Our group focuses on the physics and engineering of light on a mesoscopic-scale ranging from tens of microns down to tens of nanometers.  In this regime, myriads of fascinating optical phenomena can be explored both theoretically and experimentally.

 

Metamaterials
  A metamaterial is a material which gains its properties from its structure rather than directly from its composition. Metamaterial is a conceptual breakthrough that emerged less than a decade ago, and now the field of metamaterials have exploded in the last few years.  Recently, researchers have demonstrated fishnet-type 3D bulk metamaterials having negative index of refraction at optical frequency that bends the light in the wrong direction.  Our group will investigate unexplored functionalities that only the metamaterial can provide and we will search for new application areas of metamaterials. 
 
Optomechanics
  Ultrahigh-Q whispering-gallery cavity is an ideal template to study the mechanical oscillation or cooling of a cantilever-like dielectric structure.  The underlying mechanism of this mechanical oscillation or cooling is originated from the radiation pressure of confined photons inside the cavity, which exerts an outward force on the cavity wall.  This is a newly developed area of research and this research renders vast opportunities for the applications of photon-induced mechanical oscillators (> 1 GHz) or the cooling of the cavity to effective cryogenic temperatures by dynamic back-action.  Even more interestingly, it is now anticipated that the quantum behavior of a macroscopic object will be attainable with further advances in this cooling technique.
 
Plasmonics 
  Surface plasmon-polariton (collective electron density wave) propagating along the interface of two materials having oppositely-signed permittivities is now being widely exploited to enable subwavelength-scale functional optical devices owing to its highly localized electromagnetic energy density profiles.  However, a fundamental bottleneck for the realization of SPP nano-optical functional devices stems from large metal loss at optical frequencies induced by ohmic resistive heating.  Hence, any type of plasmonic resonator based on a plasmonic waveguiding principle is mostly limited by the metal loss in addition to other sources of loss contributions such as roughness-induced scattering, radiation into free space/substrate or bending-induced radiation.  While other types of plasmonic cavities can be built, whispering-gallery resonances, which are also found for various types of travelling waves in axisymmetric resonant structures, are especially attractive due to their extremely high reflectivity.

Seung Hoon Lee, Muhan Choi, Teun-Teun Kim, Seungwoo Lee, Ming Liu, Xiaobo Yin, Hong Kyw Choi, Seung S. Lee, Choon-Gi Choi, Sung-Yool Choi, Xiang Zhang, and Bumki Min
Switching terahertz waves with gate-controlled active graphene metamaterials
Nature Materials, 2012, Vol. 0, No. 0, pp. 0~ 0

Sunkyu Yu, Xianji Piao, Sukmo Koo, Jung H. Shin, Seung Hoon Lee, Bumki Min, and Namkyoo Park
Mode junction photonics with a symmetrybreaking arrangement of mode-orthogonal heterostructures
Optics Express, 2011-12, Vol. 19, No. 0, pp. 25500~ 25511

Tao Lu, Lan Yang, Tal Carmon, and Bumki Min
A narrow linewidth on-chip Raman laser
IEEE Journal of Quantum Electronics, 2011-03, Vol. 47, No. 0, pp. 320~ 326

Seungwoo Lee, Seongnam Kim, Teun-Teun Kim, Yushin Kim, Muhan Choi, Seung Hoon Lee, Ju-Young Kim, and Bumki Min
Reversibly stretchable and tunable terahertz metamaterial with wrinkled layouts
Advanced Materials, 2012-07, Vol. 24, No. 0, pp. 3491~ 3497

Muhan Choi, Seung Hoon Lee, Yushin Kim, Seung Beom Kang, Jonghwa Shin, Min Hwan Kwak, Kwang-Young Kang, Yong-Hee Lee, Namkyoo Park, and Bumki Min
A terahertz metamaterial with unnaturally high refractive index
Nature, 2011-02, Vol. 470, No. 0, pp. 0~ 0

Hyun Sung Park, Jagang Park, Jaehyeon Son, Yushin Kim, Hyukjoon Cho, Jonghwa Shin, Wonju Jeon & Bumki Min
A general recipe for nondispersive optical activity in bilayer chiral metamaterials
submitted , 2018, Vol. 0, No. 0, pp. 0~ 0

Kanghee Lee, Jaehyeon Son, Jagang Park, Byungsoo Kang, Wonju Jeon, Fabian Rotermund & Bumki Min
Linear frequency conversion via sudden merging of meta-atoms in time-variant metasurfaces
Nature Photonics, 2018, Vol. 0, No. 0, pp. 0~ 0

Yong Rae Cho, Donghwan Kim, Woo Young Kim, Hyeon-Don Kim, Seungwoo Lee, Yushin Kim, Hyun Sung Park, and Bumki Min
Generation of Subwavelength-scale Poynting Vector Vortex and Saddle Array with Hyperbolic Metamaterials
submitted, 2018, Vol. 0, No. 0, pp. 0~ 0

Kanghee Lee*, Jagang Park*, Bong Joo Kang, Won Tae Kim, Hyeon-Don Kim, Soojeong Baek, Kwang Jun Ahn, Bumki Min and Fabian Rotermund
"Efficient electric-field-induced terahertz second-harmonic generation in photo-excited GaAs.
Advanced Optical Materials, 2020-09, Vol. 8, No. 18, pp. 0~ 0

Seojoo Lee*, Soojeong Baek*, Teun-Teun Kim, Hyukjoon Cho, Sangha Lee, Ji-Hun Kang, and Bumki Min
"Metamaterials for Enhanced Optical Responses and Their Application to Active Control of Terahertz Waves."
Advanced Materials,, 2020-09, Vol. 32, No. 35, pp. 0~ 0

Kanghee Lee, Seong Cheol Lee, Won Tae Kim, Jagang Park, Bumki Min and Fabian Rotermund
"Terahertz Generation by a Resonant Photoconductive Antenna."
Current Optics and Photonics, 2020-08, Vol. 4, No. 4, pp. 0~ 0