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中国物理学会期刊

非局域非线性光学腔中空间耗散孤子的形成与双稳态特性研究

Formation and Bistability of Spatial Dissipative Solitons in Nonlocal Nonlinear Optical Cavities

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  • 耗散孤子是一种在外部驱动与损耗平衡、非线性与衍射效应平衡共同作用下形成的局域化波包,在频率梳产生及精密光场调控中扮演着重要角色。针对腔内耗散孤子的调控研究,现有工作多集中于腔内填充局域非线性介质的系统,而对非局域非线性效应下腔内孤子的形成机制及调控手段尚缺乏讨论与探索。本文基于高斯泵浦驱动的非局域腔内光动力学方程,考察了不同非局域响应下腔内耗散孤子的演化行为以及失谐扫描下的光场动力学特征。理论与数值结果表明,以高斯光场作为初始态和泵浦,初始光场在弱非局域非线性效应下可演化为多孤子态;而在强非局域作用下,系统最终形成的终态则是单孤子结构。该现象可通过不同非局域宽度下系统中存在不同的非线性稳态模式进行解释。同时发现,在非局域响应效应的作用下,正、负向失谐扫描会导致腔内光场产生不同的峰数演化和混沌态分布区域。本文的研究结果揭示了非局域非线性效应对腔内耗散孤子动力学行为的影响规律,为理解非局域非线性腔内耗散孤子的形成及其动力学调控提供了新的机制与手段。

     

    Dissipative solitons are localized wave packets formed through the balance between external driving and loss, as well as between nonlinearity and diffraction. They play an important role in optical frequency comb generation and precision optical field manipulation. For the control of dissipative solitons in cavities, previous studies have mostly focused on systems with locally nonlinear media inside the cavity, while the formation and control mechanisms of cavity solitons under nonlocal nonlinear effects remain insufficiently discussed and explored. In this paper, we systematically investigate the evolution and control of dissipative solitons in a nonlinear optical cavity with a Gaussian nonlocal response, driven by a spatially confined Gaussian pump. The nonlocal response width emerges as an effective tuning parameter that deterministically governs the final soliton number, driving a clear transition from four‑soliton to three‑, two‑, and ultimately single‑soliton structures as the width of nonlocal response increases, accompanied by a monotonic increase in peak power. In parallel, stronger nonlocality suppresses early‑stage transverse splitting, reduces the propagation distance required to reach steady states, and rapidly damps oscillatory behavior in the peak power evolution. From a physical perspective, we demonstrate that cavities with varying nonlocal widths intrinsically support distinct nonlinear eigenmodes, and that the incident Gaussian field gradually evolves into the corresponding eigenmode—thereby establishing the physical mechanism to explain the different final states observed. These features can also be attributed to the fact that the nonlocally induced refractive index potential broadens and smooths into an effective parabolic profile under strongly nonlocal nonlinearity, which suppresses modulational instability and thereby favors the formation of a single soliton. Finally, we further investigate the beam dynamics under bidirectional detuning scans. Forward and backward scans yield different critical detuning values for the transitions between chaotic and soliton states. Bistability occurs under both weak and strong nonlocality, but in different detuning intervals; under strong nonlocality, the two scans also follow distinct evolution routes. Our findings provide a new framework for precision soliton management in nonlocal cavities and may inspire further beam shaping strategies.

     

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