Cyclic transformation of orbital angular momentum modes. (14th April 2016)

• Record Type: Journal Article
• Authors: Schlederer, Florian; Krenn, Mario; Fickler, Robert; Malik, Mehul; Zeilinger, Anton
• Is Part Of: New journal of physics. Volume 18:Number 4(2016:Apr.)
• Publication Date: 2016-04-14
• Subjects: photonic orbital angular momentum -- quantum transformation -- computer-designed experiment -- high-dimensional Hilbert-space -- cyclic transformation; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/18/4/043019
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: The spatial modes of photons are one realization of a QuDit, a quantum system that is described in a D -dimensional Hilbert space. In order to perform quantum information tasks with QuDits, a general class of D -dimensional unitary transformations is needed. Among these, cyclic transformations are an important special case required in many high-dimensional quantum communication protocols. In this paper, we experimentally demonstrate a cyclic transformation in the high-dimensional space of photonic orbital angular momentum (OAM). Using simple linear optical components, we show a successful four-fold cyclic transformation of OAM modes. Interestingly, our experimental setup was found by a computer algorithm. In addition to the four-cyclic transformation, the algorithm also found extensions to higher-dimensional cycles in a hybrid space of OAM and polarization. Besides being useful for quantum cryptography with QuDits, cyclic transformations are key for the experimental production of high-dimensional maximally entangled Bell-states.