Low-threshold bistable absorption in asymmetrical one-dimensional photonic crystals containing Weyl semimetal defects.

In this paper, we investigate the low-threshold optical bistable absorption in an asymmetrical one-dimensional photonic crystal structure (1D-PhC) containing a Weyl semimetal (WSM) defect layer. Dirven by the strong third-order nonlinear effect of the WSM and the field enhancement of the defect mode, low-threshold bistable absorption is achieved in the terahertz band. After optimizing the parameters, the rising threshold intensity is 83.7817 MW/m2 and the falling threshold intensity is 49.39 MW/m2, which are lower than the threshold intensities of bistable absorption in the reported works. Meanwhile, we discuss the effects of Fermi level of WSM, incident angle, and the numbers of periods of the left and right 1D-PhCs on the bistable absorption. Our work would facilitate the design of high-performance all-optical switches, all-optical logics, and optical absorbers. [ABSTRACT FROM AUTHOR]