Generation of axially splitted ultra-long multiple optical needles/optical tubes using generalized cylindrical vector Bessel Gaussian beam phase modulated by annular Walsh function filter

Based on vector diffraction theory and annular Walsh function filter, axially splitted ultra-long multiple optical needles/optical tubes of electric as well as magnetic field distributions are numerically generated by generalized cylindrical vector Bessel Gaussian beam phase modulated by annular Walsh function filter. This multiple optical structures can be conveniently tailored by properly tuning the initial phase of the Cylindrical vector beam (CVB) and Walsh order of the annular Walsh function filter. Furthermore, the effect of energy flux density (Poynting vector) as well as Spin angular momentum(SAM) distribution in the focal region are theoretically analyzed. We expect that such an axially splitted focal systems could be applicable in optical trapping and manipulation of multiple particles, optical super resolution microscopy etc.