Layout of Optics Lab               Clean room and Equipments



(1) Geometric-phase Meta-optics (4th-generation Optics)

We develop a flat optics technology (4th–generation optics) enabled by the geometric-phase (GP) effect grounded on the Pancharatnam-Berry phase in polarization-state transformation processes. In GP optical elements, desired refractive properties are obtainable by appropriately distributing optically anisotropic domains in a flat mm-thick film. Such GP elements can be easily embedded entirely within conventional refractive optic structures and, thereby, provide desired additional refractive-power properties in absence of any diffractive surface patterns.

The basis of GP modulation lies in spatially controlling the local orientation of anisotropic molecules in retardation film. Varying the angle f of anisotropic orientation makes a 2f phase change in circularly polarized incidence. This GP modulation is physically continuous throughout the spatially variant retardation film due to the unbound nature of GP. Thin anisotropic films are continuous down to sub-nanometer scale and can be deposited in multiple layers, ensuring clear, haze-less optics without compromising efficiency and transmittance. This is advantageous over the discontinuous surface corrugations of most conventional optics. With conventional optics, GP layers with spatially variant anisotropy axes can be additionally realized using nanostructured metasurfaces or liquid crystal polymers. UV-curable liquid crystal polymers used in our research are particularly attractive because they can be foldable and made at low cost.


(2) Geometric-phase (GP) Multifocal Intraocular Lenses (IOL) for Presbyopia Correction


Intraocular lens (IOL) technology for presbyopia correction and cataract surgery is of constantly growing importance as the population aging deepens in many developed societies. An ideal IOL for this purpose is desired to simultaneously support near, intermediate, and distant vision without any serious complications. The pseudophakic presbyopia correction presently relies on multifocal or extended depth-of-focus IOLs using combined refractive and diffractive surfaces to create series of axial multi-foci or enhanced field of view. In spite of their enormous success, current IOL technologies still have inherent challenging issues for further substantial improvements such as light loss, blurred vision, and posterior capsule opacification (PCO).

We have recently demonstrated a new type of multifocal and extended depth of focus (EDOF) intraocular lenses (IOLs) embedding mm-thin geometric phase (GP) lens layers. Multifocal GP IOLs are fabricated by radial alignment of anisotropic orientation in UV-curable liquid crystal polymers. It is expected that GP IOLs will alleviate the most common problems associated with multifocal and EDOF IOLs, blurred vision and photic phenomena caused by light scattering and posterior capsule opacification


(3) Laser Interference Lithography (LIL) for Fabrication of Nanograting Pixel Arrays


We develop a laser interference lithography (LIL) and nanoimprinting techniques to fabricate nanoscale patterns with arrays of sub-mm-period grating pixel arrays. The LIL system consists of a UV (351 nm) pulsed laser (Nd:YLF AONano 351-3-2-CY, Advanced Optowave Co.), a pair of acousto-optic deflectors (AOD, DTSX-400-405, AA Opto-Electronic Co.), and an XY motorized stage (450 mm x 450 mm, INNO6 Co.). By adjusting the interference angles of q and f with AODs, period (L) and orientation (f) of nanoscale gratings can be precisely defined within the ranges of L = 0.3 mm to 3 mm and f = 0o to 180o. A typical micrograph of squared grating pixels made of photoresist (AZ5206, MicroChemicals) on a silicon wafer shows a grating array of 100 nm-deep parallel corrugations, which have various pairs of L and f but are very uniformly formed within every ~10 mm2 pixel area.


(4) Non-Hermitian (Complex-index) Nanophotonics


Non-Hermitian (NH) Nanophotonics that expands the conventional resonance-based nanophotonics to the conceptually far-reaching open-system domains where various unusual physical effects take place with manifestation of anti-linear symmetry groups, exceptional-point singularities, topological parametric structures, complex energy-spectral chirality, and associated broadband time-asymmetric operations. We explore, in both theory and experiments, various strongly-interacting open-system configurations provided by optical gains, losses, scattering, radiative inter-modal coupling, and mixed direct/indirect feedback structures.

