A radially polarized beam with an annular intensity pattern was generated through a second-harmonicgeneration process by focusing an azimuthally polarized Ti:sapphire pulsed laser beam to a c-cut β-barium borate (BBO) crystal. The annular intensity pattern of the second-harmonic wave had a nearly sixfold symmetry as a result of the nonlinear susceptibility tensor of the BBO crystal. The width of the annulus was as narrow as less than l/40th of its radius.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics