• Title/Summary/Keyword: Laser crystal

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A Study on a KTP Crystal Laser System for a Cancer Using P.D.T. (KTP 크리스탈을 이용한 PDT용 레이저 시스템 개발)

  • Kim, Byoung-Mun;Nam, Hyo-Duk;Kim, Byoung-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.631-634
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    • 2004
  • The method that exists in Photodynamic Therapy uses Photosensibility drug strongly Influencing tumour accumulation together with photochemical laser effect and makes the structure of tumour be localized and become extinct. The intracavity transformation of the Nd :YAP main radiation 1079 nm was Raman converted in barium nitrate crystal and the Stokes frequency (1216 nm) was doubled using KTP or RTA crystals. The LiF or Cr:YAG crystals are used for the Q-switch. The radiation Parameters were obtained at 100 Hz pump repetition frequency. The average power at 608 nm radiation with LiF and KTP was 700 mW at multi-mode generation. The 3-6 single 10-15 ns pulses were generated during one cycle of pumping. The doubling efficiency with RTA was two times more than with KTP. The cells of Ehrlich adenocarcinoma (0.1 ml) were i.m. implanted in hind thighs of ICR white non-imbred mice. The cells were preliminarily diluted in medium 199 in the ratio of 1 to 5. HpD was intravenous administered in a dose of 10 mg/kg. The left clean-shaven hind leg was irradiated with laser light 21-27 hours after the administration of the preparation. The right non-Irradiated leg of each animal served as a control. The animals with the transplanted tumor that were not injected with HpD sewed as a control to estimate the complex effect (HpD+ irradiation). Before the administration of HpD and on 3 and 4 days after irradiation the tumor size was measured and the percent of the tumor growth inhibition was calculated. The results of animal treatments has shown high efficiency of PDT method for cancer treatment by means 0.608 m high power pulse solid state laser.

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Penetration behavior by carbon potential in laser-carburized TiZrN coatings (TiZrN 코팅의 레이저 침탄에서 탄소 포텐셜에 따른 침입 거동)

  • Lee, Byunghyun;Kim, Taewoo;Hong, Eunpyo;Kim, Seonghoon;Lee, Heesoo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.31 no.6
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    • pp.282-286
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    • 2021
  • Penetration depth and compressive residual stress of laser-carburized TiZrN coating by thickness of carbon paste were investigated in terms of carbon potential. The carbon paste was covered with a thickness of 1.1 mm using screen printing, and applied to a thickness of 0.4 mm using spin coating, and laser carburization was performed under the same conditions. As the thickness of carbon paste increased, the diffraction pattern of the laser-carburized TiZrN coating shifted to a lower angle, indicating solid solution strengthening and lattice distortion. For microstructure analysis using TEM, the defects and carbon concentration of the laser-carburized TiZrN coating increased as the carbon paste was thicker. It indicated that the variation of the carbon potential corresponds to the change in the paste thickness. In XPS depth profile analysis, high concentration of carbon and formation of carbide were observed in laser-carburized TiZrN coating with thick carbon paste. It revealed that the carbon concentration on the surface and carbon potential were changed by the thickness control of carbon paste. The compressive residual stress increased from 3.67 GPa to 4.58 GPa by the variation of carbon concentration.

Pulsed-laser-diode Intermittently Pumped 2-㎛ Acousto-optic Q-switched Tm:LuAG Laser

  • Wen, Ya;Jiang, Yan;Zheng, Hao;Zhang, Hongliang;Wang, Chao;Wu, Chunting;Jin, Guangyong
    • Current Optics and Photonics
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    • v.4 no.3
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    • pp.238-246
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    • 2020
  • The heat distribution in crystals in a 2-㎛ acousto-optic Q-switched Tm:LuAG laser pumped by pulsed-laser-diode (pulsed-LD) intermittent-pumping technology was analyzed using COMSOL software. The thermal lensing effect of the Tm:LuAG crystal can be mitigated by pulsed-LD intermittent-pumping techniques. An experimental setup using this kind of approach achieved maximum output energy of 8.31 mJ, minimum pulse width of 101.9 ns, and highest peak power of 81.55 kW, reached at a Q-switched repetition rate of 200 Hz. It offers significant improvement of performance of the output laser beam, compared to pulsed-LD double-ended pumping technology at the same repetition rate.

Effect of Pulsed Nd:YAG Laser Energy on Crystallization in $Li_2O - Al_2O_3 - SiO_2$ Glass

  • Lee, Yong--Su;Kang, Won--Ho
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2001.07a
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    • pp.104-109
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    • 2001
  • A 355 nm (3.5 eV) neodymium:yttrium aluminum gamet laser, produced by a harmonic generator, was used to create silver metallic particles as seeds for nucleation in photosensitive glass containing Ag+ and Ce3+ ions. The pulse width and frequency of the laser were 8 ns and 10 Hz, respectively. Heat treatment was conducted at 570 C for 1 h, following laser irradiation, to produce crystalline growth, after which a LiAlSi3O8 crystal phase appeared in the laser-irradiated Li2O A1203 SiO2 glass. For the Present study, we compared the effect of laser-induced crystallization on glass crystallization with that of spontaneous crystallization by heat treatment.

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