Invited Speakers

Programmable Patterning of Functional Nanofibers from 2D to 3D via Self-aligning Nanojet (SA-N) for Biological and Sensing Applications

Jiyoung Chang
University of Utah, USA
E-mail : jy.chang@utah.edu

Abstract
Functional nanofibers combine a high surface-to -volume ratio, tunable mechanical and electrical properties, and broad material versatility, making them attractive building blocks for biomedical, sensing, and wearable electronic devices. Fully exploiting these properties, however, requires the ability to place individual nanofibers at prescribed locations and orientations, not only on flat substrates but also on non-planar surfaces and within three-dimensional (3D) architectures. Conventional far-field electrospinning produces randomly oriented mats, and most existing direct-writing approaches remain confined to planar substrates. This talk will present a series of electrohydrodynamic (EHD) nanomanufacturing strategies developed in our laboratory that extend near -field electrospinning (NFES) from precise two-dimensional (2D) patterning to 3D patterning of functional nanofibers. First, I will describe Droplet-Jet mode NFES (DJ-NFES), which enables deterministic and programmable deposition of continuous nanofibers on 2D substrates, and discuss the process–structure relationships that govern fiber diameter, placement accuracy, and alignment. Next, I will introduce the Self-Aligning Nanojet (SA-N), which enables direct writing of nanofibers onto 2.5D and 3D surfaces with complex profiles. I will then show how controlled layer-by-layer stacking and fiber registration extend these capabilities from surface patterning toward hierarchical 3D nanofiber structures, and how physics-informed, data-driven models support process control across these regimes. Building on these capabilities, the talk will highlight two classes of applications. For sensing, direct patterning of piezoelectric poly(vinylidene fluoride) (PVDF) nanofibers onto curved and flexible surfaces enables conformal mechanical sensors for wearable and structural monitoring. For biological applications, precisely patterned 2D and 3D nanofiber architectures provide engineered topographical cues that guide cell alignment and organization, and serve as scaffolds for biosensing platforms. Finally, I will discuss the remaining challenges and opportunities in hardware, software, and materials for establishing NFES as a scalable nanoscale additive manufacturing technology for 3D functional devices.

Biography
Dr. Jiyoung Chang is an associate professor in the Department of Mechanical Engineering at the University of Utah. Before joining the University of Utah in 2015, Dr. Chang was a postdoctoral fellow in the Department of Physics at the University of California, Berkeley, the Lawrence Berkeley National Laboratory (LBNL), and the Kavli Energy NanoScience Institute. He received his B.S. and M.S. degrees from the School of Mechanical Engineering at Yonsei University, Korea, in 2005 and 2007, respectively, and his Ph.D. in mechanical engineering from the University of California, Berkeley, in 2012. Dr. Chang also spent one year as a postdoctoral scholar in the School of Dentistry at the University of California, San Francisco. He currently directs the Wearable NEMS Laboratory, where his research focuses on advanced micro/nanomanufacturing of functional low- dimensional materials, including near-field electrospinning, the Self-Aligning Nanojet (SA-N), piezoelectric nanofibers, and physics-informed process control, for applications in flexible and wearable electronics, sensors, and biomedical devices.

Photoacoustic imaging for non-destructive evaluation

Sung-Liang Chen
Global College, Shanghai Jiao Tong University, China
E-mail : sungliang.chen@sjtu.edu.cn

Abstract
Photoacoustic imaging combines optical excitation with acoustic detection, offering a non-contact or minimally invasive way to visualize material structures and changes beneath optically scattering or opaque surfaces. This presentation will introduce recent advances in photoacoustic microscopy (PAM) and photoacoustic remote sensing (PARS) for non-destructive evaluation (NDE), with emphasis on advanced manufacturing and energy materials. First, I will outline the imaging principles and system designs, including optical-resolution PAM, all-optical detection, and compact fiber-based probes. These approaches provide micrometer-scale lateral resolution and material-sensitive contrast without conventional contact ultrasound transducers. Second, I will discuss representative applications, such as three-dimensional operando observation of lithium-metal deposition in batteries, where PAM revealed distinct plating behaviors and spatially heterogeneous growth. Third, I will present recent progress in deep learning for optical microscopy and medical imaging, such as computational reconstruction and physics-guided deep learning. By incorporating knowledge of the optical system and the depth-dependent point-spread function, these methods improve three-dimensional image quality and extend the useful depth range while reducing the need for dense, high-resolution scanning. Wide-field PARS is another promising direction for increasing inspection throughput over larger areas. Together, these developments show how photoacoustic imaging can complement established NDE methods by providing high-resolution structural information and enabling in situ or operando monitoring of dynamic material processes. The presentation will conclude with challenges and opportunities in system integration, quantitative characterization, imaging speed, and translation to industrial inspection.

