Development of Moving Mirror Assembly in the Spectroscopic Sensor for Remote Gas Monitoring

배효욱(Hyo-Wook Bae),장한기(Hankee Jang),박도현(Do-Hyun Park),김호상(Ho-Sang Kim) Korean Society for Precision Engineering 2021 한국정밀공학회지 Vol.38 No.8

Spectroscopic sensors have been used in the field of optics and chemical analysis, and the need for remote gas monitoring in a portable form has increased. Hence, it is essential to design, manufacture, and develop a moving mirror, which that can generate the optical path difference for spectroscopic sensor. It is important to verify whether it can satisfy design requirements for the actual spectroscopic interferometer application by evaluating its performance. In this paper, a moving mirror assembly with high-speed transfer capability for a portable spectroscopic sensor is fabricated and tested. For application to a portable spectrometer, design requirements, such as moving distance, speed, and stiffness, are set and the mechanical structure, including the voice coil motor and elastic guide, satisfying these requirements is proposed. Through finite element analysis, performance of the proposed moving mirror assembly is predicted. By testing the performance after fabrication, it is verified that the proposed mirror is capable of linear movement with travel distance of several millimeters and moving speed of tens of Hz. Optical testing result shows that the proposed moving mirror can generate linear motion with a tilting error below 10 arcsecond and can be applied to the actual spectroscopic interferometer in future.

비형식 교육기관의 천문대를 활용한 토성 분광 관측 및 분석 교육 프로그램의 개발과 수행

홍승아,조훈,손정주 한국현장과학교육학회 2023 현장과학교육 Vol.17 No.5

Despite their significance, spectroscopic observation and data analysis activities often present challenges in astronomy education. In this study, we propose an educational program utilizing an astronomical facility of an informal education institution to observe Saturn spectroscopy and analyze the corresponding data. The educational activities followed the R&E (Research and Education) process. Gifted middle school students submitted their prepared proposal to the Goheng Deokheung Observatory, which allowed them to use a spectrometer for observing Saturn and analyzing the collected data. Throughout this process, the students applied individually developed research plans and activity sheets, allowing us to analyze the difficulties and educational effects they encountered during the investigative activities. The Deokheung Observatory, affiliated with a youth training institute in Goheng and equipped with a high-dispersion spectrometer, was selected as the collaborating institution. The focus of the educational activity was on spectroscopic observation of Saturn, investigating its rotation and the orbital direction of its rings. During the initial stages of the education, students were guided to understand the observation target, develop research plans, and acquire the necessary background knowledge for processing and analysing spectroscopic observation data. In the middle of the activity, students performed scientific investigations by directly analyzing data related to Saturn and its rings. Towards the end of the education, data processing and analysis were conducted, allowing students to derive investigative results by comparing them with actual research outcomes and subsequently writing reports. Through this research, we were able to specifically identify the challenges students face during spectroscopic observation activities and R&E educational processes, confirming the potential for collaboration with external astronomical institutions and the feasibility of spectroscopic education. 천문 교육에서 분광 관측과 자료 분석 교육활동은 그 중요성에 비해 실제로 수행해 보기 어려운 경우가 많다. 본 연구는 학교 밖 교육기관의 천문시설을 활용하여 토성을 분광 관측하고 관측한 데이터를 분석하는 교육 프로그램을 개발하였다. 교육활동은 중학교 영재 학생을 대상으로 R&E(Research and Education)과정에 따라 진행되었으며, 고흥 덕흥 천문대로 학생들이 직접 작성한 제안서를 제출하여, 분광기를 사용한 토성 관측자료를 얻을 수 있었고, 데이터를 직접 분석하였다. 각각의 과정별로 개발한 탐구 계획서와 탐구 활동지를 적용하여 학생들이 탐구활동을 수행하면서 겪는 어려움과 교육적 효과를 확인하였다. 협력 기관으로 고분산 분광 관측 기기를 보유하고 있으며, 분석 교육 경험이 있는 고흥 청소년 수련원 소속의 덕흥 천문대를 선택하였다. 교육활동에서는 토성을 분광 관측 대상으로 선정하여 행성의 자전과 그 행성 고리의 공전 방향을 조사하였다. 교육의 초기 단계에서는 학생들이 관측 대상에 대한 이해와 탐구 계획서 작성, 분광 관측 데이터 처리 및 분석 방법에 필요한 배경지식을 습득하도록 지도하였다. 활동 중반에서는 학생들이 직접 토성과 토성 고리에 관한 정보를 분석하면서 과학적 탐구를 수행하였고, 교육 후반에서는 데이터 처리 및 분석을 진행하며 실제 연구 결과와의 비교를 통해 탐구 결과를 도출하고 보고서를 작성하였다. 이를 통해 학생들이 분광 관측활동과 R&E 교육과정에서 겪는 구체적인 어려움과 학교 밖 천문 기관과의 협력 및 분광 교육의 가능성을 확인할 수 있었다.

