• 한국광학회지
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• 제8권2호
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• pp.116-121
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• 1997

주위온도에 따른 레이저다이오드의 광출력의 변화는 정전류로 구동하는 경우와 정전압으로 구동하는 경우에 서로 다르다. 레이저다이오드를 정전류로 구동하는 경우에는 온도증가에 따라 밀도반전이 감소하므로 광출력이 감소한다. 그러나 정전압으로 구동하는 경우에는 이러한 열효과에 의한 광출력의 감소이외에 내부저항과 임계전압의 감소에 의한 주입전류의 증가효과가 있어서 열효과를 일부 상쇄하므로 광출력의 변화가 정전류로 구동할 때보다 적다. 특히 정전압으로 레이저다이오드를 구동하는 경우에 이 두가지 효과에 의한 광출력의 변화폭이 비슷하여 서로 상쇄되는 동작점 부근에서는 온도에 따른 광출력의 변화가 아주 적어져 정전류로 구동하는 때보다 훨씬 광출력이 안정함을 실험적으로 확인하였다.

• Journal of the Optical Society of Korea
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• 제19권2호
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• pp.182-187
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• 2015

This paper presents a new graphical method for selecting a pair of optical glasses to simultaneously achromatize and athermalize an imaging lens made of materials in contact. An athermal glass map that plots thermal glass constant versus inverse Abbe number is derived through analysis of optical glasses and plastic materials in visible light. By introducing the equivalent Abbe number and equivalent thermal glass constant, although it is a multi-lens system, we have a simple way to visually identify possible optical materials. Applying this method to design a phone camera lens equipped with quarter inch image sensor having 8-mega pixels, the thermal defocuses over $-20^{\circ}C$ to $+60^{\circ}C$ are reduced to be much less than the depth of focus of the system.

• 한국광학회:학술대회논문집
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• 한국광학회 1997년도 Advance Program of 14th optics andquantum Electronics conference, 1997제14 회 광학 및 양자전자 학술 발표회 논문 요약집
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• pp.13-13
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• 1997

• 한국안전학회지
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• 제31권5호
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• pp.1-6
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• 2016

The performance of a set of low-cost optical components used for measuring the optical density of PM particles was evaluated in the present study. To this end, the set of low-cost optical components was replaced with that of general optical components used to measure the PM optical density under identical experimental conditions. The optical densities measured from the set of general optical components were then compared to those obtained from the set of low-cost optical components. While the optical density is measured, another key parameter, the dimensionless extinction constant of PM particles (which is needed to optically measure the PM concentration) was also determined in the present study. The experimental results indicate that the optical density and PM concentration measurements performed by low-cost optical components are feasible, producing trackable variations in the OD and concentrations compared to values obtained from the set of general optical components.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
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• pp.153-154
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• 2009

In this study, a new accommodation-dependent crystalline lens with a constant volume and homogeneous refractive index is developed. The human lens parameters, such as curvature and thickness, are calculated at the central parts of the lens, and the asphericity is adjusted at the peripheral parts of the lens due to accommodation. We propose a accommodating schematic eye which is suitable for easy paraxial calculations because the refractive index of the lens remains uniform and constant.

• KSBB Journal
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• 제32권1호
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• pp.35-45
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• 2017

In this work the optical fiber glucose and lactate biosensors were developed by using fluorescent dye and enzyme immobilized on the end tip of an optical fiber. 3-Glycidyloxypropyl)methyldiethoxysilane (GPTMS), (3-Aminopropyl) trimethoxysilane (APTMS) and Methyltrimethoxysilane (MTMS) were used to immobilize glucose oxidase (GOD), lactate oxidase (LOD) and ruthenium(II) complex (tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II), $Ru(dpp)_3^{2+}$) as oxygen sensitive fluorescent dye. MTMS sol-gel was an excellent supporting material for the immobilization of $Ru(dpp)_3^{2+}$, GOD, and LOD on the optical fiber. Storage stability of the optical fiber glucose sensor was kept constant over 20 days, while the optical fiber lactate sensor had constant storage stability over 17 days. The optical fiber glucose and lactate biosensors also maintained good operational stability for 20 hours and 14 hours, respectively. The activities of the immobilized enzymes were most excellent at pH 7 and at $25^{\circ}C$. On-line monitoring of glucose and lactate in a simulated process was performed with the optical fiber glucose and lactate biosensors. On-line monitoring results were agreed with those of off-line data measured with high performance liquid chromatography (HPLC).

