Epsilon-near-zero materials in nonlinear optics: from theory to applications

Epsilon-near-zero (ENZ) materials have been key players in recent photonic applications due to their versatility in growth, excellent compatibility, and ability to be dynamically modulated. From a foundation in the recently developed carrier kinetic models of nonlinearities in ENZ materials, we discuss our efforts to realize scalable and high-quality Al:ZnO (AZO) films via a unique atomic layer deposition (ALD) process, and the use of AZO in both switching and frequency shifting applications. Throughout, we highlight the advantages and challenges that exist and conclude with an outlook for ENZ materials in the area of nonlinear optics.