• Title/Summary/Keyword: Q-switched

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Output Characteristics of a Yb:YAG Laser Q-Switched by a Semiconductor Saturable Absorber and an Output Coupler Composed of a Polarizer and a Quarter-Wave Plate (편광기와 1/4 파장판으로 구성된 출력경과 반도체 포화 흡수체에 의해 Q-스위칭된 Yb:YAG 레이저 출력 특성 연구)

  • Ahan, Cheol Yong;Kim, Hyun Chul;Lim, Han Bum;Kim, Hyun Su
    • Korean Journal of Optics and Photonics
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    • v.25 no.2
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    • pp.90-94
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    • 2014
  • We propose a Yb:YAG laser Q-switched by a semiconductor saturable absorber and a laser output coupler composed of a polarizer and a quarter-wave plate, and we investigate the output characteristics of the proposed Q-switched laser. We show that the laser power can be varied by rotation of the quarter-wave plate.

Pulsed-laser-diode Intermittently Pumped 2-㎛ Acousto-optic Q-switched Tm:LuAG Laser

  • Wen, Ya;Jiang, Yan;Zheng, Hao;Zhang, Hongliang;Wang, Chao;Wu, Chunting;Jin, Guangyong
    • Current Optics and Photonics
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    • v.4 no.3
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    • pp.238-246
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    • 2020
  • The heat distribution in crystals in a 2-㎛ acousto-optic Q-switched Tm:LuAG laser pumped by pulsed-laser-diode (pulsed-LD) intermittent-pumping technology was analyzed using COMSOL software. The thermal lensing effect of the Tm:LuAG crystal can be mitigated by pulsed-LD intermittent-pumping techniques. An experimental setup using this kind of approach achieved maximum output energy of 8.31 mJ, minimum pulse width of 101.9 ns, and highest peak power of 81.55 kW, reached at a Q-switched repetition rate of 200 Hz. It offers significant improvement of performance of the output laser beam, compared to pulsed-LD double-ended pumping technology at the same repetition rate.

Measurement of excitation efficiency and passively Q-switched characteristics of laser diode end-pumped Nd:YAG laser by using $Cr^{4+}$:YAG as a saturable absorber ($Cr^{4+}$:YAG 포화 흡수체를 이용한 레이저 다이오드 뒷면 여기 Nd:YAG 레이저의 들뜸 효율 및 Q-switching 특성 연구)

  • 정태문;김광석;문희종;이종훈;김철중;이종민
    • Korean Journal of Optics and Photonics
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    • v.9 no.4
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    • pp.231-235
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    • 1998
  • Passively Q-switched, laser diode(LD) end-pumped Nd:YAG laser was demonstrated by using $Cr^{4+}$:YAG as a saturable absorber. In addition , we could calculate an excitation efficiency, which is an important parameter to evaluate the pumping geometry, directly by measuring the absorbed power in Nd:YAG at threshold condition. We found that output parameters such as average power, pulse duration, and repetition rate strongly depended on the low intensity transmission of $Cr^{4+}$:YAG and driving current of lase diode. The maximum Q-switched output power of 1 W was obtained with 40 kHz repetition rate. The pulse duration was varied from 50 ns to 200 ns.

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Simulation of Manipulating Various Pulsed Laser Operations Through Tuning the Modulation Depth of a Saturable Absorber (포화 흡수체의 투과변조깊이 조절을 통한 다양한 펄스상태 조작 방법에 관한 전산 모사)

  • Gene, Jinhwa;Yeom, Dong-Il;Kim, Byoung Yoon
    • Korean Journal of Optics and Photonics
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    • v.28 no.6
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    • pp.351-355
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    • 2017
  • In this paper, we conduct a simulation of manipulating various pulsed laser operations through tuning the modulation depth of the saturable absorber in a laser cavity. The research, showing that various pulsed operations could be manipulated from Q-switching through Q-switched mode locking to mode locking by tuning the modulation depth of the saturable absorber in a cavity, has been studied by experimental means. We conduct a simulation with the Haus master equation to verify that these experimental results are consistent with expectations from theory. The time dependence of the gain was considered to express Q-switching fluctuation through applying a rate equation with the Haus master equation. Laser operation was manipulated from mode locking through Q-switched mode locking to Q-switching as modulation depth was increased, and this result agreed well with the theoretical expectation.

Laser micromachining of micron-size aperture for electron beam microcolumn application using the piezo-switched Nd:YAG laser (Piezo Q-Switched Nd:YAG 레이저에 의한 초미니 전자빔 장치용 Micron-Size Aperture의 레이저 미세가공)

  • 안승준;김대욱;김호섭;최성수
    • Journal of the Korean Vacuum Society
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    • v.8 no.4A
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    • pp.456-460
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    • 1999
  • Experimental studies of laser micromachining on Mo diaphragm using piezo Q-switched Nd:YAZ laser have been performed. Application of miniaturized micorcolumn electron gun arrays as a potential electron beam lithography or portable mini-scanning electron microscope (SEM) application have recently extensively examined. The conventional microcolumn fabrication technique would give a limitation on the minimization of aberration, In this paper, we obtained 20~30 $\mu \textrm m$aperture of laser micromachining on Mo diaphragm using piezo Q-swithed Nd:YAG laser. The geometrical figures, such as the diameter and the preciseness of the drilled aperture are dependent upon the total energy of the laser pulse train, laser pulse width, and the diameter of laser spot in addition to the materials-dependent parameters.

