• Title/Summary/Keyword: nonlinear optics.

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Characterization of Supercontinuum Generation as a function of Pump Wavelength and Intensity in Photonic Crystal Fiber (광자 결정 광섬유에서 펌프광원의 파장과 입력파워에 따른 초 광대역 광원 발생의 특성)

  • Kim, Jong-Doo;Yee, Ki-Ju;Jeon, Min-Yong;Ahn, Seong-Joon;Choi, Yong-Gyu
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.490-493
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    • 2005
  • We have experimentally studied supercontinuum generation in a photonic crystal fiber as a function of pump wavelength and intensity with 100 fs pulsewidth. A supercontinuum over 750 nm spectral width with amplitude variation less than 10 dB has been achieved. It was generated by coupling femtosecond pulses from a mode-locked Ti:Sapphire laser into a 2 m long photonic crystal fiber. Adjusting the parameters of the pump source, it was also possible to control different spectral features of the supercontinuum radiation.

Reagentless Determination of Human Serum Components Using Infrared Absorption Spectroscopy

  • Hahn, Sang-Joon;Yoon, Gil-Won;Kim Gun-Shik;Park Seung-Han
    • Journal of the Optical Society of Korea
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    • v.7 no.4
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    • pp.240-244
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    • 2003
  • Simultaneous determination of concentrations for four major components in human blood serum was investigated using a Fourier-transform mid-infrared spectroscopy. Infrared spectra of human blood serum were measured in 8.404 ∼ 10.25 ${\mu}m$ range where the highest absorption peaks of glucose are located. A partial least square (PLS) algorithm was utilized to establish a calibration model for determining total protein, albumin, globulin and glucose levels which are commonly measured metabolites. The standard error of cross validation obtained from our multivariate calibration model was 0.24 g/dL for total protein, 0.15 g/dL for albumin, 0.17 g/dL for globulin, and 6.68 mg/dL for glucose, which are comparable with or meet the criteria for clinical use. The results indicate that the infrared absorption spectroscopy can be used to predict the concentrations of clinically important metabolites without going through a chemical process with a reagent.

Synthesis and Properties of Novel T-type Nonlinear Optical Polyurethane Containing Tricyanovinylthienyl Group with Enhanced Thermal Stability of Dipole Alignment

  • Cho, You-Jin;Kim, Mi-Sung;Lee, Ju-Yeon
    • Bulletin of the Korean Chemical Society
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    • v.32 no.2
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    • pp.424-430
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    • 2011
  • A novel T-type polyurethane 7 containing 1-(2,5-dioxyphenyl)-2-(5-(1,2,2-tricyanovinyl)-2-thienyl)ethenes as NLO chromophores, which constitute part of the polymer backbone, was prepared. Polyurethane 7 is soluble in common organic solvents such as DMF and DMSO. It shows a thermal stability up to $270^{\circ}C$ from TGA thermogram with $T_g$ value obtained from DSC thermogram near $155^{\circ}C$. The second harmonic generation (SHG) coefficient ($d_{33}$) of poled polymer film at 1560 nm fundamental wavelength is $3.56{\times}10^{-9}$ esu. Polymer 7 exhibits a thermal stability even at $5^{\circ}C$ higher than $T_g$, and no significant SHG decay is observed below $160^{\circ}C$, which is acceptable for nonlinear optical device applications.

Study on the Interference Phenomena of Nonlinear Optical Signals (비선형 광신호의 간섭현상 연구)

  • 이은성;한재원;박승남;이충희
    • Korean Journal of Optics and Photonics
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    • v.3 no.4
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    • pp.239-243
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    • 1992
  • We have investigeted the interference phenomena of the second harmonic waves of Nd:YAG laser generated at KDP single crystals and the nitrogen CARS signals. To get the phase difference between the successively generated nonlinear optical signals, a phase shifting unit made of BK-7 glass and a high pressure gas cell are used. Coherence lengths of several samples for the nonlinear signals are measured. Adjusting the thickness of the phase shifting unit where the CARS signals make destructive interference completely, the CARS spectrum of nitrogen suppressed over wide wavelength range is obtained. Also, we have observed the change in degree of suppression of the spectrum for the variation of the thickeness of the phase shifting unit.

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