Publication Date

2009

Comments

This is the prepublished version harvested from ArXiv. The published version is located at http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVF-4V77966-3&_user=1516330&_coverDate=04%2F01%2F2009&_rdoc=31&_fmt=high&_orig=browse&_origin=browse&_zone=rslt_list_item&_srch=doc-info(%23toc%235533%232009%23997179992%23919056%23FLA%23display%23Volume)&_cdi=5533&_sort=d&_docanchor=&_ct=48&_acct=C000053443&_version=1&_urlVersion=0&_userid=1516330&md5=7fcc0aaf2e001d0dc6c11266b06d8a10&searchtype=a

Abstract

We study the azimuthal modulational instability of vortices with different topological charges, in the focusing two-dimensional nonlinear Schrödinger (NLS) equation. The method of studying the stability relies on freezing the radial direction in the Lagrangian functional of the NLS in order to form a quasi-one-dimensional azimuthal equation of motion, and then applying a stability analysis in Fourier space of the azimuthal modes. We formulate predictions of growth rates of individual modes and find that vortices are unstable below a critical azimuthal wave number. Steady-state vortex solutions are found by first using a variational approach to obtain an asymptotic analytical ansatz, and then using it as an initial condition to a numerical optimization routine. The stability analysis predictions are corroborated by direct numerical simulations of the NLS. We briefly show how to extend the method to encompass nonlocal nonlinearities that tend to stabilize such solutions.

Pages

1399-1405

Volume

282

Issue

7

Journal Title

OPTICS COMMUNICATIONS