• Title/Summary/Keyword: Beam splitter

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Investigation on the characteristics of a cavity-dumped Nd:glass laser (Cavity-dumping형 Nd:glass laser의 제작 및 특성 조사)

  • 차용호;강응철;남창희
    • Korean Journal of Optics and Photonics
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    • v.6 no.2
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    • pp.130-134
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    • 1995
  • A small signal gain coefficient of Nd:glass was measured and a cavity-dumped laser was constructed. To measure the small signal gain coefficient, we constructed a resonator consisting of Nd:glass, Pockels cell, polarizing beam splitter. The measured small signal gain coefficient was $0.088 cm_{-1}$ when the input energy was 100 J and the round-trip internal loss of the resonator was 56%. The cavity-dumped laser was constructed using Nd:glass. 2 m radius of curvature HR-mirrors, Pockels cell, polarizinig beam splitter and $\lambda/4$ plate. The output energy of cavity-dumped laser was 0.85 J at 140 J input energy and the laser pulse width was 8 ns.s 8 ns.

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Spatial Analysis of Turbulent Flow in Combustion Chamber using High Resolution Dual Color PIV (고분해능 이색 PIV를 이용한 가솔린 엔진 연소실내 난류의 공간적 해석)

  • Lee, K.H.;Lee, C.S.;Lee, H.G.;Chon, M.S.;Joo, Y.C.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.6
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    • pp.132-141
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    • 1998
  • Particle image velocimetry(PIV), a planar measuring technique, is an efficient tool for studying the complicated flow field such as in-cylinder flow, and intake port flow. PIV can be also used for analyzing the integral length scale of turbulence, which is a measure of the size of the large eddies that contain most of the turbulence kinetic energy. In this study, dual color scanning PIV was designed and demonstrated by using a rotating mirror and a beam splitter. This PIV system allowed enlargement of flexibility in the intensity of vectors to be calculated by spatial filtering technique, even in combustion chamber with high velocity gradient and high vorticity$({\sim}1000s^{-1})$. A new color image processing algorithm was developed, which was used to find the direction of particle movement directly from the digital image. These measuring techniques were successfully applied to obtaining the turbulence intensity (~0.1m/s) and the turbulent integral length scale of vorticity(~1mm).

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Body Vibration Compensated Laser Doppler Vibrometer using Adaptive Filtering (적응필터링 기법을 사용하여 자체진동을 보상하는 레이저 도플러 진동측정계)

  • 최성욱;조영균;김호성;장태규;강민식
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.11
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    • pp.516-520
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    • 2003
  • A novel dual beam heterodyne Laser Doppler Vibrometer (LDV) in conjunction with FM demodulators, which utilizes a residual beam to eliminate the perturbationdue due to the vibrometer body vibration without any external reference surface, has been developed. Residual laser beam from the beam splitter is used to pick up the vibration of damper, which is mounted in the vibrometer, and combined with reference beam at the photodetector. The output signal of this detector and main signal are processed to extract the object vibration, using a least mean square adaptive algorithm. It is shown experimentally that the body vibration of 1-5 Hz can be effectively removed from the measured signal using DSP technology to extract unperturbed 100 Hz original signal.

Output characteristics of a confocal unstable resonator copper vapor laser (공초점 불안정공진기 구리증기레이저의 출력특성)

  • 정지철;유영태;윤재순;백세종;임기건
    • Korean Journal of Optics and Photonics
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    • v.10 no.3
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    • pp.221-225
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    • 1999
  • The positive branch confocal unstable resonator equipped with an intra-cavity beam splitter has been studied experimentally to achieve low beam divergence in the copper vapor laser. Output laser beams of 0.15 mrad divergence was achieved from the laser system with a 10 cm curvature convex mirror (M=30), and laser beams of 0.1 mrad was achieved for a 5 cm curvature convex mirror (M=60). The power density of the far-field beam from the M=60 resonator laser was 130 times higher than the case of the 2 mrad-operation with the plane-parallel resonator. We also observed the self-mode-locking from the unstable resonator laser pulses.

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Optical system design of a mobile LIDAR for air polution research (대기오염 연구용 이동형 LIDAR 광학계 설계)

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.7 no.3
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    • pp.191-195
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    • 1996
  • A optical system of a movile LIDAR is designed for air pollution research. After the inverse Cassegrain type collimator, the laser beam falls on the mirror which serve for coinciding optical axis of laser beam and the receiving telescope. Then, it is directed into the atmosphere and back scattered radiation back to the receiving telescope by the scanning mirror. The unit of scanning mirror allows to rotate the mirror along the altitude 0$^{\circ}$~60$^{\circ}$, and the azimuth 0$^{\circ}$~360$^{\circ}$. The scanning mirror is not connected with the receiving telescope but placed on the roof of the mobile. The received beam is spatial filtered by a spatial filter and collimated by a fabric lens. Thereafter, the beam is devided into 2 channel for registration by a beam splitter. Each laser beam is transformed into an electrical signal by means of the photomultifier and then processed to be analyzed.

