Generation and evolution of the terahertz vortex beam

He, Jingwen; Wang, Xinke; Hu, Dan; Ye, Jiasheng; Feng, Shengfei; Kan, Qiang; Zhang, Yan

doi:10.1364/oe.21.020230

Cited by 191 publications

(111 citation statements)

References 41 publications

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“…Currents that are excited by the co-polarized incident field will therefore radiate in the cross-polarization. For this reason, complementary "V" [180][181][182][183] and "C"-shaped 44,184 metallic resonators, such as that which is shown in Fig. 14(a), are a popular choice, as these shapes are naturally amenable to this form of commutation of current vectors.…”

Section: B Transmitarraysmentioning

confidence: 99%

Tutorial: Terahertz beamforming, from concepts to realizations

et al. 2018

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The terahertz range possesses significant untapped potential for applications including high-volume wireless communications, noninvasive medical imaging, sensing, and safe security screening. However, due to the unique characteristics and constraints of terahertz waves, the vast majority of these applications are entirely dependent upon the availability of beam control techniques. Thus, the development of advanced terahertz-range beam control techniques yields a range of useful and unparalleled applications. This article provides an overview and tutorial on terahertz beam control. The underlying principles of wavefront engineering include array antenna theory and diffraction optics, which are drawn from the neighboring microwave and optical regimes, respectively. As both principles are applicable across the electromagnetic spectrum, they are reconciled in this overview. This provides a useful foundation for investigations into beam control in the terahertz range, which lies between microwaves and infrared light. Thereafter, noteworthy experimental demonstrations of beam control in the terahertz range are discussed, and these include geometric optics, phased array devices, leaky-wave antennas, reflectarrays, and transmitarrays. These techniques are compared and contrasted for their suitability in applications of terahertz waves.

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Section: B Transmitarraysmentioning

confidence: 99%

Tutorial: Terahertz beamforming, from concepts to realizations

et al. 2018

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“…Several methods, including spiral phase plates [14,15], computer-generated holograms [16,17], metasurfaces [18], and Pancharatnam-Berry phase optical elements (PBOEs) [19,20] have been implemented to generate THz vortex beams; however, they are either fixed without tunability and switchability, or suffer from low efficiency. Liquid crystal (LC) is an excellent candidate for THz devices [21][22][23][24][25][26][27][28].…”

Section: Principlesmentioning

confidence: 99%

Generating, Separating and Polarizing Terahertz Vortex Beams via Liquid Crystals with Gradient-Rotation Directors

Shen

Chen

et al. 2017

Crystals

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Liquid crystal (LC) is a promising candidate for terahertz (THz) devices. Recently, LC has been introduced to generate THz vortex beams. However, the efficiency is intensely dependent on the incident wavelength, and the transformed THz vortex beam is usually mixed with the residual component. Thus, a separating process is indispensable. Here, we introduce a gradient blazed phase, and propose a THz LC forked polarization grating that can simultaneously generate and separate pure THz vortices with opposite circular polarization. The specific LC gradient-rotation directors are implemented by a photoalignment technique. The generated THz vortex beams are characterized with a THz imaging system, verifying features of polarization controllability. This work may pave a practical road towards generating, separating and polarizing THz vortex beams, and may prompt applications in THz communications, sensing and imaging.

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“…One of the possible applications of such beam shaping is vortex beam generation, which can be realized by determining the polarization state distribution. Based on this method, the vortex beam properties can be used in a THz holographic imaging system [25].…”

Section: Introductionmentioning

confidence: 99%

Detection of the polarization spatial distribution of THz radiation generated by two-color laser filamentation

Smirnov¹,

Kulya²,

Tcypkin³

et al. 2017

Nanosystems: Phys. Chem. Math.

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The spatial distribution of the terahertz radiation polarization is experimentally measured from a femtosecond laser two-color filament in air. Terahertz radiation generation from two-color plasma filamentation with a β-BBO crystal located behind the lens leads to the spatial inhomogeneity of the polarization distribution. Inhomogeneity of the terahertz field polarization is determined by the polarization of the fundamental harmonic of the pump radiation after passing through the β-BBO crystal. A spatial inhomogeneity of the fundamental harmonic polarization is observed owing to the β-BBO crystal acting as a phase plate illuminated by a spherical front.

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Generation and evolution of the terahertz vortex beam

Cited by 191 publications

References 41 publications

Tutorial: Terahertz beamforming, from concepts to realizations

Tutorial: Terahertz beamforming, from concepts to realizations

Generating, Separating and Polarizing Terahertz Vortex Beams via Liquid Crystals with Gradient-Rotation Directors

Detection of the polarization spatial distribution of THz radiation generated by two-color laser filamentation

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