CDPT - SPMS In-person Seminar on Topological Light
We are pleased to announce the resumption of the CDPT Research Group Seminar Series starting from the next week onwards.
Our first seminar will feature a special NTU–SUTD Intelligent Topological Light Seminar, with presentations by members of Asst Prof Yijie Shen's research group, together with invited speakers Prof Joel Yang from SUTD and Assoc Prof Wu Lin from SUTD.
Date: 13 August 2026 (Thursday)
Time: 3:00 PM – 5:00 PM
Venue: MAS EC Room 2 (SPMS-MAS-03-07) In-person Seminar
Host: Asst Prof Yijie Shen
3:00 – 3:10 PM
Speaker: Asst Prof Yijie Shen
Opening Remarks: Topological light from foundations to applications
3:10 – 3:30 PM
Speaker: Dr Guo Zhenyu (Research Fellow)
Title: Optical skyrmions: from classical to quantum
Abstract: Optical skyrmions are topologically nontrivial structures formed by continuous mappings from real space to an optical state space. The rich degrees of freedom of structured light enable their controlled generation, propagation, transformation, and light–matter interactions. More recently, optical skyrmions have been extended into the quantum regime, where topological textures can be encoded either in multiple degrees of freedom of a single photon or in the nonlocal correlations between entangled photons. This talk will review the fundamental principles and recent developments of optical skyrmions, from their construction in classical light to quantum skyrmions in single-photon and biphoton systems, with particular emphasis on the interplay among topology, entanglement, and robustness against optical perturbations.
3:30 – 3:50 PM
Speaker: Dr Wang Benquan (Presidential Postdoctoral Fellow)
Title: There is plenty of room at AI Photonics: information optics from nano- towards pico-science
Abstract: The Abbe–Rayleigh diffraction limit has long stood as a fundamental physical barrier to observing and studying the nano-world through far-field optics. In this talk, I will show how this barrier can be overcome not by building better optical hardware, but by introducing advanced light fields and scientific AI models, a shift from a hardware-centric paradigm to one of information optics. In detail, I will introduce several label-free far-field optical techniques that, using only a concise optical setup enabled by artificial intelligence, measure and image deeply sub-wavelength objects. They reach picometre-scale precision in dimensional measurement and λ/11 resolution in imaging objects of arbitrary shape. Collectively, these works establish a foundation for picoscience and provide core technology for semiconductor manufacturing, optical computing, and next-generation optical communication.
3:50 – 4:20 PM
Speaker: Prof Joel Yang (SUTD)
Title: Nanoscale 3D printing of photonic elements
Abstract: 3D printing nanostructures with Two-Photon Polymerization Lithography (TPL) for photonic applications is a relatively new endeavor in additive manufacturing, with capabilities to create freeform structures at sub-wavelength dimensions. Focusing on the resolution limit of TPL (~1 micron pitch for 3D structures), we have demonstrated the printing of structural colors, generated from nanoscale features of dielectric materials. This physical approach differs from the chemical approach for synthesizing pigments and dyes, where colors arise due to optical absorption. We show results using a “print and shrink” process that enable us to print beyond the resolution capabilities and material selection of TPL. We produce photonic crystals with complete bandgaps in the visible spectrum, in high-index TiO2 with ~100 nm half-pitch lattices. We formulated resins that result in structures of both high and low index dielectrics, respectively titanium dioxide, and glass. Equipped with TPL as a nanoscale 3D printer, structural color geometries are conveniently integrated in a single print run with other user-defined optics. Doing so enables one to produce structured light from incoherent light sources, holographic color prints, and control of the light-field for 3D representation, for enhanced information content and optical security.
4:20 – 4:50 PM
Speaker: Assoc Prof Wu Lin (SUTD)
Title: Multiscale Particle-in-Cell Simulations for Next-Gen. Plasmonics & Optoelectronics
Abstract: Computational simulations are redefining electromagnetism, especially in modeling quantum plasmas—materials where electron dynamics are fast, nonlinear, and strongly coupled to electromagnetic fields. Traditional methods like Finite-Difference Time-Domain (FDTD) and Finite Element Method (FEM) often fall short in these regimes, while the Particle-in-Cell (PIC) method excels by capturing self-consistent interactions between particles and fields. Using PIC, we explore nonlinear electron transport in graphene antennas and plasmonic resonators, revealing unexpected even-order nonlinearities that enable frequency-tunable infrared upconversion. Notably, we uncover a mechanism for second-harmonic generation driven by electron funneling in THz optical resonators, where ultrafast electron-surface scattering reduces the required field intensity by 3–4 orders of magnitude. Room-temperature metals and semimetals, acting as cold quantum plasmas, emerge as a promising platform for low-field, high-efficiency nanophotonic applications. PIC’s ability to model ultrafast, non-equilibrium carrier dynamics makes it a powerful tool for designing next-generation devices across plasmonics, optoelectronics, and photonics.