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Sample records for passively q-switched mode-locking

  1. Five simultaneously Q-switch mode-locked passive laser modulators

    NASA Astrophysics Data System (ADS)

    Chen, Junewen

    2007-02-01

    Five types of passive Q-switched as well as simultaneously Q-switch mode-locked modulators: plastic dye sheets ( Kodak 9850 cellulose acetate dye sheets), lithium fluoride crystals containing F II - color centers ( LiF: F II -), chromium doped yttrium aluminum garnet crystals ( Cr 4+:YAG), ionic color filter glass ( Schott RG1000 color filter glass) and the single crystal semiconductor wafers ( GaAs, Fe doped InP, Zn doped InP, S doped InP, etc.) used for the modulation of the Nd:hosted(Nd:YAG, Nd:YVO 4, and Nd:LSB) lasers have been investigated in detail in our researches. We have also investigated into the applications of the Q-switch mode-locked pulses train for the development of higher resolution solid state laser range finder. We will also present the high accuracy laser ranging results, the micro-motor that driven mechanical parts from the stepping digital ranging readout, to precisely control the best focus of a miniature zoom lens modular. The core simultaneously Q-switch mode-locked modulators microchip laser is the key part of our automatic optical inspection system.

  2. All-solid-state passively Q -switched mode-locked Nd-doped fiber laser

    SciTech Connect

    Zenteno, L.A.; Po, H.; Cho, N.M. )

    1990-01-15

    We report the generation of {ital Q}-switched mode-locked pulses from a Nd-doped fiber laser that uses a solid-state solution of BDN-I dye as the saturable absorber and is pumped by a GaAlAs laser diode. For an absorbed pump power of 110 m W, pulses of 8-nsec duration at a repetition rate of 14 MHz can be generated under an 800-nsec-wide {ital Q}-switched envelope at a repetition rate of 100 kHz, yielding an average output power of 8 m W near 1.06 {mu}m. This corresponds to approximately 9 W of peak power in the main mode-locked pulse.

  3. Passively Q-switched and mode-locked dual-wavelength Nd:GGG laser with Cr4+:YAG as a saturable absorber

    NASA Astrophysics Data System (ADS)

    Chu, Hongwei; Zhao, Shengzhi; Li, Yufei; Yang, Kejian; Li, Guiqiu; Li, Dechun; Zhao, Jia; Qiao, Wenchao; Li, Tao; Feng, Chuansheng; Zhang, Haijuan

    2014-03-01

    By using neodymium-doped gadolinium gallium garnet (Nd:GGG) as a laser medium, a simultaneously passively Q-switched and mode-locked (QML) dual-wavelength laser with Cr4+:YAG as a saturable absorber is presented. The laser simultaneously oscillated at 1061 nm and 1063 nm, corresponding to a frequency difference of 0.53 THz. QML pulses with nearly 100% modulation depth were observed. The mode-locked pulse duration underneath the Q-switched envelope was estimated to be about 908 ps. The experimental results indicated that the dual-wavelength QML Nd:GGG laser can be an excellent candidate for the generation of THz waves.

  4. As-grown uniform MoS2/mica saturable absorber for passively Q-switched mode-locked Nd:GdVO4 laser

    NASA Astrophysics Data System (ADS)

    Xu, Yuanyuan; Yang, Cheng; Ge, Pengguang; Liu, Jie; Jiang, Shouzhen; Li, Chun; Man, Baoyuan

    2016-08-01

    Molybdenum disulfide (MoS2) has recently attracted growing attention due to its distinctive properties and potential applications in optoelectronics and electronics. Here, large-area and high-quality MoS2 film with uniform thickness was obtained by thermally decomposing ammonium thiomolybdate. Besides, it is firstly demonstrated that the as-grown MoS2/mica can be directly inserted into Nd:GdVO4 laser cavity as saturable absorber for the output of diode-pumped passively Q-switched mode-locked pulse trains. Using the MoS2 saturable absorbers, the stable Q-switched mode-locked pulse trains with high modulation depth were realized, suggesting that the broadband MoS2 SA could potentially be employed in mode-locking laser system

  5. Passively Q-switched mode locking in a compact Nd:GdVO4/Cr:YAG self-Raman laser

    NASA Astrophysics Data System (ADS)

    Peng, Jiying; Zheng, Yi; Zheng, Kai; Chang, Xiaowei

    2012-11-01

    Passively Q-switched mode locking in a compact Nd:GdVO4 self-Raman laser with a Cr:YAG saturable absorber was demonstrated. The picosecond first stokes at 1173 nm was successfully obtained. When the optical cavity length changed from 167 mm to 120 mm, the mode-locked pulse repetition rate increased from 0.9 GHz to 1.25 GHz. At the maximum diode pump power of 10 W and with a pulse repetition rate of 0.9 GHz, an average output power up to 105 mW has been achieved at 1173 nm. In addition, the yellow laser output at 586.5 nm was also realized by frequency doubling with an LBO crystal.

  6. Doubly active Q switching and mode locking of an all-fiber laser.

    PubMed

    Cuadrado-Laborde, Christian; Díez, Antonio; Cruz, Jose L; Andrés, Miguel V

    2009-09-15

    Simultaneous and independent active Q switching and active mode locking of an erbium-doped fiber laser is demonstrated using all-fiber modulation techniques. A magnetostrictive rod attached to the output fiber Bragg grating modulates the Q factor of the Fabry-Perot cavity, whereas active mode locking is achieved by amplitude modulation with a Bragg-grating-based acousto-optic device. Fully modulated Q-switched mode-locked trains of optical pulses were obtained for a wide range of pump powers and repetition rates. For a Q-switched repetition rate of 500 Hz and a pump power of 100 mW, the laser generates trains of 12-14 mode-locked pulses of about 1 ns each, within an envelope of 550 ns, an overall energy of 0.65 microJ, and a peak power higher than 250 W for the central pulses of the train. PMID:19756079

  7. Q-switched and mode-locked Er{sup 3+}-doped fibre laser using a single-multi-single fibre filter and piezoelectric

    SciTech Connect

    Ji Wang; Yunjun Zhang; Aotuo Dong; Xiaoxin Xu; Youlun Ju; Baoquan Yao

    2014-04-28

    The active Q-switched and passive mode-locked Er{sup 3+}-doped all-fibre laser is presented. The fibre laser centre wavelength is located at 1563 nm and determined by the homemade singlemulti- single (SMS) in-line fibre filter. The laser spectrum width is nearly 0.1 nm. The active Q-switched mechanism relies on the polarisation state control using a piezoelectric to press a segment of passive fibre on the circular cavity. The nonlinear polarisation rotation technology is used to realise the passive self-started modelocked operation. In the passive mode-locked regimes, the output average power is 2.1 mW, repetition frequency is 11.96 MHz, and single pulse energy is 0.18 nJ. With the 100-Hz Q-switched regimes running, the output average power is 1.5 mW. The total Q-switched pulse width is 15 μs, and every Q-switched pulse is made up by several tens of mode-locked peak pulses. The calculated output pulse energy of the Q-switched fibre laser is about 15 μJ, and the energy of every mode-locked pulse is about 64–68 nJ during a Q-switched pulse taking into account the power fraction propagating between pulses. (lasers)

  8. Q-switched and mode-locked Er3+-doped fibre laser using a single-multi-single fibre filter and piezoelectric

    NASA Astrophysics Data System (ADS)

    Wang, Ji; Zhang, Yunjun; Dong, Aotuo; Xu, Xiaoxin; Ju, Youlun; Yao, Baoquan

    2014-04-01

    The active Q-switched and passive mode-locked Er3+-doped all-fibre laser is presented. The fibre laser centre wavelength is located at 1563 nm and determined by the homemade singlemulti- single (SMS) in-line fibre filter. The laser spectrum width is nearly 0.1 nm. The active Q-switched mechanism relies on the polarisation state control using a piezoelectric to press a segment of passive fibre on the circular cavity. The nonlinear polarisation rotation technology is used to realise the passive self-started modelocked operation. In the passive mode-locked regimes, the output average power is 2.1 mW, repetition frequency is 11.96 MHz, and single pulse energy is 0.18 nJ. With the 100-Hz Q-switched regimes running, the output average power is 1.5 mW. The total Q-switched pulse width is 15 μs, and every Q-switched pulse is made up by several tens of mode-locked peak pulses. The calculated output pulse energy of the Q-switched fibre laser is about 15 μJ, and the energy of every mode-locked pulse is about 64-68 nJ during a Q-switched pulse taking into account the power fraction propagating between pulses.

  9. Diode pumped Nd:YAG laser with active Q-switching and mode locking for hole drilling

    NASA Astrophysics Data System (ADS)

    Solokhin, S. A.; Sirotkin, A. A.; Garnov, S. V.

    2011-06-01

    A diode-pumped Nd:YAG laser operating with active-passive Q-switch mode locking, has been developed. The acousto-optic repetition train was one kilohertz with generated pulse train widths 65 ns, single pulse widths 200 ps and an average power of 6.5 W. Improvement of efficiency of small diameter deep holes laser drilling in different materials was studied.

  10. Active/passive mode-locked laser oscillator

    DOEpatents

    Fountain, William D.; Johnson, Bertram C.

    1977-01-01

    A Q-switched/mode-locked Nd:YAG laser oscillator employing simultaneous active (electro-optic) and passive (saturable absorber) loss modulation within the optical cavity is described. This "dual modulation" oscillator can produce transform-limited pulses of duration ranging from about 30 psec to about 5 nsec with greatly improved stability compared to other mode-locked systems. The pulses produced by this system lack intrapulse frequency or amplitude modulation, and hence are idealy suited for amplification to high energies and for other applications where well-defined pulses are required. Also, the pulses of this system have excellent interpulse characteristics, wherein the optical noise between the individual pulses of the pulse train has a power level well below the power of the peak pulse of the train.

  11. Q-switching and mode-locking in a diode-pumped frequency-doubled Nd : YAG laser

    SciTech Connect

    Donin, Valerii I; Yakovin, Dmitrii V; Gribanov, A V

    2012-02-28

    A new method for obtaining Q-switching simultaneously with mode-locking using one travelling-wave acousto-optic modulator in a frequency-doubled Nd : YAG laser cavity is described. Further shortening of output laser pulses (from 40 to 3.25 ps) is achieved by forming a Kerr lens in the frequency-doubling crystal. At an average power of {approx} 2 W and a Q-switching rate of 2 kHz, the peak power of the stably operating reached {approx} 50 MW.

  12. Q-switched mode-locked and azimuthally polarized Nd:GdVO4 laser with semiconductor saturable absorber mirror

    NASA Astrophysics Data System (ADS)

    Hong, Kun-Guei; Hung, Bi-Jin; Lin, Shih-Ting; Wei, Ming-Dar

    2016-06-01

    A Q-switched mode-locked Nd:GdVO4 laser with azimuthal polarization was generated using a semiconductor saturable absorber mirror. On the basis of the birefringence of the laser crystal inducing different equivalent lengths for ordinary and extraordinary rays, beams were azimuthally polarized around the edge of a stable cavity region. At a pump power of 9 W, the repetition rate and width for the Q-switched envelope were 318 kHz and 0.91 µs, and the mode-locked pulse repetition rate and pulse width were 455 MHz and 65 ps, respectively. The degree of polarization was controllable up to 95.4 ± 1.4%.

  13. An automatic mode-locked system for passively mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Sha; Xu, Jun; Chen, Guoliang; Mei, Li; Yi, Bo

    2013-12-01

    This paper designs and implements one kind of automatic mode-locked system. It can adjust a passively mode-locked fiber laser to keep steady mode-locked states automatically. So the unsteadiness of traditional passively mode-locked fiber laser can be avoided. The system transforms optical signals into electrical pulse signals and sends them into MCU after processing. MCU calculates the frequency of the signals and judges the state of the output based on a quick judgment algorithm. A high-speed comparator is used to check the signals and the comparison voltage can be adjusted to improve the measuring accuracy. Then by controlling two polarization controllers at an angle of 45degrees to each other, MCU extrudes the optical fibers to change the polarization until it gets proper mode-locked output. So the system can continuously monitor the output signal and get it back to mode-locked states quickly and automatically. States of the system can be displayed on the LCD and PC. The parameters of the steady mode-locked states can be stored into an EEPROM so that the system will get into mode-locked states immediately next time. Actual experiments showed that, for a 6.238MHz passively mode-locked fiber lasers, the system can get into steady mode-locked states automatically in less than 90s after starting the system. The expected lock time can be reduced to less than 20s after follow up improvements.

  14. Nanosecond pulses in a THz gyrotron oscillator operating in a mode-locked self-consistent Q-switch regime.

    PubMed

    Alberti, S; Braunmueller, F; Tran, T M; Genoud, J; Hogge, J-Ph; Tran, M Q; Ansermet, J-Ph

    2013-11-15

    An experimental study of a nanosecond pulsed regime in a THz gyrotron oscillator operating in a self-consistent Q-switch regime has been carried out. The gyrotron is operated in the TE(7,2) transverse mode radiating at a frequency of 260.5 GHz. The 5 W nanosecond pulses are obtained in a self-consistent Q-switch regime in which the cavity diffraction quality factor dynamically varies by nearly 2 orders of magnitude on a subnanosecond time scale via the nonlinear interaction of different mode-locked frequency-equidistant sidebands. The experimental results are in good agreement with numerical simulations performed with the TWANG code based on a slow time scale formulation of the self-consistent time-dependent nonlinear wave particle interaction equations. PMID:24289692

  15. Q-switched-like soliton bunches and noise-like pulses generation in a partially mode-locked fiber laser.

    PubMed

    Wang, Zhenhong; Wang, Zhi; Liu, Yan-Ge; Zhao, Wenjing; Zhang, Hao; Wang, Shangcheng; Yang, Guang; He, Ruijing

    2016-06-27

    We report an intermediate regime between c.w. emission and noise-like pulses (NLPs) regime in an Er-doped partially mode-locked fiber laser with nonlinear polarization rotation. In this regime, the soliton bunches stochastically turn up from a quasi-cw background in the Q-switched-like envelope. The soliton bunches normally last for tens or hundreds of intracavity round-trips. When the soliton bunches vanish, typical NLPs chains are generated sporadically at location where the soliton bunches collapses. These results would be helpful to understand the generation and property of the NLPs regime. PMID:27410624

  16. WS₂ as a saturable absorber for ultrafast photonic applications of mode-locked and Q-switched lasers.

    PubMed

    Wu, Kan; Zhang, Xiaoyan; Wang, Jun; Li, Xing; Chen, Jianping

    2015-05-01

    Two-dimensional (2D) nanomaterials, especially the transition metal sulfide semiconductors, have drawn great interests due to their potential applications in viable photonic and optoelectronic devices. In this work, 2D tungsten disulfide (WS2) based saturable absorber (SA) for ultrafast photonic applications was demonstrated. WS2 nanosheets were prepared using liquid-phase exfoliation method and embedded in polyvinyl alcohol (PVA) thin film for the practical usage. Saturable absorption was discovered in the WS2-PVA SA at the telecommunication wavelength near 1550 nm. By incorporating WS2-PVA SA into a fiber laser cavity, both stable mode locking operation and Q-switching operation were achieved. In the mode locking operation, the laser obtained femtosecond output pulse width and high spectral purity in the radio frequency spectrum. In the Q-switching operation, the laser had tunable repetition rate and output pulse energy of a few tens of nano joule. Our findings suggest that few-layer WS2 nanosheets embedded in PVA thin film are promising nonlinear optical materials for ultrafast photonic applications as a mode locker or Q-switcher. PMID:25969240

  17. Modulation frequency characteristics of the Q-switched envelope in a doubly Q-switched and mode-locked laser with acousto-optic modulator and Cr4+:YAG saturable absorber

    NASA Astrophysics Data System (ADS)

    Qiao, Junpeng; Zhao, Jia; Li, Yufei; Zhao, Shengzhi; Li, Guiqiu; Li, Dechun; Qiao, Wenchao; Chu, Hongwei

    2015-11-01

    The modulation frequency characteristics of the Q-switched envelope in a doubly Q-switched and mode-locked Nd:GGG laser with an acousto-optic modulator (AOM) and Cr4+:YAG saturable absorber are given. At a fixed incident pump power, the repetition rates of the Q-switched envelope and the related laser characteristics versus the modulation frequency of AOM for different small signal transmissions of Cr4+:YAG saturable absorbers have been measured. The experimental results show that the repetition rates of the Q-switched envelope, the average output power, the average peak power, and the pulse widths of the Q-switched envelopes are subharmonics of the modulation frequency at a fixed incident pump power. Furthermore, the mechanism for these behaviors is discussed.

  18. All fiber passively Q-switched laser

    DOEpatents

    Soh, Daniel B. S.; Bisson, Scott E

    2015-05-12

    Embodiments relate to an all fiber passively Q-switched laser. The laser includes a large core doped gain fiber having a first end. The large core doped gain fiber has a first core diameter. The laser includes a doped single mode fiber (saturable absorber) having a second core diameter that is smaller than the first core diameter. The laser includes a mode transformer positioned between a second end of the large core doped gain fiber and a first end of the single mode fiber. The mode transformer has a core diameter that transitions from the first core diameter to the second core diameter and filters out light modes not supported by the doped single mode fiber. The laser includes a laser cavity formed between a first reflector positioned adjacent the large core doped gain fiber and a second reflector positioned adjacent the doped single mode fiber.

  19. Cavity length dependence of mode beating in passively Q-switched Nd-solid state lasers

    NASA Astrophysics Data System (ADS)

    Zameroski, Nathan D.; Wanke, Michael; Bossert, David

    2013-03-01

    The temporal intensity profile of pulse(s) from passively Q-switched and passively Q-switched mode locked (QSML) solid-state lasers is known to be dependent on cavity length. In this work, the pulse width, modulation depth, and beat frequencies of a Nd:Cr:GSGG laser using a Cr+4:YAG passive Q-switch are investigated as function cavity length. Measured temporal widths are linearly correlated with cavity length but generally 3-5 ns larger than theoretical predictions. Some cavity lengths exhibit pulse profiles with no modulation while other lengths exhibit complete amplitude modulation. The observed beat frequencies at certain cavity lengths cannot be accounted for with passively QSML models in which the pulse train repetition rate is τRT-1, τRT= round-trip time. They can be explained, however, by including coupled cavity mode-locking effects. A theoretical model developed for a two section coupled cavity semiconductor laser is adapted to a solid-state laser to interpret measured beat frequencies. We also numerically evaluate the temporal criterion required to achieve temporally smooth Q-switched pulses, versus cavity length and pump rate. We show that in flash lamp pumped systems, the difference in buildup time between longitudinal modes is largely dependent on the pump rate. In applications where short pulse delay is important, the pumping rate may limit the ability to achieve temporally smooth pulses in passively Q-switched lasers. Simulations support trends in experimental data. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  20. BRIEF COMMUNICATIONS: Dye-jet laser pumped by the second harmonic of a Q-switched and mode-locked YAG:Nd3+ laser

    NASA Astrophysics Data System (ADS)

    Golubev, V. A.; Goncharov, A. N.; Maĭorov, A. P.; Makukha, V. K.; Smirnov, Vitalii A.; Tarasov, V. M.

    1981-05-01

    A report is given of the operating parameters of a dye jet laser pumped by the second harmonic of a cw Q-switched mode-locked YAG:Nd3+ laser. The dye laser emitted a continuous train of 250 nsec pulses at a repetition frequency of 25 kHz or a sequence of ultrashort pulse trains. A Lyot filter was used to tune the emission wavelength in the range 560-630 nm.

  1. Generation of Q-switched mode locking controlled rectangular noise-like soliton bunching in a Tm-doped fiber laser.

    PubMed

    Qiao, Tian; Chen, Weicheng; Lin, Wei; Yang, Zhongmin

    2016-08-01

    We report on an interesting phenomenon of the combination of Q-switched mode locked pulses (QSMLP) and rectangular noise-like pulses (RNLP) as a unit in a Tm-doped ring fiber laser which contains a Fabry-Perot (F-P) subcavity based on the nonlinear polarization evolution (NPE) technique. The RNLP and QSMLP are independently generated in the ring cavity and F-P subcavity, respectively. A notable characteristic is that the physical parameters of RNLP, e.g. repetition rate and pulse duration, are controlled by QSMLP. Thus, they form as a composite bunching, which is termed as "Q-switched mode locking controlled rectangular noise-like soliton bunching (QRNSB)". Further investigation shows that the existence of QRNSB only occurs in high pumping conditions, while both fundamental mode-locking pulses and the coexistence of QSMLP and solitons are achieved in low pumping ones. Our work can enrich the understanding of the nonlinear dynamics in fiber lasers. PMID:27505838

  2. Passive mode locking in erbium-ytterbium fiber lasers

    NASA Astrophysics Data System (ADS)

    Thai, Serey; Hayduk, Michael J.

