Polychromatic cylindrically polarized beams (Vol. 47 No. 5-6)

Various polarization patterns (arrows) and intensity distributions (underlying doughnut) of a co-rotating radially polarized X-wave

Cylindrically polarized beams represent a class of solutions, where the polarization can be radially or azimuthally distributed across the intensity profile. These beams have very intriguing properties, both from a fundamental and an applied perspective. Despite their great success, they have been almost exclusively studied and realized within the monochromatic regime.

An open question is if non-monochromatic cylindrically polarized solutions of Maxwell equations exist. New research answers to this question by employing X waves with orbital angular momentum (the polychromatic counterpart of Bessel beams) as building blocks to generate optical pulses with radial and azimuthal polarization. This approach is different from the monochromatic case where Hermite-Gaussian beams are typically used. Solutions are investigated in the paraxial and the nonparaxial regime and the role of the pulse’s spectrum in the polarization properties of the pulse itself is pointed out. Analysis shows that the generalization of the concept of non-uniform polarization to the domain of optical pulses leads to new intriguing applications, such as spatially resolved Raman spectroscopy. Cylindrically polarized X-waves with orbital angular momentum could also open new intriguing scenarios for fundamental research and quantum optics.

M. Ornigotti, C. Conti and A. Szameit, Cylindrically polarized nondiffracting optical pulses, J. Opt. 18, 075605 (2016)