• Current Optics and Photonics
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• v.3 no.1
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• pp.8-15
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• 2019

We describe a common optical system that merges a LADAR system, which generates a point cloud, and a more traditional imaging system operating in the LWIR, which generates image data. The optimum diameter of the entrance pupil was determined by analysis of detection ranges of the LADAR sensor, and the result was applied to design a common optical system using LADAR sensors and LWIR sensors; the performance of these sensors was then evaluated. The minimum detectable signal of the $128{\times}128-pixel$ LADAR detector was calculated as 20.5 nW. The detection range of the LADAR optical system was calculated to be 1,000 m, and according to the results, the optimum diameter of the entrance pupil was determined to be 15.7 cm. The modulation transfer function (MTF) in relation to the diffraction limit of the designed common optical system was analyzed and, according to the results, the MTF of the LADAR optical system was 98.8% at the spatial frequency of 5 cycles per millimeter, while that of the LWIR optical system was 92.4% at the spatial frequency of 29 cycles per millimeter. The detection, recognition, and identification distances of the LWIR optical system were determined to be 5.12, 2.82, and 1.96 km, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.1-8
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• 2021

The performance of hidden camera cameras is improving day by day due to miniaturization and advanced technology integration according to the speed of technological development of smartphones. As this external networking computing environment is advanced and diversified, exposure to hidden cameras in addition to general safety cameras is also increasing. On the other hand, the technology for detecting and preventing hidden cameras is not keeping up with the development and speed of these hidden cameras. Therefore, in this study, the heat of the hidden camera was detected using infrared thermal detection technology based on general image and thermal image synthesis technology, and the reflectance of each wavelength according to the difference in ambient temperature was analyzed to reduce the false positive rate.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.48-53
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• 2004

Spectral irradiance measurement system was developed to measure the spectral irradiance of optical sources in the wavelength range from 250[nm] to 1600[nm]. Our system is composed of source system, fore-optics, monochromator system, optical detector system, and automatic control system. Optical detector system with PMT, Si, InGaAs, and IR enhanced InGaAs detectors is used to measure the wide spectrum of optical sources in ultraviolet visible, and infrared wavelength regions. Spectral irradiance of the 1[kW] quartz-halogen tungsten lamp was measured and compared in the wavelength range from 250[nm] to 1600[nm]. The differences between our results and those reported by NIST are below 3[%], 3.5[%], and 5[%] in the wavelength range of 450∼700[nm], 700∼1600[nm], 250∼400[nm], respectively.

• Journal of the Optical Society of Korea
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• v.8 no.4
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• pp.174-181
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• 2004

Various kinds of systems, that can do target recognition and position detection simultaneously by using infrared sensing detectors, have been developed. In this paper, the detection system TRSS (Thermal target Recognition by Spiral Scanning) adopts linear array shaped uncooled IR detector and uses spiral type fast scanning method for relative position detection of target objects, which radiate an IR region wavelength spectrum. It can detect thermal energy radiating from a 9 m-size target object as far as 200 m distance. And the maximum field of a detector is fully filled with the same size of target object at the minimum approaching distance 50 m. We investigate two types of lens systems. One is a singlet lens and the other is a doublet lens system. Every system includes one aspheric surface and free positioned aperture stop. Many designs of F/1.5 system with ${\pm}5.2^{\circ}$ field at the Efl=20, 30 mm conditions for single element and double elements lens system respectively are compared in their resolution performance [MTF] according to the aspheric surface and stop position changing on their optimization process. Optimum design is established including mechanical boundary conditions and manufacturing considerations.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.1-12
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• 2014

In this paper, we developed an explosion proof type and portable combustible gas leak detector and proposed an algorithm to improve the accuracy for measuring gaseous concentrations. The nation's first we developed an infrared gas leak detector with explosion proof standard(Ex d ib) and improved measuring accuracy by using linearization recursion equation and 2nd Lagrange interpolation polynomial. Together, we advanced their performances and added their easy functions after investigating field demands. To compare our and other company's detectors, we performed measurement tests with eight standard gases made by Korea Gas Safety Corporation. We demonstrated the excellence of our instruments in measuring accuracy other than detecters through experimental results.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.3
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• pp.124-133
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• 1995

