title: Stochastic electromagnetic beams focused by a bifocal lens.
abstract: In this paper, we study the focusing of a stochastic electromagnetic beam by a bifocal lens. By taking the electromagnetic Gaussian Schell-model (EGSM) beam as an example, the changes in the spectral density, in the spectral degree of coherence, and in the spectral degree of polarization of the EGSM beam as the beam is focused by an unapertured bifocal lens are investigated. It is shown that the spectral density, the spectral degree of coherence, and the spectral degree of polarization of the focused electromagnetic EGSM beams depend upon the coherence lengths and focal lengths of the bifocal lens. The influence of the coherence lengths and the focal lengths on the focused spectral density, the spectral degree of coherence, and the spectral degree of polarization are investigated in great detail.
authors.affiliation: Department of Electronic Science & Technology, Institute of Optics & Photonics, Huaqiao University, Quanzhou, Fujian, China.
authors.forename: Guowen
authors.initials: G
authors.lastname: Zhang
authors.forename: Jixiong
authors.initials: J
authors.lastname: Pu