Focusing properties of radially polarized helico-conical Lorentz-Gauss beam

Helico-conical wavefront modulation affects focusing properties and plays an important role in many optical systems. Radially polarized Lorentz-Gauss beams were modulated with helico-conical wavefront and their focusing properties were investigated by vector diffraction theory. Results show that focusing properties may be alerted considerably by helico-conical parameters, and some novel focal patterns appear. The focal patterns turn on spiral inteinsity curves, and the effect of numerical aperture is weaker than that of helico-conical parameters. Some optical gradient force distributions are also calculated to show that focusing radially polarized helico-conical Lorentz-Gauss beam may find wide applications in optical manipulation.