• Title/Summary/Keyword: ultrafast

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Non-Destructive Evaluation of Material Properties of Nanoscale Thin-Films Using Ultrafast Optical Pump-Probe Methods

  • Kim, Yun-Young;Krishnaswamy, Sridhar
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.2
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    • pp.115-121
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    • 2012
  • Exploration in microelectromechanical systems(MEMS) and nanotechnology requires evaluation techniques suitable for sub-micron length scale so that thermal and mechanical properties of novel materials can be investigated for optimal design of miro/nanostructures. The ultrafast optical pump-probe technique provides a contact-free and non-destructive way to characterize nanoscale thin-films, and its ultrahigh temporal resolution enables the study of heat-transport phenomena down to a sub-picosecond regime. This paper reviews the principle of optical pump-probe technique and introduces its application to the area of micro/nano-NDE.

The World's Thinnest Graphene Light Source (세상에서 가장 얇은 그래핀 발광 소자)

  • Kim, Young Duck
    • Vacuum Magazine
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    • v.4 no.3
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    • pp.16-20
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    • 2017
  • Graphene has emerged as a promising material for optoelectronic applications including as ultrafast and broadband photodetector, optical modulator, and nonlinear photonic devices. Graphene based devices have shown the feasibility of ultrafast signal processing for required for photonic integrated circuits. However, on-chip monolithic nanoscale light source has remained challenges. Graphene's high current density, thermal stability, low heat capacity and non-equilibrium of electron and lattice temperature properties suggest that graphene as promising thermal light source. Early efforts showed infrared thermal radiation from substrate supported graphene device, with temperature limited due to significant cooling to substrate. The recent demonstration of bright visible light emission from suspended graphene achieve temperature up to ~3000 K and increase efficiency by reducing the heat dissipation and electron scattering. The world's thinnest graphene light source provides a promising path for on-chip light source for optical communication and next-generation display module.