<p>The propagation of vortex beams in anisotropic nonlocal nonlinear media(ANNM) gives rise to distinctive structural transformations. This paper investigates the dynamical behavior of an off-axis chirped Laguerre-elliptic Gaussian vortex beam (OACLEGVB) in such media, employing a combined approach of analytical derivation and high-resolution numerical simulation. Anisotropic nonlocality makes it difficult for OACLEGVB to maintain structural stability, and instead enables the periodic conversion between Laguerre-Gaussian (LG) modes and Hermite-Gaussian (HG) modes. The normalized rotation angular momentum <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$J_o$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>J</mi> <mi>o</mi> </msub> </math></EquationSource> </InlineEquation> is effectively governed solely by the second-order chirp parameter(SOCP), the mode parameter, and the anisotropic nonlocality parameter(ANP). The normalized revolution angular momentum <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$J_e$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>J</mi> <mi>e</mi> </msub> </math></EquationSource> </InlineEquation> is precisely manipulated by the off-axis parameter(OAP), the SOCP, the ANP and the incident direction. Interestingly, when the power is constant(<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$P = P_{cx} = P_{cy}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>P</mi> <mo>=</mo> <msub> <mi>P</mi> <mrow> <mi mathvariant="italic">cx</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>P</mi> <mrow> <mi mathvariant="italic">cy</mi> </mrow> </msub> </mrow> </math></EquationSource> </InlineEquation>), the parameters of the higher-order mode beams have a linear relationship with those of the fundamental mode beams. The anisotropic nonlocal modulation breaks the rotational symmetry of the beam, resulting in the normalized orbital angular momentum not being a constant value and triggering periodic oscillation phenomena. This study provides a theoretical foundation for the precise control of propagation trajectory, mode interconversion, and optical field structuring of the OACLEGVB in anisotropic nonlocal nonlinear media.</p>

Controlled mode conversion of the off-axis chirped Laguerre-elliptic Gaussian vortex beams in anisotropic nonlocal nonlinear media

期刊论文
发表日期：

2026年6月14日

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Rongquan Chen,
Ruilin Xiao,
Shenglan Zhang,
Houquan Liu,
Shijie Deng,
Ming Chen

摘要

The propagation of vortex beams in anisotropic nonlocal nonlinear media(ANNM) gives rise to distinctive structural transformations. This paper investigates the dynamical behavior of an off-axis chirped Laguerre-elliptic Gaussian vortex beam (OACLEGVB) in such media, employing a combined approach of analytical derivation and high-resolution numerical simulation. Anisotropic nonlocality makes it difficult for OACLEGVB to maintain structural stability, and instead enables the periodic conversion between Laguerre-Gaussian (LG) modes and Hermite-Gaussian (HG) modes. The normalized rotation angular momentum $J_o$ $J_{o}$ is effectively governed solely by the second-order chirp parameter(SOCP), the mode parameter, and the anisotropic nonlocality parameter(ANP). The normalized revolution angular momentum $J_e$ $J_{e}$ is precisely manipulated by the off-axis parameter(OAP), the SOCP, the ANP and the incident direction. Interestingly, when the power is constant( $P = P_{cx} = P_{cy}$ $P = P_{cx} = P_{cy}$ ), the parameters of the higher-order mode beams have a linear relationship with those of the fundamental mode beams. The anisotropic nonlocal modulation breaks the rotational symmetry of the beam, resulting in the normalized orbital angular momentum not being a constant value and triggering periodic oscillation phenomena. This study provides a theoretical foundation for the precise control of propagation trajectory, mode interconversion, and optical field structuring of the OACLEGVB in anisotropic nonlocal nonlinear media.