Our research aims to establish pioneering subjects pertaining to unexplored territories between non-Hermitian quantum mechanics and conventional nanophotonics technology. Toward this end, we introduce NH dynamics for open quantum systems as a new theoretical tool, explore complex-valued potential configurations realized in photonics systems, potentially discover new NH-photonic properties, and finally establish robust foundations of NH nanophotonic structures and elements as a promising device class for the next generation optical systems in numerous technology areas.



l Prof. Song

(1984) BS, Dept. of Physics, Yonsei University, Seoul, Korea

(1989) Ph.D, Dept. of Physics, KAIST (Korean Advanced Institute of Science and Technology), Seoul, Korea

(1989-1997) Senior Researcher, ETRI (Electronics and Telecommunication Research Institute), Korea

(1997-present) Professor, Department of Physics, Hanyang University, Seoul, Korea


l Post Doc.

(Dr. Youngsun Choi), Non-Hermitian photonics

(Dr. Jongkyun Hong), Non-Hermitian electronic circuits for photonics


l Students

(Kunpyo Kim), Non-Hermitian photonics

(Minjeong Kim), Non-Hermitian 2nd stopband photonics

(Hyongju Na), 3D waveguide display

(Younghwa Ryu), Geometric-phase micro-nano optics

(Jonghyuk Park), Geometric-phase non-Hermitian Optics

(Kwangwuk Yu), Non-Hermitian topological photonics

(Kiyoung Lee), Non-Hermitian photonics

(Seungmin Lee), 3D projection display

(Wontae Im), Diffractive optical elements for display

(Jaewoong Ko), Non-Hermitian topological photonics

(Jiwon Ahn), Geometric-phase optics

(Jaesung Jeong), Diffractive optics for laser applications


l Lectures on Nanophotonics

0-Introduction to Nanophotonics

1-Second-order stopband and leaky-mode resonator

2-GMR and Topological Photoncs

3-Optical properties of materials-dielectrics and metals

4-Dispersion relation of surface plasmon-polaritons

5-SPP Excitation

6-EM energy density in metals

7-Localized particle plasmons

8-Dispersion relation of metal nanorods and nanotips

9-Dispersion relation of SPPs on thin metal films

10-Dielectric loaded SPP waveguides

11-Metal-Insulator-Metal plasmonic slot-waveguides


l Special Lectures on Micro-optics, Nano-optics, and SPP Technologies

1. Micro- and nano-optics based on diffraction effect for next generation technologies

2. Guided-mode resonance (GMR) effect for filtering devices in LCD display panels

3. Surface-plasmons: A basic

4. Surface-plasmon waveguides and biosensor applications

5. Efficient light emission from LED, OLED, and nanolasers via surface-plasmon resonance

6. SPP on real metals

7. SPP on metal-insulator-metal, metal nanorods, metal nanotips

8. SPP Photovotaics


l Recent Papers

²  Ki Young Lee, Seungjin Yoon, Seok Ho Song, Jae Woong Yoon, “Topological beaming of light,” Science. Advances 8, eadd8349 (December 2022). Abstract

²  Seungmin Lee, Gayeon Park, Seonho Kim, Yeonghwa Ryu, Jae Woong Yoon, Ho Sik Hwang, In Seok Song, Chang Sun Lee, and Seok Ho Song, “Geometric-phase intraocular lenses with multifocality,” Light: Science & Applications 11, 320 (November 2022). Abstract

²  Hyungju Rah, Seungmin Lee, Yeong Hwa Ryu, Gayeon Park, and Seok Ho Song, “Waveguide-type Multidirectional Light Field Display,” Current Optics and Photonics 6, 375-380 (August 2022). Abstract

²  Gunpyo Kim, Seok Ho Song, and Jae WoongYoon, “Inverse‑cavity structure for low‑threshold miniature lasers,” Scientific Reports 12, 11333 (July 2022). Abstract

²  Seong-O Yang, Seungmin Lee, Seok Ho Song, and Jihyung Yoo, “Development of a distributed optical thermometry technique for battery cells,” Inter. J. of Heat and Mass Transfer 194, 123020 (May 2022). Abstract

²  Ki Young Lee, Kwang Wook Yoo, Sangmo Cheon, Won-Jae Joo, Jae Woong Yoon, and Seok Ho Song, “Synthetic Topological Nodal Phase in Bilayer Resonant Gratings,” Phys. Rev, Lett. 128, 053002 (February, 2022). Abstract


