Abstract: Metasurfaces are thin, periodically patterned subwavelength strcuture that exhibit optical properties not present in their constituent materials. The modes and spectral features can be used for applications often considered impossible with conventional optics such as perfect reflectivity, strong mode confinement, and other goals. In this talk, I will present work on two types of metasurfaces operating in the mid-infared. The first project studies the thermal stability of a "laser sail", a metasurface designed to be both highly reflective and have low absorption. This sail could one day be used as a spacecraft. With a GW-scale laser, the radiation pressure could accelerate the surface to a signicant fraction of the speed of light. The second project studies the possibility of integrating graphene into a metasurface exhibiting extremely narrow spectral features in order to modulate the frequency of the mode in situ. Such a device would find applications in free-space optical communication and trace gas sensing.