• Title/Summary/Keyword: photonic crystals

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Fabrication and Optical Properties of 2D Photonic Crystal Assisted Thin Film Phosphors

  • Oh, Jeong-Rok;Ko, Ki-Young;Do, Young-Rag
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.594-597
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    • 2008
  • This presentation introduces a simple strategy for producing 2D photonic crystal layers (PCL) with different structures. In an attempt to improve extraction efficiency from the thin film phosphors (TFPs), this study have examined the effects of the structural variables of the 2D PCLs on the light extraction efficiency of TFPs.

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Photonic Band Gap Characteristics by Shape of Lattice with Uniformity Area (동일한 면적을 가지는 격자의 모양에 따른 광자 밴드갭 특성에 관한 연구)

  • 김기욱;오범환;이승걸;박세근;이일항
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.07a
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    • pp.226-227
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    • 2003
  • 광자 크리스탈 (Photonic Crystals)은 서로 다른 유전체의 주기적인 구조로 이루어져 있으며, 전자기파가 특정한 주파수 범위에서 전파하지 못하고 차단되는 영역인 광자 밴드갭 (Photonic Band Gap)이 존재한다. 이러한 광자 밴드갭의 존재로 인하여 빛의 흐름을 조절할 수 있다는 점 때문에 반사거울, 휘어진 도파로(bent waveguide), 레이저, 채널 드롭핑 필터(channel dropping filter) 등 여러 가지 다양한 분야에 응용될 수 있다. (중략)

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Design and Performance Analysis of a Multi Wavelength Terahertz Modulator Based on Triple-Lattice Photonic Crystals

  • Ji, Ke;Chen, Heming;Zhou, Wen
    • Journal of the Optical Society of Korea
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    • v.18 no.5
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    • pp.589-593
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    • 2014
  • Terahertz (THz) communication has important applications in high-speed and ultra broadband wireless access networks. The THz modulator is one of the key devices in a THz communications system. Wavelength division multiplexing (WDM) can expand the capacity of THz communications systems, so research on multi wavelength THz modulators has significant value. By combining photonic-crystal and THz technology, a novel type of multi wavelength THz modulator based on a triple-lattice photonic crystal is proposed in this paper. Compared to a compound-lattice photonic crystal, a triple-lattice photonic crystal has a larger gap width of 0.196. Simulation results show that six beams of THz waves can be modulated simultaneously with high performance. This modulator's extinction ratio is as large as 34.25 dB, its insertion loss is as low as 0.147 dB, and its modulation rate is 2.35 GHz.

Control of Optical Hysteresis in Block Copolymer Photonic Gels: A Step Towards Wet Photonic Memory Films

  • Kim, Eun-Ju;Gang, Chang-Jun;Jang, Yu-Rim;Senthilkumar, S.;Gang, Yeong-Jong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.279-279
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    • 2010
  • Smart gels have recently associated with photonic crystals to form photonic gels. Since these photonic gels are capable of reversibly converting the volume change of gels induced in response to external chemical or electric stimuli into characteristic optical signals, they have been considered not only as a good platform for label-free chemical or biological detection, actuators or optical switches but also as a good model system to investigate gel swelling behaviour. Recently, we reported block copolymer photonic gels self-assembled from polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) block copolymers, and demonstrated that selective swelling of lamellar structure allows extremely large tunability of the photonic stop band from UV region to IR region ($\lambda$ peak=350~1,600 nm). Herein we report block copolymer photonic gels which exhibit strong tunable optical hysteresis and their applications. As nonlinear responses in swelling of hydrogels were often observed, photonic gels exhibit optical hysteresis with change of external pH. We demonstrate such optical hysteresis can be precisely programmed by controlling ion-pairing affinity. We anticipate that photonic gels with carefully tunned optical hysteresis are applicable to optical memory devices.

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Well Defined One-Dimensional Photonic Crystal Templated by Rugate Porous Silicon

  • Lee, Sung Gi
    • Journal of Integrative Natural Science
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    • v.6 no.3
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    • pp.183-186
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    • 2013
  • Well defined 1-dimentional (1-D) photonic crystals of polystyrene replicas have been successfully obtained by removing the porous silicon from the free-standing rugate porous silicon/phenylmethylpolysiloxane composite film. Rugate porous silicon was prepared by an electrochemical etching of silicon wafer in HF/ethanol mixture solution. Exfoliated rugate porous silicon was obtained by an electropolishing condition. A composite of rugate porous silicon/phenylmethylpolysiloxane composite film was prepared by casting a toluene solution of phenylmethylpolysiloxane onto the top of rugate porous silicon film. After the removal of the template by chemical dissolution, the phenylmethylpolysiloxane castings replicate the photonic features and the nanostructure of the master. The photonic phenylmethylpolysiloxane replicas are robust and flexible in ambient condition and exhibit an excellent reflectivity in their reflective spectra. The photonic band gaps of replicas are narrower than that of typical semiconductor quantum dots.