²  Kyung‑Sun Na, Chang Su Lee, Da Ran Kim, Seok Ho Song, Soo Yeon Cho, Eun Chul Kim, Hyun Seung Kim, and Ho Sik Hwang, “Development of a novel multifocal lens using a polarization directed flat lens: possible candidate for a multifocal intraocular lens,” BMC Ophthalmology 21, 444 (27 December, 2021). Abstract

²  Seok Ho Song, In Seok Song, Se Jin Oh, Hyeck-Soo Son, and Min Ho Kang, “Optical bench simulation for intraocular lenses using field-tracing technology,” PLoS ONE 16, e0250543 (15 December 2021). Abstract

²  Ki Young Lee, Kwang Wook Yoo, Youngsun Choi, Gunpyo Kim, Sangmo Cheon, Jae Woong Yoon, and Seok Ho Song, “Topological guided-mode resonances at non-Hermitian nanophotonic interfaces,” Nanophotonics 10, 1853-1860 (5 April 2021). Abstract

²  Kang Nyeong Lee, Jiwon Lee, Juil Hwang, Chungha Lee, Ji Sook Kim, Seok Ho Song, Oh Young Lee, and Kwang-Geol Lee, “Association Between Visceral Hypersensitivity in Irritable Bowel Syndrome, Intestinal Microbiota, and Mast Cells: How to Detect Mast Cells Using Confocal Microscopy,” J Neurogastroenterol Motil 27, 657-659 (October 2021). Abstract

²  Junghyun Park, Byung Gil Jeong, Sun Il Kim, Duhyun Lee, Jungwoo Kim, Changgyun Shin, Chang Bum Lee, Tatsuhiro Otsuka, Jisoo Kyoung, Sangwook Kim, Ki-Yeon Yang, Yong-Young Park, Jisan Lee, Inoh Hwang, Jaeduck Jang, Seok Ho Song, Mark L. Brongersma, Kyoungho Ha, Sung-Woo Hwang, Hyuck Choo, and Byoung Lyong Choi, “All-solid-state spatial light modulator with independent phase and amplitude control for three-dimensional LiDAR applications,” Nature Nanotechnology 16, 69 (January 2021). Abstract


²  Won-Jae Joo, Jisoo Kyoung, Majid Esfandyarpour, Sung-Hoon Lee, Hyun Koo, Sunjin Song, Young-Nam Kwon, Seok Ho Song, Jun Cheol Bae, Ara Jo, Myong-Jong Kwon, Sung Hyun Han, Sung-Han Kim, Sungwoo Hwang, and Mark L. Brongersma, “Metasurface-driven OLED displays beyond 10,000 pixels per inch,” Science 370, 459-463 (23 October 2020). Abstract

²  Youngsun Choi, Jae Woong Yoon, Jong Kyun Hong, Yeonghwa Ryu, and Seok Ho Song, “Direct observation of time-asymmetric breakdown of the standard adiabaticity around an exceptional point,” Communications Physics 3, 140 (14 August 2020). Abstract


²  Choloong Hahn, Maude Amyot-Bourgeois, Howard Northfield, Youngsun Choi, Seok Ho Song, R. Niall Tait, and Pierre Berini, “Nanofabrication of plasmonic structures on insulating substrates by resist-on-metal bilayer lift-off,” Nanotechnology 30, 054003 (December 2018). Abstract

²  Jeong Yub Lee, Yongsung Kim, Seunghoon Han, Jaekwan Kim, Jae Woong Yoon, Ki Young Lee, Seok Ho Song, Kiyeon Yang, and Chang Seung Lee, “CMOS-compatible Si metasurface at visible wavelengths prepared by low-temperature green laser annealing,” Nanotechnology 30, 045301 (November, 2018). Abstract

²  Joong-Sung Lee, Seung-Jin Yoon, Hyungju Rah, Mark Tame, Carsten Rackstuhl, Seok Ho Song, Changhyoup Lee, and Kwang-Geol Lee, “Quantum plasmonic sensing using single photons,” Opt. Express 26, 29272 (Oct. 2018). Abstract

