Nanoscale surface modification for tailoring radiation properties
From Thermal-FluidsPedia
Much contemporary research in radiative transfer is aimed at exploiting near-field effects. If a sphere is placed on or very near (within a few wavelengths) of a substrate, then the enhancement demonstrated by Heltzel, 2006 (see High-energy radiation-surface interactions) can be used to focus incident laser energy onto a very small area (smaller than the nanosphere itself.) Theppakuttai (2006) used this effect to imprint surface features on a silicon substrate.
Heltzel et al. (2005) and Heltzel (2006) compared the experimental results of Theppakuttai (2006) with predictions from using solutions of the near-field equations to provide boundary conditions for solving the conventional heat equation within the substrate. Predictions of the melt zone diameter agreed well with the observed values. No damage was predicted or observed below a laser fluence of 50 mJ/cm2.
Greffet et al. (2002) showed that nano-contoured surfaces can produce highly directionally and wavelength dependent surface properties.
References
Faghri, A., Zhang, Y., and Howell, J. R., 2010, Advanced Heat and Mass Transfer, Global Digital Press, Columbia, MO.
Greffet, J.J., Carminati, R., Joulain, K., Mulet, J. P., Mainguy, S. and Chen, Y., 2002, ‘‘Coherent Emission of Light by Thermal Sources, Nature (London), Vol. 416, pp. 61-64.
Heltzel, A.J., 2006, Laser/Microstructure Interaction and Ultrafast Heat Transfer, PhD Dissertation, Mechanical Engineering Department, The University of Texas at Austin, Austin, TX.
Heltzel, A. Theppakuttai, S., Howell, J.R. and Chen, S., 2005, ‘‘Analytical and Experimental Investigation of Laser-Microsphere Interaction, for Nanoscale Surface Modification,” J. Heat Transfer, vol. 127, pp. 1231-1235.
Theppakuttai, S., 2006, Laser Micro/Nano Scale Processing of Glass and Silicon, PhD Dissertation, Mechanical Engineering Department, The University of Texas at Austin, Austin, TX.