• Title/Summary/Keyword: VUV

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Fluoride single crystals for UV/VUV nonlinear optical applications

  • Shimamura Kiyoshi;Villora Encarnacion G.;Muramatsu Kenichi;Kitamura Kenji;Ichinose Noboru
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.4
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    • pp.133-140
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    • 2006
  • The growth characteristics and properties of large size $SrAlF_5$ single crystals are described and compared with those of $BaMgF_4$. Transmission spectra in the vacuum ultraviolet wavelength region indicate a high transparency of $SrAlF_5$ (about 90% without considering surface reflection loses) down to 150 nm, on contrast to the optical loses observed for $BaMgF_4$. The ferroelectric character of $SrAlF_5$ is evidenced by the reversal of the spontaneous polarization in a hysteresis loop. The higher potential of $SrAlF_5$ in comparison with $BaMgF_4$ for the realization of all-solid-state lasers in the ultraviolet wavelength region by the quasi-phase matching (QPM) technique is pointed out. $SrAlF_5$, besides a higher grade of transparency, shows a nonlinear effective coefficient similar to that of quartz and uniaxial nature, on contrast to the one order smaller nonlinear coefficient and biaxial character of $BaMgF_4$. The refractive index of $SrAlF_5$ from the ultraviolet to the near-infrared wavelength region is measured by the minimum deviation method. The Sellmeier and Cauchy coefficients are obtained from the fits to the curves of the ordinary and extraordinary refractive indices, and the grating period for the first order QPM is estimated as a function of the wavelength. The poling periodicity for 193 nm SHG from 386 nm is $4{\mu}m$.

Synthesis of Mn-doped Zn2SiO4 phosphor particles by solid-state method at relatively low temperature and their photoluminescence characteristics (상대적으로 낮은 온도에서의 고상법에 의한 망간이 도핑된 Zn2SiO4 형광체 입자의 제조 및 형광특성)

  • Lee, Jin-Hwa;Choi, Seung-Ok;Lee, Dong-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.228-233
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    • 2010
  • Mn-doped $Zn_2SiO_4$ phosphor particles having submicrometer sizes were synthesized by a solid-state reaction method using methyl hydrogen polysiloxane-treated ZnO, fumed $SiO_2$ and various Mn sources. The crystallization and photoluminescent properties of the phosphor particles were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM), and by their photoluminescence(PL) spectra. Due to the effect of the dispersion and coherence of the methyl hydrogen polysiloxane-treated ZnO, the Mn-doped $Zn_2SiO_4$ particles were successfully obtained by a solid state method at $1000^{\circ}C$, and the maximum PL intensity of the prepared particles under vacuum ultra violet(VUV) excitation occurred at a Mn concentration of 0.02mol and a sintering temperature of $1000^{\circ}C$.

Photoluminescence Properties of Novel $Mg_{2}SnO_{4}:Mn$ Phosphor (새로운 $Mg_{2}SnO_{4}:Mn$ 형광체의 광 발광 특성)

  • Kim, Kyung-Nam;Jung, Ha-Kyun;Park, Hee-Dong;Kim, Do-Jin
    • Journal of the Korean Ceramic Society
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    • v.38 no.9
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    • pp.817-821
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    • 2001
  • A new $Mg_{2-x}MN_xSnO_4$ phosphor with an inverse spinel structure was synthesized by the solid-state reaction technique. The photoluminescence properties of the $Mg_2SnO_4$:Mn phosphors were investigated under 147nm -vacuum ultraviolet ray excitation. The Mn-doped $Mg_2SnO_4$ phosphor exhibited high emission intensity with the spectrum centered at 500nm wavelength. It was explained that the green emission in $Mg_2SnO_4$:Mn phosphor has originated from energy transfer from $^4T_1$ to $^6A_1$ of $Mn^{2+}$ ion at tetrahedral site of the spinel structure. The $Mn^{2+}$ ion concentration exhibiting the maximum emission intensity under the excitation of 147nm-vacuum ultraviolet ray was 0.25mol%. And the decay time of the phosphor was shorter than 10ms.

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Analysis on the Discharge Characteristics of New Cell Structure for Luminous Efficacy Improvement in an AC Plasma Display Panel (교류형 플라즈마 표시키의 발광 효율 개설을 위한 실 구조의 방전 특성 분석)

  • Bae, Hyun-Sook;Whang, Ki-Woong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.6
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    • pp.7-13
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    • 2008
  • Through two-dimensional numerical simulations, we analyzed the effects of new cell structure for the luminous efficacy improvement in an ac plasma display panel. In the new structure with 5 electrodes, two auxiliary electrodes are arranged between X and Y electrodes with long gap. Through the application of adequate auxiliary pulse on the address electrode, the luminous efficacy in the new cell structure showed the improvement of 52[%] in comparison with that of conventional cell structure with short gap between X and Y electrodes. Consequently, as the short gap discharge between auxiliary electrodes decreases and the long gap discharge between X and Y electrodes increases, the result of VUV generation efficacy shows higher improvement. The reliability of simulation result could he confirmed by the experimental result in the test panel.

Laser absorption spectroscopy of ternary gas mixture of He-Ne-Xe in External Electrode Fluorescent Lamp (EEFL) (레이저 흡수 분광법을 이용한 He-Ne-Xe 상종가스의 외부전곡 램프의 $1s_4$ 공명준위와 $1s_5$ 준안정준위의 제논 원자 밀도에 대한 연구)

  • Jeong, S.H.;Oh, P.Y.;Lee, J.H.;Cho, G.S.;Choi, E.H.
    • Journal of the Korean Vacuum Society
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    • v.15 no.6
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    • pp.576-580
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    • 2006
  • Mercury-free lamp, external electrode fluorescent lamp (EEFL) which includes the xenon gas, is now going on the research for the replacement of mercury lamp. The densities of excited xenon atom in the $1s_4$ resonance state and the $1s_5$ metastable state are investigated in the EEFL by a laser absorption spectroscopy under various gas pressures. We have measured the absorption signals for both $1s_4$ resonance and the $1s_5$ metastable state in the EEFL by varying the discharge currents for a given pressure. This basic absorption characteristic is very important for improvement of the VUV luminous efficiency of the EEFL as well as plasma display panel.

