• Title/Summary/Keyword: Optical transparency

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Electromagnetic Induced Absorption in 5-level Atom using Density Matrix Equation (밀도행렬방정식을 이용한 5-준위 원자에서의 전자기 유도 흡수)

  • 권미랑;문한섭;김경대;박현덕;김중복
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.08a
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    • pp.200-201
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    • 2000
  • 원자와 빛의 결맞음 효과로서 나타나는 많은 흥미로운 현상들 중에서 전자기파 유도 투과(Electro-magnetic Induced Transparency ; EIT)는 원자가 공진주파수를 가진 레이저와 상호작용하였을 때, 광자를 흡수하지 않고 투과하는 현상으로서, 주로 3준위 구도에서 연구되어왔다. 그러나 최근 축퇴된 2준위 구도에서 원자와 빛의 결맞음 효과가 연구되면서 EIT와 정반대의 현상인 전자기 유도 흡수(Electromagnetic Induced Absorption ; EIA)의 관측이 보고되었고 그것과 연관된 물리적 특성들의 연구가 시도되고 있다. (중략)

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Transparent Polyimide Nanocomposite Films with Various Equi-biaxial Stretching Ratios (다양한 이축연신 비율에 따른 투명 폴리이미드 나노복합체 필름)

  • Kim, Young-Min;Chang, Jin-Hae
    • Polymer(Korea)
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    • v.36 no.4
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    • pp.478-485
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    • 2012
  • A series of transparent polyimide (PI) nanocomposite films was synthesized from bicyclo(2,2,2)oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BTDA) and 1,3-bis(3-aminophenoxy)benzene (BAPB) with various organoclay contents via solution intercalation polymerization to poly(amic acid)s, followed by thermal imidization. Varying organoclay loading in a range of 0 to 1.5 wt% produced variations in the optical transparency, morphology, and oxygen barrier property of the hybrids. An optimum oxygen barrier property was observed for the hybrids containing 1.0 wt% Cloisite 30B; these properties were degraded gradually by further increases in the clay content. The PI hybrid films were found to exhibit excellent optical transparency and almost no color. However, the transparency of the hybrid films decreased slightly with increasing organoclay content. Transparent PI hybrid films containing 1.0 wt% Cloisite 30B were stretched equi-biaxially with various stretching ratios in a range of 100-140% to investigate their optical transparency and oxygen permeability in detail; the variations of clay dispersion and morphology were also determined as a function of equi-biaxial stretching ratio. PI hybrid films with ${\geq}120%$ stretching were found to contain homogeneously dispersed clay in the polymer matrix and exfoliated nanocomposites. The highest barrier to oxygen permeation was found at an equi-biaxial stretching ratio of 130%.

Quasi-phase matched optical parametric oscillators using periodically poled $KNbO_3$ crystals (주기적으로 분극 반전된 $KNbO_3$를 이용한 준위상 정합 광 매개 진동자)

  • Lee Gwang Jo;Kim Jung Hyeon;Im Min Ho;O Hyeon Ho;Lee Don Hui;Yun Chun Seop
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.230-231
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    • 2003
  • $KNbO_3$is one of the best materials for efficient nonlinear frequency conversion, due to its large nonlinear optical coefficient ($d_{33}$ = 20.6 pm/V), wide transparency range (0.4 ~ 5 $\mu$m) and freedom from photorefractive effects. Quasi-phase-matched second harmonic generation using periodically poled $KNbO_3$ (PPKN) crystals has been reported. Here we report on fabrication of PPKN and demonstration of a pulsed optical param etric oscillator (QPM OPO) pumped by an Nd:YAG laser. (omitted)

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Post Deposition Annealing Effect on the Structural, Electrical and Optical Properties of ZnO/Ag/ZnO Thin Films

