• Title/Summary/Keyword: 연속발진레이저

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Lasing Characteristics of GaAs-Based 1300 nm Wavelength Region InAs Quantum Dot Laser Diode (GaAs 기반 1300 nm 파장대역 InAs 양자점 레이저 다이오드의 발진 특성)

  • Kim, K.W.;Choa, N.K.;Song, J.D.;Lee, J.I.;Park, Jeong-Ho;Lee, Y.J.;Choi, W.J.
    • Journal of the Korean Vacuum Society
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    • v.18 no.4
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    • pp.266-271
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    • 2009
  • We have investigated the lasing characteristics of GaAs-based 1300 nm wavelength region InAs Quantum Dot Laser Diode grown by Migration Enhanced Molecular Beam Epitaxy. Under a pulsed and CW operation, we observed the state switching of lasing wavelength from ground state (1302 nm) to excited state (1206 nm) due to the gain saturation of ground state. Under a pulsed operation, $J_{th}=92A/cm^2$, $\lambda_L=1311\;nm$ and under a CW operation, $J_{th}=247A/cm^2$, $\lambda_L=1320\;nm$.

Compensation of thermal tensing effect and oscillation of $TEM_{00}$ mode by using a Quarter-Wave Plate in a resonator of high Power cw Nd:YAG laser ($\lambda$/4-판을 이용한 연속발진 고출력 Nd:YAG 레이저의 열 렌즈 보상과 $TEM_{00}$모드 발진)

  • 신성숙;장원권;석성수;박덕규;이성만;윤미정;김선국;김용기;차병헌
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.52-53
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    • 2003
  • 다이오드 레이저의 개발과 발달에 의해 고출력의 다이오드 펌핑 고체 레이저(DPSSL, Doode-Pumped Solid State Laser)가 개발되었고 다양한 분야에서 그 응용성이 증가하고 있다. 고출력 레이저 발생의 경우에 펌핑에 의한 레이저 매질 내부의 열 발생이 중요하게 대두되고, 이러한 열로 인해 레이저 빔의 왜곡이 생겨나 빔질이 저하된다. 레이저 빔질의 개선은 가우시안(Gaussian) 분포를 따르는 빔에 대해 기술하고 있는 광학 공식들과 직접적인 산업현장에서의 유용성 때문에 매우 중요한 문제가 된다. (중략)

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A Study on Measurement of Premixed Spray Flame using Cross-correlation PIV (상호상관 PIV를 이용한 예혼합 분무화염의 계측에 관한 연구)

  • Yang Young-Joon;Kim Bong-Hwan
    • Journal of Energy Engineering
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    • v.14 no.4 s.44
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    • pp.259-267
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    • 2005
  • In an attempt to elucidate combustion mechanism or premixed spray flame in detail, both the enlarged photographing, which was performed for spray cross-sectional images of premixed spray flame, and the cross-correlation PIV, which was performed for consecutive time-series images to obtain instantaneous two dimensional flow field, were applied. This study indicated that CW laser as well as pulse laser could be applied for PIV. Furthermore, the results of cross-correlation PIV, which was self-made PIV program, was shown in good agreement with those of PDA. Therefore, it was verified that cross-correlation PIV using CW laser in this study could be effectively used for observing structure of premixed spray flame.

Construction and operational characteristics of a Ultra-Short pulse Cr4+:YAG laser (극초단 펄스 Cr4+:YAG 레이저의 제작 및 동작 특성)

  • Lee Bong Yeon;Lee Dong Han;Lee Chi Weon;Yoon Seok Beom;Choo Han Tae
    • Korean Journal of Optics and Photonics
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    • v.15 no.5
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    • pp.455-460
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    • 2004
  • We have developed a mode-locked ultra-short pulse C $r^{4+}$:YAG laser, as well as a continuous wave C $r^{4+}$:YAG laser. The laser was pumped by a Nd:YAG laser and its characteristics were investigated. In continuous wave mode, we obtained as much as 600 mW at 1.436 ${\mu}{\textrm}{m}$ with pumping power of 6 W, by using an output coupler with a reflectivity of 98%. The power slope efficiency was 10%, when the gain medium was cooled to 19$^{\circ}C$. The tuning range was varied from 1.39 ${\mu}{\textrm}{m}$ to 1.55 ${\mu}{\textrm}{m}$ and the maximum power was 400 mW at 1.492 ${\mu}{\textrm}{m}$ with a 3-plate birefringent filter. The C $r^{4+}$:YAG laser was mode-locked by a Kerr lens mode locking method. Mode locking at 1.436 ${\mu}{\textrm}{m}$was initiated by slightly rocking a mirror mount. But the pulses were very unstable because of the strong water absorption at this region. So we shifted the lasing wavelength to 1.492 ${\mu}{\textrm}{m}$ by using a 3-plate birefringent filter. Then we obtained stable state mode-locking with the maximum average power of 280 mW for a pumping power of 6 W. The pulse width of 43 fs was measured using an autocorrelator and the repetition rate was 104.5 MHz.

