Research of bound states in the continuum and their polarization control in dielectric metamaterials

Abstract Optical metasurfaces exhibiting quasi-bound states in the continuum (q-BICs) display a distinctive polarization dependence. Accordingly, we examine the correlation between the q-BIC and the polarization form of the outgoing light, and put forth a method for generating pure line-polarized light via the q-BIC. The generator is a dielectric metasurface comprising silicon cleavage rings arranged periodically on a silicon dioxide substrate, which supports symmetry-protected bound states in the continuum. The proposed q-BIC is unable to be excited by x -direction polarized light, conversely, y -direction polarized light is completely eliminated due to the resonance of the q-BIC. Ultimately, we achieve perfectly x -direction polarized transmitted light at the resonance wavelength, with the transmitted light remaining unaffected by the polarization form of the incident light. By leveraging the q-BIC resonance, we have successfully converted arbitrarily polarized incident light into linearly polarized light using dielectric metasurfaces, and the conversion wavelength is highly tunable. This result can be utilized to in fields such as linear narrowband filters and polarization sensitive devices.