• 한국광과학회:학술대회논문집
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• 한국광과학회 1999년도 학술대회지
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• pp.40-40
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• 1999

• 한국광과학회:학술대회논문집
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• 한국광과학회 1996년도 학술대회지
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• pp.32-32
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• 1996

• 비파괴검사학회지
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• 제32권2호
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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.

• Journal of Photoscience
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• 제8권1호
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• pp.33-37
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• 2001

Picosecond absorption spectroscopy has been employed in the study of the solvent dynamics of 1, 2, 4, 5-tetracyanobenzene/biphenyl derivative radical ion pairs, and the resulting rates of radical ion pair separation are faster in acetonitrile than in dichloromethane. In an effort to account quantitatively for such solvent effect on the rate of radical ion pair separation, an equation for the rate of radical ion pair separation is introduced, in which the rate depends exponentially on the electrostatic interaction energy in the radical ion pair. In our analysis of the types of electrostatic interaction energy based on the conducting spheres in dielectric continuum was chosen, and the rate equation employing this electrostatic energy provided information on the distance on the distance of radical ion pair separation and solvation energy of the radical ion pair, thereby providing quantitative explanation for the observed solvent effect on the rate of radical ion pair sepaaration.

• 한국레이저가공학회지
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• 제8권2호
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• pp.7-12
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• 2005

The material processing of UV nanosecond pulse laser cannot be avoided the material shape change and contamination caused by interaction of base material and laser beam. Nowadays, ultra short pulse laser shorter than nanosecond pulse duration is used to overcome this problem. The advantages of this laser are no heat transfer, no splashing material, no left material to the adjacent material. Because of these characteristics, it is so suitable for micro material processing. The processing of sapphire wafer was done by UV 355nm, green 532nm, IR 1064nm. X-Y motorized stage is installed to investigate the proper laser beam irradiation speed and cycles. Also, laser beam fluence and peak power are calculated.

• Bulletin of the Korean Chemical Society
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• 제13권1호
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• pp.17-20
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• 1992

Photoionization processes of TMPD in $H_2O$ and $D_2O$ were studied, by measuring steady-state absorption, emission, fluorescence excitation spectra, and fluorescence lifetimes on picosecond time scale. The steady-state absorption spectra showed that there exists a cation-ion pair (Wurster's Blue) in $H_2O$ and in $D_2O$ in the electronic ground state. Temperature and excitation wavelength dependence were also studied and the results show that the photoionization reaction in water is an activated process and the fluorescence lifetime is independent of the vibrational excess energy in the uv excitation range of 283-310 nm.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2005년도 춘계학술발표대회 논문집
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• pp.15-20
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• 2005

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2005년도 춘계학술발표대회 논문집
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• pp.77-80
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• 2005

• Bulletin of the Korean Chemical Society
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• 제15권6호
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• pp.413-416
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• 1994

• 한국광학회:학술대회논문집
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• 한국광학회 1988년도 광학 및 양자전자학 워크샵
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• pp.33-36
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• 1988

The distributed feedback dye laser is a source of single picosecond pulses tunable in a very wide wavelength range. Operational principles, experimental arrangements, and recent applications are reviewed.