알곤레이저 펌핑에 의한 연속발진 Rh-6G 섹소레이저의 에너지 전환

  • 방영운;이민희
    • Proceedings of the Optical Society of Korea Conference
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    • 1988.06a
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    • pp.29-32
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    • 1988
  • 섹소레이저의에서 출력의 증가를 위하여 사용되는 색소혼합법을 펌핑광원으로 알곤레이저를 이용할 경우 펌핑광원에 대한 정보를 정확히 알 수 있으므로 에너지전달과정을 해석적으로 분석할 수 있다. 본 연구에서는 주색소로 Rh-6G 색소를 선택하였고, 전환색소로는 Coumarin-545 색소를 선택하여 Rh-6G 색소레이저에서 색소혼합에 대한 출려력특성을 조사하여 에너지전달과정을 해석하였다.

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High-Power Continuous-Wave Laser-Induced Damage to Complementary Metal-Oxide Semiconductor Image Sensor (고출력 CW 레이저에 의한 CMOS 영상 센서의 손상 분석)

  • Kim, Jin-Gyum;Choi, Sungho;Yoon, Sunghee;Jhang, Kyung-Young;Shin, Wan-Soon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.1
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    • pp.105-109
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    • 2015
  • This paper presents the results of an experimental analysis of the high-power laser (HPL)-induced damage to a complementary metal-oxide semiconductor (CMOS) image sensor. Although the laser-induced damages to metallic materials have been sufficiently investigated, the damages to electric-optic imaging systems, which are very sensitive to HPLs, have not been studied in detail. In this study, we experimentally analyzed the HPL-induced damages to a CMOS image sensor. A near-infrared continuous-wave (CW) fiber laser was used as the laser source. The influences of the irradiance and irradiation time on the permanent damages to a CMOS image sensor, such as the color error and breakdown, were investigated. The experimental results showed that the color error occurred first, and then the breakdown occurred with an increase in the irradiance and irradiation time. In particular, these damages were more affected by the irradiance than the irradiation time.

CW Operation of LD-pumped Nd -YLF Laser- (레이저 다이오드로 펌핑되는 Nd:YLF 레이저의 발진 특성)

  • 강응철
    • Korean Journal of Optics and Photonics
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    • v.4 no.3
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    • pp.289-293
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    • 1993
  • A Nd:YLF laser pumped by a CW GaAlAs laser diode(LD) at 792 nm has been designed and fabricated. The output power was investigated as a function of LD spectrum and pump power. A folded laser resonator was desinged to compensate for the astigmatism produced at the Brewster surface of Nd:YLF rod. We obtained output power of CW 1.1 Watt when the pumping power was 2.8 Watt and the output wavelength of LD was temperature tuned to the peak absorption line of Nd:YLF. The overall efficiency was 39 % and slope efficiency was 41 %.

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Design and operational characteristics of cw and KLM Ti : sapphire lasers with a symmetric Z-type cavity configuration (Z-형태의 대칭형 레이저 공진기 구조를 갖는 연속 발진 및 Kerr-렌즈 모드-록킹되는 티타늄 사파이어 레이저의 설계와 동작 특성)

  • Choo, Han-Tae;Ahn, Bum-Soo;Kim, Gyu-Ug;Lee, Tae-Dong;Yoon, Byoung-Won
    • Korean Journal of Optics and Photonics
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    • v.13 no.4
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    • pp.347-355
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    • 2002
  • We have constructed a high efficiency and broad tunable cw Ti:sapphire laser with a four-mirror symmetric Z-type laser cavity to increase the laser usability. From theoretical analyses and experimental data for a symmetric Z-type laser cavity containing a Kerr medium, the cavity mode size and the Kerr-lens mode-locking (KLM) strength for KLM lasers can be confirmed as function of the position in the cavity, the intracavity laser power, and the stability parameter. As a result, the slope efficiency and the maximum average output power of cw Ti:sapphire laser at 5 W pumping power of Ar-ion laser were 31.3% and 1420 ㎽ respectively. The tunablility was ranged from 730 ㎚ to 908 ㎚ with average output power above 700 ㎽. We obtained the KLM operation easily by self-aperturing effect in the Kerr medium and the slope efficiency and the maximum average output power of KLM Ti:sapphire laser was 16% and 550 ㎽ respectively. The spectral bandwidth was 33 ㎚ at the center wavelength of 807 ㎚ and the pulse width was 27 fs with a repetition rate of 82 ㎒.