Professor William Putnam Receives an Air Force Office of Scientific Research Young Investigator Program Award

Prof. Putnam

AFOSR logoPlease join us in congratulating Prof. William Putnam on receiving an Air Force Office of Scientific Research (AFOSR) Young Investigator Program (YIP) award for his proposal, entitled "Superradiant Smith-Purcell Emission in the Mid-Infrared via Guided-Wave Electron Optics”. The 2021 AFOSR YIP awards were given to 36 outstanding young engineers and scientists who have show exceptional ability and promise to conduct basic research in science and engineering. The objectives of the awards are to foster creative basic research, and to increase the opportunities for early-career scientists to recognize the Air Force mission and the related challenges in science and engineering.

Electron beams have been used to build high-power, tunable sources of electromagnetic radiation for the past century. In such sources, electron beams, propagating through free space, interact with and amplify traveling electromagnetic waves. At microwave frequencies, that is around the gigahertz-domain, this amplification is significant, and electron-beam-driven sources have been very successful. However, at higher frequencies, including the infrared part of the electromagnetic spectrum, the interactions between electron-beams and traveling electromagnetic waves are too brief for significant amplification.

In this three-year program, Prof. Putnam’s team aims to extend these interactions via specially designed, chip-scale electron “lenses”. These microfabricated lenses can guide electron beams such that the interaction between the beams and infrared electromagnetic waves can be extended to significant lengths. Such long interaction lengths can result in significant amplification and, accordingly, high-power infrared output radiation. The ultimate goal of the program is to make compact, high-power sources of infrared light for spectroscopy and medical applications.

Professor Putnam also recently received a 2020 College of Engineering Best ECE Teaching Award.