    1999-11-01

    A novel mode-locked erbium-ytterbium fiber laser operating at 1550 nm using multiple quantum well (MQW) saturable absorbers was developed. The laser was constructed in a Fabry-Perot configuration using a fiber Bragg grating as a front reflector and a fiber Bragg grating output as a back reflector of the laser cavity. The passive mode-locking element placed inside the laser cavity is a 75 period InGaAs/InAlAs MQW saturable absorber grown lattice matched on an InP substrate. The output of the laser was taken through the other available port of a wavelength-division demultiplexer. The laser produced mode-locked output pulse trains at 16.67-MHz repetition rate and 10 mW of average output power.

  3. Self-organization of the Q-switched mode-locked regime in a diode-pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Donin, V. I.; Yakovin, D. V.; Gribanov, A. V.

    2015-06-01

    A new Q-switched mode-locked generation regime of a solid-state laser, in which a Q-switch is "spontaneously" formed at the frequency of relaxation oscillations, has been observed for the first time. The new generation has been implemented by means of the previously proposed method of an acoustic modulator of a traveling wave in combination with a spherical mirror of a cavity. Stable pulse trains with a repetition frequency of ~30 kHz and a duration of ~2 µs have been observed in the diode-pump Nd:YAG laser with an average output power of ~3 W. Each train contains about 200 equispaced single pulses with a duration of ~45 ps.

  4. Passively mode-locked Yb:LuVO4 oscillator

    NASA Astrophysics Data System (ADS)

    Rivier, Simon; Mateos, Xavier; Liu, Junhai; Petrov, Valentin; Griebner, Uwe; Zorn, Martin; Weyers, Markus; Zhang, Huaijin; Wang, Jiyang; Jiang, Minhua

    2006-11-01

    Passive mode locking of the ytterbium doped orthovanadate crystal Yb:LuVO4 is reported for the first time. We demonstrate what we believe to be the shortest pulses directly generated with an Yb-doped crystalline laser using a semiconductor saturable absorber. The pulses at 1036 nm have a duration as short as 58 fs for an average power of 85 mW.

  5. Synchronization of active/passive mode-locked erbium fiber lasers

    NASA Astrophysics Data System (ADS)

    Kaechele, Walter; Haus, Joseph W.; Hayduk, Michael J.; Erdmann, Reinhard K.; Teegarden, Kenneth J.

    1997-07-01

    Injection seeding of a passively mode-locked fiber laser by an actively mode-locked fiber laser source is described. The passively mode-locked laser employs a multiple quantum well saturable absorber to establish pulsed operation. Mode-locked synchronized operation was maintained with average injection powers as low as 1.3 mW. Stable synchronized pulses were observed with pulse widths as narrow as 10 ps.

  6. cw passive mode locking of a Ti:sapphire laser

    SciTech Connect

    Sarukura, N.; Ishida, Y.; Nakano, H.; Yamamoto, Y. )

    1990-02-26

    cw passive mode locking of a Ti:sapphire laser is achieved with 1,1{prime}-dietyl-2,2{prime}-dicarbocyanine iodide as the saturable absorber dye, using a 5 {mu}m thin dye jet flow. The pulse width is 4.0 ps, which is almost the transform-limited pulse for the observed spectrum width. The output power is {similar to}50 mW, when it is pumped by a 5 W cw Ar laser, while the tuning range is 745--755 nm.

  7. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers.

    PubMed

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-01-01

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers. PMID:27457338

  8. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers

    PubMed Central

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-01-01

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers. PMID:27457338

  9. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-07-01

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers.

  10. Statistical light-mode dynamics of multipulse passive mode locking.

    PubMed

    Weill, Rafi; Well, Rafi; Vodonos, Boris; Gordon, Ariel; Gat, Omri; Fischer, Baruch

    2007-09-01

    We study the multipulse formation in passive mode locking in the framework of the statistical light-mode dynamics theory. It is a many-body theory that treats the complex many-mode laser system by statistical mechanics. We give a detailed theory and experimental verification for the important case of multiple-pulse formation in the laser cavity. We follow and extend our former work on the subject. We give a detailed analysis with a rigorous calculation of the partition function, the free energy, and the order parameter in the coarse-graining method within the mean-field theory that is exact in the light-mode system. The outcome is a comprehensive picture of multipulse formation and annihilation, pulse after pulse, in an almost quantized manner, as the noise ("temperature") or the light power is varied. We obtain the phase diagram of the system, showing a series of first-order phase transitions, each belonging to a different number of pulses. We also study the hysteresis behavior, typical for such thermodynamic systems. We elaborate on the role of the saturable absorber structure in determining the multipulse formation. The theoretical results are compared to experimental measurements that we obtained with mode-locked fiber lasers, and we find an excellent agreement. PMID:17930204

  11. A stable 2 μm passively Q-switched fiber laser based on nonlinear polarization evolution

    NASA Astrophysics Data System (ADS)

    He, X.; Luo, A.; Lin, W.; Yang, Q.; Yang, T.; Yuan, X.; Xu, S.; Xu, W.; Luo, Z.; Yang, Z.

    2014-08-01

    A passively Q-switched thulium-doped fiber (TDF) laser based on the nonlinear polarization evolution technique was demonstrated with the central wavelength of 1898.4 nm. With the increasing pump power, the pulse repetition frequency of the Q-switched TDF laser from 87.6 to 110.1 kHz was achieved, while the corresponding pulse duration was changed from 1171 to 785.7 ns. The power instability of the TDF laser was measured to be about ±1.5% during 8 h. In addition, the mode-locked phenomenon was also observed in our all-fiber TDF laser by carefully adjusting the polarization controllers.

  12. Passively mode-locked single-polarization microstructure fiber laser.

    PubMed

    Ortaç, B; Lecaplain, C; Hideur, A; Schreiber, T; Limpert, J; Tünnermann, A

    2008-02-01

    The generation of high-power and stable ultra-short pulses from a passively mode-locked purely normal dispersion fiber laser is reported using the unique combination of a photonic crystal fiber featuring single-polarization, single-mode, and low nonlinearity with a high modulation depth semiconductor saturable absorber mirror. The environmentally-stable, self-starting fiber laser generates 1.6 W of average power at a repetition rate of 63 MHz, corresponding to a pulse energy of 25 nJ. The emitted pulses are positively chirped with a pulse duration of 3.7 ps. They are compressible down to a near transform-limited duration of 750 fs. Numerical simulations are in good agreement with the experimental results. PMID:18542292

  13. Monolithic passively Q-switched Cr:Nd:GSGG microlaser

    NASA Astrophysics Data System (ADS)

    Schmitt, Randal L.

    2005-09-01

    Optical firing sets need miniature, robust, reliable pulsed laser sources for a variety of triggering functions. In many cases, these lasers must withstand high transient radiation environments. In this paper we describe a monolithic passively Q-switched microlaser constructed using Cr:Nd:GSGG as the gain material and Cr4+:YAG as the saturable absorber, both of which are radiation hard crystals. This laser consists of a 1-mm-long piece of undoped YAG, a 7-mm-long piece of Cr:Nd:GSGG, and a 1.5-mm-long piece of Cr4+:YAG diffusion bonded together. The ends of the assembly are polished flat and parallel and dielectric mirrors are coated directly on the ends to form a compact, rugged, monolithic laser. When end pumped with a diode laser emitting at ~807.6 nm, this passively Q-switched laser produces ~1.5-ns-wide pulses. While the unpumped flat-flat cavity is geometrically unstable, thermal lensing and gain guiding produce a stable cavity with a TEM00 gaussian output beam over a wide range of operating parameters. The output energy of the laser is scalable and dependent on the cross sectional area of the pump beam. This laser has produced Q-switched output energies from several μJ per pulse to several 100 μJ per pulse with excellent beam quality. Its short pulse length and good beam quality result in high peak power density required for many applications such as optically triggering sprytrons. In this paper we discuss the design, construction, and characterization of this monolithic laser as well as energy scaling of the laser up to several 100 μJ per pulse.

  14. Optical parametric oscillator of mid-IR, visible and UV ranges with synchronous pumping by a Q-switched mode-locked Nd : YAG laser

    NASA Astrophysics Data System (ADS)

    Donin, V. I.; Yakovin, M. D.; Yakovin, D. V.

    2016-07-01

    The parametric generation in a nonlinear PPLN crystal synchronously pumped by a Q-switched mode-locked Nd : YAG laser with a pulse duration of 45 ps is studied. The output pump intensity in the nonlinear crystal reaches ~10 GW cm-2. At a pulse repetition rate of 1 kHz, the average output power at the idler wavelength (~3.6 μm) is ~12 mW, the peak power is ~25 kW, and the conversion efficiency (with respect to the absorbed power) is ~10%. The radiation linewidth at the signal wavelength (~1.5 μm) is 13 cm-1. Along with the signal and idler waves, the output emission spectrum contains lines at wavelengths of 822, 754, 624, 532, 463, 442, 392 and 355 nm. The tunable radiation with wavelengths in the vicinity of 392, 463 and 822 nm is observed for the first time. The tuning ranges for the new lines are measured (5 – 10 nm) and their origin is explained.

  15. Passively Q-switched side pumped monolithic ring laser

    NASA Technical Reports Server (NTRS)

    Li, Steven X. (Inventor)

    2012-01-01

    Disclosed herein are systems and methods for generating a side-pumped passively Q-switched non-planar ring oscillator. The method introduces a laser into a cavity of a crystal, the cavity having a round-trip path formed by a reflection at a dielectrically coated front surface, a first internal reflection at a first side surface of the crystal at a non-orthogonal angle with the front, a second internal reflection at a top surface of the crystal, and a third internal reflection at a second side surface of the crystal at a non-orthogonal angle with the front. The method side pumps the laser at the top or bottom surface with a side pump diode array beam and generates an output laser emanating at a location on the front surface. The design can include additional internal reflections to increase interaction with the side pump. Waste heat may be removed by mounting the crystal to a heatsink.

  16. Semiconductor saturable absorber mirror passively Q-switched 2.97 μm fluoride fiber laser

    NASA Astrophysics Data System (ADS)

    Li, J. F.; Luo, H. Y.; He, Y. L.; Liu, Y.; Zhang, L.; Zhou, K. M.; Rozhin, A. G.; Turistyn, S. K.

    2014-06-01

    A diode-cladding-pumped mid-infrared passively Q-switched Ho3+-doped fluoride fiber laser using a reverse designed broad band semiconductor saturable mirror (SESAM) was demonstrated. Nonlinear reflectivity of the SESAM was measured using an in-house Yb3+-doped mode-locked fiber laser at 1062 nm. Stable pulse train was produced at a slope efficient of 12.1% with respect to the launched pump power. Maximum pulse energy of 6.65 µJ with a pulse width of 1.68 µs and signal-to-noise ratio (SNR) of ~50 dB was achieved at a repetition rate of 47.6 kHz and center wavelength of 2.971 µm. To the best of our knowledge, this is the first 3 µm region SESAM-based Q-switched fiber laser with the highest average power and pulse energy, as well as the longest wavelength from mid-infrared passively Q-switched fluoride fiber lasers.

  17. Semiconductor saturable absorber mirror passively Q-switched 2.97 μm fluoride fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Luo, Hongyu; He, Yulian; Liu, Yong; Luo, Binbin; Sun, Zhongyuan; Zhang, Lin; Turitsyn, Sergei K.

    2014-05-01

    A diode-cladding-pumped mid-infrared passively Q-switched Ho3+-doped fluoride fiber laser using a reverse designed broad band semiconductor saturable mirror (SESAM) was demonstrated. Nonlinear reflectivity of the SESAM was measured using an in-house Yb3+-doped mode-locked fiber laser at 1062 nm. Stable pulse train was produced at a slope efficient of 12.1% with respect to the launched pump power. Maximum pulse energy of 6.65 μJ with a pulse width of 1.68 μs and signal to noise ratio (SNR) of ~50 dB was achieved at a repetition rate of 47.6 kHz and center wavelength of 2.971 μm. To the best of our knowledge, this is the first 3 μm region SESAM based Q-switched fiber laser with the highest average power and pulse energy, as well as the longest wavelength from mid-infrared passively Q-switched fluoride fiber lasers.

  18. Passively Q-switched high-energy all-solid-state holographic Nd:YAG laser with a multiloop cavity

    NASA Astrophysics Data System (ADS)

    Lebedev, V. F.; Pogoda, A. P.; Boreysho, A. S.; Smetanin, S. N.; Fedin, A. V.

    2015-02-01

    A high-energy, high-beam-quality laser based on a single Nd:YAG rod with laser diode side-pumping and multiloop self-adaptive reciprocal cavity is presented. The optimized laser cavity geometry allowed to change the laser oscillation from single 200-ns self-Q-switched pulse followed by low-intensity free-running lasing to repetitive high-intensive pulses by periodically writing and erasing holographic gain gratings in the active Nd:YAG medium. The intensified self-Q-switching pulse train oscillation was realized by the interaction with a diffusely reflecting target placed in the focal plane of a lens at the laser output. Effects of shortening of the repetitive laser pulses down to 70-ns duration, stabilization of the pulse repetition period (~ 5 μs), and mode-locking temporal modulation of the pulses were observed. The use of a passive F2-:LiF Q-switch resulted in stable giant pulse train oscillation with total output energy of up to 0.43 J, individual pulse energy of 50 mJ, and its peak power of 4 MW at the individual pulse duration of 12 ns.

  19. Regimes of operation states in passively mode-locked fiber soliton ring laser

    NASA Astrophysics Data System (ADS)

    Gong, Y. D.; Shum, P.; Tang, D. Y.; Lu, C.; Guo, X.; Paulose, V.; Man, W. S.; Tam, H. Y.

    2004-06-01

    The principal of passively mode-locked fiber soliton ring lasers is summarized, including its three output operation states: normal soliton, bound-solitons and noise-like pulse. The experimental results of the passively mode-locked fiber soliton ring lasers developed by us are given. Bound-solitons with different discrete separations and three-bound-solitons state have been observed in our fiber laser for the first time. The relationship among three operation states in fiber soliton laser is analyzed.

  20. Numerical simulation of passively mode-locked fiber laser based on semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Yang, Jingwen; Jia, Dongfang; Zhang, Zhongyuan; Chen, Jiong; Liu, Tonghui; Wang, Zhaoying; Yang, Tianxin

    2013-03-01

    Passively mode-locked fiber laser (MLFL) has been widely used in many applications, such as optical communication system, industrial production, information processing, laser weapons and medical equipment. And many efforts have been done for obtaining lasers with small size, simple structure and shorter pulses. In recent years, nonlinear polarization rotation (NPR) in semiconductor optical amplifier (SOA) has been studied and applied as a mode-locking mechanism. This kind of passively MLFL has faster operating speed and makes it easier to realize all-optical integration. In this paper, we had a thorough analysis of NPR effect in SOA. And we explained the principle of mode-locking by SOA and set up a numerical model for this mode-locking process. Besides we conducted a Matlab simulation of the mode-locking mechanism. We also analyzed results under different working conditions and several features of this mode-locking process are presented. Our simulation shows that: Firstly, initial pulse with the peak power exceeding certain threshold may be amplified and compressed, and stable mode-locking may be established. After about 25 round-trips, stable mode-locked pulse can be obtained which has peak power of 850mW and pulse-width of 780fs.Secondly, when the initial pulse-width is greater, narrowing process of pulse is sharper and it needs more round-trips to be stable. Lastly, the bias currents of SOA affect obviously the shape of mode-locked pulse and the mode-locked pulse with high peak power and narrow width can be obtained through adjusting reasonably the bias currents of SOA.

  1. A passively mode locked thulium doped fiber laser using bismuth telluride deposited multimode interference

    NASA Astrophysics Data System (ADS)

    Jung, M.; Lee, J.; Song, W.; Lee, J. H.; Shin, W.

    2016-03-01

    We experimentally demonstrate a passively mode-locked thulium doped fiber laser using a bismuth telluride deposited multimode interference (MMI) fiber at a wavelength of 1958 nm. Our MMI based saturable absorber was fabricated by fusion splicing with single mode fiber and null core fiber. The center wavelength and insertion loss of MMI fiber were measured to be ~ 1958 nm and 3.4 dB. We observed a passively mode locked thulium doped fiber laser operating at a wavelength of 1958 nm. The temporal pulse width of output pulses is 4.2 ps with repetition rate of 22.7 MHz.

  2. 1357 nm passively Q-switched crystalline ceramic laser based on multilayer graphene

    NASA Astrophysics Data System (ADS)

    Feng, Chao; Zhang, Huanian; Wang, Qingpu; Xu, Shicai; Fang, Jiaxiong

    2016-05-01

    1357 nm single wavelength passively Q-switched Nd:YAG ceramic lasers are demonstrated with a multilayer graphene sheets saturable absorber (SA). During an increase in the incident pump power, the laser exhibited stable Q-switched oscillation, which showed that our graphene SA provided Q-switched modulation successfully. The maximum average output power was 340 mW, and the corresponding pulse width, pulse repetition rate, single pulse energy and peak power were 380 ns, 209 kHz, 53 μJ and 139 W, respectively. Our results illustrate that graphene can be used as an SA for 1357 nm passively Q-switched Nd:YAG ceramic lasers.

  3. Adjustable high-repetition-rate pulse trains in a passively-mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Si Fodil, Rachid; Amrani, Foued; Yang, Changxi; Kellou, Abdelhamid; Grelu, Ph.

    2016-07-01

    We experimentally investigate multipulse regimes obtained within a passively-mode-locked fiber laser that includes a Mach-Zehnder (MZ) interferometer. By adjusting the time delay imbalance of the MZ, ultrashort pulse trains at multi-GHz repetition rates are generated. We compare the observed dynamics with high-harmonic mode locking, and show that the multi-GHz pulse trains display an inherent instability, which has been overlooked. By using a recirculation loop containing the MZ, we demonstrate a significant improvement of the pulse train stability.

  4. A diode pumped passively mode-locked Nd:CaGdAlO4 laser

    NASA Astrophysics Data System (ADS)

    Rao, H.; Cong, Z. H.; Qin, Z. G.; Feng, C.; Wang, Q. P.; Liu, Z. J.; Zhang, X. Y.; Zhang, S. S.; Liu, Y.; Men, S. J.; Xia, J. B.; Di, J. Q.; Xu, X. D.; Xu, J.

    2016-04-01

    A diode pumped passively mode-locked Nd:CaGdAlO4 (Nd:CGA) laser was demonstrated. By using a semiconductor saturable-absorber mirror (SESAM) as the modulator, stable mode-locked pulses with a duration of 6.0 ps and a repetition rate of 88.3 MHz have been achieved at a central wavelength of 1078.6 nm. The maximum output power of 452 mW was obtained under a pump power of 10 W.

  5. Passive mode locking of thin-disk lasers: effects of spatial hole burning

    NASA Astrophysics Data System (ADS)

    Paschotta, R.; Aus der Au, J.; Spühler, G. J.; Erhard, S.; Giesen, A.; Keller, U.

    We recently demonstrated that passive mode locking of a thin-disk Yb:YAG laser is possible and that this concept leads to sources of femtosecond pulses with very high average power. Here we discuss in detail the effect of spatial hole burning on the mode-locking behavior of such lasers. We have developed an efficient numerical model and arrive at quantitative stability criteria which agree well with experimental data. The main result is that stable soliton mode locking can in general be obtained only in a certain range of pulse durations. We use our model to investigate the influence of various cavity parameters and the situation for different gain media. We also consider several methods to reduce the effect of spatial hole burning in order to expand the range of possible pulse durations.

  6. Passively mode-locked Yb3+:Sc2SiO5 thin-disk laser.

    PubMed

    Wentsch, Katrin Sarah; Zheng, Lihe; Xu, Jun; Ahmed, Marwan Abdou; Graf, Thomas

    2012-11-15

    Experimental investigations on a passively mode-locked Yb(3+):Sc(2)SiO(5) (Yb:SSO) thin-disk laser are presented. The mode-locking was performed with a commercially available semiconductor saturable absorber mirror. The laser was operated at a repetition rate of 27 MHz and generated a maximum average output power of 27.8 W with a pulse duration of 298 fs. The spectrum was centered at 1036 nm. The beam was measured to be close to diffraction limited (M(2)<1.1). The promising results confirm the suitability of Yb:SSO for mode-locked thin-disk laser oscillators and indicate that this comparably new material deserves further attention by optimizing the crystal quality (growth and polishing) and doping levels for further power scaling. PMID:23164901

  7. Passively mode-locked picosecond erbium-doped fiber lasers using multiple quantum well saturable absorbers

    NASA Astrophysics Data System (ADS)

    Hayduk, Michael J.; Krol, Mark F.; Pollock, Clifford R.; Teegarden, Kenneth J.; Wicks, Gary W.; Kaechele, Walter

    1998-07-01

    An experimental study of the mode-locking process in erbium- doped fiber lasers (EDFLs) operating at 1.55 micrometer using multiple quantum well saturable absorbers is described. The self-starting passively mode-locked laser was constructed in a Fabry-Perot configuration using the saturable absorber as the back reflector of the cavity. Picosecond pulses that ranged from 3.1 to 38.8 ps were generated using a series of saturable absorbers. The pulse widths were dependent upon the optical properties of the saturable absorber used as the mode- locking element as well as the dispersive elements contained within the cavity. The output power of the EDFL varied from 0.2 to 6.7 mW and was also dependent upon the saturable absorber used in the cavity.

