One of the hallmarks of these systems is the possibility of realizing asymmetric mode-switching and omni-polarizer action through the dynamic encirclement of exceptional points (EPs). Here, we offer a new perspective on the operating principle of these devices, and we theoretically and experimentally show that linear asymmetric mode-switching and omni-polarizer action can be easily realized—with the same performance and limitations—using simple configurations that emulate the physics involved in encircling EPs without the complexity of actual encirclement schemes. The proposed concept of “encirclement emulators” and our theoretical and experimental results may allow better assessment of the limitations, practical potential, and applications of EP encirclements in non-Hermitian photonics.
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- Award ID(s):
- 1741694
- PAR ID:
- 10221975
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optica
- Volume:
- 8
- Issue:
- 4
- ISSN:
- 2334-2536
- Format(s):
- Medium: X Size: Article No. 563
- Size(s):
- Article No. 563
- Sponsoring Org:
- National Science Foundation
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