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Nanophotonics and Nanoplasmonics Group

Contact: Dr. Ning Liu

Lecturer in Nanophysics,
Department of Physics,

Email: Ning.Liu@ul.ie

Information and communication technology (ICT) has been driven by constant miniaturisation to achieve smaller and faster devices. The industry has reached a fundamental material barrier as feature size decreases below 10 nm. In this regime the conventional material properties needed for electron transport are fundamentally changed due to the parasitic capacitance and signal propagation delay. To sustain our rapidly increasing need for processing power, light is proposed to transport information on-chip. Light can carry more information by offering much larger signal bandwidth via parallelism of wavelength division multiplexing at very high clock rates. However, conventional optical components cannot reach the same integration density as that for integrated electronics due to diffraction limits of light.

The current research interests of the group is to develop novel materials and exploit new concepts to realize optical computation in a scalable and cascadable manner with low energy consumption, without compromising the integration density. One solution to the above problem is to use propagating surface plasmons to carry the optical information. Surface plasmons can meet the large bandwidth demands by high-performance computation while still maintain high integration density.

The group tries to accomplish the above goal by endeavouring in the following four aspects: (1) Exploit the new concept of ‘hot’ electron transfer at metal-insulator-semiconductor surface to realize low threshold signal amplification in plasmonic waveguides; (2) Use MOCVD and patterned self-assembly methods to fabricate high-gain heterogeneous waveguides for gain-assisted applications; (3) Explore surface plasmon enhanced energy conversion through nonlinear process; (4) Utilize these novel materials as building blocks to construct multi-terminal plasmonic networks to perform logic functions with low energy consumption.

 

References:

  1. 1.  N. Liu, H. Wei, J. Li, Z. X. Wang, X. R. Tian, A. L. Pan, and H. X. Xu, ‘Plasmonic Amplification with Ultra-High Optical Gain at Room Temperature’, Scientific Reports 3, 1967 (2013).
  2. 2. N. Liu, Z. P. Li, and H. X. Xu, ‘Polarization dependent study on propagating surface plasmons in silver nanowires launched by a near field scanning optical fiber tip’, Small 8, 2641 (2012).
  3. H. Wei, Z. P. Li, X. R. Tian, Z. X. Wang, F. Z. Cong, N. Liu, S. P. Zhang, P. Nordlander, N. J. Halas, and H. X. Xu, ‘Quantum dot-based local field imaging reveals plasmon-based interferometric logic in silver nanowire networks’, Nano Lett. 11, 471-475 (2011).