  8. Environmentally stable, simple passively mode-locked fiber ring laser using a four-port circulator.

    PubMed

    Masuda, Shin; Niki, Shoji; Nakazawa, Masataka

    2009-04-13

    We present here a self-starting passively mode-locked fiber ring laser with a novel cavity configuration using a four-port optical circulator. Our special ring cavity design enables highly stable mode-locked operation between 25 and 60 degrees C to be maintained without the need for any polarization-adjusting devices. The pulse width and the integrated timing jitter from 10 Hz to 10 MHz of our fiber ring laser were measured to be 120 fs and 39.1 fs, respectively. As a result, a robust and environmentally stable all-fiber mode-locked fiber ring laser with a simple ring cavity configuration in a small package has been achieved. PMID:19365487

  9. Bidirectional passively mode-locked soliton fiber laser with a four-port circulator.

    PubMed

    Ouyang, Chunmei; Shum, Ping; Wu, Kan; Wong, Jia Haur; Lam, Huy Quoc; Aditya, Sheel

    2011-06-01

    We present an all-fiber bidirectional passively mode-locked soliton laser with what we believe is a novel cavity configuration. Using a four-port circulator, we incorporate two different semiconductor saturable absorber mirrors (SESAMs) into the laser cavity, which enables bidirectional mode locking. The laser allows the generation of two independent countercirculating mode-locked pulse trains, each with an individual fundamental repetition rate that can be adjusted by varying the SESAM pigtail length. Two countercirculating pulse trains with repetition rates of 21.3 and 15.2 MHz are obtained simultaneously. By controlling the intracavity loss imposed on these two pulse trains, either one of the two pulse trains can be switched on or off. The bidirectional operation with other repetition rates is also demonstrated. PMID:21633458

  10. Repetition rate switching in a passively mode-locked fibre laser

    NASA Astrophysics Data System (ADS)

    Tian, X. L.; Tang, M.; Gong, Y. D.; Shum, P.

    2006-09-01

    Here we demonstrated a dispersion stretched passively mode-locked fiber laser. The laser was mode-locked by nonlinear polarization rotation (NPR) technical. Both dispersion managed soliton and noise-like pulses were observed in the experiment. Harmonic mode-locked noise-like pulses were observed. By changing the pump power or rotating the waveplates, noise-like pulse could split and always form equally spaced pulse train, thus the repetition rate of the output pulse could be switched among different orders of harmonic frequency. The experiment results were analyzed. We found that peak power clamping caused by NPR module led to pulse splitting, the pulse interaction through the Raman light drives the pulse to space equally.

  11. Three-dimensional graphene based passively mode-locked fiber laser.

    PubMed

    Yang, Y; Loeblein, M; Tsang, S H; Chow, K K; Teo, E H T

    2014-12-15

    We present an all-fiber passively mode-locked fiber laser incorporating three-dimensional (3D) graphene as a saturable absorber (SA) for the first time to the best of our knowledge. The 3D graphene is synthesized by template-directed chemical vapor deposition (CVD). The SA is then simply formed by sandwiching the freestanding 3D graphene between two conventional fiber connectors without any deposition process. It is demonstrated that such 3D graphene based SA is capable to produce high quality mode-locked pulses. A passively mode-locked fiber laser is constructed and stable output pulses with a fundamental repetition rate of ~9.9 MHz and a pulse width of ~1 ps are generated from the fiber laser. The average output power of the laser is ~10.5 mW while the output pulse is operating at single pulse region. The results imply that the freestanding 3D graphene can be applied as an effective saturable absorption material for passively mode-locked lasers. PMID:25607096

  12. Passive Q-Switching Laser Performance of Yb:YVO4 Crystal

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Hong; Chen, Xiao-Wen; Han, Wen-Juan; Kong, Wei-Jin; Liu, Jun-Hai

    2014-12-01

    We report on the passive Q-switching laser performance of Yb:YVO4 crystal. Utilizing a Cr4+:YAG crystal plate as the saturable absorber, which is of an initial transmission as high as 99.3%, we demonstrate a stable passively Q-switched laser operation at 1017.2 nm, producing an average output power of 0.87 W at a pulse repetition rate of 71.4 kHz, with a slope efficiency of 30%. The resulting pulse energy, duration, and peak power are 12.2 μJ, 87 ns, and 0.14 kW, respectively.

  13. Diode pumped CW and passively Q-switched Nd:LGGG laser at 1062 nm

    NASA Astrophysics Data System (ADS)

    Yang, H.; Jia, Z. T.; Zhang, B. T.; He, J. L.; Liu, S. D.; Yang, Y.; Tao, X. T.

    2012-05-01

    We report a Nd:LGGG laser at 1062 nm in the operations of the continuous-wave (CW) and passively Q-switching. The maximum CW output power of 5.62 W was obtained, corresponding to an optical-to-optical conversion efficiency of 49.0% and slope efficiency of 55.9%. By using Cr4+:YAG with initial transmission of 94% as the saturable absorber, for the first time, we got the maximum passively Q-switched output power of 1.21 W, accompanied with a highest pulse repetition rate of 27.1 kHz and a shortest pulse width of 9.1 ns.

  14. Passive Q-switching of Yb bulk lasers by a graphene saturable absorber

    NASA Astrophysics Data System (ADS)

    Loiko, P. A.; Serres, J. M.; Mateos, X.; Liu, J.; Zhang, H.; Yasukevich, A. S.; Yumashev, K. V.; Petrov, V.; Griebner, U.; Aguiló, M.; Díaz, F.

    2016-04-01

    Compact Yb:KLu(WO4)2 and Yb:LuVO4 lasers diode-pumped at 978 nm are passively Q-switched by a single-layer graphene saturable absorber. The Yb:KLu(WO4)2 laser generated 165 ns/0.49 μJ pulses at 1030 nm with 170 mW average output power and 12 % slope efficiency. With the Yb:LuVO4 laser, 152 ns/0.83 μJ pulses were achieved. The output power reached 300 mW at 1024 nm, and the slope efficiency was 10 %. Laser operation in a plano-plano cavity is achieved with both crystals with thermal lensing playing a key role in their performance. A model describing graphene Q-switched Yb lasers is developed. Our results indicate the potential of graphene for passive Q-switching of ~1 μm bulk lasers.

  15. Can silicon carbide serve as a saturable absorber for passive mode-locked fiber lasers?

    PubMed

    Cheng, Chih-Hsien; Lin, Yung-Hsiang; Chen, Ting-Hui; Chen, Hsiang-Yu; Chi, Yu-Chieh; Leeb, Chao-Kuei; Wua, Chih-I; Lin, Gong-Ru

    2015-01-01

    The study presents a novel demonstration of a passively mode-locked erbium-doped fiber laser (EDFL) that is based on a silicon carbide (SixC1-x) saturable absorber. When the C/Si composition ratio is increased to 1.83, the SixC1-x film transforms from two-photon absorption to nonlinear saturable absorption, and the corresponding value reaches -3.9 × 10(-6) cm/W. The Si-rich SixC1-x film cannot mode lock the EDFL because it induced high intracavity loss through two-photon absorption. Even when a stoichiometric SiC is used, the EDFL is mode locked, similar to an EDFL operating under weak nonlinear-polarization-rotation condition. A C-rich SixC1-x film containing sp(2)-orbital C-C bonds with a linear absorbance of 0.172 and nonlinear absorbance of 0.04 at a 181 MW/cm(2) saturation intensity demonstrates nonlinear transmittance. The C-rich SixC1-x saturable absorber successfully generates a short mode-locked EDFL pulse of 470 fs. The fluctuation of the pulse-train envelope dropps considerably from 11.6% to 0.8% when a strong saturable-absorption-induced self-amplitude modulation process occurs in the C-rich SixC1-x film. PMID:26558531

  16. Numerical simulation and optimization of passively q-switched erbium microchip lasers

    NASA Astrophysics Data System (ADS)

    Belghachem, Nabil; Mlynczak, Jarslow

    2015-08-01

    In this article we present a procedure of optimization of passively q-switched erbium microchip lasers. The procedure is based on the rate equation model, validated by comparing the numerical results to the experimental results of pulse generation in different types of erbium/ytterbium glass microchips q-switched by Co2+ : MgAl2O4 saturable absorber. Some Degnan’s optimization limitations in case of microchip lasers were also shown and the reabsorbtion cross section of erbium glass was also estimated.

  17. Tunable passively harmonic mode-locked Yb-doped fiber laser with Lyot-Sagnac filter.

    PubMed

    Li, Ming; Zou, Xin; Wu, Jian; Shi, Jindan; Qiu, Jifang; Hong, Xiaobin

    2015-10-10

    A novel passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all normal dispersion is proposed and experimentally demonstrated based on a semiconductor saturable absorption mirror and tunable Lyot-Sagnac filter. By only tuning the bandwidth of the filter at fixed pump power, the repetition rate of 9.87 to 167.8 MHz (corresponding to 17th-order harmonic) is obtained. This is the highest repetition rate and harmonic order for a passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all-normal dispersion to the best of our knowledge. The signal-to-noise ratio and super-mode suppression ratio for all harmonic orders are higher than 65 and 35 dB, respectively, which shows the high stability of the fiber laser. PMID:26479821

  18. Passively mode-locked 1 GHz MOPA system generating sub-500-fs pulses after external compression

    NASA Astrophysics Data System (ADS)

    Ulm, Thorsten; Harth, Florian; Klehr, Andreas; Erbert, Götz; L'huillier, Johannes

    2012-06-01

    We compared the performance of DQW and TQW edge-emitters in a passively mode-locked 1GHz MOPA system at 1075 nm wavelength. Passive mode-locking is induced by applying a reverse DC voltage to the absorber section. The average power is increased up to 0.9Wby a single-stripe pre-amplifier and a tapered amplifier. After compensation of the quadratic chirp in a grating compressor we achieved a pulse duration of 342 fs. We found that the oscillator gain current and the absorber bias voltage have significant impact on the pulse duration. Both parameters were used to optimize the MOPA system with respect to the shortest pulse length after compression.

  19. High brightness photonic band crystal semiconductor lasers in the passive mode locking regime

    SciTech Connect

    Rosales, R.; Kalosha, V. P.; Miah, M. J.; Bimberg, D.; Posilović, K.; Pohl, J.; Weyers, M.

    2014-10-20

    High brightness photonic band crystal lasers in the passive mode locking regime are presented. Optical pulses with peak power of 3 W and peak brightness of about 180 MW cm{sup −2} sr{sup −1} are obtained on a 5 GHz device exhibiting 15 ps pulses and a very low beam divergence in both the vertical and horizontal directions.

  20. Performance of passive Q-switched solar-pumped high-power Nd:YAG lasers

    NASA Astrophysics Data System (ADS)

    Noter, Yoram; Naftali, Nir; Pe'er, Idit L.; Yogev, Amnon; Lando, Mordechai; Shimony, Yehoshua

    1997-09-01

    Q-switched, solar-pumped, high power Nd:YAG lasers are attractive for a variety of applications requiring high instantaneous peak power density. The Q-switching can be obtained by an acousto-optic, electro-optic or passive device. Passive Q-switching seems an excellent choice for space as well as for other applications since it neither requires an external driver nor an electrical power supply. In recent years Cr+4:YAG single crystals were extensively used as passive Q-switches for flashlamp-pumped high power Nd:YAG lasers, demonstrating their superior thermal superior thermal characteristics and durability. In this work we report the first operation of passive Q- switched, solar-pumped, high power Nd:YAG lasers. The concentrated solar energy for he optical pumping of the laser was obtained by a 3-stage combination of imaging and non-imaging optics. It included: i) Weizmann Institute solar tower heliostats, ii) 3D compound parabolic concentrator, and iii) 2D compound parabolic concentrator in which the laser rod was placed. 72 mm long laser rods with either 3 mm or 4 mm diameter were used. The passive Q-switch was made from a Cr$=+4):YAG single crystal having a low- intensity transmission of 72 percent at 1.06 (mu) . Its rear surface was coated by a high reflectivity coating, serving as the rear mirror of the cavity. Output coupling mirrors with various reflectivities were used. The passive Q-switch demonstrated excellent durability and reliability during all the experiments. Repetition rates of 6-39 kHz were measured, showing higher repetition rates at higher laser power levels. The pulses demonstrated shorter full width at half maximum (FWHM) time for higher laser power elves, and the FWHM time range was 190-310 nsec. The maximal measured average power was 14 W. Thermal lensing was measured as a function of the absorbed solar power in the laser rod. It is estimated that laser peak power densities of approximately 100 kW/cm2 were achieved in the experiments. It is

  1. Passively mode-locked erbium-doped fiber lasers using multiple quantum well saturable absorbers

    NASA Astrophysics Data System (ADS)

    Hayduk, Michael Joseph

    1997-09-01

    An experimental study of the mode-locking process in erbium-doped fiber lasers (EDFL's) operating at 1.55 μm using multiple quantum well saturable absorbers is presented. The self-starting passively mode-locked laser was constructed in a Fabry-Perot configuration using the saturable absorber as the back reflector of the cavity. Picosecond pulses that ranged from 14.2 to 38.8 ps were generated using a series of saturable absorbers. The pulse widths were dependent upon the optical properties of the saturable absorber used as the mode-locking element. The output power of the EDFL varied from 0.2 to 6.7 mW and was also dependent upon the saturable absorber used in the cavity. Soliton mode-locking using saturable absorbers was the mechanism responsible for the generation of the picosecond pulses by the EDFL. The long-lived carrier lifetime in the quantum wells was the primary optical property of the saturable absorber that determined the final pulse width. The carrier lifetimes of the eight individual saturable absorbers were investigated using time-resolved pump/probe experimental techniques. The lifetimes ranged from 40 to 1757 ps. The soliton mode- locking process allowed pulse widths of up to 45 times shorter than these carrier lifetimes to be produced. A self-starting passively mode-locked solid-state Cr4+:YAG laser was also developed using a novel saturable absorber mirror structure. The laser produced femtosecond pulses that were tunable from 1.488 to 1.535 μm. The average output power of the laser ranged from 40 to 80 mW at a repetition rate of 95 MHz. A minimum pulse width of 120 fs was generated at 1.488 μm. The high peak power of these pulses combined with its tunability in the 1.5 μm region made this laser an ideal spectroscopic source for use in the time-resolved pump/probe experiments.

  2. Timing characterization of 100 GHz passively mode-locked discrete mode laser diodes.

    PubMed

    Bitauld, David; Osborne, Simon; O'Brien, Stephen

    2011-07-18

    We report on the characterization of the timing stability of passively mode-locked discrete mode diode laser sources. These are edge-emitting devices with a spatially varying refractive index profile for spectral filtering. Two devices with a mode-locking frequency of 100 GHz are characterized. The first device is designed to support a comb of six modes and generates near Fourier limited 1.9 ps pulses. The second supports four primary modes resulting in a sinusoidal modulation of the optical intensity. Using a cross-correlation technique, we measured a 20 fs pulse to pulse timing jitter for the first device, while, for the second device, a mode-beating (RF) linewidth of 1 MHz was measured using heterodyne mixing in a semiconductor optical amplifier. Comparison of these results with those obtained for an equivalent Fabry-Perot laser indicates that the spectral filtering mechanism employed does not adversely affect the timing properties of these passively mode-locked devices. PMID:21934760

  3. High-power diode-pumped passively mode-locked Yb:YAG lasers.

    PubMed

    Aus der Au, J; Schaer, S F; Paschotta, R; Hönninger, C; Keller, U; Moser, M

    1999-09-15

    We obtained 74-kW peak power and 3.5-W average output power in 1-ps pulses from a diode-pumped Yb:YAG laser at 1030 nm that was passively mode locked with a semiconductor saturable-absorber mirror. Another laser produced 57-kW peak power and as much as 8.1-W average output power in 2.2-ps pulses, split into two nearly diffraction-limited beams (M(2)<1.2) . To our knowledge, these are by far the highest reported peak and average output powers from a diode-pumped mode-locked laser in this pulse-duration regime. PMID:18079780

  4. Frequency doubling of a passively mode-locked monolithic distributed Bragg reflector diode laser.

    PubMed

    Jedrzejczyk, D; Prziwarka, T; Klehr, A; Brox, O; Wenzel, H; Paschke, K; Erbert, G

    2014-05-20

    In this work, frequency doubling of a passively mode-locked 3.5 mm long monolithic distributed Bragg reflector diode laser is investigated experimentally. At 1064 nm, optical pulses with a duration of 12.4 ps are generated at a repetition rate of 13 GHz and a peak power of 825 mW, resulting in an average power of 133 mW. Second-harmonic generation is carried out in a periodically poled MgO-doped LiNbO₃ ridge waveguide at a normalized nonlinear conversion efficiency of 930%/W. A maximum average second-harmonic power of 40.9 mW, corresponding to a pulse energy of 3.15 pJ, is reached in the experiment at an opto-optical conversion efficiency of 30.8%. The normalized nonlinear conversion efficiency in mode-locked operation is more than 2 times larger compared to continuous-wave operation. PMID:24922212

  5. Gas laser mode-locking using an external acoustooptic modulator with a potential application to passive ring gyroscopes

    SciTech Connect

    Dunn, R.W.; Hendow, S.T.; Small, J.G.; Stijns, E.

    1982-11-15

    In this Letter, we show that the fundamental pulsation frequency of the mode-locked laser can be multiplied by an integer number by simply changing the length of a secondary cavity formed by the AOM and an external mirror. Furthermore, we show that a mode-locked laser may be used to enhance the SNR in passive ring gyroscopes by matching multiple modes of the laser to those of the passive cavity.

  6. Optimization of passively mode-locked quasi-continuously diode-pumped Nd:GdVO4 laser in bounce geometry

    NASA Astrophysics Data System (ADS)

    Frank, Milan; Jelínek, Michal; Kubeček, Václav

    2015-01-01

    In this paper the operation of pulsed diode-pumped Nd:GdVO4 laser oscillator in bounce geometry passively modelocked using semiconductor saturable absorber mirror (SAM), generating microjoule level picosecond pulses at wavelength of 1063 nm, is reported. Optimization of the output coupling for generation either Q-switched mode locked pulse trains or cavity dumped single pulses with maximum energy was performed, which resulted in extraction of single pulses as short as 10 ps and energy of 20 uJ. In comparison with the previous results obtained with this Nd:GdVO4 oscillator and saturable absorber in transmission mode, the achieved pulse duration is five times shorter. Using different absorbers and parameters of single pulse extraction enables generation of the pulses with duration up to 100 ps with the energy in the range from 10 to 20 μJ.

  7. Can silicon carbide serve as a saturable absorber for passive mode-locked fiber lasers?

    PubMed Central

    Cheng, Chih-Hsien; Lin, Yung-Hsiang; Chen, Ting-Hui; Chen, Hsiang-Yu; Chi, Yu-Chieh; Leeb, Chao-Kuei; Wua, Chih-I; Lin, Gong-Ru

    2015-01-01

    The study presents a novel demonstration of a passively mode-locked erbium-doped fiber laser (EDFL) that is based on a silicon carbide (SixC1−x) saturable absorber. When the C/Si composition ratio is increased to 1.83, the SixC1−x film transforms from two-photon absorption to nonlinear saturable absorption, and the corresponding value reaches −3.9 × 10−6 cm/W. The Si-rich SixC1−x film cannot mode lock the EDFL because it induced high intracavity loss through two-photon absorption. Even when a stoichiometric SiC is used, the EDFL is mode locked, similar to an EDFL operating under weak nonlinear-polarization-rotation condition. A C-rich SixC1−x film containing sp2-orbital C–C bonds with a linear absorbance of 0.172 and nonlinear absorbance of 0.04 at a 181 MW/cm2 saturation intensity demonstrates nonlinear transmittance. The C-rich SixC1−x saturable absorber successfully generates a short mode-locked EDFL pulse of 470 fs. The fluctuation of the pulse-train envelope dropps considerably from 11.6% to 0.8% when a strong saturable-absorption-induced self-amplitude modulation process occurs in the C-rich SixC1−x film. PMID:26558531

  8. Passively Q-switched microchip lasers based on Yb:YAG/Cr4+:YAG composite crystal

    NASA Astrophysics Data System (ADS)

    Ren, Yingying; Dong, Jun

    2014-02-01

    Efficient passively Q-switched microchip laser based on Yb:YAG/Cr4+:YAG composite crystal has been demonstrated under high brightness single-emitter laser-diode pumping. Maximum average output power of 1.5 W was obtained when the absorbed pump power was 3.65 W, the corresponding optical-to-optical efficiency was over 41%. The slope efficiency was 52.3%. The effect of the cavity length on the performance of Yb:YAG/Cr4+:YAG composite crystal passively Q-switched microchip lasers was investigated. Laser pulses at 1030 nm with pulse width of 466 ps and peak power of 91 kW were achieved with cavity length of 1.7 mm, while laser pulses with pulse width of 665 ps and peak power of 79 kW were obtained with cavity length of 3.7 mm.

