[1] Beijersbergen M W,Allen L. Astigmatic laser mode converters and transfer of orbital angular momentum.Optics Communications,1993,96(3):123~132
[2] Allen L,Beijerbergen M W,Spreeuw R J C,et al.Orbital angular momentum of light and the transformation of laguerre-gaussian laser modes.Phys Rev,1990,A45(11):8185
[3] Abramochki E,Volosrnikov V.Beam transformations and nontransformed beams.Optics Comm, 1991,83(2):123~135
[4] Eppich B, Fiberg A T. Twist of coherent fields and bram quality.SPIE,1996,2870:260~267