Tapering Enhanced Stimulated Superradiant Amplification

There is a considerable and rapidly growing demand for free space propagating high power THz sources. Free Electron Laser (FEL) technology is by far the most powerful THz source technology hitherto demonstrated. However, FEL facilities are large and expensive, and could not in their present form be transformed into field deployable instruments, such as required by most applications. In response to this problem, RadiaBeam Technologies and UCLA are developing Tessatron, a THz source based on two innovations: (1) use of Tapering Enhanced Stimulated Superradiant Amplification (TESSA) high efficiency energy extraction scheme, and (2) use of a zero-slippage waveguide to support high bandwidth interaction over considerable length. As a result, numerical models indicates that Tessatron can achieve unprecedented efficiency and high output power, in a very compact footprint, while being composed of simple and robust building blocks consistent with field deployable usage. During the Phase II, the TESSA modeling tools were fully developed, and the Theseus undulator system (a key building component of Tessatron) has been designed, engineered, fabricated, tuned and fiducialized. Originally Phase II pursued a different goal of building a UV TESSA system (which is still on target). However, this work inspired the invention of the Tessatron, which represents a major commercial opportunity. In Phase IIB we propose to carry out a proof of concept Tessatron experiment at UCLA, followed by the construction of the full scale high average power Tessatron system at RadiaBeam. This project has the potential to disrupt the field of high average and peak power THz sources. There are many unique characteristics of the proposed source such as compactness, high efficiency and high bandwidth. The very high extraction efficiency will enable scaling up the average power to unprecedented levels for power-hungry security, medical and industrial applications. This is a rapidly growing cutting edge market with many exciting possibilities that can be realized by advances in THz source performance, such as pursued herein. Besides the technical and commercial benefit, this project also offers a strong scientific case, as the subject of tapered high efficiency FEL is presently at the forefront of the scholarly debate about the future of light source technology.