Vortex sensing diffraction gratings.

We demonstrate a specially designed vortex sensing diffraction grating that generates multiple vortex patterns in the different diffracted orders. When this grating is illuminated with a separate vortex beam, the sign and order of the topological charge of the incident beam can be easily detected. Experimental results are shown for a variety of vortex beams including fractional values of the topological charge, and where both the diffraction grating and incident vortex illumination beam are generated by two different liquid crystal displays (LCDs). The programmability offered by the LCDs offers extremely convenient flexibility.

[1]  M. Berry,et al.  Dislocations in wave trains , 1974, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[2]  Erez Hasman,et al.  Topological spin-orbit interaction of light in anisotropic inhomogeneous subwavelength structures. , 2008, Optics letters.

[3]  S. Barnett,et al.  Interferometric methods to measure orbital and spin, or the total angular momentum of a single photon. , 2004, Physical review letters.

[4]  P. Dirac.  Quantised Singularities in the Electromagnetic Field , 1931 .

[5]  A. Bekshaev,et al.  Spatial characteristics of vortex light beams produced by diffraction gratings with embedded phase singularity , 2008 .

[6]  H J Tiziani,et al.  Optical particle trapping with computer-generated holograms written on a liquid-crystal display. , 1999, Optics letters.

[7]  A. Vaziri,et al.  Entanglement of the orbital angular momentum states of photons , 2001, Nature.

[8]  He,et al.  Direct observation of transfer of angular momentum to absorptive particles from a laser beam with a phase singularity. , 1995, Physical review letters.

[9]  Karlton Crabtree,et al.  Optical processing with vortex-producing lenses. , 2004, Applied optics.

[10]  A. Ohnishi,et al.  Computational design of solar reflection and far-infrared transmission films for a variable emittance device. , 2003, Applied optics.

[11]  Jeffrey A. Davis,et al.  Polarization-multiplexed diffractive optical elements with liquid-crystal displays. , 2005, Applied optics.

[12]  Michael V Berry,et al.  Optical vortices evolving from helicoidal integer and fractional phase steps , 2004 .

[13]  K. T. Gahagan,et al.  Optical vortex trapping of particles , 1996, Summaries of papers presented at the Conference on Lasers and Electro-Optics.

[14]  David G Grier,et al.  Modulated optical vortices. , 2003, Optics letters.

[15]  Andrew G. White,et al.  Generation of optical phase singularities by computer-generated holograms. , 1992, Optics letters.

[16]  S. Barnett,et al.  Free-space information transfer using light beams carrying orbital angular momentum. , 2004, Optics express.