OSE Seminar by Dr. Roberto Paiella on Metasurface-enhanced light emission
Posted: March 20, 2018
Date: Wednesday, March 21, 2018
Time: 11:00 AM to Noon
Location: CHTM, Rm. 101
Map to CHTM:
Parking passes are available at the receptionist's desk.
Metallic nanostructures can be used as optical antennas to control the radiation properties of nearby light emitters, via the near-field excitation and subsequent radiative decay of plasmonic oscillations. Here this basic idea is investigated as a means to increase the efficiency and functionality of optoelectronic light-emitting devices. Large enhancements in the radiative efficiency of III-nitride LED materials have been obtained through the use of localized surface-plasmon resonances and lattice surface modes in periodic arrays of metallic nanocylinders. Unidirectional beaming at geometrically tunable angles has also been demonstrated, based on the excitation of surface plasmon polaritons and their diffractive scattering by a phased array of asymmetric metallic nanoparticles. The latter approach is currently being generalized to the use of gradient metasurfaces (i.e., planar nanoantenna arrays designed to introduce a linearly graded phase shift upon reflection), which can provide remarkable flexibility in tailoring far-field radiation patterns. Finally, we are investigating the design of dielectric metasurfaces supporting strong Mie-resonant lattice surface modes, that can produce similarly large enhancements in spontaneous emission rates without the additional optical absorption losses of plasmonic systems.
Roberto Paiella is a Professor of Electrical and Computer Engineering and a Faculty Member of the Photonics Center at Boston University, with a joint appointment in the Division of Materials Science and Engineering. He received the B.S. and M.S. degrees in Electrical Engineering from Columbia University in 1993 and 1994, and the Ph.D. degree in Applied Physics from Caltech in 1998. His thesis research was focused on the nonlinear optical properties and applications of semiconductor optical amplifiers. In 1998 he joined Bell Laboratories, Lucent Technologies, as a Postdoctoral Member of the Technical Staff, where he developed high-speed quantum cascade lasers for ultrafast pulse generation and optical wireless communications. His current research at BU is focused on group-IV semiconductor photonics, plasmonic control of radiation and absorption processes, and terahertz optoelectronics. Dr. Paiella has coauthored over 80 journal articles, delivered more than 30 invited talks, and edited a book on “Intersubband Transitions in Quantum Structures”. He is a program committee member of Photonics West and CLEO, and an editorial board member of Scientific Reports.