Exact solution of the vectorial field structure of a light beam

An alternative way of finding electromagnetic solutions based on the closest solution defined by Martinez-Herrero et al.   [J. Opt. Soc. Am. A 18, 1678 (2001)] has been proposed. It is found that by identifying the components of closest solution f→ as the components of the planewave spectrum of realistic fields at z = 0, an exact solution of the electromagnetic fields satisfying the Maxwell equations can also be obtained. This solution is applied to calculate the fields of a radially polarized Laguerre–Gaussian laser beam. It shows that although both formalisms are correct ways of finding electromagnetic solutions, as the beam waist size is less than a laser wavelength, the longitudinal electric field near the focus obtained from our solution can be significantly larger than that by Martinez-Herrero et al.