Research Interests: We are interested in theoretical and experimental studies on light interaction with structured materials, with an emphasis on the fundamental understanding of emerging optical phenomena in a deep sub-wavelength scale. From our previous studies, we have revealed various optical behaviors in the structured materials, including gigantic enhancement of light by a small gap in metal [1, 2], fractional tunneling resonance in metamaterial systems [3], polariton interaction with one-dimensional (1D) interfaces in a two-dimensional (2D) system [4, 5], perfect anti-reflection by the universal impedance matching [6], drastic change of optical response in dense metasurfaces [7], and effective description of optical metamaterials [8].
References
[1] J. H. Kang, D. S. Kim, and Q. H. Park, Phys. Rev. Lett. 102, 093906 (2009)
[2] J. H. Kang and Q. H. Park, IEEE Trans. THz. Sci. Tech. 6, 371 (2016)
[3] J. H. Kang and Q. H. Park, Scientific Rep. 3, 2423 (2013)
[4] J. H. Kang et al., Nano Lett. 17, 1768 (2017)
[5] J. H. Kang†, S. Wang, and F. Wang, Phys. Rev. B 99, 165408 (2019)
[6] K. Im*, J. H. Kang*, and Q. H. Park, Nature Photon. 12, 143 (2018)
[7] J. H. Kang et al., ACS Appl. Mat. Inter. 10, 19331 (2018)
[8] S. Lee and J. H. Kang†, Crystals 11, 684 (2021)
Current Research Projects:
Low-dimensional polaritonics
Light interaction with spatiotemporal media
Ultrasmall plasmonic resonators
Quantum-corrected model for plasmonics
In the scope of our investigations, all the above projects involve optical metamaterial and metasurfaces.
Analytical Calculations: Our study intensively deals with the classical theory of electromagnetism based on Maxwell's equations, as well as the quantum theory of plasmonics. The following are mostly involved mathematical schemes:
Fourier analysis of vector spaces
System of coupled integral equations
Wiener-Hopf theory
Born approximation
Numerical Methods: We are using a homemade finite-difference time-domain (FDTD) program written in C++ and intensively implemented for parallel and multi-threaded computing. We are also using commercial software COMSOL as a complement. Our numerical systems are as the following
Windows-based (for FDTD and COMSOL)
AMD Ryzen Threadripper 5995wx (64 cores) with 1TB of memory (2EA)
AMD Ryzen Threadripper 3995wx (64 cores) with 1TB of memory (1EA)
AMD Ryzen Threadripper 3975x (32 cores) with 256 GB of memory (2EA)
Intel Core-i9 7920x (12 cores) with 256 GB of memory (1EA)
AMD Ryzen Threadripper 2950x (16 cores) with 256 GB of memory (1EA)
Linux-based (exclusively for FDTD)
Intel core-i7 5820k (6 cores) with 32 GB of memory (8EA, MPI-clustered)
Experimental Techniques: We are performing microwave near- and far-field measurements of optical systems including metamaterials, for an experimental confirmation of our theoretical predictions through "microwave spectroscopy". Currently, we have the following microwave measurement setup:
HP-Agilent 8719C network analyzer (up to 18 GHz)
3672C vector network analyzer (up to 43.5 GHz)
Straight rectangular waveguides (1.7 GHz - 28 GHz)
SH 1000 dual-ridge horn antennas (1 GHz - 18 GHz)
LB-180400H-KF broadband horn antennas (18 GHz - 40 GHz)
Near-field microwave probe (2.6 GHz - 3.95 GHz, 1/20 sub-wavelength spatial resolution)