  9. Passively Q-switching induced by the smallest single-walled carbon nanotubes

    SciTech Connect

    Xu, X. T.; Zhai, J. P.; Wang, J. S.; Chen, Y. P.; Yu, Y. Q.; Zhang, M.; Li, I. L.; Ruan, S. C.; Tang, Z. K.

    2014-04-28

    We report a passively Q-switched erbium-doped fiber laser (EDFL) by using the smallest single-walled carbon nanotubes (SWNTs) with a diameter of 0.3 nm as the saturable absorber. These small SWNTs are fabricated in the nanochannels of a ZnAPO-11 (AEL) single crystal. By inserting one of the AEL crystal into an EDFL cavity pumped by a 980 nm laser diode, stable passive Q-switching is achieved for a threshold pump power of 206.2 mW, and 4.73 μs pulses with a repetition rate of 41.78 kHz and an average output power of 3.75 mW are obtained for a pump power of 406 mW.

  10. Pulse synchronisation in passively Q-switched lasers emitting at 1.053 and 1.064 {mu}m

    SciTech Connect

    Bagdasarov, V Kh; Denisov, N N; Malyutin, A A; Chigaev, I A

    2009-10-31

    Pulse synchronisation with an accuracy of no worse than {+-}5 ns is demonstrated in passively Q-switched neodymium phosphate glass and Nd:YAG lasers. Two operating regimes are realised: the 'sub-threshold' regime (when the slave Nd:YAG laser does not generate a giant pulse if its passive Q switch is not irradiated by the master Nd:glass laser) and the 'above-threshold' regime (when the pulse irradiating the passive Q switch of the slave laser advances its generation). (control of laser radiation parameters)

  11. Reciprocal passive mode locking of a rhodamine 6G dye laser and the Ar+ pump laser

    SciTech Connect

    Yasa, Zafer A.; Amer, Nabil M.

    1981-02-01

    We report that a rhodamine 6G dye laser, internally pumped within the extended cavity of an Ar+-ion laser, is mode locked when its cavity length is matched to half that of the pump laser: the 5145-Å argon laser line is passively mode locked by the combination of the saturable absorption and the lasing action of the dye, which is in turn synchronously pumped and mode locked. Tunable (5650–5950-Å) ~10 psec pulses are generated, and the average output power is ~80 mW.

  12. Reciprocal passive mode locking of a rhodamine 6G dye laser and the Ar/sup +/ pump laser

    SciTech Connect

    Yasa, Z.A.; Amer, N.M.

    1981-02-01

    A rhodamine 6G dye laser, internally pumped within the extended cavity of an Ar/sup +/-ion laser, is mode locked when its cavity length is matched to half that of the pump laser: the 5145-A argon laser line is passively mode locked by the combination of the saturable absorption and the lasing action of the dye, which is in turn synchronously pumped and mode locked. Tunable (5650-5950-A)approx.10 psec pulses are generated, and the average output power is approx.80 mW.

  13. Self-stabilized and dispersion-compensated passively mode-locked Yb:Yttrium aluminum garnet laser

    NASA Astrophysics Data System (ADS)

    Agnesi, A.; Guandalini, A.; Reali, G.

    2005-04-01

    Self-stabilized passive mode-locking of a diode-pumped Yb:yttrium aluminum garnet laser with a semiconductor saturable absorber was achieved using an off-phase-matching second-harmonic crystal. According to the numerical model, such a condition is accomplished by self-defocusing in the nonlinear crystal in the presence of positive intracavity dispersion. Robust mode locking with Fourier-limited 1.0-ps pulses was obtained, whereas mode locking, unassisted by the nonlinear crystal, yielded 2.2-ps pulses, with the laser operating near the edge of the stability region in order to minimize the saturation energy of the semiconductor device.

  14. Generation of single longitudinal mode in a pulsed passively Q -switched Nd:YAG laser

    SciTech Connect

    Hariri, A.; Soltanmoradi, F.; Nayeri, M. )

    1990-08-01

    It is shown that a single longitudinal mode in a passively {ital Q}-switch Nd:YAG laser can be obtained by adjusting an intracavity saturable absorber gelatin film (BDN) to work as a mirror in a three-mirror Fabry--Perot resonator. With a 0.13-mm-thick gelatin film of 40% unsaturated transmission, a temporally smooth single-laser pulse of {similar to}10 ns duration has been obtained.

  15. 1.21 W passively mode-locked Tm:LuAG laser.

    PubMed

    Feng, T; Yang, K; Zhao, J; Zhao, S; Qiao, W; Li, T; Dekorsy, T; He, J; Zheng, L; Wang, Q; Xu, X; Su, L; Xu, J

    2015-05-01

    A watt-level output passively mode-locked Tm:LuAG bulk laser with an InGaAs semiconductor saturable absorber mirror (SESAM) is demonstrated for the first time. A maximum average output power of 1.21 W at 2022.9 nm has been achieved with a pulse duration of 38 ps and a repetition rate of 129.2 MHz. The results indicate the potential of Tm:LuAG crystals as candidate for realizing high power ultrafast lasers at 2 μm. PMID:25969273

  16. Theory of stationary ultarshort pulses in solid-state laserswith passive mode locking

    SciTech Connect

    Komarov, K.P.

    1986-02-01

    The formation of steady-state pulses in solid-state lasers with passive mode locking is investigated under conditions when the refractive index is frequency dispersive and nonlinear. The case of a noninertial absorber is considered as well as that of an inertial one. It is shown that when the nonlinearity of the refractive index exceeds a certain critical level phase modulation of the pulse leads to instability of the steady-state regime. The possibility is discussed of forming extremely short pulses in wide-band amplifying media such as alexandrite.

  17. Picosecond pulse generation in a passively mode-locked Bi-doped fibre laser

    SciTech Connect

    Krylov, Aleksandr A; Kryukov, P G; Dianov, Evgenii M; Okhotnikov, Oleg G

    2009-10-31

    CW passive mode locking is achieved in a bismuth-doped fibre laser using a semiconductor saturable absorber mirror optimised for operation in the range 1100-1200 nm. The pump source is a cw ytterbium fibre laser (1075 nm, maximum output power of 2.7 W), and the pulse parameters can be tuned by varying the intracavity group velocity dispersion using a diffraction grating pair. Stable laser pulses are obtained with a duration down to {tau}{sub p} {approx} 1.1 ps. (control of laser radiation parameters)

  18. Passive mode locking of an energy transfer continuous-wave dye laser

    SciTech Connect

    French, P.M.W.; Taylor, J.R.

    1986-08-01

    The first passive mode locking of a continuous-wave energy transfer dye laser is reported. Using an argon ion laser-pumped mixture of rhodamine 6G and sulphur rhodamine 101 as the active medium, pulses of less than 500 fs duration have been generated over the spectral range 652-694 nm using two different saturable absorbers in a simple linear cavity without dispersion optimization. Pulses as short as 120 fs have been measured using standard second-harmonic generation autocorrelation techniques.

  19. The design of passively Q-switched solid-state lasers

    NASA Astrophysics Data System (ADS)

    Xiao, Guohua

    The passively Q-switched laser has been of intense interest because it is generally simple, convenient, and requires a minimum of intracavity elements and no external high voltage or RF drivers. Z-scan technique was used to obtain more realistic values of the ground and excited state absorption cross sections of Cr:YAG, one of the most important solid state saturable absorbers. Other spectroscopic research revealed that Cr:YAG performs stably over the wide temperature range from -70 to +80°C. A generalized model of a passively Q-switched laser was developed. It enables performance optimization including general cases in which the saturable absorber exhibits both ground and excited state absorption at the laser wavelength. Based on the theory, we built and tested a Nd:glass laser passively Q-switched by a Cr4+:YAG crystal and found excellent agreement with our model. The model was then extended to the case where an optical parametric oscillator (OPO) is contained inside the passively Q-switched laser cavity. In such a laser there is no output at the fundamental or pump wavelength. When the OPO signal field begins to build up, it acts as a loss for the pump and cavity dumps the pump resonator. The extended model describes the complicated interactions between the fundamental laser gain medium, saturable absorber, fundamental laser cavity, and OPO cavity. The model developed enables one to select OPO parameters which optimize the system's performance. Application of the model to a very compact, lightweight, eye-safe laser range finder operating at 1.54 μm will also be presented. Many applications demand lasers to be operated over a wide temperature range (-55-75°C). Efforts were dedicated to obtaining information on the temperature dependence of the emission cross section of Nd,Cr:GSGG and the optical properties of certain laser resonator optics. The data serve as input parameters to the models to design passively Q-switched laser systems with predictable

  20. Passively Q-switched diode-pumped Yb:YAG laser using Cr 4+-doped garnets

    NASA Astrophysics Data System (ADS)

    Kalisky, Y.; Labbe, C.; Waichman, K.; Kravchik, L.; Rachum, U.; Deng, P.; Xu, J.; Dong, J.; Chen, W.

    2002-06-01

    We investigate the repetitive modulation in the kHz frequency domain of a passively Q-switched, diode-pumped Yb:YAG laser, by Cr 4+:YAG, Cr 4+:LuAG, and Cr 4+:GSGG saturable absorbers. The results presented here are focused towards the design of a passively Q-switched Yb:YAG microlaser. The free-running performance of both rod and a disk Yb:YAG is characterized and experimental parameters such as gain and loss are evaluated. These values, together with the value of the stimulated emission cross-section, e.g. σem=3.3×10 -20 cm 2 were found to fit between our experimental results and an existing numerical model which relates the experimental and physical parameters to the minimal threshold pumping power. Q-switched pulses with maximum peak power of ≈10.4 kW, with energy of ≈0.5 mJ/pulse, were extracted with 30% extraction efficiency.

  1. Passively Q-switched diode-pumped Yb:YAG laser using Cr4+-doped garnets

    NASA Astrophysics Data System (ADS)

    Kalisky, Yehoshua Y.; Labbe, Christophe; Waichman, Karol; Kravchik, Leonid; Rachum, U.; Deng, Peizhen; Xu, Jun; Dong, Jun; Chen, Wei

    2002-03-01

    We investigated the operation of a diode-pumped Yb:YAG laser passively Q-switched, by Cr4+:YAG, Cr4+:LuAG, and Cr4+:GSGG saturable absorbers. The results presented here are focused towards the design of a passively Q-switched Yb:YAG microlaser. The free-running performance of both rod and a disk Yb:YAG is characterized, and experimental parameters such as gain and loss are evaluated. These values, together with the value of the stimulated emission cross section, e.g. (sigma) emequals3.3x10-20 cm2 were found to fit between our experimental results and an existing numerical model which relates the experimental and physical parameters to the minimal threshold pumping power. Q-switched pulses with maximum peak power of approximately equals 10.4-kW, and energy of approximately equals 0.5 mJ/pulse were extracted with 30% extraction efficiency.

  2. Multi-Billion Shot, High-Fluence Exposure of Cr(4+): YAG Passive Q-Switch

    NASA Technical Reports Server (NTRS)

    Stephen, Mark A.; Dallas, Joseph L.; Afzal, Robert S.

    1997-01-01

    NASA's Goddard Space Flight Center is developing the Geoscience Laser Altimeter System (GLAS) employing a diode pumped, Q-Switched, ND:YAG laser operating at 40 Hz repetition rate. To meet the five-year mission lifetime goal, a single transmitter would accumulate over 6.3 billion shots. Cr(4+):YAG is a promising candidate material for passively Q-switching the laser. Historically, the performance of saturable absorbers has degraded over long-duration usage. To measure the multi-billion shot performance of Cr(4+):YAG, a passively Q-switched GLAS-like oscillator was tested at an accelerated repetition rate of 500 Hz. The intracavity fluence was calculated to be approximately 2.5 J/cm(exp 2). The laser was monitored autonomously for 165 days. There was no evidence of change in the material optical properties during the 7.2 billion shot test.. All observed changes in laser operation could be attributed to pump laser diode aging. This is the first demonstration of multi-billion shot exposure testing of Cr(4+):YAG in this pulse energy regime

  3. Passively Q-switched waveguide lasers based on two-dimensional transition metal diselenide.

    PubMed

    Cheng, Chen; Liu, Hongliang; Tan, Yang; Vázquez de Aldana, Javier R; Chen, Feng

    2016-05-16

    We reported on the passively Q-switched waveguide lasers based on few-layer transition metal diselenide, including molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2), as saturable absorbers. The MoSe2 and WSe2 membranes were covered on silica wafers by chemical vapor deposition (CVD). A low-loss depressed cladding waveguide was produced by femtosecond laser writing in a Nd:YAG crystal. Under optical pump at 808 nm, the passive Q-switching of the Nd:YAG waveguide lasing at 1064 nm was achieved, reaching maximum average output power of 115 mW (MoSe2) and 45 mW (WSe2), respectively, which are corresponding to single-pulse energy of 36 nJ and 19 nJ. The repetition rate of the Q-switched waveguide lasers was tunable from 0.995 to 3.334 MHz (MoSe2) and 0.781 to 2.938 MHz (WSe2), and the obtained minimum pulse duration was 80ns (MoSe2) and 52 ns (WSe2), respectively. PMID:27409862

  4. Passively Q-switched nd:YAG laser via a WS2 saturable absorber

    NASA Astrophysics Data System (ADS)

    Wang, Xi; Wang, Yonggang; Duan, Lina; Li, Lu; Sun, Hang

    2016-05-01

    In this work, we report a passively Q-switched Nd:YAG laser at 1064 nm by using WS2 solution as the saturable absorber (SA). The WS2 solution with different concentrations (0.25, 0.5, and 1 mg/ml) were fabricated by the liquid-phase-exfoliated method and injected into quartz cells. Such liquid absorbers have the virtues of adjustable optical absorption, high heat dissipation and non-contact damage. By inserting those WS2 solutions in the laser cavity, stable Q-switched laser operations were obtained. The corresponding pulse duration as short as 922 ns was obtained. The result shows that the WS2 material can be act as absorber for solid-state lasers.

  5. Continuous-wave and passively Q-switched cladding-pumped planar waveguide lasers.

    PubMed

    Beach, R J; Mitchell, S C; Meissner, H E; Meissner, O R; Krupke, W F; McMahon, J M; Bennett, W J; Shepherd, D P

    2001-06-15

    Greater than 12 W of average output power has been generated from a diode-pumped Yb:YAG cladding-pumped planar waveguide laser. The laser radiation developed is linearly polarized and diffraction limited in the guiding dimension. A slope efficiency of 0.5 W/W with a peak optical-optical conversion efficiency of 0.31 W/W is achieved. In a related structure, greater than 8 W of Q -switched average output power has been generated from a Nd:YAG cladding-pumped planar waveguide laser by incorporation of a Cr(4+): YAG passive Q switch monolithically into the waveguide structure. Pulse widths of 3 ns and pulse-repetition frequencies as high as 80 kHz have been demonstrated. A slope efficiency of 0.28 W/W with a peak optical-optical conversion efficiency of 0.21 W/W is achieved. PMID:18040479

  6. Dual-wavelength passively Q-switched Nd:GYSGG laser by tungsten disulfide saturable absorber.

    PubMed

    Gao, Y J; Zhang, B Y; Song, Q; Wang, G J; Wang, W J; Hong, M H; Dou, R Q; Sun, D L; Zhang, Q L

    2016-06-20

    A dual-wavelength passively Q-switched Nd:GYSGG laser using vacuum evaporating tungsten disulfide (WS2) as a saturable absorber was demonstrated for the first time to the best of our knowledge. The WS2 saturable absorber was prepared simply by evaporating nanometer WS2 powders onto a quartz substrate in a vacuum. By inserting the WS2 saturable absorber into the laser cavity, stable Q-switched laser operation was achieved with a maximum average output power of 367 mW, a pulse repetition rate of 70.7 kHz, the shortest pulse width of 591 ns, and pulse energy of about 1.05 μJ. By vacuum evaporation method, a high-quality WS2 saturable absorber can be produced, and it seems to be a suitable method for fabrication of 2D transition metal dichalcogenides. PMID:27409120

  7. LASERS: Small autonomous passively Q-switched Nd3+:YAG laser with a Cr4+:YAG Q switch emitting pulse trains

    NASA Astrophysics Data System (ADS)

    Buzinov, N. M.; Dmitriev, Valentin G.; Zabavin, V. N.; Kazakov, A. A.; Maslov, A. A.; Spitsyn, E. M.

    2007-04-01

    The energy and time characteristics of a passively Q-switched Nd3+:YAG laser with a Cr4+:YAG Q switch emitting pulse trains are studied and analysed theoretically. The description and technical parameters of a small autonomous laser with intracavity second-harmonic generation (ICSHG) in the pulse-train regime are presented. The laser provides a high total pulse-train energy for a relatively low peak power of a single pulse, stable operation in a wide temperature range, and has a small weight and size, which is convenient in operation. The enhanced reliability and stability of the laser operation are provided by its original technical design: the ICSHG scheme for type II phase matching without polarisers, the use of temperature-noncritical phase matching in KTP crystals, dust- and moisture-proof casing, and battery-operated pulsed power supply for the pump flashlamp.

  8. Efficient continuous wave and passively mode-locked Tm-doped crystalline silicate laser.

    PubMed

    Yang, K J; Bromberger, H; Heinecke, D; Kölbl, C; Schäfer, H; Dekorsy, T; Zhao, S Z; Zheng, L H; Xu, J; Zhao, G J

    2012-08-13

    An efficient continuous wave and passively mode-locked thulium-doped oxyorthosilicate Tm:LuYSiO5 laser is demonstrated. A maximum slope efficiency of 56.3% is obtained at 2057.4 nm in continuous wave operation regime. With an InGaAs quantum well SESAM, self-starting passively mode-locked Tm:LuYSiO5 laser is realized in the 1929 nm to 2065 nm spectral region. A maximum average output power of 130.2 mW with a pulse duration of 33.1 ps and a repetition rate of about 100 MHz is generated at 1984.1 nm. Pulses as short as 24.2 ps with an average output power of 100 mW are obtained with silicon prisms where used to manage the intracavity dispersion. The shortest pulse duration of about 19.6 ps is obtained with an average output power of 64.5 mW at 1944.3 nm. PMID:23038503

  9. Passive Q-switching of microchip lasers based on Ho:YAG ceramics.

    PubMed

    Lan, R; Loiko, P; Mateos, X; Wang, Y; Li, J; Pan, Y; Choi, S Y; Kim, M H; Rotermund, F; Yasukevich, A; Yumashev, K; Griebner, U; Petrov, V

    2016-06-20

    A Ho:YAG ceramic microchip laser pumped by a Tm fiber laser at 1910 nm is passively Q-switched by single- and multi-layer graphene, single-walled carbon nanotubes (SWCNTs), and Cr2+:ZnSe saturable absorbers (SAs). Employing SWCNTs, this laser generated an average power of 810 mW at 2090 nm with a slope efficiency of 68% and continuous wave to Q-switching conversion efficiency of 70%. The shortest pulse duration was 85 ns at a repetition rate of 165 kHz, and the pulse energy reached 4.9 μJ. The laser performance and pulse stability were superior compared to graphene SAs even for a different number of graphene layers (n=1 to 4). A model for the description of the Ho:YAG laser Q-switched by carbon nanostructures is presented. This modeling allowed us to estimate the saturation intensity for multi-layered graphene and SWCNT SAs to be 1.2±0.2 and 7±1  MW/cm2, respectively. When using Cr2+:ZnSe, the Ho:YAG microchip laser generated 11 ns/25 μJ pulses at a repetition rate of 14.8 kHz. PMID:27409113

  10. Reduced group delay dispersion in quantum dot passively mode-locked lasers operating at elevated temperature

    NASA Astrophysics Data System (ADS)

    Mee, J. K.; Raghunathan, R.; Murrell, D.; Braga, A.; Li, Y.; Lester, L. F.

