title: Controlling the orbital angular momentum of high harmonic vortices.
abstract: Optical vortices, which carry orbital angular momentum (OAM), can be flexibly produced and measured with infrared and visible light. Their application is an important research topic for super-resolution imaging, optical communications and quantum optics. However, only a few methods can produce OAM beams in the extreme ultraviolet (XUV) or X-ray, and controlling the OAM on these beams remains challenging. Here we apply wave mixing to a tabletop high-harmonic source, as proposed in our previous work, and control the topological charge (OAM value) of XUV beams. Our technique enables us to produce first-order OAM beams with the smallest possible central intensity null at XUV wavelengths. This work opens a route for carrier-injected laser machining and lithography, which may reach nanometre or even angstrom resolution. Such a light source is also ideal for space communications, both in the classical and quantum regimes.
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: Fanqi
authors.initials: F
authors.lastname: Kong
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bouchard
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: Zhengyan
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: Graham G
authors.initials: GG
authors.lastname: Brown
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: Dong Hyuk
authors.initials: DH
authors.lastname: Ko
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: T J
authors.initials: TJ
authors.lastname: Hammond
authors.affiliation: Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: Ladan
authors.initials: L
authors.lastname: Arissian
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|The Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Boyd
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Ebrahim
authors.identifier: 0000-0002-8168-7304
authors.initials: E
authors.lastname: Karimi
authors.affiliation: Department of Physics, University of Ottawa, 25 Templeton St, Ottawa, Ontario, Canada K1N 6N5.|Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
authors.forename: P B
authors.initials: PB
authors.lastname: Corkum