Metal-dielectric optical microcavity with tunable Q factor

We consider a layered metal–dielectric microcavity with a liquid crystal used as a resonator layer. The transformation of the microcavity spectra is shown experimentally using three methods, namely, mechanical rotation of the sample, heating, and applying external voltage. The obtained spectra exhibit multiple vanishing resonant lines. It is found the vanishing resonant lines are not a spectral manifestation of the bound state in the continuum for this system. Despite the absence of true bound states in the continuum, an experimental tuning of the resonance Q factor via changing the radiation loss rate is demonstrated through variation of the optical properties of the liquid crystal layer.