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Quantitative Measurement of Ethane Using Mid-infrared Cavity Ring-down Spectroscopy
김용희,천병재,이림,고광훈,박승규,김택수,박현민 한국광학회 2023 Current Optics and Photonics Vol.7 No.4
Quantitative measurement of trace ethane is important in environmental science and biomedical applications. For these applications, we typically require a few tens of part-per-trillion level measurement sensitivity. To measure trace-level ethane, we constructed a cavity ring-down spectroscopy setup in the3.37 μm mid-infrared wavelength range, which is applicable to multi-species chemical analysis. Wedemonstrated that the detection limit of ethane is approximately 300 parts per trillion, and the measured concentration is in agreement with the amounts of the injected sample. We expect that these results can be applied to the chemical analysis of ethane and applications such as breath test equipment.
이림,김용희,천병재,김택수,박승규,고광훈,송기희 한국광학회 2023 Current Optics and Photonics Vol.7 No.6
We analyzed the absorption spectra of acetone in the 3.37 µm mid-infrared range using the off-axis integrated cavity output spectroscopy technique to develop a real-time, in-line breath analysis device. The linear relationship between acetone concentration and absorption increase was confirmed as 0.32%/ ppm, indicating that the developed device allows for a quantitative analysis of acetone concentration in exhaled breath. To further confirm the feasibility of using our device for breath analysis, we measured the acetone concentration of human breath samples at the sub-ppm level.
200-W Continuous-wave Thulium-doped All-fiber Laser at 2050 nm
신재성,차용호,천병재,정도영,박현민 한국광학회 2021 Current Optics and Photonics Vol.5 No.3
A 200-W continuous-wave thulium-doped all-fiber laser at 2050 nm was developed with a master oscillator power amplifier configuration. For the master oscillator, a single-mode thulium-doped fiber laser was built with fiber Bragg gratings. The operating power of the oscillator was 10.1 W at a pump power of 20.9 W, and the slope efficiency was measured to be 53.0%. All emitted wavelengths of the oscillator were located between 2049.2 nm and 2049.9 nm, and no other peaks in different wavelength ranges were observed. The maximum output power of the final amplified beam was 204.6 W at a pump power of 350.4 W. The slope efficiency of the amplifier was measured to be 58.4%.
40-W 200-ns 300-kHz Thulium-doped Fiber Laser at 2050 nm
신재성,차용호,천병재,박현민 한국광학회 2021 Current Optics and Photonics Vol.5 No.5
A 40-W 200-ns 300-kHz thulium-doped fiber laser at 2050 nm with a master oscillator power amplifier configuration was developed, for application to lithium-isotope separation. The master oscillator generated a 5.35 W continuous-wave beam, which the pulse generator then broke into 200-ns pulses at 300 kHz. Then, the laser beam was amplified by passing through a two-stage amplifier. The output power finally obtained was 42.0 W at 2050 nm, and was stable for a long time, over 2 hours. In spite of this achievement, mode instability was observed in the output beam. This can be solved in the future by using a method such as tight coiling.
보안 라이브러리를 활용한 차량 ECU 진단 통신 보안 구현
김정은(Jeongeun Kim),천병재(Byoungjae Chun),박승범(Seungbum Park) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
Digital revolution into automotive makes drivers more convenient while increasing the possibility of automotive hacking. Recently, the demands for preventing it are increasing since it has been proved by lots of security researchers. Some corporations have been developing a technology for authentication such as a network firewall. Automotive ECUs usually implement different tasks like flashing SW, Input/Output Control, parameters calibration, in-line coding through diagnostics. It could cause ECU malfunction; even threaten the driver’s life; if unauthorized user tries to programming manipulated firmware or transmitting arbitrarily a Input/Output Control service via automotive networks. In this study, we’ve implemented secure diagnostic mechanisms, that is, strengthen the ability of authentication with crypto library and analyzed a performance.