The focusing properties of vector beams have attracted great attention and quickly became the
subject of extensive worldwide research due to their applications in lithography, optical storage,
microscopy, material processing, and optical trapping. Focusing properties of the radially polarized
beam and generalized cylindrical vector beams in high numerical aperture system with designed pure
phase filter are analyzed in detail by using vector Debye diffraction theory. By utilizing diffractive
optical element to partly change the polarization of vector beams, the energy density of light field in the
vicinity of focus is studied by the numerical analysis. Numerical simulation result shows that optical
bubbles can be obtained by changing the composition and polarization of the incident beams. At last,
optical tweezers are constituted by two optical bubbles around the focus.
Recently, cylindrical vector beams have drawn considerable attention for their interesting
properties and potential applications in super-resolution optical imaging, optical trapping and
manipulating. It’s easy to obtain inhomogeneous status of polarization by designing the diffractive
optical elements particularly. With the change of the polarization of cylindrical vector beams, three dimensional (3D) flattop fields could be obtained. Numerical analysis shows that the full width at half
maximum of the proposed 3D flattop light field is nearly 5λ for axial distributions. The result shows a
potential application of the cylindrical vector beams in laser beam shaping system and laser cutting.
This article deals with designing broadband and high efficiency metal multi-layer dielectric grating (MMDG) used to
compress and stretch ultra-short laser pulse. The diffraction characteristics of MMDG are analyzed with the method of
rigorous coupled-wave analysis (RCWA). Taking the diffraction efficiency of the -1 order as the value of merit function,
the parameters such as groove depth, residual thickness, duty cycle are optimized to obtain broadband and high
diffraction efficiency. The optimized MMDG shows an ultra-broadband working spectrum with the average efficiency
exceeding 97% over 135nm wavelength centered at 800nm and TE polarization. The optimized MMDG should be useful
for chirped pulse amplification.