    2014-09-01

    A detailed study of the pulse characteristics emitted from a monolithic Quantum Dot (QD) passively Mode-Locked Laser (MLL) has been performed using a state-of-the-art Frequency Resolved Optical Gating (FROG) pulse measurement system. While traditionally the time-domain pulse characteristics of semiconductor MLLs have been studied using digital sampling oscilloscope or intensity autocorrelation techniques, the FROG measurements allow for simultaneous characterization of time and frequency, which has been shown to be necessary and sufficient for true determination of mode-locked stability. In this paper, FROG pulse measurements are presented on a two-section QD MLL operating over wide temperature excursions. The FROG measurement allows for extraction of the temporal and spectral intensity and phase profiles from which the Group Delay Dispersion (GDD) can be determined. The magnitude of the GDD is found to decrease from 16.1 to 3.5 ps/nm when the temperature is increased from 20 to 50 oC, mirroring the trend of pulse width reduction at elevated temperature, which has been shown to correlate strongly with reduced unsaturated absorption. The possibility to further optimize pulse generation via intra-cavity dispersion compensation in a novel three-section MLL design is also examined, and shows strong potential toward providing valuable insight into the optimal cavity designs and operating parameters for QD MLLs.

  11. VCSEL end-pumped passively Q-switched Nd:YAG laser with adjustable pulse energy.

    PubMed

    Goldberg, Lew; McIntosh, Chris; Cole, Brian

    2011-02-28

    A compact, passively Q-switched Nd:YAG laser utilizing a Cr4+:YAG saturable absorber, is end-pumped by the focused emission from an 804 nm vertical-cavity surface-emitting laser (VCSEL) array. By changing the VCSEL operating current, we demonstrated 2x adjustability in the laser output pulse energy, from 9 mJ to 18 mJ. This energy variation was attributed to changes in the angular distribution of VCSEL emission with drive current, resulting in a change in the pump intensity distribution generated by a pump-light-focusing lens. PMID:21369256

  12. The passive Q-switching regime in a solid state laser with a multiloop cavity

    NASA Astrophysics Data System (ADS)

    Pogoda, A. P.; Burkovskii, G. V.; Makarchuk, P. S.; Khakhalin, I. S.; Boreisho, A. S.; Fedin, A. V.

    2016-03-01

    A compact, pulsed-periodic YAG: Nd3+ laser with self-pumped phase-conjugate multiloop cavity and passive Q-switching by YAG: Cr 4+ and GSGG: Cr 4+ crystals has been studied. It is established that the energy and temporal parameters of radiation in separate pulses of a periodic train can be controlled almost without changing the pulse train energy. A regime of generating modulated radiation pulses with a peak power of up to 30 MW and a spatial brightness of 1.7 × 1015 W/(cm2 sr) at a radiation beam quality parameter of M 2 < 1.2 has been realized in experiment.

  13. Azimuthally polarized, passively Q-switched Yb-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Zou, Lin; Yao, Yao; Han, Xiahui; Liu, Jinyu; Xu, Yun; Li, Jianlang

    2015-11-01

    An azimuthally polarized and passively Q-switched ytterbium-doped fiber laser was demonstrated. With the involvement of a single lens inside the laser resonator, a birefringent crystal was used as the polarization discriminator, and a Cr4+:YAG crystal acted as the saturable absorber and also the output coupler. For the simplicity and low optical loss of the resonator cavity, this fiber laser emitted azimuthally polarized pulse with a high slope efficiency of 72.6% and high average power of 4.11 W. The laser pulse had 132-ns duration and 112-kHz repetition rate at the absorbed pump power of 6.40 W.

  14. Influence of pumping schemes on the characteristics of self-similar pulses in a passively mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Huo, Jiayu; Xu, Tiantian; Guo, Yubin; Wang, Ke; Gao, Bo

    2016-05-01

    Self-similar pulses are one of the domestic and international research hotspots in the field of nonlinear fiber optics because it can suppress optical wave breaking at high energies. The influence of pumping schemes on the characteristics of self-similar pulses in a passively mode-locked Yb-doped fiber laser is theoretically investigated. The temporal profile and optical spectrum of self-similar pulses in passively mode-locked fiber lasers of different pumping schemes are obtained in the simulation. This study focuses on analyzing the influence of gain bandwidth of gain fiber on the pulse duration, peak power, and single-pulse energy of self-similar pulses.

  15. Pulse and noise properties of a two section passively mode-locked quantum dot laser under long delay feedback

    NASA Astrophysics Data System (ADS)

    Simos, Christos; Simos, Hercules; Mesaritakis, Charis; Kapsalis, Alexandros; Syvridis, Dimitris

    2014-02-01

    We present a numerical analysis that focuses on the temporal pulse properties of a monolithic two-section passively mode locked quantum dot laser subject to optical feedback from a very long external cavity. Pulse duration, shape and intensity noise are studied for the first time to our knowledge versus feedback delay and strength for the case of a passively mode locked semiconductor laser. These temporal characteristics are correlated to the previously observed dependence of repetition rate and timing jitter on cavity parameters in order to highlight the dynamics and complete the corresponding theoretical explanations.

  16. High-peak-power single-oscillator actively Q-switched mode-locked Tm3+-doped fiber laser and its application for high-average output power mid-IR supercontinuum generation in a ZBLAN fiber.

    PubMed

    Kneis, Christian; Donelan, Brenda; Manek-Hönninger, Inka; Robin, Thierry; Cadier, Benoît; Eichhorn, Marc; Kieleck, Christelle

    2016-06-01

    A single-oscillator actively Q-switched mode-locked (QML) thulium-doped silica fiber laser is presented and used to pump a ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber for mid-infrared (mid-IR) supercontinuum (SC) generation. The fiber laser provided high-peak-power levels directly from the oscillator delivering single mode-locked pulse energies up to 48 μJ, being 2-4 orders of magnitude higher than conventional continuous wave mode-locked lasers. By pumping a ZBLAN fiber specially designed for high-output-power SC generation, 7.8 W have been achieved in all spectral bands with a spectrum extending to 4.2 μm. PMID:27244410

  17. Passively mode-locked Yb:CaF2 thin-disk laser.

    PubMed

    Dannecker, Benjamin; Délen, Xavier; Wentsch, Katrin S; Weichelt, Birgit; Hönninger, Clemens; Voss, Andreas; Ahmed, Marwan Abdou; Graf, Thomas

    2014-09-22

    We report on the first demonstration of a passively (SESAM) mode-locked Yb:CaF(2) thin-disk laser operating at a repetition rate of 35 MHz with close to diffraction-limited beam quality (M(2) ≈ 1.1) at an average output power of up to 6.6 W. The optical efficiency was 15.3%. Nearly transform limited pulses with a duration of 445 fs and a spectral width of 2.6 nm at full width half maximum (FWHM) were obtained at the maximum output power. This corresponds to a pulse-energy of approximately 0.19 μJ and a peak-power of 0.4 MW. PMID:25321699

  18. Passively mode-locked fiber laser by a cell-type WS2 nanosheets saturable absorber

    PubMed Central

    Yan, Peiguang; Liu, Aijiang; Chen, Yushan; Wang, JinZhang; Ruan, Shuangchen; Chen, Hao; Ding, Jinfei

    2015-01-01

    A cell-type saturable absorber has been demonstrated by filling the single mode photonic crystal fiber (SMPCF) with tungsten disulfide (WS2) nanosheets. The modulation depth, saturable intensity, and non-saturable loss of this SA are measured to be 3.53%, 159 MW/cm2 and 23.2%, respectively. Based on this SA, a passively mode-locked EDF laser has been achieved with pulse duration of 808 fs and repetition rate of 19.57 MHz, and signal-noise-ratio (SNR) of 60.5 dB. Our results demonstrate that the cell-type WS2 nanosheets SA can serve as a good candidate for short-pulse mode locker. PMID:26213180

  19. Graphene-based passively mode-locked bidirectional fiber ring laser.

    PubMed

    Mamidala, Venkatesh; Woodward, R I; Yang, Y; Liu, H H; Chow, K K

    2014-02-24

    We present an all-fiber bidirectional passively mode-locked soliton laser with a graphene-based saturable absorber for the first time to the best of our knowledge. Our design includes a four-port circulator to introduce different sections of cavity for the two counter-propagating pulses, so they have distinct output characteristics. Simultaneous bidirectional operation is achieved by appropriately adjusting the net cavity birefringence and loss. In the clockwise direction, the laser emits ~750 fs pulses at 1561.6 nm, with a repetition rate of 7.68 MHz. In the counter clockwise direction, the central wavelength, pulse width, and repetition rate are 1561.0 nm, ~850 fs, and 6.90 MHz, respectively. PMID:24663774

  20. Interaction and motion of solitons in passively-mode-locked fiber lasers

    SciTech Connect

    Liu, Xueming

    2011-11-15

    Interaction and motion of multiple solitons in passively-mode-locked (PML) fiber lasers are investigated numerically. Three types of relative motions of two solitons are found in PML fiber lasers. The numerical results show that the relative motion of solitons attributes to the phase shift, which corresponds to the instantaneous frequency at pulse peak to be nonzero. Different from the classical dynamics of billiard balls, the interaction of solitons is similar to the Feynman diagram which is a pictorial way to represent the interaction of particles. After solitons interact with one another, their shapes do not change, but their phases shift and relative motions change. The theoretical results demonstrate that the separation of neighboring solitons in the laser cavity is about several hundred picoseconds to several nanoseconds. The theoretical predictions are in good agreement with the experimental results.

  1. Tuning the external optical feedback-sensitivity of a passively mode-locked quantum dot laser

    NASA Astrophysics Data System (ADS)

    Raghunathan, R.; Grillot, F.; Mee, J. K.; Murrell, D.; Kovanis, V.; Lester, L. F.

    2014-07-01

    The external optical feedback-sensitivity of a two-section, passively mode-locked quantum dot laser operating at elevated temperature is experimentally investigated as a function of absorber bias voltage. Results show that the reverse-bias voltage on the absorber has a direct impact on the damping rate of the free-running relaxation oscillations of the optical signal output, thereby enabling interactive external control over the feedback-response of the device, even under the nearly resonant cavity configuration. The combination of high temperature operation and tunable feedback-sensitivity is highly promising from a technological standpoint, in particular, for applications requiring monolithic integration of multi-component architectures on a single chip in order to accomplish, for instance, the dual-objectives of stable pulse quality and isolation from parasitic reflections.

  2. A passively mode locked thulium doped fiber laser using bismuth telluride deposited multimode interference

    NASA Astrophysics Data System (ADS)

    Jung, M.; Lee, J.; Song, W.; Lee, Y. L.; Lee, J. H.; Shin, W.

    2016-05-01

    We proposed a multimode interference (MMI) fiber based saturable absorber using bismuth telluride at  ∼2 μm region. Our MMI based saturable absorber was fabricated by fusion splicing with single mode fiber and null core fiber. The MMI functioned as both wavelength fixed filter and saturable absorber. The 3 dB bandwidth and insertion loss of MMI were 42 nm and 3.4 dB at wavelength of 1958 nm, respectively. We have also reported a passively mode locked thulium doped fiber laser operating at a wavelength of 1958 nm using a multimode interference. A temporal bandwidth of  ∼46 ps was experimentally obtained at a repetition rate of 8.58 MHz.

  3. Passively Q-switched flashlamp pumped Nd:YAG laser using liquid graphene oxide as saturable absorber

    NASA Astrophysics Data System (ADS)

    Adnan, N. N.; Bidin, N.; Taib, N. A. M.; Haris, H.; Fakaruddin, M.; Hashim, A. M.; Krishnan, G.; Harun, S. W.

    2016-06-01

    The performance of passively Q-switched Nd:YAG laser operating at 1060 nm is demonstrated using liquid graphene oxide (GO) composite solution as saturable absorber for the first time. The Q-switched Nd:YAG laser is pumped by a xenon flashlamp. The GO was prepared using the simplified Hummer's method and then mixed with polyethylene oxide to form a composite solution. The Q-switched pulsed laser operates at wavelength of 1064.5 nm with a threshold pump energy of 33.64 J. The maximum output Q-switched laser energy of 41.6 mJ achieved at the maximum pump energy of 81 J. The corresponding pulse width is 98.67 ns.

  4. Self-starting passively mode-locked tunable femtosecond Cr 4+:YAG laser using a saturable absorber mirror

    NASA Astrophysics Data System (ADS)

    Hayduk, M. J.; Johns, S. T.; Krol, M. F.; Pollock, C. R.; Leavitt, R. P.

    1997-02-01

    We have demonstrated self-starting, passive mode-locking of a Cr 4+:YAG laser using a saturable absorber mirror structure. Highly stable femtosecond pulses tunable from 1488 to 1535 nm were generated with average output powers ranging from 40 to 80 mW. Nearly transform limited pulses of 120 fs duration were obtained at 1488 nm.

  5. All solid-state cw passively mode-locked Ti:sapphire laser using a colored glass filter

    SciTech Connect

    Sarukura, N.; Ishida, Y.; Yanagawa, T.; Nakano, H. )

    1990-07-16

    All solid-state cw passive mode locking of a Ti:sapphire laser is accomplished using a colored glass filter, instead of an organic dye, as a saturable absorber. The tuning range is remarkably wide (785--855 nm), and 2.7 ps pulses are obtained directly from the cavity.

  6. High-power femtosecond pulse generation in a passively mode-locked Nd:SrLaAlO4 laser

    NASA Astrophysics Data System (ADS)

    Liu, Shan-De; Dong, Lu-Lu; Zheng, Li-He; Berkowski, Marek; Su, Liang-Bi; Ren, Ting-Qi; Peng, Yan-Dong; Hou, Jia; Zhang, Bai-Tao; He, Jing-Liang

    2016-07-01

    A high optical quality Nd:SrLaAlO4 (Nd:SLA) crystal was grown using the Czochralski method and showed broad fluorescence spectrum with a full width at half maximum value of 34 nm, which is beneficial for generating femtosecond laser pulses. A stable diode-pumped passively mode-locked femtosecond Nd:SLA laser with 458 fs pulse duration was achieved for the first time at a central wavelength of 1077.9 nm. The average output power of the continuous-wave mode-locked laser was 520 mW and the repetition rate was 78.5 MHz.

  7. Coherence collapse in monolithic quantum-dash-based passive mode-locked lasers

    NASA Astrophysics Data System (ADS)

    Merghem, K.; Rosales, R.; Azouigui, S.; Martinez, A.; Van Dijk, F.; Aubin, G.; Ramdane, A.

    2010-04-01

    Monolithic semiconductor mode-locked lasers (MLLs) are rising considerable interest for such diverse applications as very high speed optical time division multiplexing sources (40-160 GHz), all-optical signal processing, and low noise sampling for signal monitoring of optical networks. In a large number of these applications, MLLs may be subjected to optical feedback generated by unwanted reflections in optical systems which may greatly degrade laser performance. A number of experimental studies have been performed to evaluate the sensitivity of MLLs to optical feedback showing an increase of phase noise [1-5]. Quantum-dash (Qdash) based Fabry Perot lasers have been shown to exhibit an improved tolerance to feedback [6]. In this work, optical feedback tolerance is investigated for a monolithic quantum-dash-based passive mode-locked laser emitting at 1.58 μm. The two-section device generates ~5 ps pulses at a repetition rate of 17 GHz. The onset of the coherence collapse (CC) regime is experimentally determined by measuring the broadening of the longitudinal modes in the optical spectrum. Depending on bias condition, the CC regime is reached for values of feedback ranging from -35 dB to -29 dB at which emitted pulses were slighly broadened. The radio-frequency (RF) linewidth was simultaneously assessed and a drastic reduction of the RF linewidth with increasing feedback strength is evidenced. This indicates a reduction of the phase noise, thus implying a low "high frequency" timing jitter. We in particular observed an RF linewidth narrowing down to a value of less than 1 kHz under optical feedback.

  8. Passive mode-locking of a diode-pumped Nd:YVO(4) laser by intracavity SHG in PPKTP.

    PubMed

    Iliev, Hristo; Chuchumishev, Danail; Buchvarov, Ivan; Petrov, Valentin

    2010-03-15

    Experimental results on passive mode-locking of a Nd:YVO(4) laser using intracavity frequency doubling in periodically poled KTP (PPKTP) crystal are reported. Both, negative cascaded chi((2)) lensing and frequency doubling nonlinear mirror (FDNLM) are exploited for the laser mode-locking. The FDNLM based on intensity dependent reflection in the laser cavity ensures self-starting and self-sustaining mode-locking while the cascaded chi((2)) lens process contributes to substantial pulse shortening. This hybrid technique enables generation of stable trains of pulses at high-average output power with several picoseconds pulse width. The pulse repetition rate of the laser is 117 MHz with average output power ranging from 0.5 to 3.1 W and pulse duration from 2.9 to 5.2 ps. PMID:20389592

  9. Continuous-wave and passively Q-switched Nd:LYSO lasers

    NASA Astrophysics Data System (ADS)

    Zhuang, S. D.; Xu, X. D.; Wang, Z. P.; Li, D. Z.; Yu, H. H.; Xu, J.; Guo, L.; Chen, L. J.; Zhao, Y. G.; Xu, X. G.

    2011-04-01

    Continuous-wave (CW) and passively Q-switched performance of a Nd-doped oyorthosilicate mixing crystal, (Nd0.005Lu0.4975Y0.4975)2SiO5 (Nd:LYSO), were reported. As a result, new dual-wavelength all-solid-state lasers at 1075 and 1079 nm were achieved. When the absorbed pump power was 3.87 W, the CW laser produced 1.1 W output, corresponding to an optical conversion efficiency of 28.4% and a slope efficiency of 32.4%. By using a Cr4+:YAG wafer as the saturable absorber, we achieved Q-switching operation of Nd:LYSO crystal. The maximal average output power, shortest pulse width, largest pulse energy and highest peak power were measured to be 294 mW, 27.5 ns, 34.3 μJ and 1.18 kW, respectively. By difference frequency, these dual-wavelength lasers have potential applications for the generation of a broadband coherent radiation from 0.7-1.3 THz.

  10. Diode-end-pumped passively mode-locked high-power Nd:YVO4 laser with a relaxed saturable Bragg reflector.

    PubMed

    Chen, Y F; Tsai, S W; Lan, Y P; Wang, S C; Huang, K F

    2001-02-15

    We demonstrate a high-power passively mode-locked Nd:YVO (4) laser that uses a saturable Bragg reflector (SBR) with strain relaxation. 23.5 W of average power with ~21.5-ps cw mode-locked pulse trains was generated at a 50-W pump power. Experimental results show that appropriate strain relaxation in the SBR makes the mode-locking operation less sensitive to temperature variation. PMID:18033546

  11. Radially polarized and pulsed output from passively Q-switched Nd:YAG ceramic microchip laser.

    PubMed

    Li, Jian-lang; Ueda, Ken-ichi; Musha, Mitsuru; Zhong, Lan-xiang; Shirakawa, Akira

    2008-11-15

    For the first time, to the best of our knowledge, a radially polarized laser pulse was produced from a passively Q-switched Nd:YAG ceramic microchip laser with a piece of Cr4+:YAG crystal as the saturable absorber and multilayer concentric subwavelength grating as the polarization-selective output coupler. The averaged laser power reached 450 mW with a slope efficiency of 30.2%. The laser pulse had a maximum peak power of 759 W, a minimum pulse duration of 86 ns, and a 6.7 kHz repetition rate at 3.7 W absorbed pump power. The polarization degree of the radially polarized pulse was measured to be as high as 97.4%. Such a radially polarized laser pulse with a high peak power and a short width is important to numerous applications such as metal cutting. PMID:19015709

  12. A high repetition rate passively Q-switched microchip laser for controllable transverse laser modes

    NASA Astrophysics Data System (ADS)

    Dong, Jun; Bai, Sheng-Chuang; Liu, Sheng-Hui; Ueda, Ken-Ichi; Kaminskii, Alexander A.

    2016-05-01

    A Cr4+:YAG passively Q-switched Nd:YVO4 microchip laser for versatile controllable transverse laser modes has been demonstrated by adjusting the position of the Nd:YVO4 crystal along the tilted pump beam direction. The pump beam diameter-dependent asymmetric saturated inversion population inside the Nd:YVO4 crystal governs the oscillation of various Laguerre-Gaussian, Ince-Gaussian and Hermite-Gaussian modes. Controllable transverse laser modes with repetition rates over 25 kHz and up to 183 kHz, depending on the position of the Nd:YVO4 crystal, have been achieved. The controllable transverse laser beams with a nanosecond pulse width and peak power over hundreds of watts have been obtained for potential applications in optical trapping and quantum computation.

  13. Passively Q-switched Nd:YAG ceramic microchip laser with azimuthally polarized output

    NASA Astrophysics Data System (ADS)

    Li, J.-L.; Lin, D.; Zhong, L.-X.; Ueda, K.; Shirakawa, A.; Musha, M.; Chen, W.-B.

