Physics Seminar Series

“Dynamic control of optical properties with gated-graphene metamaterials”

Prof. Teun-Teun Kim

Center for Integrated Nanostructure Physics (CINAP)

Institute for Basic Science (IBS)

Sungkyunkwan University (SKKU)

May 311 (Thu.), 04:00 PM

#1323, E6-2

Abstract:

In this talk, I will present recent my research results with different design of artificial media, called metamaterials which consist of the arrangement of periodic subwavelength optical elements that exhibit unusual optical properties beyond what natural materials can offer. I will show the gate-induced switching and linear modulation of terahertz waves can be achieved in a hybrid material system consisting of artificially constructed meta-atoms and an atomically thin graphene layer [1]. It has been experimentally demonstrated that by integrating graphene with metamaterials, significant transmission amplitude modulation of up to 50% with high modulation speed of about 80ns was achieved with gated graphene metamaterials. Based this approach, I will introduce electrically controllable unique optical properties such as optical activity [2], anomalous refraction, and focusing [3], and analogue of electromagnetically induced transparency (EIT) [4] by integrating 2D graphene layer onto metamaterials with different functional unit cells. The switching and linear modulation of unique optical properties are realized by changing coupling among meta-atoms or electrical conductivity of metallic structures caused by increased sheet conductivity of the single layer graphene. Benefitting from the electrically controllable unique optical properties, the proposed graphene based meta-devices are expected to provide a myriad of important applications such as active polarization controllers, active slow light devices, ultrasensitive sensors and nonlinear devices. 

Reference 

[1] S. H. Lee, et al, Nature Materials 11,936-641 (2012)

[2] T. -T. Kim, et al, Science Advances 3, e1701377 (2017)

[2] T. -T. Kim, et al, Advanced Optical Materials 6(1)1700507, (2018)

[3] T. -T. Kim, et al, ACS Photonics, 5(5), 1800-1807(2018).

Department of Physics, KAIST