PHYSICS/BK21 Colloquium[09.12.4]
관련링크
본문
“Doubly Terahertz Nano Metamaterials”
Ø* Speaker : Prof. Dae Sik Kim [Seoul National University]
Ø* Place : Demonstration Lecture Hall 122, Postech Information Research Laboratories
Ø* Date & Time : Dec, 4(Fri) 4:00 ~ 5:00 pm
ØAbstract
Thin layers of semiconductors, superconductors, correlated electron systems, and polymers are the
core elements of modern science and technology. Metamaterials research also heavily utilizes thin
films, nonlinear index increases of which caused by photo-excitation, voltage, or temperature have
been used to actively control technologically important long wavelength electromagnetic waves.
These control attempts are however met with only partial success, because the l/1,000 ~ l/100,000
films are optically too thin even considering the large dielectric constants, and also because the
Control has limited spectral range around resonance. Here, we show that broadband, long
wavelength nano antennas on VO2 (vanadium dioxide) films, initially transparent to incoming
electromagnetic waves, achieve a 100,000 to 1 extinction by phase transition of the underlying
thin film, thereby increasing the dielectric constant to over 500,000. Our scheme, utilizing strongly
evanescent wavevector components below the nanoscale features, offering orders of magnitudes
tenability of nonlinearities and dielectric constants, bridges the gap between thin film technology,
nanotechnology, and active metamaterials researches.
Contact Person : Prof. Dong-Eon Kim(054-279-2089, kimd@postech.ac.kr)