Dynamic light-driven metasurface: Harnessing quasibound states in the continuum for laser-induced selective crystallization

We present the design of an asymmetric metasurface made of germanium antimony tellurium nanowires that supports quasibound states in the continuum. A fully coupled optothermal model is used to show that, when exposed to brief and intense laser pulses, the metasurface undergoes a partial, geometrically controlled crystallization, thereby inducing an ultrafast dynamic wavelength shift of the quasibound state in the continuum of the order of 350 nm with pump intensities as low as 35 MW/cm2. The proposed approach highlights the potential for controlling nanostructures' response through laser illumination, opening avenues for applications in dynamic optical modulation and beyond.