• The Bulletin of The Korean Astronomical Society
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• v.31 no.2
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• pp.22.2-22.2
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• 2006

• The Bulletin of The Korean Astronomical Society
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• v.31 no.2
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• pp.23.1-23.1
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• 2006

• Bulletin of the Korean Space Science Society
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• 2007.04a
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• pp.43-43
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• 2007

• Journal of Sensor Science and Technology
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• v.7 no.6
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• pp.432-436
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• 1998

Recently, the PDLC(Polymer Dispersed Liquid Crystal) is being developed lively to make a large display device using a liquid crystal. Because of low light loss, high brightness, and simple fabrication process, it is made easily to large display device, In this study, the response time and light transmittance by the applied voltage is measured to analyze the electro-optical characteristics of PDLC. The He-Ne laser is applied to the PDLC cell, the light transmittance is measured using the photodiode and the result is analyzed and displayed graphically by the digital oscilloscope. The result of comparison between the PDLC and the present LCD is used to study the potential as a display device.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.61.1-61.1
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• 2010

한국천문연구원의 대형광학망원경 개발사업(K-GMT)은 거대마젤란망원경(GMT; Giant Magellan Telescope)의 지분 10% 확보를 목표로 2009년부터 2018년까지 수행하고 있는 사업이다. 2009년 GMT사업에 공식 참여한 한국천문연구원은 GMT 이사회와 과학자문위원회 등에 적극적으로 참여하여 활동하였다. 본 사업의 2차년도에 해당하는 2010년에는 K-GMT 과학기기워킹그룹을 중심으로 거대망원경 여름학교와 국제워크숍을 개최할 예정이며 GMT 이사회 한국 개최, GMT 부경 시험 모델 개발, GMT 1세대 관측기기 후보로 선정된 GMTNIRS 개념설계연구 등이 수행될 예정이다. 본 발표에서는 GMT 및 K-GMT의 2010년 주요 활동 계획을 보고한다.

• Korean Journal of Optics and Photonics
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• v.16 no.1
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• pp.71-78
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• 2005

A null lens system of autostigmatic type, consisting of two mirrors, is designed for testing a large aspherical mirror. The system is theoretically analyzed to determine the limitation of measurement accuracy according to the manufacturing and alignment errors. We confirmed that irregularity of the null lens surface is the principal factor among tolerances in limiting measurement accuracy. Consequently, we can predict that measurement accuracy will be from 5λ/100 to 4λ/1000 according to the amount of this irregularity. That is, we can present the limitation of possible measurement accuracy with actual alignment and manufacturing errors.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.26.3-26.3
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• 2010

한국천문연구원의 대형광학망원경 개발사업(K-GMT)은 거대마젤란망원경(GMT; Giant Magellan Telescope)의 지분 10% 확보를 목표로 2009년부터 2018년까지 수행하고 있는 사업이다. 2009년 GMT사업에 공식 참여한 한국천문연구원은 GMT 이사회와 과학자문위원회 등에 적극적으로 참여하여 활동하였다. 본 사업의 2차년도에 해당하는 2010년에는 K-GMT 과학기기워킹그룹을 중심으로 거대망원경 여름학교와 국제워크숍을 개최할 예정이며 GMT 이사회 한국 개최, GMT 부경 시험 모델 개발, GMT 1세대 관측기기 후보로 선정된 GMTNIRS 개념설계연구 등이 수행될 예정이다. 이 발표에서는 GMT 및 K-GMT의 2010년 주요 활동 계획을 보고한다.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.57-59
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• 2008

• Korean Journal of Optics and Photonics
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• v.28 no.2
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• pp.75-82
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• 2017

We present a new type of receiver-transmitter optical system that can be adapted to the sensor head of a displacement-measuring interferometer. The interferometer is utilized to control positioning error and repetition accuracy of a wafer, down to the order of 1 nm, in a semiconductor manufacturing process. Currently, according to the tendency of scale-up of wafers, an interferometer is demanded to measure a wider range of displacement. To solve this technical problem, we suggest a new type of receiver-transmitter optical system consisting of a GRIN lens-Collimating lens-Afocal lens system, compared to conventional receiver-transmitter using a single collimating lens. By adapting this new technological optical structure, we can improve coupling efficiency up to about 100 times that of a single conventional collimating lens.

• Korean Journal of Optics and Photonics
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• v.16 no.1
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• pp.79-84
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• 2005

To increase the tolerance for passive fiber alignment, a single mode polymer waveguide with a large core structure is demonstrated. The large core waveguide is designed to have a mode profile comparable to that of a thermally expanded core (TEC) fiber, and it can be connected to a high-contrast waveguide through an adiabatic transition taper structure. From a waveguide with a rectangular core of 25 ${\times}$ 25 ${\mu}{\textrm}{m}$$^2$, a single mode propagation is observed when the index contrast is as low as 0.0005. A UV-cured injection molding method is used to fabricate the thick core structure. Due to the large mode size, the insertion loss of the device is below 0.5 dB until the lateral displacement of the TEC fiber is 4.5 ${\mu}{\textrm}{m}$. The low insertion loss is important for reproducible passive alignment.