Generation and characterization of twist beam

The characterization of the twist beam can not be accomplished by using only the beam propagation ratios because the transverse cross section keeps changing during propagation. The generation and characterization of the twist Gaussian beam by two cylinder lenses are studied theoretically and experimentally. The twist coefficient is introduced to characterize the level of twist. The beam propagation ratios for the twist Gaussian beam at an azimuth angle are theoretically derived. The twist coefficients of the twist beams generated by two cylinder lenses with different angle and spacing are obtained by using the beam-transfer-matrix and the numerical simulation. The results show that the properties of the twist beam can be characterized better by the combination of the beam propagation ratios and the twist coefficient. The theoretical work is in good agreement with the experimental results.