Optical Probes of Strongly Driven Quasiparticles in Solid State Platforms

High-order Harmonic Generation (HHG) and High-order Sideband Generation (HSG) are phenomena which rely on the non-equilibrium, nonperturbative, and non-linear dynamics of quasiparticles. First demonstrated in atomic gasses, HHG has expanded to solid-state platforms and developed as a probe for the physics of quasiparticles driven by large laser fields. Microscopic theories have laid the framework with conceptual descriptions and quantitative predictions for the phenomenon. Around the same time, the related process of HSG was observed in semiconducting systems. Likewise, semiclassical and fully quantum microscopic theories have been developed to explain experimental results. For both, an increased understanding of the quasiparticle dynamics have lead to enhanced experimental understanding, connecting the observed spectra to the quantum behavior of the systems responsible for the generation. This review develops a theoretical understanding and highlights experimental triumphs of the two phenomena, and outlines future research questions which can be addressed by these complementary all-optical methods.