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.
© 2009 Optical Society of America
Original Manuscript: April 30, 2009
Revised Manuscript: August 3, 2009
Manuscript Accepted: August 27, 2009
Published: September 21, 2009
Ignacio Moreno, Jeffrey A. Davis, B. Melvin L. Pascoguin, Mark J. Mitry, and Don M. Cottrell, "Vortex sensing diffraction gratings," Opt. Lett. 34, 2927-2929 (2009)