  • Kim, Daeil
    • Journal of the Korean Society for Heat Treatment
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    • v.25 no.2
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    • pp.85-89
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    • 2012
  • Transparent conductive ZnO/Ag/ZnO (ZAZ) multilayer films were deposited by Radio frequency (RF) magnetron sputtering and direct current (DC) magnetron sputtering. The effects of post deposition vacuum annealing temperature on the structural, electrical and optical properties of the ZAZ multilayer films were investigated. The thickness of ZAZ films is kept constant at ZnO 50 nm/Ag 5nm/ZnO 45 nm, while the vacuum annealing temperatures were varied from 200 and $400^{\circ}C$, respectively. As-deposited ZAZ films exhibit a sheet resistance of $6.1{\Omega}/{\Box}$ and optical transmittance of 72.7%. By increasing annealing temperature to $200^{\circ}C$, the resistivity decreased to as low as $5.3{\Omega}/{\Box}$ and optical transmittance also increased to as high as 82.1%. Post-deposition annealing of ZAZ multilayer films lead to considerably lower electrical resistivity and higher optical transparency, simultaneously by increased crystallization of the films.

Optical Properties of Sea Water - Entrance of Tokyo Bay , Japan ( 2 ) - (해수의 광학적 성질에 관한 연구 - 일본 동경만 입구 ( 2 ) -)

  • 양용림
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.22 no.2
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    • pp.16-21
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    • 1986
  • Optical properties of sea water were studied in the entrance of Tokyo Bay, Japan. based on the data obtained from seven oceanographic stations in June. 1985. The observation of surface irradiance and underwater irradiance of sea water for eight kind of wavelength (378, 422, 481, 513, 570, 621, 653. 677nm) of sun light was conducted using the underwater irradiameter (Isigawa # SR-8). The mean att;enuation coefficient of the sea water was appeared to be 0.245 (0.042-0.776) and the attenuation co~fficient of the sea water for wavelength appeared such as 0.227 for 378 nm, 0.186 for 422 nm. O. 175 for 481 nm. O. 176 for 513 nm. O. 185 for 570 nm, 0.337 for 621 nm. O. 321 for 653 nm, O. 348 for 677 nm. The transparency was 7.0 m (5.5-9 m). water color was 10 (8.0-13.0) in the study area and the sun altitude was 60.95$^{\circ}$ (43.610-75.500). The relationship between attenuation coefficient (K) and transparency (D) was K = 2.63/ D (1.28/ D- 4. 87/D). The rate of light penetration for eight kind of wave Ie nth (378, 422. 481. 513. 570, 621, 653, 677 nm) were computed with reference to the surface light intensity respectively. The mean rate of light penetration in proportion to depths were 68.63% (46.02-86.07%) in 1 m layer, 18.40% (2.07 -48.48%) in 5m layer, 4.82% (0.042-22.30%) in 10m layer and 1.35% (0.01I-7.42%) in 20m layer. The rate of light penetration at the transparency layer with reference to the surface light intensity was shown as 10.39% (0.77-27.46%).

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Transparent Ceramics for Visible/IR Windows: Processing, Materials and Characterization

  • Jung, Wook Ki;Ma, Ho Jin;Kim, Ha-Neul;Kim, Do Kyung
    • Korean Journal of Materials Research
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    • v.28 no.10
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    • pp.551-563
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    • 2018
  • Visible and IR windows require a combination of high optical transparency and superior thermal and mechanical properties. Materials, fabrication and characterization of transparent ceramics for visible/IR windows are discussed in this review. The transparent polycrystalline $Y_2O_3$, $Y_2O_3-MgO$ nanocomposites and $MgAl_2O_4$ spinel ceramics are fabricated by advanced ceramic processing and the use of special sintering technologies. Ceramic processing conditions for achieveing fully densified transparent ceramics are strongly dependent on the initial powder characteristics. In addition, appropriate use of sintering technologies, including vacuum sintering, hot-pressing and spark plasama sintering methods, results in outstanding thermal and mechanical properties as well as high optical transparency of the final products. Specifically, the elimination of light scattering factors, including residual pores, second phases and grain boundaries, is a key technique for improving the characteristics of the transparent ceramics. This paper discusses the current research issues related to synthesis methods and sintering processes for yttria-based transparent ceramics and $MgAl_2O_4$ spinel.