²  Jae Woong Yoon, Youngsun Choi, Choloong Hahn, Gunpyo Kim, Seok Ho Song, Ki-Yeon Yang, Jeong Yub Lee, Yongsung Kim, Chang Seung Lee, Jai Kwang Shin, Hong-Seok Lee, and Pierre Berini, “Time-asymmetric loop around an exceptional point over the full optical communications band,” Nature 562, 86 (September 2018). Abstract

²  Youngsun Choi, Choloong Hahn, Jae Woong Yoon, and Seok Ho Song, “Observation of an anti-PT-symmetric exceptional point and energy-difference conserving dynamics in electrical circuit resonators,” Nature Commun. 9, 2182 (June 2018). Abstract

²  Jae Woong Yoon, Seong-Min Ma, Gun Pyo Kim, Yoonshik Kang, Joonseong Hahn, Oh-Jang Kwon, Kyuyoung Kim and Seok Ho Song, “Nanophotonic identification of defects buried in three-dimensional NAND flash memory devices,” Nature Electronics 1, 60-67 (First issue, January 2018). Abstract


²  Suntak Park, Bongje Park, Saekwang Nam, Sungryul Yun, Seung Koo Park, Seongcheol Mun, Jeong Mook Lim, Yeonghwa Ryu, Seok Ho Song, and Ki-Uk Kyung, “Electrically tunable binary phase Fresnel lens based on a dielectric elastomer actuator,” Optics Express 25, 23801 (October 2017). Abstract

²  Ki Young Lee, Jae Woong Yoon, Seok Ho Song, and Robert Magnusson, “Multiple p-n junction subwavelength gratings for transmission-mode electro-optic modulators,” Scientific Reports 7, 46508 (April 2017). Abstract

²  Youngsun Choi, Choloong Hahn, Jae Woong Yoon, Seok Ho Song, and Pierre Berini, “Extremely broadband, on-chip optical nonreciprocity enabled by mimicking nonlinear anti-adiabatic quantum jumps near exceptional points,” Nature Commun. 8, 14154 (January 2017). Abstract


²  Choloong Hahn, Elham Karami Keshmarzi, Seok Ho Song, Cha Hwan Oh, R. Niall Tait, and Pierre Berini, “Unidirectional Bragg Gratings Using Parity-Time Symmetry Breaking in Plasmonic Systems,” IEEE J. Sel. Topics in Quantum Electron. 22, 4600712 (Sept/Oct 2016). Abstract

²  Choloong Hahn, Youngsun Choi, Jae Woong Yoon, Seok Ho Song, Cha Hwan Oh, and Pierre Berini, “Observation of exceptional points in reconfigurable non-Hermitian vector-field holographic lattices,” Nature Commun. 7, 12201 (June 2016). Abstract


²  Jae Woong Yoon, Seok Ho Song, and Robert Magnusson, “Critical field enhancement of asymptotic optical bound states in the continuum,” Scientific Reports, 5, 18301 (December 2015). Abstract

²  Choloong Hahn, Seok Ho Song, Cha Hwan Oh, and Pierre Berini, “Plasmonic gain in long-range surface plasmon polariton waveguides bounded symmetrically by dye-doped polymer,” Applied Physics Letters 107, 121107 (September 2015). Abstract

²  Myoung Jin Jung, Choloong Han, Jae Woong Yoon, and Seok Ho Song, “Temperature and gain tuning of plasmonic coherent perfect absorbers,” Opt. Express 23, 19837 (July 2015). Abstract

²  Choloong Hahn, Seok Ho Song, Cha Hwan Oh, and Pierre Berini, “Single-Mode Lasers and Parity-Time Symmetry Broken Gratings Based on Active Dielectric-Loaded Long-Range Surface Plasmon Polariton Waveguides,” Opt. Express 23, 19922 (July 2015). Abstract

²  Jae Woong Yoon, Myoung Jin Jung, and Seok Ho Song, “Gain-assisted critical coupling for high-performance coherent perfect absorbers,” Optics Letters 40, 2309 (May 2015). Abstract

²  Kang Hee Seol, Kwang-Geol Lee, and Seok Ho Song, “A deep subwavelength cavity formed by total external reflection of surface plasmon polariton,” J. of Applied Physics 117, 173104 (May 2015). Abstract

²  Youngsun Choi, Jong-Kyun Hong, Jin-Ho Cho, Kwang-Geol Lee, Jae Woong Yoon, and Seok Ho Song, “Parity-time-symmetry breaking in double-slab surface-plasmon-polariton waveguides,” Opt. Express 23, 11783 (April 2015). Abstract


²  Jae Woong Yoon, Seok Ho Song, and Robert Magnusson, “Ultrahigh-Q metallic nanocavity resonances with externally-amplified intracavity feedback,” Scientific Reports, 4, 7124 (Nov. 2014).

