Abstract. The concept of the so-called closest field to a given vector function is extended to the non-polarized case. Attention is focused on transverse field solutions of the Maxwell equations whose transverse character is preserved under free propagation. The coherence matrix of the non-paraxial transverse field that is closest to a paraxial unpolarized transverse beam is given. It is shown that the intensity matrix of this closest field can be written as the sum of the intensity matrices of a non-polarized field and a totally polarized beam.

Keywords: vector beams, polarization

Print publication: Issue 3 (March 2004)
Received 12 September 2003, accepted for publication 19 December 2003
Published 24 February 2004