A Fundamental Study of Eu2+ Luminescence in Aluminum Borate Compounds (Aluminum Borate 화합물에 있어서 EU2+이온의 발광성)

  • Chang, Ki-Seog
    • Journal of the Korean Chemical Society
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    • v.44 no.4
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    • pp.350-355
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    • 2000
  • The compounds, CaAl$_2$(BO$_3$)$_2$O, SrAl$_2$(BO$_3$)$_2$O and BaAl$_2$(BO$_3$)$_2$O, are good host lattices for highly efficient $Eu^{2+}$ luminescence. The europium emission peaks at 450 nm in $Eu^{2+}$:CaAl$_2$(B0$_3$)$_2$O, 411 nm in $Eu^{2+}$: SrAl$_2$(BO$_3$)$_2$O and 375 nm in $Eu^{2+}$: BaAl$_2$(BO$_3$)$_2$O. The $Eu^{2+}$: CaAl$_2$(BO$_3$)$_2$O Phosphor shows a high output and should be a good maintenance in VUV Xe lamps. It is ideally suited for use in PDP phosphors. The $Eu^{2+}$ ion is interesting because the Stokes shift emission is a strong host dependent. The difference in the Stokes shift is oneimportant factor leadingto a difference in wavelength. If the 5d level of $Eu^{2+}$ ion is lower in energy,according to a decrease in the doping lattice size, then the emission wavelength will be longer and the Stokes shift will be smaller. Therefore, a knowledge of the relationship between the crystal lattice size and the Stokes shift. (orthe energy of the 5d level),is essential for beingable to predict $Eu^{2+}$ emission properties.

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Laser-induced plasma emission spectra of halogens in the helium gas flow and pulsed jet (헬륨 가스 플로우와 가스 펄스 젯에서 할로겐족 원소들의 레이저유도 플라즈마 방출 스펙트럼)

  • Lee, Yonghoon;Choi, Daewoong;Gong, Yongdeuk;Nam, Sang-Ho;Nah, Changwoon
    • Analytical Science and Technology
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    • v.26 no.4
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    • pp.235-244
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    • 2013
  • Detection of halogens using laser-induced breakdown spectroscopy (LIBS) in open air is very difficult since their strong atomic emission lines are located in VUV region. In NIR region, there are other emission lines of halogens through electronic transitions between excited states. However, these lines undergo Stark broadening severely. We report the observation of the emission lines of halogens in laser-induced plasma (LIP) spectra in NIR region using a helium gas flow. Particularly, the emission lines of iodine at 804.374 and 905.833 nm from LIPs have been observed for the first time. In the helium ambient gas, Stark broadening of the emission lines and background continuum emission could be suppressed significantly. Variations of the line intensity, plasma temperature, and electron density with the helium flow rate was investigated. Detection of chlorine and bromine in flame retardant of rubbers was demonstrated using this method. Finally, we suggest a pulsed helium gas jet as a practical and ecomonical helium gas source for the LIBS analysis of halogens in open air.

Photoluminance Properties of ${Al_3}{GdB_4}{O_{12}}$ Phosphors Activated by $Tb^{3+} and Eu^{3+}$ ($Tb^{3+}$ 와 Eu^{3+}$로 활성화시킨${Al_3}{GdB_4}{O_{12}}$ 형광체의 발광 특성)

  • Kim, Ki-Woon;Kang, Sei-Sun;Lee, Rhim-Youl
    • Korean Journal of Materials Research
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    • v.10 no.1
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    • pp.49-54
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    • 2000
  • The new green $Al_3GdB_4O_{12}:Tb^{3+} and red Al_3GdB_4O_{12}:Eu_{3+}$ phosphors were synthesized and then characterized their optical properties for PDP application. And also the photoluminescence properties of these phosphors were compared with the commercial green $Zn_2SiO_4:Mn^{2+} and (Y,Gd)BO_3: Eu^{3+}$ red PDP phosphors. The phosphors were synthesized by solid state reaction at 115$0^{\circ}C$ for 4hr. It was found that the emitting brightness of $Al_3GdB_4O_{12}:Tb^{3+}$(15mol%) green phosphor under 147nm excitation was higher than that of commercial $Zn_2SiO_4: Mn^{2+}$ green PDP phosphor. However, the color coordinate of this new green phosphor was inferior to the commercial one. On the other hand, the emitting intensity of $Al_3GdB_4O_{12}:Eu^{3+}$(15mol%) red phosphor was smaller than the $commercial(Y,Gd)BO_3: Eu^{3+}$ red one, but the CIE coordinate was slightly improved. The excitation spectrum showed that $Al_3GdB_4O_{12}$ phosphors had a strong excitation band at $\lambda=160nm$ associated with the host absorption. And the photoluminance excitation (PLE) intensity in VUV range for $Al_3GdB_4O_{12}:Tb^{3+}$ green phosphor was higher than that of $Zn_2SiO_4: Mn^{2+}$, but the PLE intensity of $Al_3GdB_4O_{12}:Eu^{3+}$ red phosphor was smaller than $(Y,Gd)BO_3: Eu^{3+}$.

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