Many plasma and non-plasma environments, particularly fusion facilities, are very harsh environments requiring diagnostic survivability in high-radiation, high-temperature, low pressure, high laser power, high microwave power, and/or high-magnetic field conditions. The Diagnostics Center has developed solutions to be able to image, sense, and survive in such environments such as solutions for imaging through a single multi-mode fiber and using THz radiation to measure wall temperature inside a fusion machine. The Center is also developing metamaterials to reduce surface reflections at windows and manipulate THz radiation in novel ways.