• 대한전자공학회논문지
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• 제25권8호
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• pp.874-883
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• 1988

A complete form of physical optics solution to the diffraction of electromagnetic waves by a dielectric wedge with arbitrary dielectric constant and general wedge angle is obtained for an incident plane wave with any angle. Based on the formulation of dual integral equation in the spectral domain, the physical optics solution is constructed by sum of geometrical optics term including multiple reflection inside the wedge and the edge diffracted field, of which diffraction functions are represented in a quite simple form as series of cotangent functions weighted by the Fresnel reflection coefficients. Since diffraction patterns of physical optics are discontinous at dielectric interfaces, Part II and III of these three companion papers will be concerned with correction to the error of the physical optics approximation.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.203-208
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• 1991

We present an analytic equation for the reflectivity spectrum of a Bragg reflector in terms of the front mirror reflectivity, due to the refractive index difference between the refractive index of outside medium and the average refractive index of Bragg reflector structures, and the reflectivity of a Bragg reflector calculated by the coupled wave method. We show that even Fresnel reflection causes the reflectivity spectrum of a bragg reflector to be very different from that of Bragg reflectors calculated by the coupled wave method. The reflectivity spectrum of a Bragg reflector is dramatically changed because the interference effect between the reflected wave from the front facet and that from the Bragg reflector is changed due to the difference of a phase change from a Bragg reflector when the sequence of layers in a Bragg reflector is changed.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.1-7
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• 2016

Using coherence theory, the partially coherent flat-topped vortex hollow beam is introduced. The analytical equation for propagation of a partially coherent flat-topped vortex hollow beam in turbulent atmosphere is derived, using the extended Huygens-Fresnel diffraction integral formula. The influence of coherence length, beam order N, topological charge M, and structure constant of the turbulent atmosphere on the average intensity of this beam propagating in turbulent atmosphere are analyzed using numerical examples.

• Journal of information and communication convergence engineering
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• 제11권4호
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• pp.282-287
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• 2013

A real-time digital holographic display is the core technology for the next-generation 3DTV. Holographic display requires a considerably large amount of calculation. If generating a large number of digital holograms is intended, the amount of calculation and the time required increase exponentially. This is a significant obstacle in a real-time hologram service. This paper proposes an algorithm that increases the speed of generating a Fresnel hologram by using a recursive addition operation covering the entire coordinate array of a digital hologram. The 3D object designed to calculate the digital hologram uses a depth-map image produced by computer graphics. The proposed algorithm is a technique that performs the computer-generated holography (CGH) operation with only recursive addition of all of the hologram's coordinates by analyzing the regularity between the 3D object and the digital hologram coordinates. The experimental results show that the proposed algorithm increases the operation speed by 70% over the technique using the conventional CGH equation and by more than 30% over the previously proposed recursive technique.

• Current Optics and Photonics
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• 제3권2호
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• pp.97-104
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• 2019

Based on the extended Huygens-Fresnel principle, the analytical equation for a Lorentz-Gauss vortex beam propagating through oceanic turbulence has been derived. The spreading properties of a Lorentz-Gauss vortex beam propagating through oceanic turbulence are analyzed in detail using numerical examples. The results show that a Lorentz-Gauss vortex beam propagating through stronger oceanic turbulence will spread more rapidly, and the Lorentz-Gauss vortex beam with higher topological charge M will lose its initial dark center more slowly.

• Structural Engineering and Mechanics
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• 제87권2호
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• pp.165-172
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• 2023

This paper presents a novel method for modeling elastic wave propagation in long beams. The proposed method derives a solution for the transient transverse displacement of the beam's neutral axis without assuming the separation of variables (SV). By mapping the governing equation from the space domain to the frequency domain using Fourier transformation (FT), the transverse displacement function is determined as a convolution integral of external loading functions and a combination of trigonometric and Fresnel functions. This method determines the beam's response to general loading conditions as a linear combination of the analytical response of a beam subjected to an abrupt localized loading. The proposed solution method is verified through finite element analysis (FEA) and wave propagation patterns are derived for tone burst loading with specific frequency contents. The results demonstrate that the proposed solution method accurately models wave dispersion, reduces computational cost, and yields accurate results even for high-frequency loading.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.152-156
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• 2009

본 연구는 액체의 유동과 광학적 특징에 대해 알아보고 높이 맵 기반 액체 시뮬레이션을 GPU를 이용하여 만화적으로 표현하는 것을 목표로 하고 있다. 현재까지 컴퓨터 그래픽스에서 기체와 액체 에 대한 NPR적 표현 연구는 많이 진행되었다. 본 연구에서 유체의 유동을 비 물리학적 방법인 간단한 알고리즘을 사용하여 표현하였고, 액체의 광학적 표현에서 반사와 굴절 값의 비는 프레넬 방정식을 이용하여 구했다. 액체의 만화적인 표현은 기존의 방법과 달리 환경맵 상의 반사와 굴절 값을 분할했다. 외곽선 검출은 액체의 점프 에지(jump edge)만을 표현하였다. 그 결과, 액체 시뮬레이션을 만화적으로 표현 할 수 있었다.

• 대한기계학회논문집A
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• 제28권3호
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• pp.245-250
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• 2004

This paper proposes a new method of measuring an air interface distance between a solid immersion lens(SIL) applied magneto-optic technology and the disk surface. For applying near-field recording (NFR) technology to the magneto-optic storage devices for the next generation, it is positively necessary to maintain the small air gap under about 100㎚. We design an apparatus that consists of some optical components such as a prism, a polarizer and an analyzer. By using the Fresnel reflection coefficient equation, Jones matrices calculation and Malus's law, we establish a mathematical model for understanding the characteristics of the system. The simulations are based on the mathematical model and through the simulation results which is made with various cases we can estimate the performance of the new optical gap sensor system. Experimental results, which are also based on the mathematical model for specific cases, are in good agreement with simulated ones and demonstrate the possibility as the new optical gap sensor.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.669-677
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• 2016

A miniaturized FTIR spectrometer based on lamellar grating interferometry is being developed for passive remote-sensing. Consisting of a pair of micro-mirror arrays, the lamellar grating can be fabricated using MEMS technology. This paper describes a method to compute the optical field in the interferometer to optimize the design parameters of the lamellar grating FTIR spectrometer. The lower limit of the micro-mirror width in the grating is related to the formation of a Talbot image in the near field and is estimated to be about $100{\mu}m$ for the spectrometer to be used for the wavelength range of $7-14{\mu}m$. In calculating the far field at the detection window, the conventional Fraunhofer equation is inadequate for detection distance of our application, misleading the upper limit of the micro-mirror width to avoid interference from higher order diffractions. Instead, the far field is described by the unperturbed plane-wave combined with the boundary diffraction wave. As a result, the interference from the higher order diffractions turns out to be negligible as the micro-mirror width increases. Therefore, the upper limit of the micro-mirror width does not need to be set. Under this scheme, the interferometer patterns and their FT spectra are successfully generated.