• 한국광학회지
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• 제18권4호
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• pp.256-263
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• 2007

SELFOC 소재를 사용하여 높은 수치구경을 가지는 광픽업용 대물렌즈를 설계하였다. SELFOC 소재는 radial gradient-index 분포를 가지며, 이것은 설계에 추가적인 자유도를 제공하므로, 비구면이 아닌 구면만으로 높은 수치구경의 대물렌즈의 설계가 가능하다. 이 연구에서는 quadratic constant와 광축의 굴절률, 광축 두께, 입사동 직경을 변화시키며 rms 스폿 직경 변화를 조사하였으며, Code V를 사용하여 대물렌즈의 최적화와 결상특성을 평가하였다. 이 분석에서는 quadratic constant와 광축의 굴절률이 클수록, 렌즈가 두꺼워질수록, 입사동 직경은 작을수록 더 좋은 특성을 보임을 알 수 있었다. 이 결과를 바탕으로 2매의 구면 SELFOC 렌즈로 구성된 높은 NA의 DVR용 대물렌즈를 설계하였으며, 2가지 형태의 해 Solution I, II가 존재하였다 Solution I은 두 매 모두 양의 굴절능을 가지며 compact한 광학계를 구성하지만, 비축 수차 보정이 Solution II에 비해 부족하였다. Solution II는 음-양의 굴절능으로 조합된 광학계로 비축 수차가 비교적 잘 보정되었지만, 광학계의 전장길이가 길고 렌즈의 직경이 커지는 문제점이 있었다.

• Journal of the Optical Society of Korea
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• 제9권2호
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• pp.45-48
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• 2005

We investigate effects of the injected ASE (Amplified spontaneous emission) bandwidth on the performance of the wavelength-locked Fabry-Perot laser diodes (F-P LDs) under constant injection power density and constant injection power. For the constant injection power density, we can determine the minimum injection bandwidth by the required intensity noise or the bit-error rate (BER) performance. On the other hand, there exists the optimal ASE bandwidth for the constant injection power to minimize the intensity noise.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.444-450
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• 2010

The traditional approach to inverting aerosol extinction makes use of the assumption of a constant LIDAR ratio in the entire Mie-LIDAR signal profile using the Fernald method. For the large uncertainty in the cloud optical depth caused by the assumed constant LIDAR ratio, an not negligible error of the retrieved aerosol extinction below the cloud will be caused in the backward integration of the Fernald method. A new algorithm to determine aerosol extinction below a cirrus cloud from Mie-LIDAR signals, based on a new cloud boundary detection method and a Mie-LIDAR signal modification method, combined with the backward integration of the Fernald method is developed. The result shows that the cloud boundary detection method is reliable, and the aerosol extinction below the cirrus cloud found by inverting from the modified signal is more efficacious than the one from the measured signal including the cloud-layer. The error due to modification is less than 10% taken in our present example.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.183-186
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• 1991

In order to prepare the functional organic optic meterials, the capacitive coupled gas flow type plasma polymerization apparatus was designed and manufactured. Styrene and para-Xylene monomer were adopt as organic materisl. Optical constant, refrative index, extinction coefficient of organic thin films by the gas flow type plasma polymerization appratus were determined by envelope method using spectrophotometry. The refractive index of plasma polymerized thin films was decreased in accordance to increase of wave length and discharge time. The extinction coefficient was very small compared with refractive index. From the experimental result of optical constant and film thickness, it was considered that the films which had required optical properties and thickness can be prepared by control of polymerization condition.