• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.407.1-407.1
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• 2016

Electrochromism is defined as a phenomenon which involves persistently repeated change of optical properties between bleached state and colored state by simultaneous injection of electrons and ions, sufficient to induce an electrochemical redox process. Due to this feature, considerable progress has been made in the synthesis of electrochromic (EC) materials, improvements of EC properties in EC devices such as light shutter, smart window and variable reflectance mirrors etc. Among the variable EC materials, solid-state inorganics in particular, metal oxide semiconducting materials such as nickel oxide (NiO) have been investigated extensively. The NiO that is an anodic EC material is of special interest because of high color contrast ratio, large dynamic range and low material cost. The high performance EC devices should present the use of standard industrial production techniques to produce films with high coloration efficiency, rapid switching speed and robust reversibility. Generally, the color contrast and the optical switching speed increase drastically if high surface area is used. The structure of porous thin film provides a specific surface area and can facilitate a very short response time of the reaction between the surface and ions. The large variety of methods has been used to prepare the porous NiO thin films such as sol-gel process, chemical bath deposition and sputtering. Few studies have been reported on NiO thin films made by using sol-gel method. However, compared with dry process, wet processes that have the questions of the durability and the vestige of bleached state color limit the thin films practical use, especially when prepared by sol-gel method. In this study, we synthesis the porous NiO thin films on the fluorine doped tin oxide (FTO) glass by using sputtering and anodizing method. Also we compared electrical and optical properties of NiO thin films prepared by sol gel. The porous structure is promised to be helpful to the properties enhancement of the EC devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.2
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• pp.104-110
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• 2001

Structural, optical and electrical properties of Cd$_{1-x}$ Zn$_{x}$S films deposited by chemical bath deposition(CBD), which is a very attractive method for low-cost and large-area solar cells, are presented. Especially, in order to control more effectively the zinc component of the films, zinc acetate, which was used as the zinc source, was added in the reaction solution after preheating the reaction solution and the pH of the reaction solution decreased with increasing the concentration of zinc acetate. The films prepared after preheating and pH control had larger zinc component and higher optical band gap. The crystal structures of Cd$_{1-x}$ Zn$_{x}$S films was a wurtzite type with a preferential orientation of the (002) plane and the lattice constants of the films changed from the value for CdS to those for ZnS with increasing the mole ratio of the zinc acetate. The minimum lattice mismatch between Cd$_{1-x}$ Zn$_{x}$S and CdTe were 2.7% at the mole ratio of (ZnAc$_2$)/(CdAc$_2$+ZnAc$_2$)=0.4. As the more zinc substituted for Cd in the films, the optical transmittance improved, while the absorption edge shifted toward a shorterwavelength. the photoconductivity of the films was higher than the dark conductivity, while the ratio of those increased with increasing the mole ratio of zinc acetate. acetate.

• Korean Journal of Optics and Photonics
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• v.19 no.5
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• pp.370-375
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• 2008

High-speed high-resolution terahertz time-domain spectroscopy (THz-TDS) is demonstrated using the asynchronous-opticalsampling (AOS) method. A time-domain signal with a 10-ns time window is rapidly acquired by using two femtosecond lasers with slightly different repetition frequencies to generate and detect a terahertz pulse wave, without a mechanical delay stage. The spectrum obtained by the fast Fourier transformation (FFT) of the time-domain waveform has a frequency resolution of 100 MHz. The time resolution of our spectrometer is measured using the cross-correlation method to be 278 fs. A transmission spectrum of water vapor is measured and the absorption lines are analyzed in the frequency range from 0.1 to 1.2 THz.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.669-677
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• 2016

A miniaturized FTIR spectrometer based on lamellar grating interferometry is being developed for passive remote-sensing. Consisting of a pair of micro-mirror arrays, the lamellar grating can be fabricated using MEMS technology. This paper describes a method to compute the optical field in the interferometer to optimize the design parameters of the lamellar grating FTIR spectrometer. The lower limit of the micro-mirror width in the grating is related to the formation of a Talbot image in the near field and is estimated to be about $100{\mu}m$ for the spectrometer to be used for the wavelength range of $7-14{\mu}m$. In calculating the far field at the detection window, the conventional Fraunhofer equation is inadequate for detection distance of our application, misleading the upper limit of the micro-mirror width to avoid interference from higher order diffractions. Instead, the far field is described by the unperturbed plane-wave combined with the boundary diffraction wave. As a result, the interference from the higher order diffractions turns out to be negligible as the micro-mirror width increases. Therefore, the upper limit of the micro-mirror width does not need to be set. Under this scheme, the interferometer patterns and their FT spectra are successfully generated.

