Birefringent Optical twister

摘要

Out-of-phase superposition of two identical beams with position and momentum shifts in orthogonal directionsadds a unit orbital angular momentum to the optical field, and we call this operation an optical twister. Here we show astable and compact twister configuration using a birefringent plate introducing spatial walk-off followed by a cylindricallens transforming part of the walk-off into momentum shifts. Pre- and post-selection of polarization states achieves the outof-phase superposition.