http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effects of Surface Termination on Directional Emission from Photonic Crystal Waveguides
정교방 한국광학회 2008 Current Optics and Photonics Vol.12 No.1
We numerically investigate by the finite-difference time-domain method the effects of surface termination on directional emission exiting a photonic crystal waveguide. The directed power and far-field beam profile for the original proposal [E. Moreno et al., Phys. Rev. B 69, 121402 (2004)] and its enhancement [S. K. Morrison et al., Appl. Phys. Lett. 86, 081110 (2005)] are computed for different values of some important parameters. We find another surface termination condition with a positive surface displacement in the structure of the original proposal which has a negative surface displacement. Our surface termination is more effective than the original structure, and nearly as effective as the termination for the enhancement, for directional emission. Besides, our termination is simpler than that for the enhancement. We confirm the effectiveness of directional emission from our termination in its far-field beam profile, radiation intensity distribution, and additionally the wave-vector space representation by the Fourier analysis.
Properties of Surface Modes Used for Directional Emission from Photonic Crystal Waveguides
정교방 한국광학회 2008 Current Optics and Photonics Vol.12 No.1
Directional emission of light exiting a photonic crystal waveguide by a coherent action of radiative surface modes was recently demonstrated, and subsequently the substantial enhancement of the directional emission was achieved by engineering the surface and adjusting relevant parameters. Here we present the analysis of surface modes causing the enhanced emission by the plane wave expansion method and the finite-difference time-domain method. In particular, surface band structures are calculated for nonradiative and radiative surface modes, respectively, and intensity profiles of some representative modes for nonradiative and radiative cases are given.
제한된 수의 투사를 이용한 비 균일 경계 값을 가진 공간 분포의 재구성
鄭敎龐 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.2
A reconstruction method that makes use of smoothness of distributions and other apriori information, called the finite domain direct inversion (FDDI) method, was applied to the reconstruction of simulated distribution characteristic of a real experimental situation, e.g. measurements on a gas mixture within a duct. It was found that an abrupt discontinuity of a distribution at the periphery of its domain (and zero outside the domain) poses difficulty in the FDDI reconstruction because the basis functions used in the method cannot accommodate the discontinuity well. The inversion method was extended to include shifting functions which dealt specifically with the nonzero peripheral values of the distribution. We developed a systematic way of finding suitable shifting functions that improve the reconstructions substantially.
광자 크리스탈 채널드롭 터널링을 이용한 파장분할 소자에 대한 연구
鄭敎龐,吳世澤 弘益大學校 科學技術硏究所 2003 科學技術硏究論文集 Vol.14 No.-
We design a 1 X 4 wavelength demultiplexer based on channel drop tunneling in photonic crystals. We show the results of simulation of the demultiplexer device for tunneling properties of electromagnetic waves in a two-dimensional photonic crystal, with an application of the finite-difference time-domain method with perfectly-matched-layer absorbing boundary condition. We find four frequencies at which the channel drop tunneling occurs, and design a 1 X 4 wavelength demultiplexer based on the frequencies. To improve the channel drop transmission, we separate spurious reflections in photonic crystal waveguide simulations using a large computational domain, and obtain the results of highly efficient transmission.