Figure 5

Intensity profiles of obtained LG* modes having helical wavefront: (a1) , (a2)
, (a3)
and (a4)
. Mach-Zehnder Interferogram: (b1 (b2)) One-start spiral fringes corresponding to right (left) handed
with OAM charge l = 1(−1). (b3 (b4)) Two-starts spiral fringes corresponding to right (left) handed
with OAM charge l = 2(−2).