• 제목/요약/키워드: Photonic band

검색결과 149건 처리시간 0.027초

Fabrication and Optical Characterization of Colloidal 3-D Photonic Crystals

  • N. Y. Ha;Y. Woo;Park, Byungchoo;J. W. Wu
    • 한국진공학회지
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    • 제12권S1호
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    • pp.15-16
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    • 2003
  • 3-D photonic band-gap structures are fabricated from dielectric colloidal polystyrene beads through a centrifuge method. The fabricated photonic crystals exhibit opalescent colors under white light and show a clear diffraction peak dependent on the incident angle of the light beam. Also the scanning electron microscope image was taken to verify the face-centered cubic crystal structure. Bragg's law and Snell's law are employed to describe the position of angle resolved diffraction peaks. It was shown that the optically deduced effective refractive index and lattice constants were in good agreement with the crystal structure identified by scanning electron microscope.

New Phosphor and Material Structures for Displays

  • Summers, Christopher J.;King, Jeffrey;Park, Woun-Jhang
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.243-252
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    • 2002
  • We propose a new concept: that of photonic crystal phosphors (PCPs) for display and phosphor related applications. It is well known that microcavities with dimensions comparable to the emitting wavelength strongly enhance light-matter interactions, resulting in a significant increase in spontaneous emission rate, which can be directly translated into enhancement in phosphor efficiency. In recent simulations we have demonstrated that when a microcavity is formed in a nano-phosphor structure, the luminescence band is modified, and can be made spectrally sharp and tunable by engineering the geometry/material properties of the cavity and the surrounding photonic crystal lattice. New phosphor material structures based on photonic crystals are proposed. Applications to thin film EL phosphors and particle phosphors are discussed. Additionally, economic methods of synthesizing and incorporating PCPs into current display applications are proposed.

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양자우물 - 양자선 상전이 현상의 광양자테 레이저 (Quantum well - quantum wire phase transiton of photonic quantum ring laser)

  • Kwon, O-Dae;Noik Pan;Kim, Junyeon
    • 한국광학회:학술대회논문집
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    • 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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    • pp.38-39
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    • 2003
  • The GaAs semiconductor whispering gallery modes, produced in the peripheral Rayleigh band region of W/sub Rayleigh/ = (${\Phi}$/2)( 1-n/sub eff/n), exhibit novel properties of ultralow thresholds open to nano-ampere regime associated with photonic quantum ring (PQR) production (Fig 1 (a)). The PQR phenomena are associated with a photonic field-driven phase transition of quantum well(QW)-to-quantum wire (QWR) and hence the photonic (non-de Broglie) quantum corral effects, on the Rayleigh cavity confined carriers in dynamic steady state, occur as schematically shown in Fig 1. (omitted)

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포토닉 밴드갭 구조를 이용한 두껍고 유전상수가 높은 패치 안테나의 성능 향상 (Improvement of Performance of Thick and High Dielectric Patch Antennas using Photonic Bandgap Structures)

  • 기철실;박익모;임한조;한해욱;이정일
    • 한국전자파학회논문지
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    • 제13권1호
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    • pp.1-6
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    • 2002
  • 본 논문에서는 표면파의 전파를 억제하는 포토닉 밴드갭 구조가 기판의 두께가 두껍고 유전상수가 높은 패치 안테나의 복사효율과 후방 복사를 획기적으로 개선할 수 있음을 보였다.

Wideband Slow Light in a Line-defect Annular Photonic-crystal Waveguide

  • Kuang, Feng;Li, Feng;Yang, Zhihong;Wu, Hong
    • Current Optics and Photonics
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    • 제3권5호
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    • pp.438-444
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    • 2019
  • In this theoretical study, a line-defect photonic-crystal waveguide hosted in an annular photonic crystal was demonstrated to provide high-performance slow light with a wide band, low group-velocity dispersion, and a large normalized delay-bandwidth product. Combined with structural-parameter optimization and selective optofluid injection, the normalized delay-bandwidth product could be enhanced to a large value of 0.502 with a wide bandwidth of 58.4 nm in the optical-communication window, for a silicon-on-insulator structure. In addition, the group-velocity dispersion is on the order of $10^5$ ($ps^2/km$) in the slow-light region, which could be neglected while keeping the signal transmission unchanged.

WDM 시스템에 적합한 광결정 대역 통과 필터 설계 (Photonic Crystal Based Bandpass Filter Design for WDM Communication Systems)

  • 박동수;김상인;박익모;임한조
    • 한국광학회지
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    • 제16권3호
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    • pp.266-274
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    • 2005
  • 본 논문에서는 2차원 광결정 공진기의 결합을 통해 WDM시스템에 적합한 특성을 가지는 공진 필터를 설계하였다. 공진기간의 결합에 있어서 고려해야 할 요소를 시영역에서의 모드 결합이론(coupling modes in time)을 적용하여 이론적으로 분석하였으며, 전자회로 등가화를 이용하여 쉽게 그 요소를 결정할 수 있음을 보였다. 공진기 결합에 있어서 공진기 간의 간격에 따른 위상천이에 대해서 외부감쇄에 의한 Q-factor를 조정함으로써 보상할 수 있음을 확인하였고, 2차원 광결정 점결함 공진기를 이용하여 500GHz의 대역폭을 가지며 통과대역에서 0.5 dB 리플을 가지는 3차 Chebyshev 대역 통과 필터를 설계하였다.

TeOx(22 1차원 광자결정의 광학 특성평가 (Optical Properties of TeOx(2x One-dimensional Photonic Crystals)

  • 공헌;여종빈;이현용
    • 한국전기전자재료학회논문지
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    • 제27권12호
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    • pp.831-836
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    • 2014
  • One-dimensional (1D) photonic crystals (PCs) were prepared by $TeO_x(2<x<3)/SiO_2$ with the difference refractive index, and fabricated by sputtering technique from a $TeO_2$ and $SiO_2$ target. The $TeO_x$(2$Ar:O_2=40:10$). A 10-pair $TeO_x(2<x<3)/SiO_2$ 1D PCs were fabricated with the structure parameters of filling factor=0.5185, and period=410 nm. The properties of 1D PCs with and without a defect layer were evaluated by UV-VIS-NIR. A normal mode 1D PC have a photonic band gap (PBG) in the near infrared (NIR) region from 1,203 to 1,421 nm. In the case of 1D PC containing a defect layer, a defect level appears at 1,291 nm. The measured transmittance (T) spectra are nearly corresponding to calculated results. After He-Cd laser exposure, the defect level is shifted from 1,291 nm to 1,304 nm.

Electro-controllable omni-directional laser emissions from a helical polymeric network composite film

  • Jang, Won-Gun;Park, Byoung-Choo;Kim, Min-A;Kim, Sun-Woong;Kim, Yun-Ki;Choi, Eun-Ha;Seo, Yoon-Ho;Cho, Guang-Sup;Kang, Seung-Oun;Takezoe, Hideo
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.883-886
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    • 2008
  • In optical information technology, an electro-controllable Photonic Band Gap (PBG) in a photonic crystal (PC) material is potentially useful for the manipulation of light. Despite a great deal of research on PBGs, the reliable use of electro-active PBG material systems is restricted to only a few cases because of the complex and limiting nature of the structures involved. Here, we propose a PBG system that uses a liquid crystal (LC) polymer composite. The composite is made of nematic LCs (NLCs) embedded in polymeric helical networks of photo-polymerized cholesteric LCs (CLCs). The composite film shows a large field-induced reversible color shift over 150 nm of the reflection band, due to the reorientational undulation of the helical axis, similar to the Helfrich effect.

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