“…To date, various tuning mechanisms have been successfully demonstrated, such as the use of phase-change materials, − mechanical stretching, − the injection of free-carriers, , and the use of thermo-optical effects . Among these, the integration of optical metasurfaces into liquid crystal (LC) cells has proven to be a successful strategy for realizing pronounced metasurface resonance tuning. − Because of their optical birefringence, i.e., the difference between the ordinary ( n o ) and extraordinary ( n e ) refractive indices, integrating LCs with metasurfaces provides an avenue to actively tune the optical properties of a device after fabrication. Utilizing this opportunity, it has been demonstrated that LC metasurfaces can be tuned with various stimuli, such as by changing the temperature or by applying an external electric field. ,,, The use of an external voltage together with temperature has also been suggested to further enhance the functionality of devices based on metasurfaces .…”