My research centres on the fundamentals and applications of optical super-resolution (focusing) effects in near-field optics, nanophotonics and plasmonics, with particular interests in surface nano-imaging (optical nanoscope) and nano-engineering (nano-structuring, laser cleaning).
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Nanoscope: White-light super-resolution microscopy (50 nm resolution)
The imaging resolution of a conventional optical microscope is limited by optical diffraction to ~200 nm in the visible spectrum. Efforts to overcome such limits have stimulated the development of optical nanoscopes using metamaterial superlenses, nanoscale solid immersion lenses and molecular fluorescence microscopy. These techniques, however, are complex to engineer, operate, and do not work well with white-light illumination. The nanoscope developed by us, dubbed the microsphere nanoscope, is based our groundbreaking discovery that optically transparent microspheres (2 um < diameter < 9 um) are natural super-resolution lenses that have 50-nm imaging resolution; they are simple to integrate with conventional microscopes to work in both transmission and reflection modes. Since the work was published in Nature Communication (vol.2, Art. 218), it has attracted overwhelming public interests and media coverage across the world. It was ranked the number ONE science and technology news on BBC websites on March 2, 2011 with millions reading (http://www.bbc.co.uk/news/science-environment-12612209). It was also reported by many large news agencies across the world, including New York Times, Daily Mail, Independent, Australian BC, Singapore Straits-Times, China Xinhua and a huge number of science and engineering websites. It was also feature in Laser focus world, and was selected by the RCUK in 2011 as one of the ’50 big ideas for the future’.
The microsphere nanoscope has set new world records in imaging resolution (50-nm) and magnification (x8) of optical nanoscopes. Theoretical estimation shows that the resolution can be further pushed down to 20 nm using higher-index microspheres. The microsphere nanoscope presents the possibility to directly observe the living virus in real time.
- Z.B. Wang and L. Li, "MICROSCOPY: White-light microscopy could exceed 50 nm resolution", Laser Focus World, 07, 61-64 (2011) - invited feature article
- Z.B. Wang, W. Guo, L. Li, B.S. Luk'yanchuk, A. Khan, Z. Liu, Z.C. Chen, M.H. Hong, "Optical virtual imaging at 50 nm lateral resolution with a white-light nanoscope", Nat. Commun. 2, 218 (2011)
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Nanoplasmonics: nanoparticles chain for single-molecule surface enhanced Raman scattering
- Z.B. Wang, B.S. Luk'yanchuk, W. Guo, S.P. Edwardson, D.J. Whitehead, L. Li, Z. Liu and K.G. Watkins, "The influences of particle number on hot spots in strongly coupled metal nanoparticles chain", J. Chem. Phys. 128, 094705 (2008)
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Nanofabrication: parallel laser nano-fabrication system using microsphere lenses
- Z.B. Wang, M.H. Hong, B.S. Luk'yanchuk, Y. Lin, Q.F. Wang, and T.C. Chong, "Angle effect in laser nanopatterning with particle-mask", J. Appl. Phys. 96, 6845-6850 (2004)
- Z. B. Wang, M. H. Hong, B. S. Luky’anchuk, S.M. Huang, Q.F. Wang, L.P. Shi, T.C. Chong, "Parallel nanostructuring of GeSbTe film with particle-mask", Appl. Phys. A 79, 1603-1606 (2004)
- W. Guo, Z.B. Wang, L. Li, D.J. Whitehead, B.S. Luk'yanchuk, Z. Liu, "Near-field laser parallel nanofabrication of arbitrary-shaped patterns", Appl. Phys. Lett. 90, 243101 (2007)
- Z. B. Wang, W. Guo, A. Pena, D. J. Whitehead, B.S. Luk’yanchuk, L. Li, Z. Liu, Y. Zhou, and M.H. Hong, "Laser micro/nano fabrication in glass with tunable-focus particle lens array", Opt. Express 16, 19706-19711 (2008)
- Z. B. Wang, W. Guo, B. S. Luk'yanchuk, D. J. Whitehead, L. Li, and Z. Liu, "Optical Near-field Interaction between Neighboring Micro/Nano-particles", J. Laser Micro/Nanoeng. 3, 14-18 (2008)
- W. Guo, Z.B. Wang, L. Li, Z. Liu, B.S. Luk’yanchuk and D.J. Whitehead, "Chemical-assisted Laser Parallel Nanostructuring of Silicon in Optical Near Fields", Nanotechnology 19, 455302 (2008)
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Nanoplasmonic: enery flow at nanoscale