Fiber-Optic Bolometers for Fusion Plasma Diagnostics

Bolometers are widely used in fusion devices for measurement of plasma radiation. They are essential for energy balance estimate, exhaust control, disruption mitigation, and study of plasma instability. Existing bolometers are electronic devices and their performance show significant degradation in the harsh environment in fusion devices characterized by the presence of strong electromagnetic interference and high temperature. This project will explore fiber-optic bolometers that will be immune to electromagnetic interference, resulting in higher detection sensitivity. Additionally, the fiber-optic bolometers promise lower cost per channel and smaller sensor size for improved spatial resolutions and increased mechanical robustness. The project is based on six years of fundamental research of the team and their collaborators. A single-channel FOB system has been successfully tested at a major fusion facility that shows the distinct advantages of fiber-optic bolometers compared with their electronic counterparts. This SBIR project is aimed at addressing the technical challenges in transforming the technology into a viable product widely available for the fusion community. Specifically, the project will study the feasibility of low-cost, high-efficient fabrication methods of fiber-optic bolometers, construct a four-channel fiber-optic bolometer system, and test its performance in the lab environment. Thermal fusion has the enormous potential of providing immense energy with no emission of greenhouse gases and minimum waste. Commercialization of the fiber-optic bolometers will provide the fusion community a critically important tool for the development and operation of fusion devices.