Far-infrared slab lensing and subwavelength imaging in crystal quartz

We examine the possibility of using negative refraction stemming from the phonon polariton response in an anisotropic crystal to create a simple slab lens with plane parallel sides, and show that imaging from such a lens should be possible at room temperature despite the effects of absorption that are inevitably present due to phonon damping. In particular, we consider the case of crystal quartz, a system for which experimental measurements consistent with all-angle negative refraction associated with the phonon polariton response have already been demonstrated. Furthermore, we investigate the possibility of subwavelength imaging from such materials, and show that it should be possible for certain configurations.