A theoretical self-consistent thermoelectric model has been developed for optimal thermal design in the self-signal processing infraed detectors. The model is achived by employing the coupled thermoelectric equation which allows which allows the simultaneous investigation of the termal and electrical aspects of device behavior. The thermal limitation of detectivity and responsivity are determined by the enegy gap, carrier concentration, lifetime, and mobility as a function of the temperature. The calculated results indicate that the detectivity is decreased at bias fields above about 50 V/cm, because the performence is limiting by temperature when the bias voltage reached the level associated with Joule heating. It has been also found that the improvement in the mid-band modulation transfer function(MTF) may be restricted by increasing the bias fields. Further, the important paramerers in the thermal optimization of SPIR detector, such as temperature in the device, ambipolar velocity, element thickness and length, are also considered. The analytical study provides a mathematical basis for optimal design of such a photoconductive IR detector and the agreement between the experimental and theoretical results are seen to be good.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.366-369
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• 1999

Synthetic diamond films have been deposited on the silicon(100) surface and molybdenum substrates using an microwave plasma enhanced vapor deposition (MWPECVD) method. The effect of deposition time, surface morphology, X-ray diffraction pattrm, infrared transmittance and Raman Scattering have been studied, The diamond film deposited on Mo substrate for (100) hours at 40 torr H$_2$-CH$_4$O$_2$ gas system have been shown 1${\mu}{\textrm}{m}$/h of growth rate and good crystallization

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.85.2-85.2
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• 2013

We developed autoguiding system for IGRINS (Immersion Grating Infrared Spectrograph) which is a high resolution near-IR spectrograph. This instrument will be attached on the 2.7m telescope at the McDonald observatory in 2013 November. IGRINS consists of three near-Infrared detector modules, i. e., H and K band spectrograph modules and a K band slit camera module, within which we are using the slit camera for autoguiding of the telescope. Comparing to typical optical CCDs, however, the infrared array shows non-uniform responses, higher noises, and many bad pixels. In this poster, we present methods to improve center finding functions and algorithms for the infrared array and the simulator test results of the IGRINS Slit-Camera Package.

• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.401-406
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• 2010

We have measured and analyzed the dark data of two PICNIC IR arrays (P574 and P560) obtained through the Cosmic Infrared Background ExpeRiment (CIBER). First, we identified three types of bad pixels: the cold, the hot, and the transient, which are figured in total as 0.06% for P574 and 0.19% for P560. Then, after the bad pixels were masked, we determined the dark noise to be 20.5 ${\pm}$ 0.05 $e^-$ and 16.1 ${\pm}$ 0.05 $e^-$, and the dark current to be 0.6 ${\pm}$ 0.05 $e^-$/sec and 0.7 ${\pm}$ 0.05 $e^-$/sec for P574 and P560, respectively. Finally, we discussed glitches and readout modes for a future mission.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1604-1611
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• 2018

Utilizing Sb-based bulk epilayers on large-scale low-cost substrates such as GaAs for fabricating infrared (IR) photodetectors is presently attracting significant attention worldwide. For this study, three sample series of $GaAs_xSb_{1-x}$, $In_{1-x}Ga_xSb$, and $InAs_xSb_{1-x}$ with different compositions were grown on semi-insulating GaAs substrates by using molecular beam epitaxy (MBE) and appropriate InAs quantum dots (QDs) as a defect-reduction buffer layer. Photoluminescence (PL) signals from these samples were observed over a wide IR wavelength range from $2{\mu}m$ to $12{\mu}m$ in agreement with the expected bandgap, including bowing effects. In particular, interband PL signals from $InAs_xSb_{1-x}$ and $In_{1-x}Ga_xSb$ samples even at room temperature show promising potential for IR photodetector applications.