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Final Diffraction Patterns of the Beam Splitters used in the Soft XRay Interferometer by a He-Ne Laser

  • Oh, Chul-Han;Choi, Dae-Uk;Park, Sung-Jin;Howells, M.R.;Moller, E.J.
    • Journal of the Optical Society of Korea
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    • v.4 no.1
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    • pp.7-10
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    • 2000
  • The soft x-ray(10nm-100nm) interferometer is a modified Mach-Zehnder type interferometer and it consists of two beam-splitters and four totally reflecting mirrors. The beam-splitters used here are 50% transmission and 50% reflection grating type. The diffraction patterns of beam splitters(1st B.S.) were investigated with a He-Ne laser. The diffraction patterns produced by the soft x-ray interferometer (2nd B.S.) were also investigated in intensities positions. The diffraction patterns of 20 degree grazing incidence on the beam splitters(1st B.S.) show a circular array of spots. Both the reflected and the transmitted beams show the same patterns but symmetric circles on the screen. The maximum intensity appears roughly when n is in the zeroth and odd orders and the suppressed peak(missing order) appears when n is in even orders. Intensities of 3 center fringes(n = 0, $\pm$1) are stronger than others. These results confirm the reduced grating equation and make agree with the intensity distribution function. It was found that the final patterns produced by the soft x-ray interferometer (2nd B.S.) consisted of fine fringes which were caused by two of three diffraction beams that were arrived at the second beam-splitter.

Acquirement of in vivo epidermal cross-sectional image by using swept source optical coherence tomography (SS-OCT 방식을 이용한 생체의 표피단면 영상 획득)

  • Kim, Hoon-Sup;Lim, Hae-Jin;Eom, Jin-Seob
    • Journal of Industrial Technology
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    • v.28 no.A
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    • pp.163-166
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    • 2008
  • In this paper, the swept source optical coherence tomography system has realized using a free-space interferometer based on a beam splitter. Personal computer has completed the control for tunable wavelength laser digitally and the B-scan motor as well. From each experiment for an onion and a salmon egg, we confirmed that the in vivo epidermal cross-sectional images for them can be obtained appropriately.

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Design and Fabrication of Color Cube Prism for Display (디스플레이용 Color Cube의 설계 및 제작)

  • 우석훈;문진수;남성림;문일춘;강건모;황보창권
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.220-221
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    • 2002
  • 전달된 정보를 표시하는 다양한 디스플레이 광학기기 중 반사형 LCOS 프로젝션 시스템은 칼라의 구현을 위해 광원에서 나온 빔을 색분리계를 통해 각각 R, G, B 로 나누고, LC(Liquid Crystal)를 통해 각각의 이미지를 변조한 후 다시 합성하게 된다. 광원으로부터 입사한 백색 광선은 PBS(polarize beam splitter) array를 거쳐 s-편광파로 바뀌게 되고, 각각의 다이크로익 필터와 거울들을 거쳐 R, G, B의 3개의 채널로 분리된다. (중략)

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광간섭법을 이용한 절대높이 측정 정밀도 향상에 관한 연구

  • 안근식;장경영;문희관
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.493-498
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    • 1993
  • This paper proposes a high precision measurement technique to obtain the height of gage block. The proposed technique is consisted of two steps : In the first step, laser position transducer and electric micrometer are adopted to obtain a coarse value of the height of gage block, and then, second, heterodyne laser interferometry is adopted to acquire the precision value. The experiment results show that accuract in the order of a few nanometer is achieved for the gage blacks of as high as a few millimeter.

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Measurement of the small vibration using a fiber-optic displacement sensor (광섬유 변위 센서를 이용한 미소 진동의 측정에 관한 연구)

  • Park, Woo-Jong;Lee, Hyuk
    • Proceedings of the KIEE Conference
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    • 1993.11a
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    • pp.353-355
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    • 1993
  • A single-mode fiber-optic interferometer for measuring small vibrations was constructed. The interferometer is based on the Fabry-Perot configuration that uses a single mode bidirectional fiber coupler as a beam splitter and employs peak detection scheme in the signal processing. The instrument was used to measure the displacement of the translator clamped to a piezo crystal.

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