• Journal of Sensor Science and Technology
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• v.6 no.5
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• pp.414-422
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• 1997

CdS thin films with low resistivity and adequate transmittance in the visible region for the window of CdS/CdTe hetero junction solar cel1 were prepared by close spaced vapor transport(CSVT) method. The electrical and optical properties of the CdS thin films were investigated in terms of the deposition conditions, such as the substrate temperature, the working pressure, and the source temperature. The substrate temperature, the working pressure, and the source temperature for the optimum deposition of the CdS thin films were $300^{\circ}C$, 100mTorr, and $730^{\circ}C$, respectively. The resistivity and the transmittance of the CdS thin films deposited under this condition were about $7.21{\times}10^{3}{\Omega}cm$ and over 65%, respectively. The crystallinity, the resistivity, and optical band gap were improved greatly compared to the CdS thin films deposited by general high vacuum evaporation.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.70.1-70.1
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• 2015

Korea Astronomy and Space Science Institute(KASI) joined the Gemini Observatory as a 'Limited-Term Partner' in 2014, and is providing the Gemini facility for Korean community through K-GMT Science Program starting from 2015. The access to Gemini facility is expected to open a new window of opportunities in the field of optical and infrared observational researches and to help efficient development of science cases for GMT. We will present the short and long-term expectations and possible outcomes of the KASI-Gemini partnership.

• Ceramist
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• v.10 no.3
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• pp.75-85
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• 2007

Over the past few years, due to the great development of optical communications, an increasing R&D activity has been focused on the design and manufacture of the integrated optic amplifiers, with particular reference to their application in wavelength-division-multiplexing (WDM) systems. In this technological context, rare-earth-doped oxide glasses, which had been widely used for solid state lasers, gained much attention as highly performing materials in the third telecom window, around 1.5 micron. The aim of the present paper is to provide a brief overview of the progress made, with particular reference to the authors' work in this area, and to shortly discuss its perspectives.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.61-68
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• 2013

Automatic measurement system is required since cycle time and cost of production are increased by various factors in manual systems. This paper presents a machine vision based prototype measurement system for the automotive axisymmetric shape parts which are generally measured by a manual system that is required the tolerance of the part is very small on each machined surface. This measurement system adopts a method in which optical lens is transferred along the profile of the part to minimize measurement cycle time. The main interest of this paper is a development of an optimum measurement algorithm to the outside diameter of the parts that can be applied to various combinations of hardware. The operating system used to implement the whole system is Window XP and corresponding environment.

• 한국해양학회지
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• v.9 no.2
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• pp.59-64
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• 1974

Relative light intensity was observed with underwater illuminometer (Cs Photoelectric cell, glass window) at the mouth of Yeong-il Bay, and relative vertical clearness and extinction coefficient were calculated from the relative light intensity data. Relationship between extinction coefficient and transparency in this region is also shown.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.268-272
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• 2004

Transparent materials such as fused silica are widely utilized in optical and optoelectronics field because of its outstanding properties, such as transparency in a wide wavelength range, strong damage resistance for laser irradiation, and high thermal and chemical stability. In this study, we made a few micro patterns on the surface of fused silica plate using laser induced wet etching. KrF excimer laser was used as a light source. There were no burrs and micro cracks on the etched surface of fused silica and the flatness of the etched surface was fairly good. We investigated the influence of etchant upon the etch rate and quality in laser induced wet etching. Pyrene-acetone solution and toluene were used as etchant. In the side of etch rate, toluene solution was better than pyrene-acetone solution. But we made in wider range of energy density using pyrene-acetone solution. But pyrene-acetone solution gave us wider window of energy density for successful micro patterning.