Abstract：Aiming at the precise measurement of terahertz(THz) beam divergence angle, a terahertz divergence angle measuring facility based on conical surface fitting was constructed based on single-frequency continuous wave terahertz source. By investigating the propagation mode of terahertz beam and analyzing its spatial characteristics of intensity distribution, the terahertz output beam is regarded as the conic surface in the far field range, and the spot image is collected by a terahertz detector, and the conic surface is constructed according to the coordinates of the edge points of the image. By means of indirect adjustment, the data of edge points are preprocessed and parameter iteration and conical surface fitting are used to calculate the divergence angle. The results show that the terahertz source divergence angle of 100GHz is 2.73°, and the relative expanded uncertainty is 3.8% (k=2).
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2024, Vol. 45 
