• 제목/요약/키워드: Photonic band

검색결과 149건 처리시간 0.026초

사각형 광결정 슬랩에서 제작된 상온 발진 광결정 밴드 가장자리 레이저 (Room temperature photonic band edge lasers from two-dimensional square lattice photonic crystal slabs)

  • 권순홍;김국현;이용희
    • 한국광학회:학술대회논문집
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    • 한국광학회 2003년도 하계학술발표회
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    • pp.236-237
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    • 2003
  • 최근 공진기 형태가 없는 2차원 광결정(photonic crystal) 레이저가 그것의 2차원 되먹임과 거울 없는 발진 현상과 같은 특이한 특성으로 인해 많은 관심을 끌고 있다. 이러한 레이저는 photonic band edge에서 빛의 군속도의 감소에 근거하여 작동한다. 이 photonic crystal band edge 레이저는 2차원 형태의 Distributed-Feedback(DFB) 레이저 형태로 볼 수 있다. 지금까지 보고된 레이저는 0.1 정도의 매우 작은 굴절률 변화를 가지고 있고 크기가 (100$\mu$m)$^2$이상으로 상당히 크다. (중략)

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Theoretical Consideration on Influences of Cavity or Pillar Shape on Band Structures of Silicon-Based Photonic Crystals

  • Ogawa, Yoshifumi;Tamura, Issei;Omura, Yasuhisa;Iida, Yukio
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제7권1호
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    • pp.56-65
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    • 2007
  • This paper describes physical meanings of various influences of cavity (or pillar) shape and filling factor of dielectric material on band structures in two-dimensional photonic crystals. Influences of circular and rectangular cross-sections of cavity (or pillar) arrays on photonic band structures are considered theoretically, and significant aspects of square and triangular lattices are compared. It is shown that both averaged dielectric constant of the photonic crystal and distribution profile of photon energy play important roles in designing optical properties. For the triangular lattice, especially, it is shown that cavity array with a rectangular cross-section breaks the band structure symmetry. So, we discuss this point from the band structure and address optical properties of lattice with a circular cross-section cavity.

Magneto-Optical Effect of One-Dimentional Magnetophotonic Crystal Utilizing the Second Photonic Band Gap

  • Uchida, H.;Tanizaki, K.;Khanikaev, A.B.;Fedyanin, A.A.;Lim, P.B.;Inoue, M.
    • Journal of Magnetics
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    • 제11권3호
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    • pp.139-142
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    • 2006
  • We fabricated new one-dimensional magnetophotonic crystal (1D-MPC) utilizing the second and third photonic band gaps where localized modes existed. Structure of the 1D-MPC was $(Ta_{2}O_{5}/SiO_{2})_{5}/Bi:YIG/(SiO_{2}/Ta_{2}O_{5})_{5}$ with optical thicknesses of 3$\lambda$ /4 for $Ta_{2}O_{5} and $SiO_2$ dielectric layers and $\lambda$ /2 for Bi:YIG defect layer, where $\lambda$ is a wavelength of a localized mode in the second photonic band gap. Faraday rotation at the localized mode in the second photonic band gap was enhanced, which was confirmed by calculation using 4${\times}$4 matrix method.

2 차원 광결정의 실공간 밴드구조 계산 (A Real-Space Band-Structure Calculation of 2D Photonic Crystals)

  • 전석기;조영삼;임세영
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.1089-1093
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    • 2003
  • The moving least square (MLS) basis is implemented for the real-space band-structure calculation of 2D photonic crystals. The value-periodic MLS shape function is thus used in order to represent the periodicity of crystal lattice. Any periodic function can properly be reproduced using this shape function. Matrix eigenequations, derived from the macroscopic Maxwell equations, are then solved to obtain photonic band structures. Through numerical examples of several lattice structures, the MLS-based method is proved to be a promising scheme for predicting band gaps of photonic crystals.

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Tunable Photonic Band Gap Materials and Their Applications

  • 강영종
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.261-261
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    • 2010
  • Photonic band gap (PBG) materials have been of great interest due to their potential applications in science and technology. Their applications can be further extended when PBG becomes tunable against various chemical and electrical stimuli. In recent, it was found that tunable photonic band gap materials can be achieved by incorporating stimuli-responsive smart gels into PBG materials. For example, the characteristic volume phase transition of gels in response to the various external stimuli including temperature, pH, ionic strength, solvent compositions and electric field were recently combined with the unique optical properties of photonic crystals to form unprecedented highly responsive optical components. Since these responsive photonic crystals are capable of reversibly converting chemical or electrical energy into characteristic optical signals, they have been considered as a good platform for label-free chemical or biological detection, actuators or optical switches as well as a model system for investigating gel swelling behavior. Herein, we report block copolymer photonic gels self-assembled from polystyrene-b-poly (2-vinyl pyridine) (PS-b-P2VP) block copolymers. In this talk, we are going to demonstrate that selective swelling of lamellar structure can be effectively utilized for fabricating PBG materials with extremely large tunability. Optical properties and their applications will be discussed.

