Focused fields of ultrashort radially-polarized laser pulses having low-order spatio-temporal couplings

We present a detailed study of the fields and propagation characteristics around the focus of ultrashort radially-polarized laser beams (RPLBs) having low-order spatio-temporal couplings. The combination of a low-order vector beam, ultrashort pulse duration, and three different STCs shows promise for exotic applications in dielectric or charged particle manipulation and potentially other strong-field phenomena. The STCs presented are all developed in a standard frequency-domain model where each case involves a different chromatic term. We present the results unique to the vector nature of the RPLBs and compare them to the linearly polarized cases, opening up opportunities for more control of the electric field around the focus with the additional element of polarization.