Direct Observation Of The Topological Charge Of A Terahertz Vortex Beam Generated By A Tsurupica Spiral Phase Plate

A terahertz (THz) spiral phase plate with high transmission (>90% after Fresnel correction) and low dispersion has been developed based on the Tsurupica olefin polymer. Direct observations of the topological charge (both magnitude and sign) of a THz vortex beam are performed by using a THz camera with tilted lens focusing and radial defect introduction. The vortex outputs with a topological charge of +/- 1 (or +/- 2) are obtained at a frequency of 2 (or 4) THz. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.