Wed, May 08
4:00 PM — 5:00 PM
Marshak Science160 Convent AvenueNew York, NY 10031
Marshak Science, 418N
"Grapheotonics: Photonics with CNTs and Graphene"Colloquium, May 8, 2013 @ 4 PM, MR 418 N
SPEAKER: Professor Stefan Strauf, Stevens Institute of Technology
"Grapheotonics: Photonics with CNTs and Graphene"
Department of Physics and Engineering Physics
Stevens Institute of Technology, Hoboken NJ 07030
Carbon allotropes such as carbon nanotubes (CNTs) and graphene have recently gained tremendous interest as a nanomaterial for optoelectronic and quantum photonics devices. In this talk I will review some of our recent work aiming to realize single-photon-sources and wavelength-tunable photodetectors with enhanced performance. The large exciton binding energies of about 400 meV in CNTs are attractive for practical devices, however optical emission suffers from blinking and spectral diffusion. We show how these detrimental effects can be eliminated by embedding the emitter into polymer cavities giving rise to 50-fold enhanced single-photon emission. Utilizing air-bridged CNTs we have also been able to demonstrate prolonged spontaneous emission and exciton dephasing times at the onset of the intrinsic regime, which are both promising properties towards on-chip quantum photonics. A second topic addresses nanostructured graphene which is known to suffer from edge disorder where armchair and zigzag edges are mixed, reducing the achievable band gap energy. We show how Raman spectroscopy can be used to determine the fractional edge composition and furthermore how edge chirality can be purified in graphene nanoribbons by triggering edge reconstruction all optical. Finally, we will discuss how the performance of broadband IR photodetectors made from CVD-grown graphene can be drastically enhanced by decoupling it from the environment.
Dr. Stefan Strauf joined Stevens Institute of Technology in 2006 as an Assistant Professor of Physics and Engineering Physics were he established an experimental nanophotonics lab. He received a PhD from Bremen University (Germany) in 2001 working on GaN and quantum optics with II-VI semiconductors. During his 4 postdoc years at UC Santa Barbara he demonstrated GaAs-based ultra-bright single photon sources and photonic crystal quantum dot nanolasers with world record performance. His current research focuses on novel graphene and CNT-based optoelectronic devices, such as quantum light sources, tunable IR detectors, and flexible solar cells as well as fundamental materials studies of nanostructured graphene. Dr. Strauf has published 60+ papers including 19 letter journal papers. He received a Max-Kade foundation postdoc fellowship in 2003, the Harvey M. Davis Memorial Award for Research Excellence in 2008, and the NSF CAREER award in 2011. His web page can be found at www.stevens.edu/nanophotonics.