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Eelectro-optic Behavior of Opal-LC Photonic Crystals

  • Kang, Dae-Seung
    • Journal of Information Display
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    • 제2권4호
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    • pp.19-22
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    • 2001
  • In this paper, we describe the electro-optic effects of photonic crystals made of a synthetic opal filled with a nematic liquid crystal(LC). By applying an external electric field, a shift in the Bragg reflection peak position(stop band) and a field-induced change in its peak reflectivity are observed. These significant surface alignment effects of the opal-LC composite are discussed in a similar manner for Freederick-type transitions of LC within a confined geometry in the presence of external fields.

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PBG 구조를 이용한 Ka Band 전력증폭기 성능개선에 관한 연구 (Improvement of Ka band Power Amplifier Employing Photonic Band Gap Structure)

  • 서철헌
    • 대한전자공학회논문지TC
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    • 제41권1호
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    • pp.65-68
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    • 2004
  • 본 논문에서는 밀리미터파 대역 전력증폭기가 출력단에 PBG (photonic bandgap structure) 구조를 설치함으로써 성능개선 되었다 PBG 구조는 Ka 대역에서 저역통과 특성을 갖도록 최적화되었다. 전력증폭기의 하모닉은 PBG 구조에 의하여 억제되었고 50 GHz에서 40dBc 개선되었다 전력증폭기의 IMD와 PAE는 PBG에 의하여 기존의 전력증폭기에 비하여 각각 $15\%$$25\%$ 개선되었다.

2차원 광결정 제작에 패턴 특성을 향상시키기 위한 공정 기술 (Fabrication Technology for Improving Pattern Quality in Two-Dimensional Photonic Crystal Structure)

  • 김해성;신동훈;김순구;이진구;이범석;김혜원;이재은;한영수;최영호
    • 한국전기전자재료학회논문지
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    • 제16권6호
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    • pp.515-521
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    • 2003
  • There are now many theoretical investigations and real manufactures for numerous applications of photonic crystals (PCs) associated with photonic band gap and photonic integrated circuits. However, there are some difficulties to design and fabricate the desired pattern quality. It is not easy to satisfy accurate critical dimension (CD) for patterns with arbitrary shapes and pitch sizes aligned in various directions. In this work, we report the optimum conditions to better fabricate and design, and greatly improve pattern quality in delineating two-dimensional (2D) PCs in the nanometer range using single- step e-beam lithography system with conventional exposure mode.

Low-threshold Photonic Crystal Lasers from InGaAsP Free-standing Slab Structures

  • Ryu, Han-Youl;Kim, Se-Heom;Kwon, Soon-Hong;Park, Hong-Gyu;Lee, Yong-Hee
    • Journal of the Optical Society of Korea
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    • 제6권3호
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    • pp.59-71
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    • 2002
  • Photonic band gap structures have a high potential for nearly zero-threshold lasers. This paper describes new-types of low-threshold photonic crystal lasers fabricated in InGaAsP slab waveguides free-standing in air. Two-types of photonic crystal lasers are studied. One is a single-cell nano-cavity laser formed in a square array of air holes. This photonic band gap laser operates in the smallest possible whispering gallery mode with a theoretical Q >30000 and exhibits low threshold pump power of 0.8 mW at room temperature. The nther laser does not have any cavity structure and the lasing operation originates from the enhanced optical density of states near photonic band edges. A very low threshold of 35 $\mu$W (incident pump power) is achieved from this laser at 80 K, one of the lowest values ever reported. This low threshold is benefited from low optical losses as well as enhanced material gain at low temperature.

FDTD 방법을 이용한 2차원 황자 크리스탈의 밴드 구조와 분산 곡선의 계산 (Calculation of band structures and dispersion surfaces in two-dimensional photonic crystals using the FDTD method)

  • 홍수완;김창모;정교방
    • 한국광학회지
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    • 제12권6호
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    • pp.479-484
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    • 2001
  • 광자 크리스탈의 광자 밴드갭이나 비정상적인 광 분산 현상 등의 특성을 분석하려면 광자 크리스탈 구조에 따른 밴드 구 조와 분산 곡선의 계산이 필요하다. 본 논문에서는 시간 영역에서의 계산 방법인 Finite-Difference Time-Domain방법과 주기적 경계 조건을 이용하여 밴드 구조와 분산 곡선을 계산하였으며, 몇 가지 간단한 2차원 크리스탈 구조에 대하여 그 계산 결과를 제시하였다. 또한 밴드갭 내부에 존재하고, 공간적으로 지역화된 디펙트 모드를 계산하였다.

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