Events Calendar

"Photonic Devices Based on Semiconductor Quantum Structures"

Dr. Igor Vurgaftman; Naval Research Laboratory 

Research in semiconductor photonics takes place at the intersection of condensed matter physics, optics, electromagnetism, and quantum theory. I will describe how the tools from different areas of physics are combined with epitaxial growth, microfabrication, and device characterization to advance semiconductor photonics using a few examples from the mid-infrared (3-6 mm) region of the spectrum. The first is the development of quantum intersubband and interband cascade lasers (QCLs and ICLs) over the last 25 years. The second is more recent and concerns the experimental demonstration and theoretical understanding of cascade laser-based and nonlinear-resonator-based frequency combs. I will start by reviewing the physical rationale for cascading active quantum wells in mid-infrared lasers, the use of interband vs. intersubband transitions, and the particular choices made in the design of these devices. I will try to add a historical perspective that may shed some light on how notable breakthroughs in the device performance came about. Then I will pivot to discussing the nature of various operating modes of equidistant infrared frequency combs, including pulsed, FM, and harmonic combs, the physical reasons for their behavior including dispersive and nonlinear-optical effects, and the current state of the field. Important open problems and unanswered questions will be outlined.

16 NOV 2021: Physics and Astronomy Colloquium
3:30pm, Online via Zoom
Zoom Link: https://uiowa.zoom.us/j/94392147007
Meeting ID: 943 9214 7007, No passcode