Monday, February 18, 2019

Abstract-Generation of terahertz vortex pulses without any need of manipulation in the terahertz region


Qinggang Lin, Shuiqin Zheng, Qiying Song, Xuanke Zeng, Yi Cai, Ying Li, Zhenkuan Chen, Lang Zha, Xinjian Pan, and Shixiang Xu

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-44-4-887

Converting a Gaussian mode to a vortex beam is much more inconvenient in the terahertz (THz) region than in the near-infrared (NIR) region due to underdevelopment of THz components and strong THz diffraction. This Letter reports the direct generation of THz vortex pulses by optical difference-frequency between two NIR chirped pulses with different topological charges (TCs). By designing a passive and transmissive device for a collinear NIR pulse pair with conjugated TCs, we have experimentally obtained stable THz vortex pulses with a TC value of 2 or 2. The process needs no THz components and so is flexible to be realized and has promising applications in the THz field.
© 2019 Optical Society of America

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