Analysis of femtosecond optical vortex beam generated by direct wave-front modulation

The generation of femtosecond optical vortex beam based on direct wave-front modulation with phase-only liquid crystal spatial light modulator is demonstrated. The spatial and temporal properties of the generated femtosecond vortices are investigated in detail. The experimental results show remarkable agreement with the results of the theoretical analysis and simulations, and indicate that the method we utilized can efficiently generate femtosecond optical vortex beam of arbitrary topological charge. The temporal and spectral properties of the femtosecond pulsed beam are hardly affected by the phase dislocation imposed on the wave-front. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)