    2009-10-01

    A passively-Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) ceramic microchip laser was demonstrated to emit azimuthally polarized beam bus using a chromium-doped YAG (Cr4+:YAG) crystal as saturable absorber and a multilayer concentric subwavelength grating as polarization-selective output coupler. The laser's output power reached 512 mW with an initial slope efficiency of nearly 60%, and the pulse had 1.15-kW peak power with 40-ns duration and 11-kHz repetition rate at 3.9-W absorbed pump power. The laser beam's polarization degree was 97.6%. The thermal lensing effect in Nd:YAG microchip remained as a problem to be solved.

  14. Diode-side-pumped, passively Q-switched Yb:LuAG laser

    NASA Astrophysics Data System (ADS)

    Kaskow, Mateusz; Galecki, Lukasz; Jabczynski, Jan K.; Skorczakowski, Marek; Zendzian, Waldemar; Sulc, Jan; Nemec, Michal; Jelinkova, Helena

    2015-10-01

    A high-gain, diode-side-pumped Yb:LuAG slab laser was designed and investigated for use at room temperature. Pumping occurred from a fast-axis collimated 2D laser diode stack emitting at a wavelength of 970 nm, with 0.8 J over a duration of 0.8 ms. The pump scheme, which enabled efficient mode matching and high gain, was analysed and experimentally verified for different dopant levels. An energy of 100 mJ with 23% slope efficiency in a near fundamental mode was achieved in the free-running regime. A peak power of 2.5 MW and a pulse energy of 10.1 mJ were demonstrated in passive Q-switching by means of a Cr:YAG saturable absorber with 39% initial transmission. The study defined the indications for optimizing such a system.

  15. Compact, passively Q-switched Nd:YAG laser for the MESSENGER mission to Mercury.

    PubMed

    Krebs, Danny J; Novo-Gradac, Anne-Marie; Li, Steven X; Lindauer, Steven J; Afzal, Robert S; Yu, Anthony W

    2005-03-20

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter, an instrument on the Mercury Surface, Space Environment, Geochemistry, and Ranging mission to the planet Mercury. The laser achieves 5.4% efficiency with a near-diffraction-limited beam. It passed all space-flight environmental tests at subsystem, instrument, and satellite integration testing and successfully completes a postlaunch aliveness check en route to Mercury. The laser design draws on a heritage of previous laser altimetry missions, specifically the Ice Cloud and Elevation Satellite and the Mars Global Surveyor, but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury. PMID:15813276

  16. Pulse bundles and passive harmonic mode-locked pulses in Tm-doped fiber laser based on nonlinear polarization rotation.

    PubMed

    Wang, Xiong; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-03-10

    We demonstrate the nanosecond-level pulses in Tm-doped fiber laser generated by passively harmonic mode-locking. Nonlinear polarization rotation performed by two polarization controllers (PCs) is employed to induce the self-starting harmonic mode-locking. The fundamental repetition rate of the laser is 448.8 kHz, decided by the length of the cavity. Bundles of pulses with up to 17 uniform subpulses are generated due to the split of pulse when the pump power increases and the PCs are adjusted. Continuous harmonic mode-locked pulse trains are obtained with 1st to 6th and even more than 15th order when the positions of the PCs are properly fixed and the pump power is scaled up. The widths of all the uniform individual pulses are mostly 3-5 ns, and pulse with width of 304 ns at fundamental repetition rate can also be generated by adjusting the PCs. Hysteresis phenomenon of the passively harmonic mode-locked pulses' repetition frequency versus pump power is observed. The rather wide 3dB spectral bandwidth of the pulse train (25 nm) indicates that they may resemble noise-like pulses. PMID:24663948

  17. Highly efficient passively Q-switched Tm,Ho:GdVO4 laser with kilowatt peak power

    NASA Astrophysics Data System (ADS)

    Du, Yanqiu; Yao, Baoquan; Liu, Wei; Cui, Zheng; Duan, Xiaoming; Ju, Youlun; Yu, Hong

    2016-04-01

    We present the experimental results on the laser characteristics of diode-pumped passively Q-switched Tm,Ho:GdVO4 and Tm,Ho:YVO4 lasers with a Cr2+:ZnS saturable absorber emitting in the 2-μm range. The Tm,Ho:GdVO4 laser exhibits better performance than the Tm,Ho:YVO4 laser. The minimum pulse duration of 32.7 ns is obtained with the pulse energy of 0.30 mJ, corresponding to the peak power of 9.1 kW. The slope efficiencies of continuous wave and passively Q-switched Tm,Ho:GdVO4 lasers are 49.9% and 36.5%, corresponding to the Q-switching efficiency of 70.2%.

  18. Variable energy, high peak power, passive Q-switching diode end-pumped Yb:LuAG laser

    NASA Astrophysics Data System (ADS)

    Kaskow, M.; Sulc, J.; Jabczynski, J. K.; Jelinkova, H.

    2014-12-01

    A new method to control the pulse energy in a passively Q-switched laser was proposed and experimentally verified for a diode-end-pumped Yb:LuAG laser. By changing the pumping area parameters it was possible to demonstrate generation of a wide range of output energies with a single laser configuration consisting of a gain medium, passive Q-switch and out-coupling mirror. The range of available energies 0.15-0.51 mJ with maximum peak power of 113 kW in simple Q-switching regime by means of a Cr:YAG saturable absorber and a Yb:LuAG gain medium pumped by a 20 W laser diode emitting at 968 nm was demonstrated.

  19. Modeling and analysis of distributed feedback quantum dot passively mode-locked lasers.

    PubMed

    Rahimi, Javad; Ahmadi, Vahid; Yavari, Mohammad Hasan

    2016-07-01

    In this paper, we investigate numerically two proposed monolithic distributed feedback quantum dot passively mode-locked lasers (DFB-QDMLLs) with and without gratings in the saturable absorber (SA) section in order to enhance two important performances of QDMLLs for ultrahigh-bit-rate and single-mode applications. We find out that depending on the length of the grating, optical pulses with durations of about 3-8 ps at approximately 2nd and 4th harmonics of cavity round-trip frequencies can be generated by the proposed structures. We also compare the temporal and spectral behaviors of these structures under specified bias conditions and SA lengths. It is shown that DFB-QDMLLs have the ability to generate optical pulses with more peak power than grating-embedded saturable absorber (GESA-DFB-QDMLL) structures which generate shorter pulses with narrower spectral bandwidths. We also show that DFB-QDMLLs operate in a larger range of absorber voltages while the other structure is very sensitive to absorber voltage and operates well for middle ranges of this parameter. PMID:27409197

  20. Single-walled carbon nanotube passively mode-locked O-band Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Steinberg, D.; Saito, L. A. M.; Rosa, H. G.; Thoroh de Souza, E. A.

    2016-05-01

    We present a detailed analysis of a nanosecond-pulse single-walled carbon nanotube (SWCNT) passively mode-locked O-band Raman fiber lasers. As gain medium, single mode fiber (SMF) and highly nonlinear Raman gain were used at three different experimental setups. By incorporating 1.0 nm mean diameter SWCNT as saturable absorbers (SA) at 2.3 km SMF long-length gain medium setup, soliton-like spectrum followed by nanosecond high chirped pulse was observed at cavity fundamental repetition rate. In order to shorter the chirped pulse, intracavity anomalous dispersion was introduced with normal dispersion shift fiber (DSF) lengths and pulse duration decreased from 4.20 to 2.30 ns. By using highly nonlinear Raman gain medium in the O-band Raman laser configuration, the laser generated clean and well-defined nanosecond high chirped pulses, achieving pulse duration as short as 2.30 ns with 230 m gain medium length. Also, we could estimate the picosecond pulse duration region as a function of gain medium length of this laser and compared with SMF pulse shortening curve. As results, the lasers presented similar tendencies, indicating a strong influence of nonlinearities and dispersion in the pulse duration shortening.

  1. Output Power Limitations and Improvements in Passively Mode Locked GaAs/AlGaAs Quantum Well Lasers

    PubMed Central

    Tandoi, Giuseppe; Ironside, Charles N.; Marsh, John H.; Bryce, A. Catrina

    2013-01-01

    We report a novel approach for increasing the output power in passively mode locked semiconductor lasers. Our approach uses epitaxial structures with an optical trap in the bottom cladding that enlarges the vertical mode size to scale the pulse saturation energy. With this approach we demonstrate a very high peak power of 9.8 W per facet, at a repetition rate of 6.8 GHz and with pulse duration of 0.71 ps. In particular, we compare two GaAs/AlGaAs epilayer designs, a double quantum well design operating at 830 nm and a single quantum well design operating at 795 nm, with vertical mode sizes of 0.5 and 0.75 μm, respectively. We show that a larger mode size not only shifts the mode locking regime of operation towards higher powers, but also produces other improvements in respect of two main failure mechanisms that limit the output power: the catastrophic optical mirror damage and the catastrophic optical saturable absorber damage. For the 830 nm material structure, we also investigate the effect of non-absorbing mirrors on output power and mode locked operation of colliding pulse mode locked lasers. PMID:23843678

  2. Passive Q-switching of an all-fiber laser induced by the Kerr effect of multimode interference.

    PubMed

    Fu, Shijie; Sheng, Quan; Zhu, Xiushan; Shi, Wei; Yao, Jianquan; Shi, Guannan; Norwood, R A; Peyghambarian, N

    2015-06-29

    A novel passively Q-switched all-fiber laser using a single mode-multimode-single mode fiber device as the saturable absorber based on the Kerr effect of multimode interference is reported. Stable Q-switched operation of an Er(3+)/Yb(3+) co-doped fiber laser at 1559.5 nm was obtained at a pump power range of 190-510 mW with the repetition rate varying from 14.1 kHz to 35.2 kHz and the pulse duration ranging from 5.69 μs to 3.86 μs. A maximum pulse energy of 0.8 μJ at an average output power of 27.6 mW was achieved. This demonstrates a new modulation mechanism for realizing Q-switched all-fiber laser sources. PMID:26191734

  3. Laser diode and pumped Cr:Yag passively Q-switched yellow-green laser at 543 nm

    NASA Astrophysics Data System (ADS)

    Yao, Y.; Ling, Zhao; Li, B.; Qu, D. P.; Zhou, K.; Zhang, Y. B.; Zhao, Y.; Zheng, Q.

    2013-03-01

    Efficient and compact yellow green pulsed laser output at 543 nm is generated by frequency doubling of a passively Q-switched end diode-pumped Nd:YVO4 laser at 1086 nm under the condition of sup-pressing the higher gain transition near 1064 nm. With 15 W of diode pump power and the frequency doubling crystal LBO, as high as 1.58 W output power at 543 nm is achieved. The optical to optical conversion efficiency from the corresponding Q-switched fundamental output to the yellow green output is 49%. The peak power of the Q-switched yellow green pulse laser is up to 30 kW with 5 ns pulse duration. The output power stability over 8 hours is better than 2.56% at the maximum output power. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by frequency doubling of a passively Q-switched end diode pumped Nd:YVO4 laser at 1086 nm.

  4. Generation of stable high order harmonic noise-like pulses in a passively mode-locked double clad fiber ring laser

    NASA Astrophysics Data System (ADS)

    Hernandez-Garcia, J. C.; Pottiez, O.; Ibarra-Escamilla, B.; Estudillo-Ayala, J. M.; Rojas-Laguna, R.; Kuzin, E.; Muñoz-Lopez, A.; Filoteo-Razo, J. D.

    2015-03-01

    We study a passively mode-locked double-clad Erbium-Ytterbium fiber ring laser producing noise-like pulse through nonlinear polarization evolution and polarization selection. Single noise-like pulsing is only observed at moderate pump power. As pump power is increased, and through polarization controllers adjustments, harmonic mode-locking of growing order were successively appearing. For pump powers close to the damage threshold of the setup, we reach harmonic orders beyond 1200 and repetition frequencies in excess of a quarter of a GHz. Finally, these experimental results could be useful in the quest for higher pulse energies and higher repetition rates in passively mode-locked fiber lasers.

  5. High-power passively Q-switched Nd:KGW laser pumped at 877 nm

    NASA Astrophysics Data System (ADS)

    Huang, K.; Ge, W. Q.; Zhao, T. Z.; Feng, C. Y.; Yu, J.; He, J. G.; Xiao, H.; Fan, Z. W.

    2016-06-01

    In this work, we demonstrate, for the first time, a high-power passively Q-switched Ng-cut Nd3+:KGd(WO4)2/Cr4+:YAG laser pumped at 877 nm. The maximum average output power of ~1.6 W is obtained at the pump power of 5.22 W, when a saturable absorber with 98 % of initial transmission is used. The corresponding pulse energy is up to 16 µJ. The maximum pulse energy of 25.3 µJ is achieved at a repetition rate of 59 kHz, by employing a saturable absorber with 95 % of initial transmission. The corresponding pulse width and average output power are 89.0 ns and 1.5 W, respectively. A careful cavity design and a good thermal management ensure nearly TEM00 output with M 2 ≤ 1.22 within the whole range of operation in both N p and N m directions at 877 nm pump.

  6. Development of monolith Nd:YAG /Cr+4:YAG passively Q-switched microchip laser

    NASA Astrophysics Data System (ADS)

    Izhnin, Ihor; Vakiv, Mykola; Izhnin, Aleksandr; Syvorotka, Igor; Ubizskii, Sergii; Syvorotka, Ihor, Jr.

    2005-09-01

    The main features of passively Q-switched microchip lasers development are considered. The active medium of laser is an epitaxial structure combining an epitaxial layer of saturable absorber Cr4+:Y3Al5O12 (Cr:YAG) grown on substrate of generating crystal Nd:YAG by liquid phase epitaxy. The modulator layer has an initial optical absorption of 36 cm-1 at wavelength of lasing (1064 nm). The epitaxial layer grown on unworking side was mechanically removed and this substrate side was optically polished. The other one was processed precisely to needed thickness. The cavity's mirrors were deposited by electron beam technique directly on each side of the structure to form a rugged, monolithic resonator. Diode laser Model ATC-C4000 with lasing wavelength 808 nm provided the CW end pumping. The output pulses parameters were investigated by means of test bench consisting of photoelectric transducer FEK-15 and Digital Phosphor Oscilloscope TDS 5052B. The obtained laser parameter are as follows: pulse width (FWHM) about 1.3 ns, repetition rate 5.5 kHz, average output power about 10 mW, pulse energy 1.0 μJ, pick power 1.2 kW. The possible solutions for laser parameter improving and optimization are discussed.

  7. Analysis of mode wavefront characteristics for passively Q-switched slab Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Zhang, Xiang; Wang, Jie; Hu, Zhiqiu; Su, Likun

    2016-01-01

    The eigenmode of resonators with symmetric circular mirrors used in solid-state lasers is investigated. Further experiments on output beam quality on a passive Q-switched zigzag slab Nd:YAG laser have been performed by adopting Hartmann-Shack and Zernike-mode reconstruction methods. By the means of peak-valley and root mean square errors of the wavefront distribution, each order of Zernike aberrations are achieved accurately. Moreover, the distribution of circle energy in the far-field and corresponding beam evaluation factors can also be obtained by further calculation. Experimental results indicate that the wavefront aberration is mainly concentrated in the first 10 Zernike aberrations, which mainly includes the defocus Z3, the low-order astigmatism Z5, the coma aberration Z6, and the spherical aberration Z10, because of the crystal thermal effect and the intracavity phase perturbation. The method can be used to further analyze the compensation of intracavity aberration and optimal design for such lasers.

  8. Passively Q-switched Ho:YLF laser pumped by Tm3+-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Ju, Youlun; Yao, Baoquan; Dai, Tongyu; Duan, Xiaoming; Li, Jiang; Ding, Yu; Liu, Wei; Pan, Yubai; Li, Chaoyu

    2016-03-01

    We demonstrate a compact and efficient passively Q-switched (PQS) Ho:YLF laser pumped by a self-made all-fiber laser. Firstly, we design and make an all-fiber laser operating at 1940 nm with a slope efficiency of 40.6%. Then, the all-fiber laser was used to pump Ho:YLF laser directly. In the CW (continues-wave) operation Ho:YLF laser, the maximum output power was 7.79 W, corresponding to the slope efficiency of 55.2%. Using Cr2+:ZnS as the saturable absorber, the average power of 6.03 W was achieved with the slope efficiency of 45.9%. The shortest pulse duration was 15.6 ns and the pulse repetition frequency was 2.3 kHz at the pump power of 20.4 W. The pulse energy was a constant as 2.7 mJ when the pump power exceeded 15 W. The beam quality factor of M2 was 1.05, indicating nearly diffraction limited beam propagation.

  9. Passive mode locking of a diode-pumped hybrid neodymium:glass and neodymium:yttrium orthovanadate lasers

    NASA Astrophysics Data System (ADS)

    Tachatraiphop, Sukanya

    In this thesis, I present the first experimental results of the passive mode locking of diode pumped hybrid Nd:glass and Nd:YVO4 lasers with weakly and strongly inhomogeneously broadened laser media: Nd:phosphate glass or Nd:silicate glass, respectively. The spectral and temporal characteristics of the mode-locked hybrid lasers are studied in term of the pump ratio and the gain peak separation of the two hybrid laser media. The mode-locked hybrid laser performance and behavior can be explained by using unsaturated and saturated gain profile in the free running state. The gain profile of the hybrid laser is controlled by the Nd:YVO4 gain via gain combination and cross saturated gain. To verify the accuracy of the numerical results, the cw hybrid laser experiment is conducted. Both simulation and experimental results show that, in both free running state and mode locking state, the spectral component of a hybrid laser is controlled by the Nd:YVO4 gain. With a proper pump of Nd:YVO4, the saturated gain profile of the hybrid laser is wider than that of Nd:glass laser. Un-smooth and narrower gain profile results by an excessive pump at Nd:YVO4. The gain narrowing effect is magnified when gain peaks of hybrid laser are overlap. Un-smooth and narrow gain profile increase mode locking instability and produce longer pulses. In the picosecond regime, the pulse duration is limited by recovery time of the saturable absorber. In the picosecond regime, the hybrid Nd:phosphate glass and Nd:YVO4 laser can mode lock at either 1054 nm or 1064 nm. Because of the soliton mechanism, the pulses can be generated in the femtosecond regime. With a strong soliton force, the wider and flatter gain profile of the hybrid laser can be utilized. The improvement of the hybrid laser performance is enhanced with a smaller negative GVD and strong pump power of Nd:glass media. In the femtosecond regime, the hybrid Nd:silicate glass and Nd:YVO 4 laser generates a shorter pulse duration and better

  10. Watt-level passively Q-switched heavily Er3+-doped ZBLAN fiber laser with a semiconductor saturable absorber mirror

    PubMed Central

    Shen, Yanlong; Wang, Yishan; Luan, Kunpeng; Huang, Ke; Tao, Mengmeng; Chen, Hongwei; Yi, Aiping; Feng, Guobin; Si, Jinhai

    2016-01-01

    A diode-cladding pumped mid-infrared passively Q-switched Er3+-doped ZBLAN fiber laser with an average output power of watt-level based on a semiconductor saturable absorber mirror (SESAM) is demonstrated. Stable pulse train was produced at a slope efficiency of 17.8% with respect to launched pump power. The maximum average power of 1.01 W at a repetition rate of 146.3 kHz was achieved with a corresponding pulse energy of 6.9 μJ, from which the maximum peak power was calculated to be 21.9 W. To the best of our knowledge, the average power and the peak power are the highest in 3 μm region passively Q-switched fiber lasers. The influence of gain fiber length on the operation regime of the fiber laser has been investigated in detail. PMID:27225029

  11. Watt-level passively Q-switched heavily Er3+-doped ZBLAN fiber laser with a semiconductor saturable absorber mirror

    NASA Astrophysics Data System (ADS)

    Shen, Yanlong; Wang, Yishan; Luan, Kunpeng; Huang, Ke; Tao, Mengmeng; Chen, Hongwei; Yi, Aiping; Feng, Guobin; Si, Jinhai

    2016-05-01

    A diode-cladding pumped mid-infrared passively Q-switched Er3+-doped ZBLAN fiber laser with an average output power of watt-level based on a semiconductor saturable absorber mirror (SESAM) is demonstrated. Stable pulse train was produced at a slope efficiency of 17.8% with respect to launched pump power. The maximum average power of 1.01 W at a repetition rate of 146.3 kHz was achieved with a corresponding pulse energy of 6.9 μJ, from which the maximum peak power was calculated to be 21.9 W. To the best of our knowledge, the average power and the peak power are the highest in 3 μm region passively Q-switched fiber lasers. The influence of gain fiber length on the operation regime of the fiber laser has been investigated in detail.

  12. CONTROL OF LASER RADIATION PARAMETERS: Passive Q switching of a neodymium laser by a Cr4+ : YAG crystal switch

    NASA Astrophysics Data System (ADS)

    Il'ichev, Nikolai N.; Gulyamova, E. S.; Pashinin, Pavel P.

