Nonlinear hyperbolic metamaterials

Abstract

We will discuss experimental studies and numerical modeling of second- and third-order nonlinear optical processes in hyperbolic metamaterials based on metallic nanorods. Second-harmonic generation and ultrafast Kerr-type nonlinearity originating from metallic component of the metamaterial will be considered. The enhanced nonlinear optical response can be facilitated using metals as active media (1). From this point of view, plasmonic structures are very promising for ultrafast all-optical applications at low light intensities providing both ultrafast nonlinear response and its enhancement. Hyperbolic metamaterials, in particular those based on plasmonic nanorod arrays, provide wealth of exciting applications providing designed linear and nonlinear properties, polarization control, spontaneous emission control and many others (2,3,4). Experiments and modeling have already demonstrated very strong Kerr- nonlinear response and its ultrafast recovery due to the nonlocal nature of the plasmonic mode of the metamaterial (5,6), so that small changes in the permittivity of the metallic component under the excitation modify the nonlocal response that in turn leads to strong changes of the metamaterial transmission. Such nonlinearities can be specifically engineered for a required wavelength range by changing the nanostructure parameters. Coupled plasmonic nanoparticles have also been proposed as a means to propagate energy through linear chains of closely coupled nanoparticle chains, while still maintaining sub-wavelength lateral widths. In this talk, we will discuss experimental studies and numerical modeling of second- and third-order nonlinear optical processes in hyperbolic metamaterials based on metallic nanorods (7-11). Second-harmonic generation and ultrafast Kerr-type nonlinearity originating from metallic component of the metamaterial will be considered, including nonlinear magneto-optical effects. Nonlinear optical response of stand-alone as well as integrated metamaterial components will be presented. Such hyperbolic metamaterials provide a new class of optical media for ultrafast strongly-nonlinear processes, with numerous applications in optical communications, extraordinarily sensitive optical spectroscopies and sub-wavelength imaging technologies.