Study and Fabrication of Transparent Electrode Film by using Thermal-Roll Imprinted Ag Mesh Pattern and Coated Conductive Polymer (열형-롤 각인으로 형성한 Ag 격자 패턴과 전도성 고분자 코팅을 이용한 투명전극 필름 제작에 관한 연구)

  • Yu, Jong-Su;Jo, Jeong-Dai;Yoon, Seong-Man;Kim, Do-Jin
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.9
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    • pp.11-15
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    • 2010
  • In this study, to fabricate a low-resistance and high optical transparency electrode film, the following steps were performed: the design and manufacture of electroforming stamp, the fabrication of a thermal roll-imprinted polycarbonate (PC) patterned films, the filled low-resistance Ag paste using doctor blade process on patterned PC films and spin coating by conductive polymers. As a result of PC films imprinted line width of $26.69{\pm}2\;{\mu}m$, channel length of $247.57{\pm}2\;{\mu}m$, and pattern depth of $7.54{\pm}0.2\;{\mu}m$. Ag paste to fill part of the patterned film with conductive polymer coating and then the following parameters were obtained: a sheet resistance of $11.1\;{\Omega}/sq$ optical transparency values at a wavelength of 550 nm was 80.31 %.

Synthesis and Characterization of Colorless Polyimide Nanocomposite Films Containing Pendant Trifluoromethyl Groups

  • Jin, Hyo-Seong;Chang, Jin-Hae;Kim, Jeong-Cheol
    • Macromolecular Research
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    • v.16 no.6
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    • pp.503-509
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    • 2008
  • A series of colorless polyimide (PI) nanocomposite films were synthesized from 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) with various organoclay contents by solution intercalation polymerization to poly(amic acid)s, followed by thermal imidization. The variation with the organoclay content of the thermomechanical properties, morphology, and optical transparency of the hybrids was examined at organoclay loadings ranging from 0 to 1.0 wt%. The hybrid films showed high optical transparency and almost no color, with cut-off wavelengths ranging from 352 and 356 nm and very low $b^*$ values of 1.19-1.77. The hybrid PI films showed good thermal properties with a glass transition temperature of $280-287^{\circ}C$. Most films did not show any significant thermal decomposition below $490^{\circ}C$. The addition of only a small amount of organoclay was sufficient to improve the tensile properties of the PI films with maximum enhancement being observed at 0.25 wt% organoclay. Moreover, these PI hybrids also had low coefficients of thermal expansion (CTE).

Change of Anti-reflective Optical Property by Nano-structural Control of Alumina Layer through Hydro-thermal Process (수열합성 공정을 통한 알루미나 코팅층의 나노구조 조절에 의한 반사방지 특성의 변화)

  • Lee, Yun-Yi;Son, Dae-Hee;Lee, Seung-Ho;Lee, Gun-Dae;Hong, Seong-Soo;Park, Seong-Soo
    • Applied Chemistry for Engineering
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    • v.21 no.5
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    • pp.564-569
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    • 2010
  • Highly anti-reflective optical property has been focussed in the field of thin film and display because of increasing demands to the high transparency and clearness of optical component. In this study, to obtain anti-reflective property, the formation of aluminium oxide with nanoscaled flowerlike frame structure was introduced as oxide material monolayer on the substrate by hydrothermal synthesis through sol-gel method. The properties of coating layer were measured by the means of UV-Vis spectroscopy, FT-IR spectroscopy, XRD, and FE-SEM. The morphology of coating layer in alumina-sol coated samples was controlled by hydrothermal temperature and time with aid of ultrasound. It was found that high transparency and anti-reflective optical properties were obtained the formation of flowerlike nanoframe structure.

Design and Performance Analysis of BLSR/4 WDM/SHR in All-Optical Transport Network (완전 광전달망에서 BLSR/4 WMD/SHR의 설계 및 성능 분석)

  • 강안구;최한규;김지홍;김광현;김호건;조규섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.10B
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    • pp.1832-1840
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    • 1999
  • This paper proposed a network to implement all optical bidirectional BLSR/4 WDM/SHR allowing restoration in the event of a failure. The proposed network can provide a high degree of transparency using all-optical components with no electric implementation and effective failure restoration due to BLSR/4 WDM/SHR architecture. This paper also presented a genetic simulation model for the survivability analysis of the proposed BLSR/4 WDM/SHR under failure scenarios, the restoration performance of the proposed network is analyzed in terms of performance parameters such as propagation time, processing time, optical switch time.

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