Simple scheme for the astigmatic transformation of laser modes

A simple astigmatic scheme for obtaining focused Laguerre–Gaussian beams upon the π/2 conversion of Hermite–Gaussian radiation modes is described. A zone in the vicinity of the focal region of a lens is estimated where the beam satisfies the conditions for the capture and confinement of microparticles. It is shown that this optical scheme uses the fractional Fourier transform, whose application in the π/2 converter is demonstrated for the first time.