Tailored structural units in plasma photonic crystal for dynamic electromagnetism manipulation

Abstract Plasma photonic crystal (PPC) offers a promising platform for the dynamic control of microwaves and terahertz waves. However, it remains a challenge for creating PPCs allowing for flexible control over their geometric configurations. Here we demonstrate an efficient method for realizing a dynamic control of structural units in PPCs using dielectric barrier discharges. Three tuning strategies are proposed: (i) modulating the structure of sub-lattice within the unit cell, (ii) varying the number of scattering elements within the unit cell, and (iii) tailoring the geometry of scattering elements, which lead to three key functionalities including bandwidth broadening, frequency band shifting, and tunable valley-topological edge states, respectively. Moreover, three distinct discharge stages of PPCs are observed using fast camera diagnostics. A phenomenological reaction-diffusion model with spatial modulations is developed to demonstrate the reconfiguration mechanism of various PPCs. Experimental observations agree well with the numerical simulations. Our method introduces an additional geometric degree of freedom for PPC control, offering benefits in terms of rapid response, enhanced flexibility, and low-cost fabrication.