Deformation due to distorted hologram for generation of Laguerre Gaussian beam

The Laguerre Gaussian(LG) beam is an optical beam that has doughnut-shaped intensity distribution and phase singularity. A phase singularity is a structure such that integration of the phase gradient along a closed path around the axis yields 2m/spl pi/. The integer m is called the charge of the phase singularity. Reliable generation of LG beams has been realized through computer holograms. For applications such as optical trapping and rotational manipulation, the profile of beam generated by hologram is often more important than its diffraction efficiency. Low diffraction efficiency can be compensated by high power light source, while a high power distorted beam may cause serious problems.