Published in Optics Express, Volume 18, Issue 5, February 16, 2010, pages 4023-4040.
Copyright © 2010 Optical Society of America. This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.18.004023. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Vector diffraction theory is applied to the case of focused TEM00 Gaussian beams passing through a spatially limiting aperture in order to investigate the propagation of these clipped focused-Gaussian beams. Beam distributions at different axial distances show that a traditional M2 propagation model cannot be used for the propagation of clipped focus-Gaussian beams. Using Luneberg’s vector diffraction theory and Fresnel approximations, an analytical model for the on-axis transverse and longitudinal electric fields and intensity distributions is presented including predictions of the maximum obtainable intensity. In addition, an analytical expression is provided for the longitudinal component of the electric field of a TEM00 mode unperturbed Gaussian beam. Experimental results are also presented and compared to the model’s predictions.