Abstract-Vectorial Properties of a Terahertz Bessel Beam

Xinke Wang,  Zhen Wu, Yan Zhang,

https://ieeexplore.ieee.org/document/8510365


As a kind of special beams, Bessel beams are always a research hot spot in optics due to its non-diffractive and self-healing properties. Here, a zero-order terahertz (THz) Bessel beam is generated by using a Teflon axicon. By applying a THz focal-plane imaging system, the evolutions of the transverse and longitudinal electric fields are coherently measured and analyzed during the propagation process of the THz Bessel beam. The work provides a comprehensive view for exactly understanding peculiar features of a THz Bessel beam.

Abstract-Vectorial diffraction properties of THz vortex Bessel beams

Zhen Wu, Xinke Wang, Wenfeng Sun, Shengfei Feng, Peng Han, Jiasheng Ye, Yue Yu, Yan Zhang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-2-1506&origin=search

A vortex Bessel beam combines the merits of an optical vortex and a Bessel beam, including a spiral wave front and a non-diffractive feature, which has immense application potentials in optical trapping, optical fabrication, optical communications, and so on. Here, linearly and circularly polarized vortex Bessel beams in the terahertz (THz) frequency range are generated by utilizing a THz quarter wave plate, a spiral phase plate, and Teflon axicons with different opening angles. Taking advantage of a THz focal-plane imaging system, vectorial diffraction properties of the THz vortex Bessel beams are comprehensively characterized and discussed, including the transverse (Ex, Ey) and longitudinal (Ez) polarization components. The experimental phenomena are accurately simulated by adopting the vectorial Rayleigh diffraction integral. By varying the opening angle of the axicon, the characteristic parameters of these THz vortex Bessel beams are exhibited and compared, including the light spot size, the diffraction-free range, and the phase evolution process. This work provides the precise experimental and theoretical bases for the comprehension and application of a THz vortex Bessel beam.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Vector characterization of zero-order terahertz Bessel beams with linear and circular polarizations

https://www.nature.com/articles/s41598-017-12524-y

As a kind of special beams, Bessel beams are always a research hot spot in optics due to its non-diffractive and self-healing properties. Here, zero-order terahertz (THz) Bessel beams with linear and circular polarizations are generated by using a THz quarter wave plate and Teflon axicons with different opening angles. By applying a THz digital holographic imaging system, the evolutions of the transverse (E x , E y ) and longitudinal (E z ) electric fields are coherently measured and analyzed during the propagation processes of the THz Bessel beams. The vectorial Rayleigh diffraction integral is used to accurately reproduce the amplitude, phase, and non-diffractive feature of each polarization component for the THz Bessel beams. With varying opening angles of the axicons, the focal spots, diffraction-free ranges, and Gouy phase shifts of the THz Bessel beams are compared and discussed. The experiment and simulation results provide a comprehensive view for exactly understanding peculiar features of THz Bessel beams.