Ultrafast multicolor concentric vector beams with controllable polarized orientation

Abstract

Novel multicolor concentric annular ultrafast vector beams (MUCAU-VB) are generated simply by using cascaded four- wave mixing (CFWM) in a glass plate pumped by two intense vector femtosecond pulses. A proof-of-principle experiment shows that up to 10 frequency up-conversion concentric annular radially polarized sidebands are obtained simultaneously based on CFWM process, where the spectra range of the first 7 order sidebands extending from 545 nm to 725 nm. The results prove the polarization transfer property from the pump beam to the signal beams even in the CFWM, a third-order optical parametric process. The pulse duration of the first order sideband is measured to be 74 fs which is according with those of two input beams. Furthermore, the multicolor concentric annular ultrafast laser beams can be modulated externally using a controllable light modulator such as space light modulator. Due to the space separated property, color lights in different rings can be modulated to different polarized states respectively. Multicolor concentric ultrafast vector beams with uniform or nonuniform polarized structures can be generated. These novel MUCAU vector beams, which are manipulated in temporal, spectral, spatial domain and polarization state simultaneously, are expected to apply in wide fields, such as manipulating particles and multicolor pump-probe experiments.