    1997-11-01

    Theoretical and experimental investigations were made of passive Q switching of a neodymium laser by a Cr4+ : YAG switch. Analytic expressions were derived for estimating the output energy of the TEM00 mode of a passively Q-switched laser from the known parameters of the Cr4+ : YAG switch, of the active element, and of the cavity. The adopted description makes it possible to cover the range from generation of the first spike of a free-running transient to generation of a giant pulse. An experimental study was made of the dependence of the output energy on the cavity parameters, on the material of the active element (in this investigation it was Nd :YAG and Cr, Nd : GSGG), and on the angle of rotation of the Cr4+ : YAG switch. The experimental results obtained agreed to within 30% with calculations.

  13. Cr{sup 4+}:YAG as passive Q-switch and Brewster plate in a pulsed Nd:YAG laser

    SciTech Connect

    Shimony, Y.; Burshtein, Z.; Kalisky, Y.

    1995-10-01

    The authors demonstrate the performance of a Nd:YAG laser, passively Q-switched with a Cr{sup 4+}:YAG plate, which plays the double role of a passive Q-switch ad a Brewster plate. The Brewster plate configuration contributes an intracavity loss of approximately 3.2 {times} 10{sup {minus}3} cm{sup {minus}1} along the cavity length. Losses contributed by the active Cr{sup 4+} ions in the plate relate to their excited state absorption. A freshly measured transmission saturation curve of Cr{sup 4+}:YAG suggests a ground state absorption cross section {sigma}{sub gs} = (8.7 {+-} 0.8) {times} 10{sup {minus}19} cm{sup 2}, and an excited state absorption cross section {sigma}{sub es} = (2.2 {+-} 0.2) {times} 10{sup {minus}19} cm{sup 2} of the Cr{sup 4+} ions at {lambda} = 1,064 nm.

  14. Doubly passively Q-switched Yb:NaY(WO4)2 laser with dual-wavelength phenomenon

    NASA Astrophysics Data System (ADS)

    Lan, Ruijun

    2015-06-01

    A diode pumped doubly passively Q-switched \\text{Yb:NaY}≤ft(\\text{W}{{\\text{O}}4}\\right)2/\\text{C}{{\\text{r}}4+}\\text{:YAG}/\\text{GaAs} laser was realized for the first time to our knowledge. Compared with the singly passively Q-switched \\text{Yb:NaY}≤ft(\\text{W}{{\\text{O}}4}\\right)2/\\text{C}{{\\text{r}}4+}\\text{:YAG} laser, this laser can generate a higher repetition rate, and more symmetric and shorter pulses. The highest repetition rate and shortest pulse width was measured to be 82 kHz and 6 ns. At certain pump power, 1022 and 1026 nm dual-wavelength lasers were obtained, and the mechanism of this phenomenon was discussed.

  15. Highly efficient passively Q-switched Yb:YAG microchip lasers under high intensity laser-diode pumping

    NASA Astrophysics Data System (ADS)

    Dong, J.; Wang, G. Y.; Cheng, Y.

    2013-03-01

    A highly efficient Cr4+:YAG passively Q-switched Yb:YAG microchip laser has been demonstrated at room temperature by high-brightness single-emitter laser-diode pumping. The maximum average output power of 1.53 W was obtained at the absorbed pump power of 3.5 W. The optical-to-optical efficiency was 44% with respect to the absorbed pump power. Laser pulses with a pulse width of 2.9 ns, pulse energy of 11.3 μJ, and peak power of 3.9 kW were obtained. The high pump power intensity from a high-brightness single-emitter laser-diode plays an important role in the alleviation of thermal effects and the efficient performance of Cr4+:YAG passively Q-switched Yb:YAG microchip lasers.

  16. Watt-level passively Q-switched heavily Er(3+)-doped ZBLAN fiber laser with a semiconductor saturable absorber mirror.

    PubMed

    Shen, Yanlong; Wang, Yishan; Luan, Kunpeng; Huang, Ke; Tao, Mengmeng; Chen, Hongwei; Yi, Aiping; Feng, Guobin; Si, Jinhai

    2016-01-01

    A diode-cladding pumped mid-infrared passively Q-switched Er(3+)-doped ZBLAN fiber laser with an average output power of watt-level based on a semiconductor saturable absorber mirror (SESAM) is demonstrated. Stable pulse train was produced at a slope efficiency of 17.8% with respect to launched pump power. The maximum average power of 1.01 W at a repetition rate of 146.3 kHz was achieved with a corresponding pulse energy of 6.9 μJ, from which the maximum peak power was calculated to be 21.9 W. To the best of our knowledge, the average power and the peak power are the highest in 3 μm region passively Q-switched fiber lasers. The influence of gain fiber length on the operation regime of the fiber laser has been investigated in detail. PMID:27225029

  17. Passively Q-switched erbium-doped fiber laser using Fe3O4-nanoparticle saturable absorber

    NASA Astrophysics Data System (ADS)

    Bai, Xuekun; Mou, Chengbo; Xu, Luxi; Wang, Shaofei; Pu, Shengli; Zeng, Xianglong

    2016-04-01

    We experimentally demonstrate passively Q-switched erbium-doped fiber laser (EDFL) operation using a saturable absorber (SA) based on Fe3O4 nanoparticles (FONPs). As a type of transition metal oxide, the FONPs have a large nonlinear optical response and fast response time. The FONP-based SA possesses a modulation depth of 8.2% and nonsaturable absorption of 56.6%. Stable passively Q-switched EDFL pulses with an output pulse energy of 23.76 nJ, a repetition rate of 33.3 kHz, and a pulse width of 3.2 µs were achieved when the input pump power was 110 mW. The laser features a low threshold pump power of ∼15 mW.

  18. A continuous-wave and passively Q-switched Nd:LaGGG laser at 937 nm

    NASA Astrophysics Data System (ADS)

    Li, Z.-Y.; Ying, H.-Y.; Yang, H.; He, J.-L.

    2013-10-01

    A diode-end-pumped continuous-wave (CW) and passively Q-switched Nd:LaGGG (GGG: gadolinium gallium garnet) laser at about 937 nm was demonstrated for the first time. The maximum CW output power of 540 mW was obtained with the optical-optical conversion efficiency of 3.2% and the slope efficiency of 4.4%. A V3+:YAG (yttrium aluminum garnet) saturable absorber with the initial transmission of 97% was used for the passive Q-switching regime. The shortest pulse width was achieved as 500 ns with the pulse repetition rate of 96 kHz. The corresponding single-pulse energy and pulse peak power were determined as 1.56 μJ and 3.12 W, respectively.

  19. Passively Q-switched a-cut Nd:GdVO4 self-Raman laser with Cr:YAG

    NASA Astrophysics Data System (ADS)

    Peng, J. Y.; Zheng, Y.; Shi, Y. X.; Shen, J. P.

    2012-10-01

    A passively Q-switched a-cut Nd:GdVO4 self-Raman solid-state laser with Cr:YAG saturable absorber was firstly demonstrated. The first Stokes at 1173 nm was successfully obtained. At the maximum incident pump power, the pulse width was about 1.8 ns and the repetition rate was 27.5 kHz. 586.5 nm yellow laser output was also realized by use of an LBO frequency doubling crystal.

  20. On the possibility of increasing the pulse energy of a passively Q-switched erbium glass minilaser

    SciTech Connect

    Izyneev, A A; Sadovskii, Pavel I; Sadovskii, S P

    2010-08-03

    A simple method to increase the output energy of a passively Q-switched erbium glass laser is proposed. Using the amplitude modulation of losses at the active element face, the fundamental mode was reliably suppressed and the laser operated in a selected higher-order mode. The output energy was experimentally increased by a factor of 2.1, and the range of allowable pump energy instability was extended threefold. (lasers)

  1. Comprehensive study of electro-optic and passive Q-switching in solid state lasers for altimeter applications

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Atul; Agrawal, Lalita; Pal, Suranjan; Kumar, Anil

    2006-12-01

    Laser Science and Technology Center (LASTEC), Delhi, is developing a space qualified diode pumped Nd: YAG laser transmitter capable of generating 10 ns pulses of 30 mJ energy @ 10 pps. This paper presents the results of experiments for comparative studies between electro-optic and passively Q-switched Nd: YAG laser in a crossed porro prism based laser resonator. Experimental studies have been performed by developing an economical bench model of flash lamp pumped Nd: YAG laser (rod dimension, \

  2. Maximum value of the pulse energy of a passively Q-switched laser as a function of the pump power.

    PubMed

    Li, Jianlang; Ueda, Ken-ichi; Dong, Jun; Musha, Mitsuru; Shirakawa, Akira

    2006-07-20

    The finite recovery time Ts of the bleached absorber is presented as one of the possible mechanisms accounting for the increase-maximum-decrease in pulse energy E with the pumping rate Wp in cw-pumped passively Q-switched solid-state lasers, by analytically evaluating the sign of the derivative partial differentialE/ partial differentialWP. The results show that, in the low pump regime (T>Ts, T is the interpulse period), the initial population density ni remains constant, the final population density nf decreases with Wp, and this results in a monotonic increase of E with Wp. In the high pump regime (Tpassively Q switched by a Cr4+:YAG absorber is demonstrated to confirm this model. The theoretical model is also applied to the analysis of three previously reported passive Q switching solid-state [Nd:GdVO4, Nd+:LaSc3(BO3)4 (Nd+:LSB), and Nd:YAG] lasers experiments. PMID:16826274

  3. Fifty-ps Raman fiber laser with hybrid active-passive mode locking.

    PubMed

    Kuznetsov, A G; Kharenko, D S; Podivilov, E V; Babin, S A

    2016-07-25

    Actively mode locked Raman lasing in a ring PM-fiber cavity pumped by a linearly polarized Yb-doped fiber laser is studied. At co-propagating pumping, a stochastic pulse with duration defined by the AOM switching time (~15 ns) is generated with the round-trip period. At counter-propagating pumping, one or several sub-ns pulses (within the AOM switching envelope) are formed. It has been found that the formation of such stable multi-pulse structure is defined by the single-pulse energy limit (~20 nJ) set by the second-order Raman generation. Adding a NPE-based saturable absorber in the actively mode locked cavity, results in sufficient shortening of the generated pulses both in single- and multi-pulse regimes (down to 50 ps). A model is developed adequately describing the regimes. PMID:27464081

  4. Long cavity and low repetition rate passively mode-locked fiber laser with high-energy right angle trapezoid shaped soliton in anomalous dispersion regime

    NASA Astrophysics Data System (ADS)

    Luo, Wenfeng; Lv, Shuyuan; Zhao, Xiaoxia; Qiao, Dun

    2015-05-01

    A long cavity passively mode locked fiber laser in the anomalous dispersion regime is reported. Nonlinear polarization rotation technique is employed to achieve the mode locking in our experiments. The output pulse from the fiber laser has the Gaussian profile spectrum and right angle trapezoid shape. Stable mode locking is achieved without using any dispersion-compensation components. The single pulse with an energy of 652 nJ and a repetition rate of 836 kHz at the pump power of approximately 500 mW is obtained and the duration of the output pulse increases linearly with the pump power. Different from the conventional low-energy soliton pulse, experimental results demonstrate that the passively mode locked fiber laser operating in the anomalous regime can also realize high energy pulse.

  5. Generation of 0. 7--0. 8. mu. picosecond pulses in an alexandrite laser with passive mode locking

    SciTech Connect

    Lisitsyn, V.N.; Matrosov, V.N.; Orekhova, V.P.; Pestryakov, E.V.; Sevast'yanov, B.K.; Trunov, V.I.; Zenin, V.N.; Remigailo, Y.L.

    1982-03-01

    Picosecond pulses of 0.7--0.8 ..mu.. wavelengths were generated in an alexandrite laser as a result of electronic--vibrational transitions /sup 4/T/sub 2/ ..-->.. /sup 4/A/sub 2/+h..omega../sub phonon/. Passive mode locking was ensured by the use of DS1 and DTTS saturable absorbers. The duration of the pulses generated using DS1 was 8 psec at wavelengths of 0.725--0.745 ..mu.., whereas the duration of the pulses generated using DTTS was 90 psec in the range 0.75--0.775 ..mu...

  6. Control over the performance characteristics of a passively mode-locked erbium-doped fibre ring laser

    SciTech Connect

    Chernysheva, M A; Krylov, A A; Dianov, E M; Ogleznev, A A; Arutyunyan, N R; Pozharov, A S; Obraztsova, E D

    2013-08-31

    We report an all-fibre ultrashort pulse erbium-doped ring laser passively mode-locked by single-wall carbon nanotubes dispersed in carboxymethylcellulose-based polymer films. Owing to intracavity dispersion management and controlled absorption in the polymer films, the laser is capable of generating both femto- and picosecond pulses of various shapes in the spectral range 1.53 – 1.56 μm. We have demonstrated and investigated the generation of almost transform- limited, inversely modified solitons at a high normal cavity dispersion. (control of laser radiation parameters)

  7. Soliton collapse and bunched noise-like pulse generation in a passively mode-locked fiber ring laser

    NASA Astrophysics Data System (ADS)

    Tang, D. Y.; Zhao, L. M.; Zhao, B.

    2005-04-01

    A passively mode-locked soliton fiber ring laser with dispersion managed cavity is reported. The laser emits intense bunched noise-like pulses including the transform limited pulses. The optical spectrum of the laser emission has a bandwidth as broad as 32.10 nm. It was found that purely depending on the linear cavity phase delay the laser could be switched between the soliton operation and the noise-like pulse emission. Numerical simulations showed that the laser emission was caused by the combined effect of soliton collapse and positive cavity feedback in the laser.

  8. Soliton collapse and bunched noise-like pulse generation in a passively mode-locked fiber ring laser.

    PubMed

    Tang, D; Zhao, L; Zhao, B

    2005-04-01

    A passively mode-locked soliton fiber ring laser with dispersion managed cavity is reported. The laser emits intense bunched noise-like pulses including the transform limited pulses. The optical spectrum of the laser emission has a bandwidth as broad as 32.10 nm. It was found that purely depending on the linear cavity phase delay the laser could be switched between the soliton operation and the noise-like pulse emission. Numerical simulations showed that the laser emission was caused by the combined effect of soliton collapse and positive cavity feedback in the laser. PMID:19495118

  9. Single-frequency, 500-ns laser pulses generated by a passively Q-switched Nd laser

    NASA Astrophysics Data System (ADS)

    Jones, D. C.; Rockwell, D. A.

    1993-03-01

    Accounts are given of the construction and performance of a narrowband Q-switched oscillator that addresses requirements for heavy amplifier saturation as well as a degree of temporal pulse-shaping prior to oscillator beam injection into the amplifier chain that can avoid the severe temporal distortion imposed by amplifier saturation. This oscillator encompasses a lamp-pumped Cr:Nd:GSGG laser rod, a saturable absorber Q switch, and several etalon surfaces forming the output coupler. This device can be used in large baseline holography.

  10. A Cr4+:YAG passively Q-switched Nd:YVO4 microchip laser for controllable high-order Hermite–Gaussian modes

    NASA Astrophysics Data System (ADS)

    Dong, Jun; He, Yu; Bai, Sheng-Chuang; Ueda, Ken-ichi; Kaminskii, Alexander A.

    2016-09-01

    A nanosecond, high peak power, passively Q-switched laser for controllable Hermite–Gaussian (HG) modes has been achieved by manipulating the saturated inversion population inside the gain medium. The stable HG modes are generated in a Cr4+:YAG passively Q-switched Nd:YVO4 microchip laser by applying a tilted pump beam. The asymmetrical saturated inversion population distribution inside the Nd:YVO4 crystal for desirable HG modes is manipulated by choosing the proper pump beam diameter and varying pump power. A HG9,8 mode passively Q-switched Nd:YVO4 microchip laser with average output power of 265 mW has been obtained. Laser pulses with a pulse width of 7.3 ns and peak power of over 1.7 kW working at 21 kHz have been generated in the passively Q-switched Nd:YVO4 microchip laser.

  11. Passively Q-switched erbium-doped fiber laser at C-band region based on WS₂ saturable absorber.

    PubMed

    Ahmad, H; Ruslan, N E; Ismail, M A; Reduan, S A; Lee, C S J; Sathiyan, S; Sivabalan, S; Harun, S W

    2016-02-10

    We demonstrate a Q-switched erbium-doped fiber laser using tungsten disulfide (WS₂) as a saturable absorber. The WS₂ is deposited onto fiber ferrules using a drop-casting method. Passive Q-switched pulses operating in the C-band region with a central wavelength of 1560.7 nm are successfully generated by a tunable pulse repetition rate ranging from 27.2 to 84.8 kHz when pump power is increased from 40 to 220 mW. At the same time, the pulse width decreases from a maximum value of 3.84 μs to a minimum value of 1.44 μs. The signal-to-noise ratio gives a stable value of 43.7 dB. The modulation depth and saturation intensity are measured to be 0.99% and 36.2  MW/cm², respectively. PMID:26906366

  12. First demonstration of passively mode-locked Yb:CaF2 thin-disk laser

    NASA Astrophysics Data System (ADS)

    Dannecker, Benjamin; Délen, Xavier; Wentsch, Katrin S.; Weichelt, Birgit; Hönninger, Clemens; Voss, Andreas; Abdou Ahmed, Marwan; Graf, Thomas

    2015-02-01

    The need for ultra-short (sub-ps) pulsed laser systems with high power and high energy has advanced the mode-locked Ytterbium-doped thin-disk technology in the last decade. Therefore several research groups have made efforts to explore new laser crystals e.g. Yb:SSO, Yb:CAlGO or Yb:Lu2O3 for the generation of sub-500 fs pulses in thin-disk oscillators. Another promising and known candidate for ultra-short pulsed lasers is Yb:CaF2, which has been so far only used in bulk laser architecture. In this work, we present the first demonstration of a mode-locked Yb:CaF2 laser in thin-disk configuration. The resonator cavity was designed for eight passes through the disk per roundtrip at a repetition rate of 35 MHz. A saturable absorber mirror (SESAM) was used to obtain the soliton mode-locking. We achieved close-to transform-limited pulses with a pulse duration of less than 445 fs and an emission spectral width of 2.6 nm at FWHM (i.e. time-bandwidth product of 0.323). At the average output power of 6.6 W this corresponds to a peak-power of 430 kW and pulse energy of 190 nJ. To the best of our knowledge, this is the highest average output power and pulse energy using Yb:CaF2 as gain material reported to date. Taking into account the dispersion, self-phase modulation, pulse energy, output coupling ratio and laser gain, the pulse-duration estimated from the soliton-equation and our numerical calculations of pulse-propagation is in good agreement with the pulse-duration obtained in the experiment. Higher powers and shorter pulse-durations with this material are the subject of our future investigations.

  13. Experimental and theoretical studies of complex pulse evolutions in a passively mode-locked ring dye laser

    SciTech Connect

    Avramopoulos, H.; French, P.M.W.; Williams, J.A.R.; New, G.H.C.; Taylor, J.R. )

    1988-09-01

    The optimization of any femtosecond laser requires the various sources of frequency chirp to be taken into account. In particular, for a passively mode-locked CPM ring dye laser, the effects of group velocity dispersion and self-phase modulation arising from time-dependent absorption saturation and the optical Kerr effect must be considered. In this paper a detailed experimental and theoretical study has been made of the role of these parameters in a Rhodamine 110 CPM dye laser. Periodic pulse evolutions are observed, when both positive and negative frequency chirp are present, which are reminiscent of those governed by the nonlinear Schrodinger equation but which are, in fact, distinctly different. Similar results have been obtained with the standard Rhodamine 6G system and it is believed that the theoretical model is generally applicable to any passively mode-locked femtosecond dye laser. An important consequence of this work is that is permits the absolute value of the net group velocity dispersion in the laser cavity to be estimated.

  14. Dual-wavelength passively q-switched single-frequency fiber laser.

    PubMed

    Zhang, Yuanfei; Yang, Changsheng; Feng, Zhouming; Deng, Huaqiu; Peng, Mingying; Yang, Zhongmin; Xu, Shanhui

    2016-07-11

    We propose a compact dual-wavelength Q-switched single-frequency fiber laser based on a 17-mm-long home-made highly Er3+/Yb3+ co-doped phosphate fiber (EYDPF) and a semiconductor saturable absorber mirror (SESAM). The short cavity length and a polarization-maintaining fiber Bragg grating (PM-FBG) ensure that only one longitudinal mode is supported by each reflection peak. The maximum pulse energy of more than 34.5 nJ was realized with the shortest pulse duration of 110.5 ns and the Q-switched fiber laser has a repetition rate reaching over 700 kHz with a temporal synchronization of pulses at two wavelengths. Besides, the optical signal-to-noise ratio (OSNR) of larger than 64.5 dB was achieved. PMID:27410881

  15. Numerical Study of Passive Q Switching of a Tm:YAG Laser with a Ho:YLF Solid-State Saturable Absorber

    NASA Astrophysics Data System (ADS)

    Kuo, Yen-Kuang; Chang, Yi-An

    2003-03-01

    In a previous work [Appl. Phys. Lett. 65 , 3060 (1994) we experimentally demonstrated that passive ]Q switching of a 2017-nm, flashlamp-pumped Tm,Cr:YAG laser with a Ho:YLF saturable absorber could be obtained with an internal focusing lens. We numerically investigate the optical performance of the Ho:YLF Q -switched Tm:YAG laser system by solving the coupled rate equations. The simulation results indicate that the results obtained numerically are in good agreement with those obtained experimentally. With typical laser configuration, a Q -switched laser pulse of 35 mJ in 30 ns is obtained.