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Laser Micromachining of Submicron Aperture for Electronbeam Microcolumn Application using Piezo Q-Switched Nd:YAG Laser

  • S.J. Ahn;Kim, D.W.;Park, S.S.
    • Proceedings of the Korean Vacuum Society Conference
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    • 1999.07a
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    • pp.78-78
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    • 1999
  • Experimental studies of laser micromachining on Mo metal using piezo Q-switched Nd:YAG laser have been performed. Miniaturized microcolumn electron gun arrays as a potential electron beam lithography or portable mini-scanning electron microscope application have recently extensively examined. For these purpose, the electro-static electron lens and deflector system called microcolumn has to be assembled. The conventional microcolumn fabrication technique would gave a limitation on the minimization of aberration. The current technique of a 1 $\mu$m misalignment would lead to ~1.3 nm coma. In order to reduce aberration, assembling the microcolumn component followed by laser drilling should be very beneficial. In this report, we will address the preliminary report of laser micromachining on Mo substrate using piezo Q-switched Nd:YAG laser. The geometrical figures, such as the diameter and the depth of the frilled aperture are dependent upon the total energy of the laser pulse train, laser pulsewidth, and the diameter of laser beam in addition to the materials-dependent parameters.

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High Power Continuous-Wave and Graphene Q-switched Operation of Er:YAG Ceramic Lasers at ~1.6 ㎛

  • Wang, Yong;Chen, Hao;Shen, Deyuan;Zhang, Jian;Tang, Dingyuan
    • Journal of the Optical Society of Korea
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    • v.17 no.1
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    • pp.5-9
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    • 2013
  • We report on high-power continuous-wave operations of an Er:YAG ceramic laser in-band pumped by a cladding-pumped Er,Yb fiber laser at 1532 nm. With an output coupler of 10% transmission, the ceramic laser yielded 16.7 W of continuous-wave output at 1645 nm for 28.8 W of incident pump power, corresponding to a slope efficiency of 61.0% with respect to the incident pump power. The lasing wavelength switched to 1617 nm when output couplers of > 20% transmission were used. Up to 16.2 W of 1617 nm output was generated for 33.0 W of incident pump power, corresponding to a slope efficiency of 51.8%. Graphene Q-switched operation of Er:YAG cermic laser at 1645 nm was also demonstrated with stable pulses of 30-74 kHz repetition rates and 1.5-6.4 ${\mu}s$ pulse widths.

Output Characteristics of a Q-Switched Nd:YAG laser with GRM(Gaussian Reflectivity Mirror) unstable resonator (GRM(Gaussian Reflectivity Mirror)을 이용한 불안정 공진기형 Q-스위치 Nd:YAG 레이저의 출력특성)

  • Lee, Hee-Chul;Kim, Yong-Pyung
    • Korean Journal of Optics and Photonics
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    • v.16 no.2
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    • pp.152-158
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    • 2005
  • We investigated the operational characteristics of a Q-switched Nd:YAG laser, which has an unstable resonator with a GRM(Gaussian reflectivity mirror). With electrical input energy of 55 J, we obtained the fundamental energy of 470 mJ at 1064 nm and the frequency doubled energy of 280 mJ at 532 nm. The Top-Hat profile of the output beam was obtained at the near field, and beam divergence was 1.7 mard.

Waveform distortion of the stimulated Brillouin scattering in a single mode optical fiber with Q-switched Nd:YAG laser

  • Lee, Sang-Hun;Cho, Jin-Hang;Kim, Chil-Min
    • Proceedings of the Optical Society of Korea Conference
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    • 2008.02a
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    • pp.335-336
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    • 2008
  • We observe the distortion of the back scattered Stokes pulse and the complementary distortion of the transmitted pulse by the stimulated Brillouin scattering when a Q-switched Nd:YAG laser pulse injected into a single mode optical fiber. We determine the constant required energy for the SBS by comparing their temporal shapes.

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Optimization of a Passively Q-switched Yb:YAG Laser Ignitor Pumped by a Laser Diode with Low Power and Long Pulse Width

  • Kim, Jisoo;Moon, Soomin;Park, Youngin;Kim, Hyun Su
    • Current Optics and Photonics
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    • v.4 no.2
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    • pp.127-133
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    • 2020
  • We successfully constructed a passively Q-switched Yb:YAG laser ignitor pumped by a diode laser with low power and long pulse width. To the best of our knowledge, this is the first study to achieve a quasi-MW output power from an optimized Q-switch Yb:YAG laser ignitor by using a pumping diode laser module emitting at under a power of 23 W. The output pulse energy of our optimized laser is 0.98 mJ enclosed in a 1.06 ns pulse width, corresponding to a peak power of 0.92 MW.