Invariance of mode transformation by an astigmatic π/2 converter upon the input-beam displacement and tilt

It is shown theoretically and experimentally that the transformation of modes by an astigmatic π/2 converter is invariant with respect to the input-beam displacement and tilt. The possibility is considered of using this property for manipulating microobjects and simultaneous generation of Laguerre–Gaussian modes of different orders with the help of the same astigmatic π/2 converter.