²  Kwang-Geol Lee, Ki-Young Choi, and Seok Ho Song, “Optimal design of green InGaN/GaN LEDs mediated by surface-plasmon gratings,” Current Applied Physics, 14, 1771-1774 (Oct. 2014).

²  Kwang-Geol Lee, Ki-Young Choi, and Seok Ho Song, “Experimental observation of a practical limit on enhancement of the spontaneous emission rate in blue GaN-LEDs by mediating surface plasmons,” Current Applied Physics, 14, 1639-1642 (Sept. 2014).

²  Dong Joo Choi, Ju Sung Maeng, Key-one Ahn, Myoung Jin Jung, Seok Ho Song, and Young-Ho Kim, “Synthesis of Cu or Cu2O-polyimide nanocomposites using Cu powders and their optical properties,” Nanotechnology, 25, 375604 (9pp) (Aug. 2014).

²  Kwang-Geol Lee, Ki-Young Choi, Jin-Ha Kim, and Seok Ho Song, “Experimental observation of electroluminescence enhancement on green LEDs mediated by surface plasmons,” Opt. Express, 22, A1303 (Aug. 2014).

²  Jae Woong Yoon, Jun Hyung Lee, Seok Ho Song, and Robert Magnusson, “Unified Theory of Surface-Plasmonic Enhancement and Extinction of Light Transmission through Metallic Nanoslit Arrays,” Scientific Reports, 4, 5683 (July 2014).

²  Jun Hyung Lee, Jae Woong Yoon, Myoung Jin Jung, Jong Kyun Hong, Seok Ho Song, and Robert Magnusson, “A semiconductor metasurface with multiple functionalities: A polarizing beam splitter with simultaneous focusing ability,” Applied Physics Letters 104, 233505 (June 2014).

²  Kilbock Lee, Seok Ho Song, and Jinho Ahn, “FDTD simulation of transmittance characteristics of one-dimensional conducting electrodes,” Opt. Express, 22, 6269 (March 2014).


²  Jae Woong Yoon, Gang Min Koh, Seok Ho Song, and Robert Magnusson, “Measurement and Modeling of a Complete Optical Absorption and Scattering by Coherent Surface Plasmon-Polariton Excitation Using a Silver Thin-Film Grating,” Phys. Rev. Lett. 109, 257402 (Dec. 2012).

²  Hojeong Yu, Youngjin Oh, Soowon Kim, Seok Ho Song, and Donghyun Kim, “Polarization-extinction-based detection of DNA hybridization in situ using a nanoparticle wire-grid polarizer,” Opt. Lett. 37, 3867 (Sept. 2012).

²  Jae Woong Yoon, Myoung Jin Jung, Seok Ho Song, and Robert Magnusson, “Analytic Theory of the Resonance Properties of Metallic Nanoslit Arrays,” IEEE J. Quantum Electron. 48, 852 (July 2012).

²  H. G. Svavarsson, J. W. Yoon, M. Shokooh-Saremi, S. H. Song, and R. Magnusson, “Fabrication and Characterization of Large, Perfectly Periodic Arrays of Metallic Nanocups,” Plasmonics, 7, 653 (March 2012).

²  R. Magnusson, H. G. Svavarsson, J. Yoon, M. Shokooh-Saremi, and S. H. Song, “Experimental observation of leaky modes and plasmons in a hybrid resonance element,” Appl. Phy. Lett. 100, 091106 (Feb. 2012).

²  Kang Hee Seol and Seok Ho Song, (Korean) “Characteristics of Nanoscale Modes Guided by the Total External Reflection of Surface Plasmon-Polaritons,” Korean J Opt. & Photon. 23, (Feb. 2012).