漩渦光在非即時自聚焦材料中的穩定化之理論研究

Theoretical Study of Stabilization of Vortex Beams in Noninstantaneous Self-focusing Media

羅子峻(Tzu-Chun Lo)

指導教授 ： 石明豐

國立臺灣大學/理學院/物理研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00188

摘要

無資料

關鍵字

漩渦光 ； 非即時 ； 自聚焦 ； 光孤子

並列摘要

Vortex beams which propagate in a self-focusing media experience azimuthal
instability that breaks the beam into pieces. The theory of stabilization of
vortex beams that propagate in noninstantaneous self-focusing media is studied in this dissertation.

At first, we use perturbation method to evaluate the growth rate of each eigenmode with different vorticity numerically. The results indicate that both relaxation time of media and temporal frequency of time varying perturbation
change the growth rate of eigenmodes that is the same as the analysis of modulation instability. When the product of relaxation time and temporal frequency is large enough, the magnitude and difference of gains of every eigenmodes becomes smaller than those in instantaneous media.

We also perform numerical simulations of the beam propagation to observe the evolution of the artificial noise along finite distances. We add several azimuthally periodic perturbations into the vortex beam and inspect the structure of the beam. We have confirmed that the stability behavior of the beam from the results of simulation is similar to the conclusion from the perturbation method. In conclusion, coherent vortex beams can be stabilized by the noninstantaneity.

並列關鍵字

Vortex ； Noninstantaneous ； Self-focusing ； soliton

參考文獻

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