Numerical simulation of broadband vortex terahertz beams propagation

International Conference of Young Scientists and Specialists "Optics-2015"

Semenova, V.A.^1 ; Kulya, M.S.^1 ; Bespalov, V.G.^1

ITMO University, Department of Photonics and Optoinformatics, 3/2B Kadetskaya line, Saint Petersburg, Russia^1

关键词: Amplitude and phase distributions;    Broadband terahertz;    Free-space communication;    Orbital angular momentum;    Radio frequency communication;    Scalar diffraction theory;    Spiral phase plates;    Terahertz communication;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/735/1/012064/pdf
DOI  :  10.1088/1742-6596/735/1/012064

来源: IOP

【 摘 要 】

Orbital angular momentum (OAM) represents new informational degree of freedom for data encoding and multiplexing in fiber and free-space communications. OAM-carrying beams (also called vortex beams) were successfully used to increase the capacity of optical, millimetre-wave and radio frequency communication systems. However, the investigation of the OAM potential for the new generation high-speed terahertz communications is also of interest due to the unlimited demand of higher capacity in telecommunications. Here we present a simulation-based study of the propagating in non-dispersive medium broadband terahertz vortex beams generated by a spiral phase plate (SPP). The algorithm based on scalar diffraction theory was used to obtain the spatial amplitude and phase distributions of the vortex beam in the frequency range from 0.1 to 3 THz at the distances 20-80 mm from the SPP. The simulation results show that the amplitude and phase distributions without unwanted modulation are presented in the wavelengths ranges with centres on the wavelengths which are multiple to the SPP optical thickness. This fact may allow to create the high-capacity near-field communication link which combines OAM and wavelength-division multiplexing.