ECE Seminar Lecture Series

Terahertz Photonics

Roman Soboloewski

Wednesday, March 10, 2021
Noon–1 p.m. Passcode: 066310









The field of THz science and technology is still in its infancy, but has already gained a very large international interest due to its numerous applications ranging from ultrahigh speed communication systems to medical imaging and diagnostics, industrial quality control, and security screening. In conventional terms, we can talk about the “THz gap,” i.e., a region of electromagnetic radiation spectrum where it is very difficult to successfully operate either electronic or photonic “classical” devices. For even the fastest FET-type transistor structures, the THz frequency of operation is extremely high, while for optics the THz radiation wavelength is far too long, since THz quanta have the energy much smaller than the thermal background energy at room temperature. We present here a novel, integrated-optoelectronics approach that combines femtosecond laser pulses with materials and devices exhibiting sub-picosecond photo response times. We review our Ultrafast Quantum Phenomena Laboratory current THz photonics research, aimed towards generation and subsequent detection of sub-picosecond electrical transients for time-resolved (THz-bandwidth) studies of novel materials and nanostructured devices. Our free-space THz spectroscopy setup is characterized by the operational frequency bandwidth of up to 5 THz and is very well suited for noninvasive tests of various chemical compounds and biological materials. As examples, we present time-resolved characterization of novel, spintronic emitters of THz transients based on the inverse spin Hall effect; femtosecond spectroscopy studies of graphene nano-flakes imbedded in a polymer medium, forming a nanocomposite with the 1% graphene content, as well as THz imaging of biomaterials, specifically, ex-vivo imaging of mouse pancreatic normal and tumor tissues. Future prospects of THz photonics will complete our presentation

Roman Sobolewski is a Professor of Electrical and Computer Engineering, Physics, and Materials Science, as well as a Senior Scientist of Laser Energetics at the University of Rochester (UR), Rochester, NY, USA. At the UR Laboratory for Laser Energetics, he is the Head of the Ultrafast Quantum Phenomena Laboratory. Prof. Sobolewski received his PhD and DSc (Habilitation) degrees in Physics from the Polish Academy of Sciences, Warszawa, Poland, in 1983 and 1992, respectively. In 2006, he was granted the State Professorship of the Republic of Poland. In 2011, he received the Spanish Government Research Scholarship and spent a semester at University of Salamanca, Spain. In 2015, he was named a Distinguished Fellow of the Kosciuszko Foundation Collegium of Eminent Scientists of Polish Origin and Ancestry. From 2009 till present, he has been a Co-Chair and Co-Organizer of the Photon Counting Applications conferences during the Biennial SPIE Europe Optics+Optoelectronics Meeting in Prague, Czechia. Dr. Sobolewski is the Optical Society of America Travelling Lecturer and already delivered lectures in China, Poland, and Italy. He is also the EU Senior ERASMUS+ Lecturer, and the Managing Committee Member in the EU COST Action: Nanoscale Coherent Hybrid Devices for Superconducting Quantum Technologies. His current research interests are concentrated on ultrafast phenomena in condensed matter, novel nanostructured electronic and photonic semiconducting and superconducting materials and devices, single-photon quantum detection and quantum communications, and on generation and detection of THz radiation transients and time-resolved THz spectroscopy. He has published over 400 peer-reviewed publications and presented well over 200 invited conference talks, lectures, seminars, and colloquia worldwide. He is a co-inventor of five US and international patents.