A Terahertz-driven Electron Gun (Wenqian Huang, MIT)
Wenqian “Ronny” Huang (MIT) will give this week’s ECE graduate student seminar, entitled “A Terahertz-driven Electron Gun”, at 12pm on Wednesday 12/3 in AVW 1146.
Abstract: Electron sources at keV-MeV energies are indispensable for applications such as ultrafast electron diffraction, x-ray generation, and electron energy-loss spectroscopy. However, the accessibility and size of current accelerators based on radio-frequency (RF) technology are limited by the achievable electric fields. Terahertz (THz) based accelerators promise unprecedented compactness compared to current RF accelerators due to the intense electric fields that can be applied in the accelerating structures. Here, electron bunches of 50 fC from a flat copper photocathode are accelerated from rest to a mean energy of 18 eV and peak energy of 95 eV by a single-cycle THz field with peak electric field of 72 MV/m at 1 kHz repetition rate. The THz pulses are generated by tilted-pulse-front-pumping in lithium niobate with a high conversion efficiency of 1%. Scaling of the THz field into the gigavolt per meter regime would translate to electron energies of ~100 keV. Furthermore, in combination with the recent demonstration of a THz linear accelerator (linac), this is a milestone toward a millimeter- to centimeter-scale relativistic electron source.
Speaker Information: Wenqian “Ronny” Huang received a B.Sc. in applied physics from Cornell University in 2009. He then joined MIT Lincoln Laboratory, where he worked on infrared detectors and laser beam combining until 2012. He is currently pursuing a Ph.D. in electrical engineering at MIT under Prof. Franz Kaertner. Research interests include terahertz generation, electron acceleration, and ultrafast nonlinear optics. He is sponsored by the NDSEG fellowship.