타원편광분석법과 흡수측정을 이용한 Zn1-xMnxS 박막의 분광학적 특성 연구

김대중,김봉진,김덕현,이종원 한국물리학회 2020 새물리 Vol.70 No.6

Zn1-xMnxS thin films were grown on GaAs(100) substrates by using hot-wall epitaxy. X-ray diffraction patterns revealed the crystal structure of the epilayer. The optical properties were investigated using spectroscopic ellipsometry at 300 K from 3.0 – 8.7 eV. The obtained data were analyzed to determine the critical points of the pseudodielectric function spectra, ⟨"(E)⟩ = ⟨"1(E)⟩+⟨"2(E)⟩, such as E0/E0+Δ0, E1, and three E2(;Δ; -)structures. These critical points were determined by fitting analytical line-shapes to numerically calculated derivatives of the pseudodielectric functions. In particular, the transmittance/absorptance measurements were carried out to obtain the optical properties of the Zn1-xMnxS epilayers, and the exact optical energy bandgap (Eg) was determined by comparing there results with the results of the ellipsometry measurements. Also, the energy band structures from the ellipsometry and the absorptance measurements were analyzed as a function of Mn concentration. The results obtained demonstrate that ellipsometry can be efficiently and non-destructively used to examine the energy bandgap of Zn1-xMnxS epilayers. 본 연구에서 사용된 Zn1-xMnxS 박막은 열벽적층성장법 (Hot-Wall Epitaxy, HWE)으로 GaAs(100) 기판 위에 Mn 조성에 변화를 주어 성장시켰다. 성장된 박막의 결정구조는 엑스선 회절 (XRD) 패턴을이용하여 확인하였다. 박막의 광학적 특성인 유사유전함수는 분광학적 타원편광분석법 (spectroscopic ellipsometry, SE)을 사용하여 실온에서 3.0 – 8.7 eV 광자에너지 범위에서 측정하였다. 유사유전함수스펙트럼 ⟨"(E)⟩ = ⟨"1(E)⟩ + ⟨"2(E)⟩에 나타난 E0/E0 + Δ0, E1, 그리고 세 개의 E2(;Δ; -)와 같은임계점 구조들은 타원편광분석법으로 측정한 데이터들을 이용하여 분석하였고, 각각의 정확한 임계점봉우리들은 유사유전함수의 데이터를 이차 미분한 이계도함수 d2⟨"(E)⟩/dE2 를 이용하여 구하였다. 특히, Zn1-xMnxS 박막의 정확한 광학적 정보를 획득하기 위하여 투과/흡수 측정을 수행하였고, 이를 타원편광분석법으로 조사된 결과와 비교분석하여 정확한 광학적 에너지 밴드갭(Eg)을 얻을 수 있었다. 또한 Mn 조성이 증가함에 따른 타원분광학적 측정과 흡수 측정으로부터 얻은 에너지밴드 구조의 변화를 분석하였고, 이를 통해 타원편광분석법이 Zn1-xMnxS 시료의 광학적 에너지밴드갭을 비파괴적으로 평가하는데 유용한방법임을 알 수 있었다.

일체형 분광편광간섭모듈 기반 분광타원편광계의 정확도 향상

김대석,황국현,심준보,최인호,최석현,헤리저데헌거흐 사이드 한국반도체디스플레이기술학회 2023 반도체디스플레이기술학회지 Vol.22 No.3

We describe an optimal alignment method for improving accuracy of dynamic spectroscopic polarimeter based on monolithic polarizing interferometer. The dynamic spectroscopic polarimeter enables real-time measurements of spectral ellipsometric parameters by using a spectral carrier frequency concept. However, the non-polarizing beam splitter used in the monolithic polarizing interferometer cannot maintain the polarization state perfectly due to phase retardation caused by optical anisotropic characteristics of the non-polarizing beam splitter, resulting in degraded measurement accuracy. The effect of the beam splitter can be minimized through optimal alignment of the polarizers used in the polarizing interferometer and the analyzer. We demonstrate how much the proposed alignment method can enhance the measurement accuracy by comparing with previous alignment approach.

