• Korean Journal of Optics and Photonics
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• v.19 no.6
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• pp.416-421
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• 2008

A scheme for predicting the concentration of a glucose solution based on its relative optical absorbance at multiple probe wavelengths was proposed and verified. The relative absorbance at each of the probe wavelength was obtained with respect to the absorbance at a reference wavelength. The single reference wavelength (1310 nm) and a group of four different probe wavelengths (1064, 1550, 1685, 1798 nm) were selected to exhibit the glucose absorbance with opposite signs, thereby enhancing the accuracy of the prediction. The final glucose concentration was estimated by taking the average of the predicted values provided by the four probe wavelengths. The absorbance of the glucose solution for the path length of 5 mm was $-1.42{\times}10^{-6}\;AU$/(mg/dL) at the reference wavelength of 1310 nm and peaked at $+8.12{\times}10^{-6}\;AU$/(mg/dL) at 1685 nm. The concentration of the glucose solution was decently predicted by means of the proposed scheme with the standard error of prediction of ${\sim}28\;mg/dL$. In addition, the influence of the ambient temperature and the fat thickness upon the prediction of the glucose concentration was examined. The absorption change with the temperature was $-9.1{\times}10^{-5}\;AU/^{\circ}C$ in the temperature range of $26{\sim}40^{\circ}C$ at the reference wavelength, and $-2.08{\times}10^{-2}\;AU/^{\circ}C$ at 1550 nm. And the absorption change with respect to the fat thickness was +1.093 AU/mm at the probe wavelength of 1685 nm.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.383-388
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• 2007

A color filter was demonstrated incorporating a patterned metal grating in a quartz substrate. The filter is created in a metal layer perforated with a symmetric two-dimensional array of circular holes, with the pitch smaller than the wavelength of the visible light. A finite-difference time-domain simulation was performed to analyze the device by investigating the effect of structural parameters like the grating height, the period, the hole size, and the refractive index of the hole-filling material on its performance. The device performance was especially optimized by controlling the refractive index of the material comprising the holes of the grating. And two different devices were fabricated by means of the e-beam direct writing with the following design parameters: the grating height of 50 nm, the two pitches of 340 nm for the red color and 260 nm for the green color. For the prepared device with the period of 340 nm, the center wavelength was 680 nm and the peak transmission 57%. And for the other device with the pitch of 260 nm, the center wavelength was 550 nm and the peak transmission was 50%. The filling of the hole with a material whose refractive index is matched to that of the substrate has led to an increase of ${\sim}15%$ in the transmission efficiency.

• Korean Journal of Optics and Photonics
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• v.19 no.1
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• pp.20-24
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• 2008

A color filter was proposed and demonstrated by incorporating a subwavelength patterned 1-dimensional grating in poly silicon. It was produced by employing the laser interference lithography method, providing much wider effective area compared to the conventional e-beam lithography. A $SiO_2$ layer was introduced on top of the silicon grating layer as a mask for the etching of the silicon, facilitating the etching of the silicon layer. It was theoretically found that the selectivity of the filter was also improved thanks to the oxide layer. The parameters for the designed device include the grating pitch of 450 nm, the grating height of 100 nm and the oxide-layer height of 200 nm. As for the fabricated filter, the spectral pass band corresponded to the blue color centered at 470 nm and the peak transmission was about 40%. Within the effective area of $3{\times}3mm^2$, the variation in the relative transmission efficiency and in the center wavelength was less than 10% and 2 nm respectively. Finally, the influence of the angle of the incident beam upon the transfer characteristics of the device was investigated in terms of the rate of the relative transmission efficiency, which was found to be equivalent to 1.5%/degree.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.341-349
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• 2021

We studies to verify results similar to those of previous experiments, and their potential as a lighting device through optical characteristics experiments and resonance and optical characteristics simulations of array devices. The photonic quantum ring (PQR) device having a mesa diameter of 40 ㎛ and an internal hole diameter of 3 ㎛ was fabricated. Through the near-field observation of the fabricated device, it was found that the PQR device operates even at ㎂, and also that the mesa and hole devices are driven independently of each other. As a result of measuring the wavelength spectrum of the device according to the location, the coupling phenomenon due to mesa and holes was confirmed.

• Explosives and Blasting
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• v.20 no.3
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• pp.49-58
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• 2002

발파공법이 소개된 이후로 계속해서 많은 우수한 발파이론이 발표되어 왔다. 그러한 이론들의 저변에 있는 궁극적인 목표는 효율의 증가와 경제성이다. 이에 본 연구는 Air-Tubes 발파공법을 소개하고 터널에서 일반발파와 비교하여 그 발파효율을 검토해 보았다 연구의 배경이 되는 곳은 산청군 시천면 내대리와 하동관 묵계리를 연결하는 2차선 국도 터널 공사 현장이며 전체 총연장은 2Km이다. 진동측정방법은 하나의 발파진동을 4개의 측정기로 측정하여 데이터분석에 사용하였다. 일반발파와 Air-Tubes의 진동측정을 4개소에서 각각 6회씩 실시하여 총 24개씩의 진동측정 데이타를 얻었고 회귀분석을 실시하여 95% 신뢰도의 발파진동 추정식을 얻었다. 시험발파 및 진동측정에 이어 매 발파마다 광파측량을 실시하여 진행장을 구하였으며 사용한 장약량은 Air-Tubes 발파시 25% 정도 적게 사용하였고 발파진동이 23% 감소하였다. 발파당 굴진장 및 Smooth blasting 발파시의 벽면의 상태는 동일하고 파쇄석의 크기는 Air-Tubes 발파시 더 작게 나타난다.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.567-576
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• 2007

In order to assess the on-site applicability of 3D absolute displacement monitoring of tunnel using digital photogrammetry, the displacement of the optical target placed at the measurement section was investigated, as planned in the OO tunnel construction site. The targets on 3 measurement lines only were considered for each point of measurement for the reconstruction of 3D cubic model for the digital vision monitoring. For each 3D model, 3 or more images have to be obtained at each point. On the last 2 measurement lines, 6 targets (crown, left and right walls) were continuously overlapped to construct 3D models so that 6 or more apices can be shared by 2 3D models. In order to compare the measurement methods of 3D absolute displacements in tunnel excavation, i. e, total station and digital image measurement, both the digital image measurement and optical measurement were conducted for 10 times in the same work section. The time and measurement results of both methods were compared.

• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.315-319
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• 1997

In photorefractive crystals, light deflection is achieved by dynamic photorefractive volume grating, which is induced by the interference of two writing beams. In this paper, we implemented and analyzed the light deflector using Ce-SBN:60 crystals, which is doped with CeO$_2$ and photorefractive effect is induced by low intensity. And we measured maximum coupling coefficient, effective charge density, diffraction efficiency as the intensity ratio and response time.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.10b
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• pp.89-93
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• 2000

광파장 및 조사시기에 따른 오이묘의 생육 반응을 검토하였다. 광원에 따른 오이 묘의 생육상태를 조사해본 결과 청색광, 적색광을 처리한 것이 생체중, 하배축 무게, 근중이 증가하면서 하배축의 신장이 억제되었고, 청색광과 적색광을 혼합하여 야간 12시간씩 조사하여 30일간 육묘해 본 결과 뿌리의 발육도 우수하고, 줄기와 잎의 생육 정도에서도 우량묘의 소질을 보였다. 청색광과 적색광을 혼합하여 야간 6시간과 12시간씩을 조사하여 30일간 육묘한 결과 하배축의 길이는 각각 60.0mm와 44.9mm였고, 하배축의 무게는 0.59g, 0.62g으로 나타나 12시간 조사구가 하배축의 신장억제효과가 큰 것으로 나타났다. 하배축의 엽록소 함량은 청색광과 적색광의 조사시간이 길어질수록 뚜렷이 증가하였고, 식물체도 진한 녹색을 나타냈다. 광처리구와 무처리구의 오이묘 하배축의 횡단면과 종단면을 검경하여 세포구조를 비교해 본 결과 광처리구의 횡단면 표피조직은 단층의 밀착된 세포로 되어 있으며, 바깥쪽 세포는 현저하게 두꺼웠다. 후각조직의 세포는 작고 부정형이며, 세포간극이 조밀하였으며, 세포구조도 치밀한 특성을 보였다. 종단면은 광처리구에서 세포가 짧고 세포간에 간극이 없는 반면 무처리구는 세포가 길고 뚜렷이 구분되지 않은 것이 관찰되어 대체로 광처리구는 무처리구에 비해 세포신장이 억제되는 대신 세포구조가 치밀하여 식물체의 도장이 억제된다는 것을 알 수 있었다.

• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.5-9
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• 2001

A wavemeter was realized using the phenomena that the phase lag between principal polarization states in an optical retarder is a function of wavelength. The change in the polarization state of the optical beam as it passes through the optical retarder is dependent on wavelength. The wavelength of the optical beam is determined by comparing the power difference between principal polarization states. A prototype wavemeter was successfully implemented using a polarization maintaining fiber with birefringence $3\times10^{-4}$ and length 100 mm as the optical retarder. The measurement resolution was 0.08 nm over a wavelength region of 1554.38 nm-1557.l9 nm, which agreed well with theoretically calculated results. In addition, the dependence of operating characteristics on temperature was analyzed theoretically and experimentally.mentally.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.106-106
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• 2012

인체 내 소량의 생체성분을 감지하는 바이오센서 기술은 질병 진단뿐만 아니라 예방 및 관리로 의료서비스 확대 및 의료비 감소 효과를 가져올 수 있는 기술이다. 광 바이오센서는 광학적인 측정방법을 이용하여 다양한 생화학물질들의 상호 반응을 검출해 낼 수 있는 바이오센서로 현재 활발하게 연구가 진행되고 있다. 일반적으로 형광물질, 발색물질 등의 발광물질을 인식물질에 표지하여 인식물질과 분석물질과의 반응 유무를 표지된 발광물질의 광 신호를 감지하여 분석물질을 검출해내는 표지식 광 바이오센서 기술이 상용화되고 있다. 그러나 이러한 분석 방법은 민감도는 우수하지만 분석 시간이 매우 느리고, 고가의 분석 장비를 필요로 하는 단점들을 가지고 있다. 이러한 단점들을 극복하기 위하여 생화학 반응 유무를 표지물질 없이 광학적 방식으로 직접 측정해내는 비 표지식 광 바이오센서 기술이 최근 들어 많이 연구되고 있다. 본 논문에서는 비표지식이면서 분광기 없이 분석 가능한 공진 반사광 바이오센서 기술에 관한 내용을 소개하고자 한다. 공진 반사광 바이오센서는 광파장 이하의 주기를 가진 주기적 공진 격자 표면에서 일어나는 항원-항체 반응에 대한 공진 반사 파장을 측정하여 원하는 바이오물질을 고감도로 검출할 수 있는 바이오센서이다. 또한, 인체 내장을 위하여 플렉시블 기판 상에 GaN LED를 집적하여 전립선암 바이오 마커 검출에 대한 결과를 소개하고자 한다.