• Title/Summary/Keyword: High refractive index

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Study on the Ophthalmic Lens Materials with High Refractive Index Containing Vinylanisole (Vinylanisole을 포함한 고굴절률 안의료용 렌즈 재료에 관한 연구)

  • Kim, Tae-Hun;Sung, A-Young
    • Journal of the Korean Chemical Society
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    • v.54 no.6
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    • pp.755-760
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    • 2010
  • This study used 3-vinylanisole and 4-vinylanisole with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (N-vinyl-2-pyrrolidone) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical characteristics of the copolymerized material showed that the refractive index is 1.4496 - 1.4894, water content 22.93 - 35.50%, visible transmittance 88.8 - 90.8%. Also, measurements showed that the refractive index increased while the water content decreased as the ratio of 3-vinylanisole and 4-vinylanisole increased. And in cases of copolymer with 3-vinylanisole, 4-vinylanisole (added 15%) the results showed transmittance of 52.8 - 82.2%, 13.2 - 26.2% respectively for UV-A and UV-B showing that they have UV-blocking effects. Based on the results of this study, the produced copolymer can be estimated to be suitable for use as ophthalmic lens material for high refractive index and UV- blocking effects.

High-reflectivity Tunable Wavelength Filters Incorporating an Apodized Bragg Grating with a High-refractive-index Polymer Layer (고굴절률 폴리머층과 에포다이즈드 브래그 격자를 이용한 고반사 파장 필터)

  • Kim, Eon-Tae;Park, Tae-Hyun;Huang, Guanghao;Oh, Min-Cheol
    • Korean Journal of Optics and Photonics
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    • v.28 no.6
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    • pp.346-350
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    • 2017
  • A tunable filter incorporating an apodized grating with a high-refractive-index polymer layer is demonstrated. In the apodized tunable filter, the reflectivity is decreased compared to that of a uniform grating, because of the gradually decreased grating depth. To increase the reflectivity of the apodized grating, a polymer of high refractive index is adopted for the apodized grating, and then high reflectivity is obtained while maintaining a narrow bandwidth. The apodized tunable filter exhibits a 3-dB bandwidth of 0.51 nm and a 20-dB bandwidth of 1.05 nm, with 98.5% reflection.

Study on characteristics of thin films for reflection of near infrared light (근적외선 반사 박막 특성 연구)

  • Chung, Youn-Gil;Park, Hyun-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.6
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    • pp.4121-4124
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    • 2015
  • Near infrared blocking function in energy saving window glass is required. The design, deposition and characteristics of optical thin films for reflection of near-infrared light were studied. The optical thin film is designed as laminated film structure with low refractive index film and high index film. Deposition experiments of $SiO_2$ and $TiO_2$ thin films with designed structure using the RF sputtering method were carried out. The characteristics of the thin film with deposition conditions were analyzed. High-refractive-index thin film of $TiO_2$/low refractive-index thin film of $SiO_2$ and high-refractive-index thin film of $TiO_2$ structure for reflection of near-infrared light was designed to be simulated. Results of simulation showed reflectance of 30% or more in the range from 930nm to 1682nm. Triple layer thin films fabricated with simulated results showed wavelength bands from 930nm to 1525nm for the reflectance of 33% or more.

Studies of Refractive Index and Hardness from the structures in Quarternary Li2O-B2O3-Al2O3-SiO2 Glasses (4성분 Li2O-B2O3-Al2O3-SiO2 유리들의 구조로부터 굴절률과 경도 연구)

  • Moon, Seong-Jun
    • Journal of Korean Ophthalmic Optics Society
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    • v.7 no.2
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    • pp.27-31
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    • 2002
  • Quarternary $Li_2O-B_2O_3-Al_2O_3-SiO_2$ glasses were fabricated by the function of $R({\equiv}Li_2Omole%/B_2O_3mole%)$ and $K({\equiv}(Al_2O_3mole%+SiO_2mole%/B_2O_3mole%)$. The structures of these glasses were investigated through refractive index and Vicker's hardness. The refractive index increased as the increase of the polarizability in the glass network. In the region of low $Li_2O$ content, the refractive index increased due to the increase of the polarizability in the glass network but, in the region of high $Li_2O$ content, the rate of increase of the refractive index decreased due to the increase of the molar volume caused by the formation of $BO_3{^-}$ units with relatively high molar volume. And, the refractive index decreased as the increase of $Al_2O_3+SiO_2$ content with the molar volume in the glass network. The increase and decrease of vicker's hardness values for those glasses depended on the fraction of tetrahedral $BO_4$ units and it of triangle $BO_3{^-}$ units with non-bridging oxygen, respectively.

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Studies of Refractive Index and Hardness In Quarternary NaBAISi Glasses (4성분 NaBAISi 유리계의 굴절률과 경도 연구)

  • Moon, Seong-Jun;Hwang, In-Sun
    • Journal of Korean Ophthalmic Optics Society
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    • v.8 no.1
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    • pp.1-5
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    • 2003
  • Quarternary $Na_2O-B_2O_3-Al_2O_3-SiO_2$ glasses were fabricated by the function of $R({\equiv}Na_2O\;mole%/B_2O_3\;mole%)$ and $K({\equiv}(Al_2O_3\;mole%+SiO_2\;mole%)/B_2O_3mole%)$. The structures of these glasses were investigated through refractive index and vicker's hardness. The refractive index increased as the increase of the polarizability in the glass network. In the region of low $Na_2O$ content, the refractive index increased due to the increase of the polarizability in the glass network, but in the region of high $Na_2O$ content, the rate of increase of the refractive index decreased due to the increase of the molar volume caused by the formation of $BO_3{^-}$ units with relatively high molar volume. And, the refractive index decreased as the increase of $Al_2O_3+SiO_2$ content with the molar volume in the glass network. The increase and decrease of vicker's hardness values for those glasses depended on the fraction of tetrahedral $BO_4$ units and it of triangle $BO_3{^-}$ units with non-bridging oxygen, respectively.