수소화된 비정질 실리콘의 타원편광분광분석 측정 및 모델링

김가현 한국태양에너지학회 2019 한국태양에너지학회 논문집 Vol.39 No.1

Spectroscopic ellipsometry is a powerful tool for analyzing optical properties of material. Ellipsometry measurement results is usually given by change of polarization state of probe light, so the measured result should be properly treated and transformed to meaningful parameters by transformation and modeling of the measurement result. In case of hydrogenated amorphous silicon, Tauc-Lorentz dispersion is usually used to model the measured ellipsometry spectrum. In this paper, modeling of spectroscopic ellipsometry result of hydrogenated amorphous silicon using Tauc-Lorentz dispersion is discussed.

Spectroscopic investigations on plasmonic enhancement of magneto-optical effect in Ni80Fe20 thin films incorporating gold-nanoparticles

Choi B.,Aryal M. 한국물리학회 2023 Current Applied Physics Vol.49 No.-

The effect of gold nanoparticles embedded in ferromagnetic Ni80Fe20 thin films on the magneto-optical response was studied by means of spectroscopic ellipsometry and magneto-optical Kerr effect spectroscopy. Au nanoparticles (Au NPs) are prepared by using post-annealing of Au films on SiO2/Si substrate, and Ni80Fe20 film was deposited on top of Au NPs. A significant enhancement of the magneto-optical response is observed in the photon energy regime near the localized surface plasmon resonance. A large MO enhancement, over 60% compared to the reference Ni80Fe20, takes place in Ni80Fe20–Au NPs. Optical constants extracted from spectroscopic ellipsometry measurements reveal a strong modification of the complex refractive index values (n, k) owing to the excitation of localized surface plasmons in Au nanoparticles. A close correlation of the MO response to the complex refractive indices (n, k) is found, in which the MO enhancement is accompanied by increasing reflectivity.

‘라이트박스’ 무색/핑크/블루 합성 다이아몬드의 분광학적 분석

최현민,김영출,이민경,석정원 한국결정성장학회 2020 한국결정성장학회지 Vol.30 No.1

이 논문은 라이트박스의 주력 상품인 세 가지 색의 합성 다이아몬드의 분광학적 특성에 대해 분석한 결과이다. 드비어스의 브랜드인 라이트박스 주얼리는 2018년 9월부터 CVD 합성 다이아몬드를 판매하기 시작했다. 본 연구에서 검사된샘플은 0.25 ct, 0.25 ct, 0.26 ct의 무색(H grade), 핑크, 청색의 합성 다이아몬드이며, 각 샘플의 테이블 중앙에는 라이트박스로고가 레이저 각인되어 있었다. 분광학적 기법에 기초한 분석 결과, 무색 샘플은 결정성장 후 색 향상을 위한 고온고압 처리과정을 거치지 않았다. 핑크 샘플은 H3, 3H, 594 nm, NV, GR1의 광학 결함이 발견되었고, 이로 인해 결정성장 후 색 향상을 위해 조사와 열처리 과정을 거친 것으로 판단했다. 또한 블루 샘플은 열처리 과정 없이 조사만 되었음을 알 수 있었다. This article reports the result on the spectroscopic analysis of the three Lightbox CVD-grown diamonds. Lightbox Jewelry, a De Beers company, has begun selling CVD laboratory-grown diamonds since September 2018. Recently, we had the opportunity to examine three Lightbox’s pendant necklaces. The 0.25 ct, 0.25 ct, and 0.26 ct round brilliant were graded as “H” n ear colorless, F ancy Vivid o rangy pink, a nd F ancy Vivid b lue with c ut g rades of excellent, respectively. T he l aserinscribed Lightbox logo under the table, large enough to be easily visible with a microscope. Based on the spectroscopic techniques, for near colorless sample was not subjected to post-growth HPHT processing to improve its color. For pink sample, optical centers at H3, 3H, 594 nm, NV, and GR1 were recorded. It was speculated that the pink sample have been received irradiation and annealing. In addition, the blue CVD synthetic sample was concluded to be irradiated without annealing.

