• The Optical Journal
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• s.100
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• pp.18-20
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• 2005

오늘날 레이저는 광통신망을 통한 인터넷 전송과 같은 통신분야, 반도체에서의 포토리소 그라피와 같은 제조 및 가공분야, 분광분석 및 원자력간 현미경과 같은 계측분야 등 다양한 영역에서 산업 및 과학기술 발전을 위해 필수불가결한 도구가 되었으며, 레이저의 응용은 앞으로 첨단기술 분야를 중심으로 지속적으로 확대되어 갈 것으로 기대된다. 이와 같이 첨단기술의 핵심요소인 레이저 및 이의 응용에 필요한 기초광학에 대한 이해는 관련기술의 발전과 폭 넓은 응용기술 개발을 위해 필수적인 것으로 사료된다.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.4
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• pp.219-227
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• 1995

A two-dimensional photoacoustic microscope utilizing photoacoustic signals generated by periodic heating of specimen surface with Argon ion laser and measured by accelerometer has been developed. Several aluminum specimens with various defects have been examined, characteristics of the microscope have been evaluated and optimal experimental conditions have been determined by examining the dependence on several experimental conditions including the modulation frequency and the beam width of laser.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.57-64
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• 2008

It is well established that fluoride products play an important role in the prevention and remineralization of carious lesion. Fluoride varnish is a concentrated topical fluoride and varnishes adhere to tooth surface, permitting prolonged fluoride exposure and uptake. In this study, the artificial initial enamel caries was caused on the sound human enamel and divided 60 specimens into three groups. Group 1 and group 2 were treated with the topical application of fluoride varnish and stored in artificial saliva for 1 and 2 weeks. Group 3 was stored in artificial saliva for 2 weeks, which acted as control group. Changes in mineral contents were analysed with the confocal laser scanning microscope. The following results were obtained: 1. In group 1 and group 2, the total fluorescence of the lesion(TFL) was reduced in remineralized area compared to in demineralized area(p<0.05). 2. The total fluorescence of the lesion of remineralized area was more reduced in group 2 than in group 1(p<0.05). 3. The total fluorescence of the lesion was more reduced in group 2 than in control group(p<0.05). 4. Confocal laser scanning microscope can be used in quantitative analysis of remineralization by fluoride varnish.

• Korean Journal of Optics and Photonics
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• v.22 no.1
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• pp.46-52
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• 2011

A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.

• Journal of Conservation Science
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• v.30 no.2
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• pp.123-136
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• 2014

Considering that decision in conservation treatment for damaged objects should consider not only various options of methodology of intervention but also possible consequences of different types of intervention, it is a difficult task to decide and propose clear and safest solution of preserving an object. In addition, it should be constantly challenged by conservators even if it is proved technique or methodology in a past treatment. Therefore, there is no absolute solution which can be applied to all practice but each decision can be different case by case. It is not possible to estimate the way how the present condition of material and environmental aspects would affect to the condition of an object in future. However if conservators keep trying to set out various ways of analysing pro and against effect of past treatments, it would be able to provide useful logics of proving efficiency and appropriateness of a certain treatment. Understanding that the advantage of laser technique is to adopt a way of cleaning an object without making a direct contact, which is different from other techniques, this paper aims at securing stability of laser techniques, although it remains a limitation in the compatibility to all other materials. This study has examined reacting process on the painted pigments against laser beam by using CLSM in order for it to display both the problems from such reacting process and the efficiency of it as a cleaning methodology. It has intended to estimate the result of laser techniques and propose the range of applicability.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.302-303
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• 2000

Edge emitting 레이저 다이오드의 전형적인 모양은 그림 1과 같다. 반도체 레이저는 다른 종류의 레이저에 비하여 체적이 매우 작으며 제조 단가가 저렴하고 대량생산이 용이할 뿐 아니라 수 mA의 전류만 흘리면 레이저가 되는 이점이 있으므로 광통신용 응용 외에도 바코드 리더, 비디오 디스크, 오디오 디스크, 레이저 프린터, 포인터 등에 폭넓게 이용된다. 하지만 다른 레이저들에 비하여 발산각이 큰 편인데 p-n 접합에 나란한 방향과 수직인 방향의 발산각은 각각 λ/w와 λ/l 로 타원모양을 갖게 된다$^{(1)}$ . LD의 발광 부분은 폭이 작으므로 일정한 높이에서 정확한 세기분포를 측정하기 위하여 그림 2와 같이 본 연구실에서 제작한 NSOM (Near-filed Scanning Optical Microscope) 구조를 이용한다$^{(2)}$ . (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.45-45
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• 2003

• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.369-372
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• 1999

We have constructed an interferometric microscopy using a Michelson interferometer and a He-Ne laser. The three dimensional image was obtained by the interference from the reflected signal by a sample surface and from the reflected signal by a mirror. The axial resolution obtained by Michelson interferometric microscopy is as good as that of the white-light interferometer, but the same fringe is obtained when optical path difference is half-wavelength. The image from Michelson interferometric microscopy was compared with the images from the various types of confocal microscopy.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.158-160
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• 2001

본 연구는 레이저 처리기술에 의한 Li$_2$O-A1$_2$O$_3$-SiO$_2$계 유리의 미세가공과 레이저에 의한 유리의 광활성반응에 관한 것으로서, 1064nm와 355nm의 파장을 갖는 Nd:YAG laser를 유리에 조사하여 유리의 파괴특성 및 광학적변화를 관찰하였다. 1064nm 레이저에 의한 유리의 파괴 부분은 광학현미경과 주사전자현미경(SEM)으로서 파괴특성을 평가하였으며, 355nm 레이저에 의한 유리의 변화는 흡수대역을 측정함으로 그 광학적 특성을 나타내었다. 이와 같은 레이저에 의한 가공은 유리내부의 3차원적인 미세구조물 형성이나, internal waveguide, 또는 광 흡수대역의 변화에 따른 광기록방법으로 응용될 것으로 예상된다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1105-1111
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• 2011

The objective of this study is to investigate the influence of surface roughness on the morphology of aluminum 6061-T6 alloy after irradiation with a Nd:YAG pulsed laser. The test specimen was prepared by a polishing process using a diamond paste ($1{\mu}m$) and emery polishing papers (#100, #220, #600, #2400) to obtain different initial surface roughness. After irradiation with ten pulsed-laser shots, the surface morphology was examined by using scanning electron microscopy (SEM), optical microscopy (OM), and atomic force microscopy (AFM). The diameter of the melted zone increased with the surface roughness because the multiple reflections and absorption of the laser beam occurred on the surface because of the surface roughness, so that the absorptance of the laser beam changed. This result was verified using the relative absorptance calculated from the diameter of the melted zone with the surface roughness and the diameter increased with the average surface roughness.