Kaloyan Bezuhanov and Alexander Dreischuh
Gerhard G. Paulus
Michael G. Schätzel and Herbert Walther
Dragomir Neshev, Wieslaw Krolikowski, and Yuri Kivshar
We show that spatial phase dislocations associated with optical vortices can be embedded in femtosecond laser beams by computer-generated holograms, provided that they are built in a setup compensating for the intro-duced spatial dispersion of the broad spectrum. We present analytical results describing two possible arrange-ments: a dispersionless 4f setup and a double-pass grating compressor. Experimental results on the generation of optical vortices in the output beam of a 20 fs Ti:sapphire laser and the proof-of-principle measurements with a broadband-tunable cw Ti:sapphire laser confirm our theoretical predictions.