Rotating Compensator Spectroscopic Ellipsometer의 개발 및 응용

이재호,방경윤,박준택,오혜근,안일신 한국반도체디스플레이기술학회 2003 한국반도체장비학회지 Vol.2 No.2

We have developed a rotating compensator spectroscopic ellipsometer (RCSE). As the ellipsometry measures a change in the polarization state of a light wave upon non-normal reflection from surface, the degree of sensitivity is enhanced greatly through the detection of relative phase change. RCSE acquires additional information from the non-ideal surface of sample and operates over the photon energy range from 1.5 to 4.5 eV. We applied RCSE to measure the optical properties of films and the line-width of patterned PR films on crystalline silicon.

Adsorption Kinetics for Polymeric Additives in Papermaking Aqueous Fibrous Media by UV Spectroscopic Analysis

Yoon, Sung-Hoon,Chai, Xin-Sheng Korean Chemical Society 2006 Bulletin of the Korean Chemical Society Vol.27 No.11

The general objective of the present study was to investigate the potential application of the UV spectroscopic method for determination of the polymeric additives present in papermaking fibrous stock solutions. The study also intended to establish the surface-chemical retention model associated with the adsorption kinetics of additives on fiber surfaces. Polyamide epichlorohydrin (PAE) wet strength resin and imidazolinium quaternary (IZQ) softening agents were selected to evaluate the analytical method. Concentrations of PAE and IZQ in solution were proportional to the UV absorption at 314 and 400 nm, respectively. The time-dependent behavior of polymeric additives obeyed a mono-molecular layer adsorption as characterized in Langmuir-type expression. The kinetic modeling for polymeric adsorption on fiber surfaces was based on a concept that polymeric adsorption on fiber surfaces has two distinguishable stages including initial dynamic adsorption phase and the final near-equilibrium state. The simulation model predicted not only the real-time additive adsorption behavior for polymeric additives at high accuracy once the kinetic parameters were determined, but showed a good agreement with the experimental data. The spectroscopic method examined on the PAE and IZQ adsorption study could potentially be considered as an effective tool for the wet-end retention control as applied to the paper industry.

Spectroscopic Study of the Planetary Nebula NGC 6210: Velocity structure and permitted lines

이성재,위진경,형식 한국지구과학회 2009 한국지구과학회지 Vol.30 No.5

Using the spectroscopic data secured with the Hamilton Echelle Spectrograph at Lick Observatory, we found the physical condition of the planetary Nebula NGC 6210. The spectral line profiles of the permitted and forbidden lines have been analyzed using IRAF and StarLink/Dipso. The hydrogen number densities (NH) are 2,000-20,000 cm−3 , and the electron temperatures are 8,100-10,300 K based on the forbidden lines. The expansion velocities, derived from the Full Width at Half Maximum (FWHM) and the double peak of the line profiles, are in the range of 10 to 45 kms−1 . The expansion velocities imply a shell structure with an accelerated nebular gas. We also derived abundances from the permitted lines of CII, CIII, NII, NIII, OII, and OIII, which may have been formed through the fluorescence mechanism. NGC 6210 is likely to be evolved from a progenitor of more than 3M⊙, which had been born near the Galactic plane. Using the spectroscopic data secured with the Hamilton Echelle Spectrograph at Lick Observatory, we found the physical condition of the planetary Nebula NGC 6210. The spectral line profiles of the permitted and forbidden lines have been analyzed using IRAF and StarLink/Dipso. The hydrogen number densities (NH) are 2,000-20,000 cm−3 , and the electron temperatures are 8,100-10,300 K based on the forbidden lines. The expansion velocities, derived from the Full Width at Half Maximum (FWHM) and the double peak of the line profiles, are in the range of 10 to 45 kms−1 . The expansion velocities imply a shell structure with an accelerated nebular gas. We also derived abundances from the permitted lines of CII, CIII, NII, NIII, OII, and OIII, which may have been formed through the fluorescence mechanism. NGC 6210 is likely to be evolved from a progenitor of more than 3M⊙, which had been born near the Galactic plane.