• Korean Journal of Acupuncture
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• v.29 no.3
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• pp.441-452
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• 2012

Objectives : As the attempts to make good uses of laser acupuncture in korean medicine have been steadily carried on, to ensure the safety is needed to increase the use of laser acupuncture. The aim of this study was to examine the safety of using laser acupuncture therapy irradiated with 830 nm laser and 905 nm laser. Methods : Fifteen rats were randomly divided into three experimental groups - Intact ; no therapy group. LAT830 ; laser acupuncture therapy(830 nm) group at GB34 GB39. LAT905 ; laser acupuncture therapy(905 nm) group at GB34 GB39. During eight weeks of treatment, LAT830, LAT905 were treated 2 times weekly, frequency 20 Hz, intensity 20 mW. Test items were mortality, body weight, food consumptions, hematological values, blood chemical values, urinalysis values, absolute organ weights and relative organ weights. Results : Statistically significant differences were not found among 3 groups. The values measured in LAT830, LAT905 and Intact(no therapy) group have shown similar results and it indicated that LAT830, LAT905 had no abnormal influence on the reaction of living bodies. There was little difference on the liver weight of relative organ weight test between laser-treated groups(LAT830, LAT905) and Intact group. Conclusions : In conclusion, laser acupuncture therapies irradiated with 830 nm laser and 905 nm laser caused no abnormal reaction of living bodies. More studies are needed to further establish the safety of many other laser acupuncture therapies.

• Korean Journal of Optics and Photonics
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• v.23 no.3
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• pp.124-127
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• 2012

We designed and fabricated dichroic filters for high-power fiber lasers to protect the pumping laser diode from counterpropagating laser beams. The transmittance at laser diode wavelengths of 905 nm~925 nm was designed to be less than 0.1% and the transmittance at the fiber laser or Brillouin scattering wavelengths of 1020 nm ~ 1100 nm was designed to be more than 99.9%. Since oxide materials have good adhesion to the $SiO_2$ substrate, $SiO_2/Ta_2O_5$ were used as coating materials. The filter was fabricated according to our optimized design and its characteristics were compared with the theoretical design. As a result, the transmittance at laser diode wavelengths of 905 nm~925 nm was measured to be less than 0.1%, and the transmittance at the fiber laser or Brillouin scattering wavelengths of 1020 nm~1100 nm was measured to be more than 95.5%, which coincided well with the theoretical design considering processing errors. The filter was found to operate well over 1W of input laser power.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.210-211
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• 2002

산업의 발전과 급속한 대도시화는 환경오염이라는 새로운 사회적 이슈를 발생시켰다. 시정(Visual Range)이란 대기의 혼탁도를 나타내는 기상요소로서, 정상적인 시각을 가진 사람이 목표를 식별할 수 있는 최대거리를 의미한다 시정은 대기오염을 판단할 수 있는 척도이며, 항만 및 공항 등에서는 인명 및 재산과 직접적인 관계를 갖고 있어, 최근 시정 측정에 대한 중요성이 높아지고 있다. 본 논문에서는 배경 잡음에 좋은 특성을 가지며, 보디- 정확한 시정 측정을 위하여 905nm 펄스 모드 반도체 레이저 다이오드를 이용한 시정계 센서를 제작하여 실험하였다. (중략)

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.905-908
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• 2011

We report fluorescence excitation and emission spectra of the CHBr molecule generated via pyrolysis of $CH_3Br$ in a molecular beam experiment. The 193 nm attenuation cross sections were estimated from the reduction of the CHBr signal as a function of the excimer laser fluence. The derived 193 nm absorption cross section for CHBr [$(3.24{\pm}0.59){\times}10^{-17}\;cm^2$] is slightly higher than the absorption cross section previously determined for CHCl [$(2.6{\pm}0.8){\times}10^{-17}\;cm^2$], but the difference is within the estimated uncertainties in the measured cross section.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.101-103
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• 2022

CCTV is mainly used as a real-time detection system for critical facilities. In the case of CCTV, although the accuracy is high, the viewing angle is narrow, so it is used in combination with a sensor such as a radar. LiDAR is a technology that acquires distance information by detecting the time it takes to reflect off an object using a high-power pulsed laser. In the case of lidar, there is a problem in that the utilization is not high in terms of cost and technology due to the limitation of the number of simultaneous processing sensors in the server due to the data throughput. The detection method by the optical mesh sensor is also vulnerable to strong winds and extreme cold, and there is a problem of maintenance due to damage to animals. In this paper, by using the 1550nm wavelength band instead of the 905nm wavelength band used in the existing lidar sensor, the effect on the weather environment is strong and we propose to develop a system that can integrate and control multiple sensors.

• Analytical Science and Technology
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• v.26 no.4
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• pp.235-244
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• 2013

Detection of halogens using laser-induced breakdown spectroscopy (LIBS) in open air is very difficult since their strong atomic emission lines are located in VUV region. In NIR region, there are other emission lines of halogens through electronic transitions between excited states. However, these lines undergo Stark broadening severely. We report the observation of the emission lines of halogens in laser-induced plasma (LIP) spectra in NIR region using a helium gas flow. Particularly, the emission lines of iodine at 804.374 and 905.833 nm from LIPs have been observed for the first time. In the helium ambient gas, Stark broadening of the emission lines and background continuum emission could be suppressed significantly. Variations of the line intensity, plasma temperature, and electron density with the helium flow rate was investigated. Detection of chlorine and bromine in flame retardant of rubbers was demonstrated using this method. Finally, we suggest a pulsed helium gas jet as a practical and ecomonical helium gas source for the LIBS analysis of halogens in open air.

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.331-335
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• 2012

A miniaturized laser beam transmitter, in which a visible laser module at ${\lambda}$=650 nm is precisely stacked upon an infrared (IR) module at ${\lambda}$=905 nm, has been proposed and constructed to provide an IR collimated beam in conjunction with a collinear monitoring visible beam. In particular, the IR beam is selectively dispersed through a perforated sheet diffuser, so as to create a rapidly diverging close-range beam in addition to a highly defined long-range beam simultaneously. The complementary close-range beam plays a role in mitigating the blind region in the vicinity of the transmitter, which is inevitably missed by the main long-range beam, thereby uniformly extending the transmitter's effective trajectory that is sensed by a receiver. The proposed transmitter was designed through numerical simulations and then fabricated by incorporating a diffuser sheet, perforated with an aperture of 2 mm. For the manufactured transmitter, the IR long-range beam was observed to have divergences of ~2.3 and 1.6 mrad in the fast and slow axes, respectively, while the short-range beam yielded a divergence of ~24 mrad. The angular alignment between the long-range IR and visible beams was as accurate as ~0.5 mrad. According to an outdoor feasibility test involving a receiver, the combination of the IR long- and short-range beams was proven to achieve a nearly uniform trajectory over a distance ranging up to ~600 m, with an average detectable cross-section of ${\sim}60{\times}80cm^2$.