I will discuss how coherent electromagnetic radiation at infrared and TeraHertz frequencies can be used to drive collective excitations in solids nonlinearly. The driven cooperative response can yield new types of functional control. I will discuss experiments in which superconducting fluctuations can be amplified by light at temperatures higher than the thermodynamic transition temperature. I will also discuss the physics of superconducting plasmons in layered superconductors and how these reveal new nonlinear THz phenomena.