Theoretical and experimental study of new dark hollow beams
一种新空心光束的理论及实验研究

A new mathematical model named hollow Gaussian beams (HGBs) is introduced to describe the dark hollow beam. The area of the dark region across the HGBs can be easily controlled by properly choosing the beam parameters. An analytical propagation formula for HGBs through paraxial optical system is derived. The evolution properties of the intensity distribution of HGBs in free space propagation are illustrated graphically using the derived propagation formula. By using matrix eigenvalues method, the laser cavity with diffraction optical elements, which can generate the dark hollow beams, was constructed. Dark hollow beams were realized in experiment and its intensity distribution properties in near field and far field were studied. The results derived from the experiment is coincident with those predicted by the theory. The dark hollow beams we have obtained can be used conveniently to analyze atoms manipulation and may provide a new method for atom cooling.