Broadband THz, extended depth of focus imaging based on step phase mask aided interferometry

We present the generation of arbitrary order Bessel beams at 0.3 THz through the implementation of suitably designed axicons based on 3D printing technology. The helical axicons, which possess thickness gradients in both radial and azimuthal directions, can convert the incident Gaussian beam into a high-order Bessel beam with spiral phase structure. The evolution of the generated Bessel beams are characterized experimentally with a three-dimensional field scanner. Moreover, the topological charges carried by the high-order Bessel beams are determined by the fork-like interferograms. This 3D-printing-based Bessel beam generation technique is useful not only for THz imaging systems with zero-order Bessel beams but also for future orbital-angular-momentum-based THz free-space communication with higher-order Bessel beams.

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Bessel-like beam generated by an axicon based on parallel-plate waveguides

Shen

Lang

et al. 2018

Appl. Opt.

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The axicon is the simplest and most effective optical element for generating the zero-order Bessel-like beam. The zero-order Bessel-like beam, which has the characteristics of small spot size, high brightness, good direction, and large collimation distance, can be applied to optical micromanipulation and power transmission. In this paper, we proposed and designed a structure for phase manipulation based on parallel-plate waveguides that can be used to realize the functionality of the axicon in the terahertz (THz) region. Meanwhile, we characterized the influence of the cone angle of the axicon and the waist radius of the incident Gaussian beam on the generated zero-order Bessel-like beam by simulation. The planar structure, consisting of a parallel stack of thin copper plates, can be easily fabricated to fulfill the phase requirement to realize the zero-order Bessel-like beam and also can be utilized in THz imaging systems, THz sensing systems, THz communication systems, etc.

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Broadband THz, extended depth of focus imaging based on step phase mask aided interferometry

Cited by 5 publications

References 12 publications

Numerical and experimental analysis of Bessel beam properties based on continuous-wave terahertz radiation

Numerical and experimental analysis of Bessel beam properties based on continuous-wave terahertz radiation

Generation of arbitrary order Bessel beams via 3D printed axicons at the terahertz frequency range

Bessel-like beam generated by an axicon based on parallel-plate waveguides

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