The Michigan Engineer News Center

Mona Jarrahi receives NSF CAREER Award

In her research Jarrahi will investigate, for the first time, the use of Ge as a promising candidate to tackle the thermal breakdown problem of photomixers.| Short Read

Mona Jarrahi, assistant professor of Electrical and Computer Engineering, was recently awarded an NSF CAREER award for her work on “Next Generation Photomixer-Based Terahertz Sources.”

Prof. Jarrahi will address the output power limitation of existing photomixers by investigating a new generation of plasmonic distributed Ge photomixers pumped at telecom wavelengths. By tackling the major obstacle of thermal breakdown of conventional photomixers, the proposed technology is expected to offer terahertz power levels that are orders of magnitude higher than is currently available from existing technologies.

A promising application of the technology is the development of high-performance terahertz imaging and spectrometry systems.

In this research she will investigate, for the first time, the use of Ge as a promising candidate to tackle the thermal breakdown problem of photomixers. She also aims to investigate the use of distributed plasmonic contact electrodes to further improve the quantum efficiency of Ge photomixers. Plasmonic electrodes are expected to significantly enhance the pump coupling efficiency, while enabling ultra-high-speed collection of photo-generated carriers. Moreover, distributed photomixer architectures mitigate the non-ideal effects associated with the high intensity optical pumps, such as the carrier screening effect and excessive heating.

Prof. Jarrahi directs the Terahertz Electronics Laboratory. She has taught the undergraduate course Electromagnetics II, and the newly created graduate level course, Terahertz Technology and Applications.


The CAREER grant is one of NSF’s most prestigious awards, conferred for “the early career-development activities of those teacher-scholars who most effectively integrate research and education within the context of the mission of their organization.”

Portrait of Catharine June


Catharine June
ECE Communications and Marketing Manager

Electrical Engineering and Computer Science

(734) 936-2965

3301 EECS

The electrons absorb laser light and set up “momentum combs” (the hills) spanning the energy valleys within the material (the red line). When the electrons have an energy allowed by the quantum mechanical structure of the material—and also touch the edge of the valley—they emit light. This is why some teeth of the combs are bright and some are dark. By measuring the emitted light and precisely locating its source, the research mapped out the energy valleys in a 2D crystal of tungsten diselenide. Credit: Markus Borsch, Quantum Science Theory Lab, University of Michigan.

Mapping quantum structures with light to unlock their capabilities

Rather than installing new “2D” semiconductors in devices to see what they can do, this new method puts them through their paces with lasers and light detectors. | Medium Read