Thursday, August 4, 2016

Speaker Rice University-ECE Seminar Series: "Terahertz lasers based upon metamaterial concepts," Benjamin Williams

SpeakerBenjamin Williams
Associate Professor, EE
University of California Los Angeles

Tuesday, August 30, 2016
4:00 PM  to 5:00 PM 

1064  Duncan Hall
Rice University
6100 Main St
Houston, Texas, USA

The terahertz frequency range lies at the junction of the electronic and photonic regimes, which means that it is fertile ground for exploring hybrid systems which combine laser gain with microwave electromagnetic design. The terahertz quantum-cascade laser is an excellent example, which produces gain via intersubband electronic transitions within heterostructure quantum wells, but typically uses sub-wavelength waveguides that have a strong resemblance to microstrip transmission line. I will discuss two examples. First, we have demonstrated passive and active composite right/left handed (CRLH) waveguides and leaky-wave antennas, can radiate in a backward, surface normal, or forward direction, depending upon excitation frequency. Second, I will discuss THz amplifying reflectarray metasurfaces, and how they enable the realization of quantum-cascade vertical-external-cavity surface-emitting-laser (VECSELs). THz metasurface VECSELs enable scalable output power levels in conjunction with directive and circular output beams with near diffraction limited beam quality.
Biography of Benjamin Williams:
Benjamin Williams is an Associate Professor in the Department of Electrical Engineering at University of California Los Angeles. He received his B.S. in Physics from Haverford College in 1996, and his M.S. in 1998 and Ph.D. in 2003 both from the Massachusetts Institute of Technology in Electrical Engineering. He is Area Director for Physical and Wave Electronics Area within the EE Department, and is Associate Editor for IEEE Journal of Quantum Electronics. He has received the APS Apker Award (1996), the DARPA Young Faculty Award (2008), the NSF CAREER Award (2012), and the Presidential Early Career Award for Scientists and Engineers (PECASE) (2016). His research interests lie in photonic materials, devices, and applications for the terahertz and mid-infrared frequency ranges, including low-dimensional semiconductors, quantum-cascade lasers, and plasmonics and metamaterials.

No comments: