Mahon, Ronan John and Murphy, J.Anthony (2013) Diffraction of an optical pulse as an expansion in ultrashort orthogonal Gaussian beam modes. Applied Optics, 30 (2). pp. 215-226. ISSN 1559-128X

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Abstract

The Laguerre–Gaussian (LG) beam expansion is described as a numerical and physical model of paraxial ultrashort pulse diffraction in the time domain. An overview of the dynamics of higher-order ultrashort planar LG modes is given through numerical simulations, and the finite width of these beams is shown to induce a dispersive-like axial broadening of the fields, which creates related variations in the on-axis amplitude of such pulses. The propagation of a pulsed plane wave scattered at an aperture is then illustrated as a finite weighted sum of individual planar LG pulses, which allows for intuitive illustration of the convergence of this expansion technique. By applying such an expansion to diffraction at a hard aperture, the planar pulsed LG beams are described as the paraxial analogs of the Bessel boundary waves typically observed in such situations, with both exhibiting superluminal group velocities along the optical axis. Numerical results of pulse diffraction at an aperture highlight the suitability of the LG expansion method for efficient and practical simulation of ultrashort fields in the paraxial regime.

Item Type:	Article
Keywords:	Gaussian beams; Numerical simulation; Optical systems; Phase shift; Defractive index; Ultrashort pulses; Diffraction; Dispersion; Pulses;
Academic Unit:	Faculty of Science and Engineering > Experimental Physics
Item ID:	13924
Identification Number:	https://doi.org/10.1364/JOSAA.30.000215
Depositing User:	Dr. Anthony Murphy
Date Deposited:	01 Feb 2021 16:57
Journal or Publication Title:	Applied Optics
Publisher:	Optical Society of America
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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