Twisting of three-dimensional Hermite-Gaussian beams

The mode converter first applied by Tamm and Weiss and generalized by Alien and co-workers can be used to transform any general astigmatic beam into a stigmatic beam with twist. For the special case of three dimensional Hermi te-Gaussian beams the transformed beams are twisted Hermite-Gaussian beams with complex arguments. Only if a set of conditions is fulfilled are the tr ansformed beams Laguerre-Gaussian beams. The influence of the input beam pa rameters on the output beam is discussed.