Liquid Crystal‐Enabled Chiral Quasi‐BIC Metasurface Laser With Temperature‐Controlled Polarization

ABSTRACT A quasi‐bound state in the continuum (quasi‐BIC), which maintains a high Q ‐factor and localization of the electromagnetic field, is implemented in a dielectric metasurface. A liquid crystal (LC) layer covering the metasurface breaks the mirror symmetry and introduces chirality, leading to a chiral quasi‐bound state in the continuum (chiral‐BIC). Using the controllability of the LC, a change in circular dichroism (CD) through heating is demonstrated. Additionally, doping the LC with dye molecules enables a low‐threshold laser that emits elliptically polarized, temperature‐tunable radiation.