Chinese Physics B, Volume. 29, Issue 9, (2020)
Recent advances in generation of terahertz vortex beams and their applications
Fig. 1. Two scenarios of methods for THz vortex beam generation (SPPs: spiral phase plates, APEs: achromatic polarization elements, DOEs: diffractive optical elements, THz LC FPG: THz liquid crystal forked polarization grating, CGHs: computer-generated holograms, STM: spatial terahertz modulator, MPs: modulated plasmas, OR: optical rectification, DFG: difference-frequency generation).
Fig. 2. 3D model of an SPP with proper THz materials. Reproduced with permission from Ref. [
Fig. 3. Three examples of
Fig. 4. Schematic of the conversion process by APEs. Reproduced with permission from Ref. [
Fig. 5. Phase profiles of two BPSAs. (a)
Fig. 6. Schematic structure of two representative metasurfaces. (a)–(c) V-shaped slit antennas structure; (d)–(e) circular sub-wavelength slits. Reproduced with permission from Refs. [
Fig. 7. Phase presentation and idea 3D schematic structure of THz LC FPG. (a) A common spiral phase distribution; (b) introduced gradient blazed phase distribution; (c) integrated phase distribution; (d) ideal 3D LC FPG. Reproduced with permission from Refs. [
Fig. 8. Local grating structures. (a) Amplitude holograms; (b) phase holograms. Reproduced with permission from Ref. [
Fig. 9. Prototype of STM. Reproduced with permission from Ref. [
Fig. 10. Geometry of 〈110〉 ZnTe crystal. Reproduced with permission from Ref. [
Fig. 11. Some experimental devices for a pair of 800 nm vortex beams and some experimental results for THz vortex beam generation. (a) Passive and transmissive device of generating collinear vortex pulse pair of 800 nm with conjugated topological charges and orthogonal polarizations. P, polarizer;
Fig. 12. Simulation results of the generation of THz vortex beams via a type of (a) RPs; (b) SVPs; and (c) DVPs. Reproduced with permission from Ref. [
Fig. 13. Some experimental and simulation results of intensity modulated THz vortex beam generation via two-color or few-cycle vortex pump laser. (a) Experimental fluencies of Gaussian and vortex second harmonics, corresponding simulating and experimentally far-field THz fluencies in two-color vortex pump field case; (b) simulating fluency and electric field of two-color pump and corresponding far-field intensity and phase of two frequency components of THz pulses in two-color vortex pump field case in Ref. [
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Honggeng Wang, Qiying Song, Yi Cai, Qinggang Lin, Xiaowei Lu, Huangcheng Shangguan, Yuexia Ai, Shixiang Xu. Recent advances in generation of terahertz vortex beams and their applications[J]. Chinese Physics B, 2020, 29(9):
Received: May. 13, 2020
Accepted: --
Published Online: Apr. 29, 2021
The Author Email: Lu Xiaowei (shxxu@szu.edu.cn)