Phonon based high quality factor split ring resonators made from boron nitride

Metallic split ring resonators have achieved broad interest in the field of metamaterials and light matter interaction in general. We present split ring resonators fabricated from the van-der Waals material Boron Nitride and designed to operate in the reststrahlen band arround 1400 cm
^-1
. We observe two distinct modes in far field transmission spectra exhibiting high quality factors of 55 and 88. Simulations allow to identify the lowest mode as an LC-mode for which the displacement current is provided by the phononinc material instead of electrons as in metallic counterparts.