title: Beam propagation of efficient frequency-doubled optical vortices.
abstract: Frequency doubling of optical vortices is demonstrated with an optical-optical efficiency exceeding 70%, using a spiral phase plate at a fundamental vortex energy of 10.6 mJ. Beam propagation of the doubled vortex output is also investigated both experimentally and theoretically. Spatial transforms in the output during propagation are observed.
authors.forename: Taximaiti
authors.initials: T
authors.lastname: Yusufu
authors.forename: Yuta
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Shungo
authors.initials: S
authors.lastname: Araki
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Takashige
authors.initials: T
authors.lastname: Omatsu