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Preparation of Hard Coating Films with High Refractive Index from Titania Nanoparticles (이산화티탄 나노입자로부터 고굴절 하드코팅 도막의 제조)

  • Kim, Nam Woo;Ahn, Chi Yong;Song, Ki Chang
    • Korean Chemical Engineering Research
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    • v.53 no.6
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    • pp.762-769
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    • 2015
  • The titania ($TiO_2$) nanoparticles with a diameter 2?3 nm were synthesized by controlling hydrolysis of titanium tetraisopropoxide (TTIP) in acid solution. Organic-inorganic hybrid coating solutions were prepared by reacting the titania nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at $120^{\circ}C$ after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films showed high optical transparency of 90% in the visible range and exhibited a pencil hardness of 2H. Also, the refractive index at 633 nm wavelength of coating films enhanced from 1.502 to 1.584 as the weight content of titania nanoparticles in the coating solutions increased from 4% to 25%.

Fabrication of High Refractive Index ZrO2 Thin Film by a Layer-by-layer Self-assembly Method (LBL-SA법을 이용한 고굴절률 ZrO2 박막 제조)

  • Choi, Chang-Sik;Lee, Ji-Sun;Lee, Mi-Jai;Lee, Young-Jin;Jeon, Dae-Woo;Ahn, Byoung-Jo;Kim, Jin-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.4
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    • pp.199-203
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    • 2017
  • $ZrO_2/PSS$ thin film with a high refractive index was fabricated on a glass substrate by a layer-by-layer self-assembly method. The surface morphology and thickness of the fabricated $ZrO_2/PSS$ thin films were measured as a function of the number of $(ZrO_2/PSS)n$. As the number of $(ZrO_2/PSS)n$ increased from n = 5 to n = 20, RMS roughness decreased from 29.01 nm to 8.368 nm. The $ZrO_2$ thin films exhibited high transmittance of 85% or more; and the 15-bilayer thin film exhibited the highest transmittance among the samples. The transmittance of the fabricated $(ZrO_2/PSS)_{15}$ thin film was ca. 90.8% in the visible range. The refractive index of the glass substrate coated by a $(ZrO_2/PSS)_{15}$ thin film with a thickness of 160 nm increased from ca. 1.52 to 1.74 at the 632 nm wavelength.

Optical diffraction gratings embedded in BK-7 glasses by tightly focused femtosecond laser

  • Yoon, Ji Wook;Choi, Won Suk;Kim, Hoon Young;Cho, Sung-Hak
    • Laser Solutions
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    • v.17 no.2
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    • pp.19-25
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    • 2014
  • Optical embedded diffraction gratings with the bulk modification in BK-7 glass plates excited by tightly focused high-intensity femtosecond (130fs) Ti: sapphire laser (peak wavelength = 790nm) were demonstrated. The structural modifications with diameters ranging from 400nm to $4{\mu}m$ were photo-induced after plasma formation occurred upon irradiation with peak intensities of more than $1{\times}1013W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around from the center of the point at which low-density plasma occurred. The maximum refractive index change was estimated to be $1.5{\times}10^{-2}$. The two optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.

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Fabrication of Internal Gratings in PDMS Using a Femtosecond Laser

  • Park, Jung-Kyu;Cho, Sung-Hak;Yu, Jae-Yong;Kim, Jae-Gu;Sugioka, Koji;Hong, Jong-Wook;Heo, Won-Ha;Hwang, Kyung-Hyun
    • Laser Solutions
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    • v.14 no.1
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    • pp.1-5
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    • 2011
  • Photo-induced gratings m flexible PDMS (polydimethly siloxane) film are directly written by a high-intensity femtosecond (130fs) Ti: Sapphire laser (${\lambda}_p$ = 800nm). The refractive index modifications with $4\;{\mu}m$ diameters were photo-induced after the femtosecond irradiation with peak intensities of more than $1{\times}10^{11}W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around the center of the point at which femtosecond laser by controlling both laser power and focused depth. The change on refractive index in the laser-modified regions was estimated to be approximately $10^{-3}$. The internal flexible symmetric diffraction gratings in PDMS film was successfully fabricated using a femtosecond laser.

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Fabrication and Characterization of PLC-based Mach-Zehnder Interferometer Sensor (PLC-기반의 마흐-젠더 간섭계 센서 제작 및 특성 평가)

  • Kim, Jun-Hyong;Yang, Hoe-Yong;Lee, Hyun-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.390-390
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    • 2008
  • In this paper, we have designed and fabricated optical waveguides based on the Mach-Zehnder Interferometer (MZI) for application to sensor. The evanecent-wave sensor based on the MZI principle has sufficiently high sensitivity to measure the change of the refractive index on surface of a waveguide. The waveguides were optimized at a wavelength of 1550 nm and fabricated according to the design rule of 0.45 delta%, which is the difference of refractive index between the core and clad. The fabrication of MZI optical waveguides was performed by a conventional Planar Lightwave Circuit (PLC) fabrication process. The fabricated MZI optical waveguide device was measured. According to the measurement result, the insertion loss of MZI optical waveguide device was below 3.5 dB and the polarization dependent loss (PDL) was within 0.1dB. In addition, we analyzed optical properties of MZI sensor according to the refractive index change of the sensor arm.

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