Biography
Dr. Sung-Liang Chen is an Associate Professor at the Global College of Shanghai Jiao Tong University and a Senior Member of IEEE. His research interests include photoacoustic imaging technology and applications, artificial intelligence for medical imaging and industrial manufacturing, and optical computing. He has published more than 80 SCI-indexed journal papers, including in Nature Photonics, Journal of the American Chemical Society, Lasers & Photonics Reviews, IEEE Transactions on Medical Imaging, and ACS Applied Materials & Interfaces. He holds five authorized Chinese invention patents. He was selected for the Shanghai Pujiang Talent Program in 2014 and the National Young Talent Program in 2015.

Fabrication of Diffraction Gratings Based on a Non-Orthogonal Lloyd’s Mirror Interferometer Using SLM-Controlled Spatial Phase Modulation

Dong Wook Shin
Hokkaido University, Japan
E-mail : dongwook.shin@eng.hokudai.ac.jp

Abstract
To be announced

Biography
Dr. Dong Wook Shin spent his early career at LG Innotek Co., Ltd., participating in the development of laser camera modules for facial recognition as a mechanical engineer until 2018. He then moved to Japan and received his M.S. and Ph.D. in Mechanical Engineering from the Department of Finemechanics at Tohoku University, Sendai, Japan in 2022 and 2025, respectively, having received Research Fellowships for Young Scientists from the Japan Society for the Promotion of Science (JSPS). He currently serves as an Assistant Professor in the Division of Mechanical and Aerospace Engineering at Hokkaido University, Sapporo, Japan. His research interests include absolute dimensional measurement based on multi-beam interferometer, precision measurements utilizing ultrashort pulse lasers, and optical methods for the fabrication and calibration of diffraction gratings and their on-machine applications toward precision manufacturing.

Fluorescence-based dimensional metrology in manufacturing

Masaki Michihata
The University of Tokyo, Japan
E-mail : michihata@nanolab.t.u-tokyo.ac.jp

Abstract
Dimensional metrology is essential for understanding manufacturing processes and ensuring product quality. However, optical measurement of surface geometry remains challenging when surfaces are covered with liquids, exhibit complex optical properties, or are difficult to access during processing. Fluorescence offers an alternative source of measurement information by converting excitation light into emission that can be spectrally separated from reflected light. By establishing a relationship between fluorescence signals and spatial coordinates, surface position, or layer thickness, this phenomenon can be used for quantitative dimensional measurement. This study presents an overview of fluorescence-based dimensional metrology, covering its principles, measurement approaches, and applications in manufacturing. Particular attention is given to how fluorescence is introduced or exploited: through fluorescent liquids surrounding a surface, autofluorescence originating from the measured material, and thin fluorescent coatings applied to the measurement surface. These approaches are discussed within a common framework that connects fluorescence generation and detection to the reconstruction of surface geometry. Examples from our research include surface topography measurement using fluorescent liquids, confocal measurement utilizing material autofluorescence, and measurement of manufacturing tools. Related studies by other research groups are also introduced to illustrate the diversity of fluorescence-based approaches and their potential for different materials and measurement environments. The discussion addresses the roles of optical configuration, calibration, and signal interpretation, together with factors that influence measurement accuracy, such as variations in fluorescence intensity, optical attenuation, and the properties of fluorescent layers. Finally, it is considered opportunities and remaining challenges for applying fluorescence-based methods to wet surfaces, manufacturing interfaces, and in-process or on-machine measurement. Emphasis is placed on selecting suitable fluorescence mechanisms for specific measurement tasks and establishing reliable links between optical signals and dimensional quantities. Through these examples, the talk explores how fluorescence can expand the range of surfaces and manufacturing conditions accessible to quantitative optical metrology.

Biography
Masaki Michihata is an Associate Professor in the Department of Precision Engineering at the University of Tokyo. He received his BS, MS, and PhD degrees in mechanical engineering from Osaka University in 2004, 2007, and 2010, respectively. He previously served as an Assistant Professor in the Department of Mechanical Engineering at Osaka University for five years, and later spent four years at the Research Center for Advanced Science and Technology (RCAST) at the University of Tokyo. Since 2019, he has led research in dimensional and in-process measurement, authoring more than 80 journal papers. His research interests include three-dimensional metrology, fluorescence-based dimensional measurement, on-machine and in-process measurement, volumetric metrology and ultra-high resolution displacement sensing. He is a member of CIRP (associate), JSPE, JSME, and JSAP.