• 대한기계학회논문집
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• 제1권2호
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• pp.73-81
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• 1977

It is well known fact that there is a theoretical analogous relation ship in terms of differential equation between the stress distribution of a bar under pure torsional moment and the deflection of a membrane subjected to a uniform pressure. This relationship has been applied to the experimental determination of torsional stresses with troublesome and elaborative measuring procedure since Griffith's invention of the soap-film apparatus. In this paper, the soap-film was replaced by a highly polished steel plate and whole visualable deflectional contour-line-map was able to obtain by using Michelson Interferometer with Ne-He Gas Laser lignt source enabling to determine the stress distribution in the vicnity of the symmetrical inner-boundary in a section. Experimental results were satisfactory and the margin of error in the measurement was lower than 1%.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2459-2463
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• 2005

Optical coherence tomography (OCT) is high resolution medical imaging system which is obtaining image inside biological objects with non-destructive method. OCT system is based on Michelson interferometer with a reciprocating mirror in the reference arm and a biological object in the sample arm. The obtained OCT image suffers from a granular or mottled image, called speckle. Speckle is caused by random interferences between reflected coherence waves. In this paper, we propose effective speckle reduction method that uses wavelet transform. With wavelet domain image, sub-windowing and thresholding are performed. Finally, speckle reduction experiments for Misgurnus mizolepis skin and rat eye images are shown.

• 산업기술연구
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• 제28권B호
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• pp.239-244
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• 2008

We have realized the swept source optical coherence tomography(SS-OCT) by using the self-fabricated wavelength swept laser(wavelength tuning range : 80nm, line-width : 0.12nm, wavelength sweeping rate : 50Hz). In addition, we have used the dual balanced detector that could make a mirror image in OCT display suppressed. We can also fabricate the comb filter of Michelson interferometer type for fast-signal processing in OCT. Using this SS-OCT system for measuring an mirror, a 1mm-depth glass and an onion, we confirmed that the in vivo epidermal cross-sectional images for them can be obtained appropriately.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1528-1530
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• 1998

In this work, a possible new PD detection technique, based on the Michelson Interferometer, has been proposed. Laser beam transmitted by optical fiber is spliced into two-laser beam by 50/50 coupler, one is reflected on diaphragm, which is vibrated by ultrasonic sound, and then modulated. The other one is reference beam. They are collected into 50/50 coupler making interferenced beam which could be detected by photo detector.

• 전자공학회논문지A
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• 제29A권4호
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• pp.14-21
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• 1992

An optical novelty filter is implemented using photorefractive materal(BaTiO$_{3}$) as a recording materal and commercial liquid crystal TV as a spatial light polarization modulator. If a signal beam incident at the proper, the loop and the crossing angle inside th e crystal is formed to get maximum diffraction efficiency and BaTiO$_{3}$ as a self-pumped phase conjugation mirror show that phase conjugate reflectivity was 20 times as much as ordinary polarization if signal beam is extraordinary. In this paper, the stoke's theorem which is a reciprocal theorem for which is a reciprocal theorem for beam path is experimentally proved, and good output images were obtained with optical experiment of novelty filter which is formed by use of Michelson interferometer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1735-1737
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• 1996

Using a modified Michelson interferometer configuration, the flatness of micro mirror cell surface was probed. Interferograms were captured at CCD camera plane by defocusing object beam onto the micro mirror with microscope objective lens. And these were compared with the interferograms made with the flat metallic mirror. Also, the theoretical analysis is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2434-2437
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• 1999

In order to detect the ultrasonic that is generated by the partial discharge of the heavy electric machinery, a Laser Doppler Vibrometer (LDV) was developed. A Michelson type interferometer which employed heterodyne signal process technique was built to measure the frequency and amplitude of vibration. The output signal of the fast photodetector was a frequency modulated signal centered at 40 MHz. The signal from the detector was amplified and downconverted to intermediate frequency centered at 1 MHz after mixing process. The voltage output that was proportional to the velocity of the moving surface(PZT) was obtained using PLL. The spectrum of the FM signal was analyzed and integration method was introduced to obtain amplitude information. This LDV can be used to measure the vibration of MEMS devices, automobiles, HDD and CDP.

• Journal of the Optical Society of Korea
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• 제9권2호
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• pp.54-58
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• 2005

A novel mode analysis method and differential mode delay measurement technique for a multimode optical fiber based on optical frequency domain reflectometry has been proposed for the first time. We have used a conventional OFDR with a tunable external cavity laser and a Michelson interferometer. A few-mode optical multimode fiber was prepared to test our proposed measurement technique. The differential mode delay (DMD) of the sample fiber was measured to be 16.58 ps/m with a resolution of 1.5 ps/m. We have also compared the OFDR measurement results with those obtained using a traditional time-domain measurement method.

• 한국광학회지
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• 제26권6호
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• pp.318-321
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• 2015

We demonstrate a frequency-resolved optical grating (FROG) device for measuring the intensity and phase versus time of several-tens-of-picoseconds laser pulses, using a thick nonlinear optical crystal. The huge pulse-front tilt generated by a holographic grating increases the temporal range of the device, which can make a single-shot measurement of laser pulses less than 100 ps in duration. To verify the measurement technique, we generate double pulses using a Michelson interferometer. The measured duration of a single pulse is about 300 fs and the measured maximum delay of two pulses is 60 ps, which implies that the proposed FROG device can measure laser pulses with maximum pulse width of about 120 ps.

• 천문학논총
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• 제29권3호
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• pp.35-44
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• 2014

In ground-based astronomical spectroscopic observations, there are many telluric absorption lines that are laid on the spectra of celestial objects. To study the physical properties of the celestial objects with these contaminated spectra, the telluric lines should be removed. A conventional method for removing the telluric lines is using the standard stellar spectrum as telluric line. In this paper, we introduce a technique to calculate synthetic telluric spectra and use them to remove telluric lines from a spectrum of a celestial object. We used Line-by-Line Radiative Transfer Model (LBLRTM) for calculating a synthetic spectrum and selected Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) model as atmospheric model. We apply our method to some spectra obtained by Bohyunsan Observatory Echelle Spectrograph (BOES) to show that the telluric lines are well removed from the observed spectra by our model within an accuracy of 2% which is close to the 1-sigma rms of the original spectra.