• Journal of applied mathematics & informatics
• /
• v.25 no.1_2
• /
• pp.315-327
• /
• 2007

Mathematical aspects of the electromagnetic surface-wave propagation are examined for the dielectric core consisting of multiple sub-layers, which are embedded in the gap between the two bounding cladding metals. For this purpose, the linear problem with a partial differential wave equation is formulated into a nonlinear eigenvalue problem. The resulting eigenvalue is found to exist only for a certain combination of the material densities and the number of the multiple sub-layers. The implications of several limiting cases are discussed in terms of electromagnetic characteristics.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.25-26
• /
• 2006

Azobenzene functionalized polymers have been extensively investigated due to the potential applications in the areas of optical switching, optical elements, optical information storage, and nonlinear optics. These applications are mainly achievable due to photoinduced properties of azobenzene groups with photoisomerization and photoinduced anisotropy. We report applications to the optoelectronic devices using inscribed one-(1D) and two-dimensional (2D) SRGs on azo polymer films. The inscribed holographic SRGs patterns were useful to control or enhance optoelectronic properties such as transparent electrode patterning, hybrid solar cell and ultraviolet GaN-based LED.

• Journal of the Optical Society of Korea
• /
• v.18 no.6
• /
• pp.762-765
• /
• 2014

We fabricated a periodically poled lithium niobate (PPLN) by direct laser-writing of a quasi-phase-matching (QPM) structure in photolithographic process. Because we do not need to prepare a photomask by electron-beam writing, the "maskless" process shortens the fabrication time and significantly reduces the cost. We evaluated the poling quality of the direct laser-written PPLN by measuring the diffraction noise from the surface relief pattern of the fabricated QPM grating and comparing the results to those from a conventional PPLN made with a photomask. The quality of the PPLN fabricated by direct laser-writing was shown to be equivalent to that fabricated by the conventional method.

• Current Optics and Photonics
• /
• v.2 no.1
• /
• pp.69-78
• /
• 2018

This paper presents a precise edge detection algorithm for the critical dimension (CD) measurement of a Thin-Film Transistor Liquid-Crystal Display (TFT-LCD) pattern. The sigmoid surface function is proposed to model the blurred step edge. This model can simultaneously find the position and geometry of the edge precisely. The nonlinear least squares fitting method (Levenberg-Marquardt method) is used to model the image intensity distribution into the proposed sigmoid blurred edge model. The suggested algorithm is verified by comparing the CD measurement repeatability from high-magnified blurry and noisy TFT-LCD images with those from the previous Laplacian of Gaussian (LoG) based sub-pixel edge detection algorithm and error function fitting method. The proposed fitting-based edge detection algorithm produces more precise results than the previous method. The suggested algorithm can be applied to in-line precision CD measurement for high-resolution display devices.

• Proceedings of the Korean Fiber Society Conference
• /
• 1998.04a
• /
• pp.28-31
• /
• 1998

Photoresponsive polymers are being intensely investigated over last two decades, which can be attributed to both fundamental and applied significance. Presently the attention is being directed to these materials in view of their possible application in nonlinear optics and optoelectronics. It was demnstrated quite early that by covalent fixation of both photochromic group and the mesogenic group to the same polymer main chain high concentration of photochromic group can be attained.(omitted)

• Electrical & Electronic Materials
• /
• v.10 no.3
• /
• pp.295-301
• /
• 1997

다양하고 방대한 양의 정보를 효과적으로 처리, 분배하는 멀티미디어 정보통신 시스템이 광신호에 의한 처리를 통해 구현되어갈 전망이다. 이를 위해 빛을 발생시키는 발광소자, 빛을 검출하는 소광소자, 광신호를 처리하는 광신호 처리소자 그리고 광신호를 전달해주는 광섬유 및 화상정보의 표시를 위한 표시소자 등이 중요한 요소기술이다. 이같은 소자의 제작에 있어 기존 물질로는 요구에 대한 대응이 어려워 보다 우수한 성능의 소재개발이 요구된다. 이에 대한 대체물질로 최근 유기물 또는 고분자가 각광을 받고 있으며, 이를 사용한 소자개발이 활발히 진행되고 있다. 이제까지 무기물로 달성하기 힘들었던 많은 기술들이 유기물로 쉽게 구현이 가능하게 되면 고성능의 소재 및 소자기술은 다가오느 정보화 시대를 더축 풍요롭게 하는데 크게 기여할 것이다.

• Korean Journal of Optics and Photonics
• /
• v.15 no.4
• /
• pp.321-324
• /
• 2004

We have composed an experimental system using the superposition method to measure the nonlinearity of photodetectors for optical fiber power measurements. Also we have measured the nonlinearity of a high power detector and of a low power detector. The two detectors have shown good linearity within 0.01% and 0.02%, respectively, in the 50 ㏈ dynamic range. These detectors are used as reference detectors in optical fiber characteristics measurements.

• Korean Journal of Optics and Photonics
• /
• v.5 no.1
• /
• pp.125-130
• /
• 1994

A new cavity configuration for passive mode locking of fiber laser is proposed and demonstrated. It consists of a dichroic mirror at one end of the cavity, and a nonlinear loop mirror, which is a Sagnac loop, at the other end. The experimental observations are described for both Er-doped fiber laser and Nd-doped fiber laser. laser.

• Korean Journal of Optics and Photonics
• /
• v.11 no.2
• /
• pp.91-96
• /
• 2000

We propose a novel in-line fiber optic circular polarizing mirror utilizing cholesteric lIquid crystal (CLC) polymer [11m for the fiber laser applications. Ions matrix representation of this device has been derived and venfied experimentally. In a Fabry-Perot cavity configuration, a CLC fiber optic rmrror has been used to achieve longitudinal mode suppression as well as to obtain passively mode~locked laser operations with 630 fs laser pulses via nonlinear polarization evoluhon.oluhon.

• Proceedings of the Optical Society of Korea Conference
• /
• 2003.02a
• /
• pp.30-31
• /
• 2003

원자와 빛과의 상호 작용의 결과로 원자에 결맞음이 유도될 수 있는데, 결맞음이 오래 지속될 수 있는 경우, 원자의 결맞음은 빛의 전파 및 비선형 광학 현상에 영향을 미친다. 느린 빛, 빠른 빛의 발생, 빛의 저장 및 재생, 낮은 출력을 이용한 합주파수 발생 및 4광파 혼합, 닮은 꼴 펄스의 발생 등은 빛이 결맞은 원자를 지나갈 때 나타날 수 있는 현상들이다. 빛과 원자와의 상호 작용은 슈뢰딩거 방정식이나 밀도 행렬 방정식을 풀어 기술할 수 있고, 빛의 전파는 맥스웰 방정식을 풀어 기술할 수 있으므로 결맞은 매질에서 빛의 전파를 이론적으로 연구하기 위해서는 두 방정식을 결합하여 해를 구해야 한다. (중략)