What do we do?
From centimeter to nanometer, from glass, polymer to metal, we aim to intelligently additively manufacture and process functional objects with laser as a powerful tool. These objects aim to be used in optical, thermal, mechanical, biomedical and many more applications. The techniques we are currently applying includes two-photon direct writing, (micro-)stereolithography, volumetric 3D printing, additive+subtractive manufacturing, binder jets, selective laser sintering, ultrafast laser ablation/ processing, etc.
Facilities
High power ultrafast laser
Light Conversion Carbide: Dual wavelength femtosecond laser: 5W@ 1030nm, 3W@ 515nm, 120kHZ, <200 fs.View more details...
Low power lasers
1. Toptica Femtofiber smart femtosecond laser: 780nm, <90 fs, 150mW 80MHZ;
2. Huaray UV nanosecond laser: 355nm, 8ns, 3W;
3. Diode lasers: 405nm, 532nm, ... .View more details...
3D printers
1. Phrozen mini 8K resin printer: resolution 22µm, forming size:165*72*180mm;
2. OctaveLight R1 ceramic DLP printer: resolution 30µm, forming size: 33*58*120mm;
3. Home-made SLA bottom-top resin printer: 405nm, forming size:125*125*180mm;
4. Home-made SLA top-bottom high-viscous slurry printer: 405nm, forming size:125*125*120mm;View more details...
Imaging and Optomechanical devices
1. Leica DMI inverted microscope;
2. Scanlab, Feltek &CTI galvos;
3. Santec UV spatial light modulator (SLM-250);
4. High-NA objective lenses;
5. Avesta autocorrelator.
And many more...View more details...
Precision stages
1. Smaract SOM-808030: nano-piezo long range xyz stage;
2. Piezoconcept C3: nanometer piezo stage;
3. Aerotech nano-presicion air bearing/ mech bearing, rotational, etc. stages
And many more...View more details...
UV forbidden material hood & clean work station
Hood: Clean room level yellow light, self-circulation.
Work station: Class 100 clean.View more details...People
Group members
Dr. Wen, X. W. Sitman
Principle Investigator
Dr. Wen, Xiewen Sitman is currently an Assistant Professor in the Dept. of Mechanical Engineering of CityU. He got the PhD degree from Rice University under the supervision of Prof. Jun Lou and Prof. Pulickel Ajayan. and he did his postdoc in Argonne National Laboratory with Dr. Gary Wiederrecht. His research interests are multiscale additive manufacturing with ultrahigh resolution, femtosecond laser manufacturing, advanced spectroscopy and Imaging. He has co-authored more than thirty papers in prestigious journals such as Nature Materials, Nature Photonics, Nature communications, Science Advances, Advanced Materials, PNAS etc.
Dr. Wang, Shixiang
Postdoctoral Researcher
Dr. Wang Shixiang received degrees of B.Sc. (2018) at Shandong Normal University and Ph.D. (2022) at Shandong University, China. Her Ph.D. work focused on dielectric waveguide-based compact pulsed lasers, embedded metallic nanoparticles and RE:LN integrated photonics based on ion beam technology and femtosecond laser micromachining.
Mr. Qiao, Jingyu
Ph. D. Student
Mr. Qiao Jingyu received his Bachelor’s degree in process equipment and control engineering from Dalian University of Technology in 2019 and Master’s degree in Materials Engineering from Southern University of Science and Technology in 2021. He worked as a research assistant at SUSTech after graduation. He has been pursuing his PhD degree at the City University of Hong Kong since 2022. His research interests include 3D-printing and micro/nano-fabrication.
Our publications
Additive manufacturing:X. Wen, et. al. "3D Printed Silica with Nanoscale Resolution." Nature Materials. 1-7.(2021)- World's finest glass printing with feature sizes better than 180 nm. Featured by NM: https://www.nature.com/articles/s41563-021-01137-6Laser ablation/ processing:
Y. Miao, ... X. Wen, et. al. "Designable Layer Edge States in Quasi‐2D Perovskites Induced by Femtosecond Pulse Laser." Advanced Science, 2201046.(2022)
Advanced Imaging:
X. Wen, et al. "Ghost imaging second harmonic generation microscopy." Applied Physics Letters 116.19 (2020): 191101.
Advanced Spectroscopy:
X. Wen, et. al. "Pathways of Exciton Triggered Hot‐Carrier Injection at Plasmonic Metal− Transition Metal Dichalcogenide Interface." Advanced Optical Materials 10 (5), 2100070 (2022)
H. Tsai, …, X.Wen, … et al. “Bright and Stable Light Emitting Diodes Made with Perovskite Nanocrystals Stabilized in Metal-Organic Frameworks” Nature Photonics. 1-7 (2021)
J. Liang, …, X.Wen, … et al. "Perovskite‐Derivative Valleytronics." Advanced Materials 32.48 (2020): 2004111.
X. Wen, et al. "Ultrafast probes of electron–hole transitions between two atomic layers." Nature communications 9.1 (2018): 1-9.
Y. Wang, …, X.Wen, … et al. "Cryo-mediated exfoliation and fracturing of layered materials into 2D quantum dots." Science advances 3.12 (2017): e1701500.
Z. Yan, …, X.Wen, … et al. "Three-dimensional mesostructures as high-temperature growth templates, electronic cellular scaffolds, and self-propelled microrobots." PNAS, 114.45 (2017): E9455-E9464.
H. Chen#, X. Wen#, et al. "Ultrafast formation of interlayer hot excitons in atomically thin MoS 2/WS 2 heterostructures." Nature communications 7.1 (2016): 1-8.
