Hongkai Zhang
Research Subjects
Hongkai Zhang has a total of 6 co-authors. Here are the top co-authors by number of shared publications:
- Dezhao Huang
Wuhan University
1 shared publication - Nan Zhang
Wuhan University
1 shared publication - Shijing Wu
School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China
1 shared publication - Xiaona Huang
School of Power and Mechanical Engineering, Wuhan University 1 , Wuhan, Hubei 430072
1 shared publication - Yanan Yue
Miami University
1 shared publication - Yunsong Pang
Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
1 shared publication
Latest Publications
- Open Access
- 12 October 2026
- Published by Science Exploration Press in Thermo-X
- Vol. 3 (1) , 202629
Raman thermometry indicates aggregation-induced localized hotspots in optical tweezers
Gold nanoparticles (Au NPs) provide useful but difficult-to-measure heating in optical tweezers used for colloidal transport, assembly, optofluidics, and bubble-mediated manipulation. Here, we combine 60 nm Au NPs with 5 μm polystyrene (PS) microspheres in a dual-laser Raman optical-tweezers platform. Au NPs serve as heat sources and PS microspheres report the microscale temperature through their Raman spectra. The PS band near 1,000 cm-1 has a calibrated temperature coefficient of -0.0054 cm-1·K-1. For Au stock-dispersion fractions of 0, 0.3, and 1 vol.%, the temperature-power coefficients are 53.5 ± 10.9, 110.4 ± 23.8, and 170.3 ± 18.2 K·W-1, respectively. At 1 vol.% Au suspension, extrapolation of the pre-bubble temperature-power relation to 0.341 W gives a PS-reported temperature of approximately 351 K, below the normal boiling point of water. Electromagnetic simulations show that normalized per-particle absorption increases from 1.00 for an isolated Au nanoparticle to 15.35 for a seven-particle cluster, supporting aggregation-induced nanoscale heating as a mechanism for bubble formation. The PS reporter thus gives the microscale thermal response, and the nanoscale hotspots associated with bubble formation are inferred, not measured directly.
- 12 October 2026
- Published by Science Exploration Press in Thermo-X
- Vol. 3 (1) , 202629
Open AccessRaman thermometry indicates aggregation-induced localized hotspots in optical tweezers
Gold nanoparticles (Au NPs) provide useful but difficult-to-measure heating in optical tweezers used for colloidal transport, assembly, optofluidics, and bubble-mediated manipulation. Here, we combine 60 nm Au NPs with 5 μm polystyrene (PS) microspheres in a dual-laser Raman optical-tweezers platform. Au NPs serve as heat sources and PS microspheres report the microscale temperature through their Raman spectra. The PS band near 1,000 cm-1 has a calibrated temperature coefficient of -0.0054 cm-1·K-1. For Au stock-dispersion fractions of 0, 0.3, and 1 vol.%, the temperature-power coefficients are 53.5 ± 10.9, 110.4 ± 23.8, and 170.3 ± 18.2 K·W-1, respectively. At 1 vol.% Au suspension, extrapolation of the pre-bubble temperature-power relation to 0.341 W gives a PS-reported temperature of approximately 351 K, below the normal boiling point of water. Electromagnetic simulations show that normalized per-particle absorption increases from 1.00 for an isolated Au nanoparticle to 15.35 for a seven-particle cluster, supporting aggregation-induced nanoscale heating as a mechanism for bubble formation. The PS reporter thus gives the microscale thermal response, and the nanoscale hotspots associated with bubble formation are inferred, not measured directly.