  16. Compact, Passively Q-Switched Nd:YAG Laser for the MESSENGER Mission to the Planet Mercury

    NASA Technical Reports Server (NTRS)

    Krebs, Danny J.; Novo-Gradac, Anne-Marie; Li, Steven X.; Lindauer, Steven J.; Afzal, Robert S.; Yu, Antony

    2004-01-01

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter (MLA) instrument which is an instrument on the MESSENGER mission to the planet Mercury. The laser achieves 5.4 percent efficiency with a near diffraction limited beam. It has passed all space flight environmental tests at system, instrument, and satellite integration. The laser design draws on a heritage of previous laser altimetry missions, specifically ISESAT and Mars Global Surveyor; but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

  17. Continuous-wave and passively Q-switched 1.06 μm ceramic Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    He, Ying; Ma, Yufei; Li, Jiang; Li, Xudong; Yan, Renpeng; Gao, Jing; Yu, Xin; Sun, Rui; Pan, Yubai

    2016-07-01

    In this paper, a diode-pumped continuous-wave and passively Q-switched 1.06 μm laser with gain medium of ceramic was demonstrated. Laser output characteristics using Nd:YAG ceramics with different doping concentrations of 1.0%, 2.0%, and 4.0% were studied. A maximum output power of 7.74 W with optical efficiency of 51.6% was obtained through the optimization of the coupler's transmission. By using Cr4+:YAG crystals with initial transmissions of 80% and 90% as saturable absorbers, the pulsed ceramic Nd:YAG laser performance was investigated.

  18. Cr4 + :Gd3Sc2Ga3O12 passive Q-switch for the Cr3 + :LiCaAlF6 laser

    NASA Astrophysics Data System (ADS)

    Kuo, Yen-Kuang; Yang, Yang; Birnbaum, Milton

    1994-05-01

    A Cr4+:Gd3Sc2Ga3O12 (Cr4+:GSGG) broad-band saturable absorber has been demonstrated to be an excellent passive Q-switch for the flashlamp-pumped tunable Cr3+:LiCaAlF6 (Cr:LiCAF) laser at room temperature. A single Q-switched laser output pulse of 11 mJ in energy and 37 ns in duration at 778 nm was obtained in a nonoptimized laser.

  19. Theoretical and experimental investigation of the nonlinear dynamical trends of passively mode-locked quantum dot lasers

    NASA Astrophysics Data System (ADS)

    Raghunathan, Ravi

    In recent years, passively mode-locked quantum dot lasers have shown great promise as compact, efficient and reliable pulsed sources of light for a range of precision and high performance applications, such as high bit-rate optical communications, diverse waveform generation, metrology, and clock distribution in high-performance computing (HPC) processors. For such applications, stable optical pulses with short picosecond pulse durations and multi-gigahertz repetition rates are required. In addition, a low pulse-to-pulse timing jitter is also necessary to prevent errors arising from the ambiguity between neighboring pulses. In order to optimize pulse quality in terms of optical characteristics such as pulse shape and pulse train behavior, as well as RF characteristics such as phase noise and timing jitter, understanding the nonlinear output dynamics of such devices is of critical importance, not only to get a sense of the regimes of operation where device output might be stable or unstable, but also to gain insight into the parameters that influence the output characteristics the most, and how they can be accessed and exploited to optimize design and performance for next generation applications. In this dissertation, theoretical and experimental studies have been combined to investigate the dynamical trends of two-section passively mode-locked quantum dot lasers. On the theoretical side, a novel numerical modeling scheme is presented as a powerful and versatile framework to study the nonlinear dynamics specific to a device, with device-specific parameters extracted over a range of operating conditions. The practical utility of this scheme is then demonstrated, first, in an analytical capability to interpret and explain dynamical trends observed in experiment, and subsequently, as a predictive tool to guide experiment to operate in a desired dynamical regime. Modeling results are compared to experimental findings where possible. Finally, optical feedback from an

  20. Passive mode locking of a femtosecond Ti:sapphire laser with pulsed synchronous pumping by a finite train of picosecond pulses

    SciTech Connect

    Borisevich, N A; Buganov, O V; Tikhomirov, S A; Tolstorozhev, G B; Shkred, G L

    1999-09-30

    An analysis is made, with the aid of the self-consistent nonlinear ABCD matrix method, of the specific features of the mechanism of passive mode locking of a femtosecond Ti:sapphire laser under conditions of pulsed synchronous pumping. The conditions of stable laser operation are studied. It is proposed to use an additional aperture as an element of negative feedback for the stabilisation of passive mode locking. Practical recommendations concerning the optimisation of a femtosecond laser are given. (control of laser radiation parameters)

  1. High-power passively mode-locked laser at 1062.4  nm based on Nd:LaGGG disordered crystal.

    PubMed

    Su, Xiancui; Zhao, Ruwei; Zhang, Baitao; Jia, Zhitai; Hou, Jia; He, Jingliang

    2015-03-10

    A diode-pumped passively continuous-wave mode-locked Nd:(La(x)Gd(1-x))3Ga5O12 (Nd:LaGGG) laser at 1062.4 nm with a semiconductor saturable absorber mirror was demonstrated for the first time, to the best of our knowledge. Pulses with duration of 12.78 ps were produced at a repetition rate of 59.8 MHz. A maximum average mode-locked output power of 3.18 W was obtained at the absorbed pumped power of 10.12 W, corresponding to a slope efficiency of 35.7% and a peak power of 4.2 kW. As far as we know, this is the highest power obtained in the passively mode-locking operation with Nd3+-doped disordered garnet crystals. PMID:25968392

  2. Observation of multipulse bunches in a graphene oxide passively mode-locked ytterbium-doped fiber laser with all-normal dispersion

    NASA Astrophysics Data System (ADS)

    Huang, Shisheng; Wang, Yonggang; Peiguang, Yan; Zhang, Gelin; Zhao, Junqing; Li, Huiquan; Lin, Rongyong; Cao, Guangzhong; Duan, Ji'an

    2014-09-01

    We give a systematic experimental study of multipulse bunches in a graphene oxide saturable absorber (GOSA) passively mode-locked all-normal dispersion ytterbium-doped fiber laser (YDFL). Some special phenomena such as harmonic multipulse bunches, harmonic mode-locking, and chaotic multipulse states are also obtained. Our experiment reveals that the inserted 2.5-nm narrow bandwidth filter plays an important role in the formation of multipulse in all-normal dispersion fiber lasers. Because of the effective gain bandwidth depends on both the 2.5-nm narrow bandwidth filter and the artificial fiber birefringence filter, the multipulse operation states are sensitive to the polarization. It is the first demonstration of multipulse evolution in a GOSA passively mode-locked all-normal dispersion YDFL.

  3. Passive mode locking of a GaSb-based quantum well diode laser emitting at 2.1 μm

    SciTech Connect

    Merghem, K.; Aubin, G.; Ramdane, A.; Teissier, R.; Baranov, A. N.; Monakhov, A. M.

    2015-09-14

    We demonstrate passive mode locking of a GaSb-based diode laser emitting at 2.1 μm. The active region of the studied device consists in two 10-nm-thick GaInSbAs/GaAlSbAs quantum wells. Passive mode locking has been achieved in a two-section laser with one of the sections used as a saturable absorber. A microwave signal at 20.6 GHz, measured in the electrical circuit of the absorber, corresponds to the fundamental photon round-trip frequency in the laser resonator. The linewidth of this signal as low as ∼10 kHz has been observed at certain operating conditions, indicating low phase noise mode-locked operation.

  4. Passively mode-locked Tm,Ho:YAG laser at 2 microm based on saturable absorption of intersubband transitions in quantum wells.

    PubMed

    Yang, Kejian; Bromberger, Hubertus; Ruf, Hartmut; Schäfer, Hanjo; Neuhaus, Joerg; Dekorsy, Thomas; Grimm, Christiana Villas-Boas; Helm, Manfred; Biermann, Klaus; Künzel, Harald

    2010-03-29

    We report the first demonstration of a solid state laser passively mode-locked through the saturable absorption of short-wavelength intersubband transitions in doped quantum wells: a continuous wave Ti:sapphire laser end-pumped Tm,Ho:YAG laser at the center wavelength of 2.091 mum utilizing intersubband transitions in narrow In(0.53)Ga(0.47)As/Al(0.53)As(0.47)Sb quantum wells. Stable passive mode-locking operation with maximum average output power of up to 160 mW for 2.9 W of the absorbed pump power could last for hours without external interruption and a mode-locked pulse with duration of 60 ps at repetition rate of 106.5 MHz was generated. PMID:20389677

  5. High-pulse-energy passively mode-locked Nd:YVO4 laser without spatial hole burning effect

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Chen, Meng; Li, Gang

    2014-05-01

    We report on a high-pulse-energy 888 nm diode-pumped passively mode-locked TEM00 Nd:YVO4 oscillator without spatial hole burning (SHB) effect in active medium. At a pump power of 40 W, the oscillator produced pulse energy up to 270 nJ at a repetition rate of 50 MHz, corresponding to average power of 13.5W with 34% optical-to-optical efficiency. To the best of our knowledge, it is the highest pulse energy obtained at the same pump power. The pulse duration produced varied from 16 to 59 ps. By varying the pump power, we observed a pulse duration ranging from 52 to 59 ps while the time-bandwidth product remained 0.88, and the factors that affect the pulse duration were also discussed. Meanwhile, a novel method of adjusting output coupling (OC) was introduced, which can simplify the structure of laser.

  6. 2 GHz passively harmonic mode-locked fiber laser by a microfiber-based topological insulator saturable absorber.

    PubMed

    Luo, Zhi-Chao; Liu, Meng; Liu, Hao; Zheng, Xu-Wu; Luo, Ai-Ping; Zhao, Chu-Jun; Zhang, Han; Wen, Shuang-Chun; Xu, Wen-Cheng

    2013-12-15

    We report on the generation of passive harmonic mode locking of a fiber laser using a microfiber-based topological insulator (TI) Bi(2)Te(3) saturable absorber (SA). The optical deposition method was employed to fabricate the microfiber-based TISA. By virtue of the excellent nonlinear optical property of the proposed TISA, the fiber laser could operate at the pulse repetition rate of 2.04 GHz under a pump power of 126 mW, corresponding to the 418th harmonic of fundamental repetition frequency. The results demonstrate that the microfiber-based TI photonic device can operate as both the high nonlinear optical component and the SA in fiber lasers, and could also find other applications in the related fields of photonics. PMID:24322220

  7. Sub-300 femtosecond soliton tunable fiber laser with all-anomalous dispersion passively mode locked by black phosphorus.

    PubMed

    Chen, Yu; Chen, Shuqing; Liu, Jun; Gao, Yanxia; Zhang, Wenjing

    2016-06-13

    By using evanescent field optical deposition method, we had successfully fabricated an effective optoelectronic device based on multi-layer black phosphorus (BP), which is been heavily investigating 2 dimensional (2D) semiconducting material with similar structure as graphene and thickness dependent direct band-gap. By placing this BP-based optoelectronic device inside a highly compact all-anomalous dispersion fiber laser cavity, stable passive mode-locking operation could be ensured and eventually a record 280 fs transmission limited soliton pulse with tunable central wavelength had been obtained through finely tailoring the cavity length. Other operation states, like bound soliton and noise-like state, had also been observed as well. This work demonstrates the enormous potential of BP for ultra-short pulse generation as an effective optoelectronic device. PMID:27410348

  8. Experimental investigations on spectrum width of square-wave pulses in passively mode-locked figure-8 fiber laser

    NASA Astrophysics Data System (ADS)

    Mei, Li; Xu, Lixin; Chen, Guoliang; Gu, Chun; Zhang, Xianming; Sun, Biao; Lin, Jian; Wang, Anting

    2014-10-01

    We have proposed and demonstrated a nanosecond square-wave fiber laser working in the 1060nm band. The passively mode-locked fiber laser based on the nonlinear optical loop mirror has a peak power clamping effect which leads to the generation of nanosecond square-wave pulses. To investigate the spectrum width of the nanosecond square-wave pulse laser, we added couplers with different coupling ratio to the bidirectional ring of the figure-8 fiber laser and analyzed the laser output. The results show that a higher output coupling ratio leads to stronger peak power clamping effect, and the peak power of the square-wave pulse gets lower and the corresponding spectrum band width is narrower.

  9. A passively mode-locked intracavity frequency doubled Nd:YVO4 femtosecond green laser based on graphene

    NASA Astrophysics Data System (ADS)

    Shi, R. P.; Bai, Y.; Qi, M.; Chen, X. M.; Wei, H. D.; Ren, Z. Y.; Bai, J. T.

    2014-02-01

    By using an atmospheric-pressure chemical vapor deposition (APCVD) method with a C2H2 carbon source, seven-layer graphene films as saturable absorbers are fabricated and transferred to an anti-reflective mirror of 1064 nm wavelength range. Based on this transmission-type graphene saturable absorber mirror (GSAM), a continuous wave (CW) passively mode-locked femtosecond green laser is achieved by 808 nm laser diode (LD) end-pumped Nd:YVO4 crystal and type-I critical phase-matched LBO crystal intracavity frequency doubling for the first time. Stable ultrashort green laser pulses as short as 374 fs are measured with a repetition rate of 71.4 MHz and an average output power of 117 mW at a central wavelength of 531.7 nm.

  10. LD-end-pumped passively Q-switched Nd:YAG ceramic laser with single wall carbon nanotube saturable absorber

    NASA Astrophysics Data System (ADS)

    Li, C. Y.; Bo, Y.; Zong, N.; Wang, Y. G.; Jiang, B. X.; Pan, Y. B.; Niu, G.; Fan, Z. W.; Peng, Q. J.; Cui, D. F.; Xu, Z. Y.

    2012-10-01

    We report on a LD-end-pumped passively Q-switched Nd:YAG ceramic laser by using a novel single wall carbon nanotube saturable absorber (SWCNT-SA). The SWCNT wafer was fabricated by electric Arc discharge method on quartz substrate with absorption wavelength of 1064 nm. We firstly investigated the continuous wave (CW) laser performance and scattering properties of Nd:YAG ceramic sample. For the case of passively Q-switched operation, a maximum output power of 376 mW was obtained at an incident pump power of 8.68 W at 808 nm, corresponding to an optical-optical conversion efficiency of 4.3%. The repetition rate as the increase of pump power varied from 14 to 95 kHz. The minimum pulse duration of 1.2 μs and maximum pulse energy of 4.5 μJ was generated at a repetition rate of 31.8 kHz.

  11. Ultrafast in-situ probing of passively mode-locked VECSEL dynamics

    NASA Astrophysics Data System (ADS)

    Scheller, Maik; Baker, Caleb W.; Gbele, Kokou; Koch, Stephan W.; Jones, R. Jason; Moloney, Jerome V.

    2015-03-01

    While Vertical-External-Cavity-Surface-Emitting-Lasers (VECSELs) have been successfully used as ultrafast laser sources with pulse durations in the hundreds of femtosecond regime, the dynamics within the semiconductor gain structure are not yet completely understood. With the high carrier densities inside the semiconductor, nonequilibrium effects such as kinetic-hole burning are expected to play a major role in pulse formation dynamics. Moreover, the nonlinear phase change by the intense light field can induce a complex dispersion, which may potentially limit the achievable pulse durations. To shed light on such nonequilibrium dynamics, we perform in-situ characterization of mode-locked VECSELs. We probe the gain media as well as the intracavity absorber with a femtosecond fiber laser source. For measuring temporal characteristics, we employ an asynchronous optical sampling technique by phase-locking the repetition rate of the VECSEL to a multiple of the probe laser with an adjustable offset frequency. This allows for probing dynamics from femtosecond to nanosecond time scales with scan rates up to hundreds of Hertz without compromise of measurement precision which can be introduced by mechanical delays covering such large temporal windows. With a resolution in the femtosecond range, we characterize gain depletion by the intracavity pulse as well as the gain recovery timescales for different power levels and operation regimes.

  12. High efficiency passively mode-locked Nd:YVO4 laser with direct in-band pumping at 914 nm.

    PubMed

    Waritanant, Tanant; Major, Arkady

    2016-06-13

    We report on the performance of a semiconductor saturable absorber mirror passively mode-locked Nd:YVO4 laser with in-band pumping at 914 nm and with the highest slope efficiency to date among the mode-locked Nd-lasers. The laser produced 6.7 W of output power with repetition rate of 87 MHz and pulse duration of 16 ps. The slope efficiency of 77.1% and the optical-to-optical efficiency of 60.7% were achieved. PMID:27410304

  13. Experimental study on the multisoliton pattern formation in an erbium-doped fiber laser passively mode-locked by graphene saturable absorber

    NASA Astrophysics Data System (ADS)

    Feng, Qi; Chen, Yu; Zhao, Chujun; Li, Ying; Wen, Jianguo; Zhang, Han

    2013-04-01

    We demonstrate an erbium-doped fiber laser passively mode-locked by few layers of graphene prepared by the mechanical exfoliation of the high oriented pyrolytic graphite through the Scotch-tape method. This all-fiber ring cavity delivered a pulse train with a repetition rate of 1.646 MHz and pulse duration of 1.656 ps. By continuously adjusting the laser cavity parameters, one can observe various soliton patterns, such as ordered-, chaotic-, bunched-, and harmonic-multisoliton state. This evidenced that a mode-locked fiber laser based on graphene saturable absorber indeed provided a well-controlled nonlinear optics platform for soliton dynamics study.

  14. CONTROL OF LASER RADIATION PARAMETERS. GENERATION OF ULTRASHORT PULSES: Passive mode locking in a cw dye laser with a rapidly relaxing absorber

    NASA Astrophysics Data System (ADS)

    Krindach, D. P.; Kur'yanov, A. A.; Novoderezhkin, V. I.

    1990-12-01

    Theoretical and experimental investigations were made of the characteristics of passive mode locking in a cw dye laser with a rapidly relaxing absorber. It was found that such a "fast" absorber was prone to fluctuations. This altered the limits and widened the mode-locking range in the direction of higher energy densities of the pulses, compared with a "slow" absorber of the DODCI type. This made it possible to generate pulses shorter than 100 fs with an average power of 30-50 mW.

  15. High-pulse-energy passively Q-switched quasi-monolithic microchip lasers operating in the sub-100-ps pulse regime.

    PubMed

    Nodop, D; Limpert, J; Hohmuth, R; Richter, W; Guina, M; Tünnermann, A

    2007-08-01

    We present passively Q-switched microchip lasers with items bonded by spin-on-glass glue. Passive Q-switching is obtained by a semiconductor saturable absorber mirror. The laser medium is a Nd:YVO(4) crystal. These lasers generate pulse peak powers up to 20 kW at a pulse duration as short as 50 ps and pulse repetition rates of 166 kHz. At 1064 nm, a linear polarized transversal and longitudinal single-mode beam is emitted. To the best of our knowledge, these are the shortest pulses in the 1 microJ energy range ever obtained with passively Q-switched microchip lasers. The quasi-monolithic setup ensures stable and reliable performance. PMID:17671554

  16. Watt-level passively mode-locked Er(3+)-doped ZBLAN fiber laser at 2.8  μm.

    PubMed

    Tang, Pinghua; Qin, Zhipeng; Liu, Jun; Zhao, Chujun; Xie, Guoqiang; Wen, Shuangchun; Qian, Liejia

    2015-11-01

    We experimentally demonstrated a stable, high-average-power, continuous-wave (CW) passively mode-locked Er(3+)-doped ZBLAN fiber laser at 2.8 μm based on a semiconductor saturable absorber mirror. A stable mode-locked laser with a signal-to-noise ratio of 52 dB and a slope efficiency of 14% was obtained. The highest average output power in excess of 1 W was generated at the incident pump power of 8.2 W, with a pulse repetition rate of 22.56 MHz and pulse duration of 25 ps. To the best of our knowledge, this is the highest average output power of a CW mode-locked ZBLAN fiber laser in the mid-infrared wavelength regime up to now. PMID:26512467

  17. High energy pulses generation with giant spectrum bandwidth and submegahertz repetition rate from a passively mode-locked Yb-doped fiber laser in all normal dispersion cavity

    NASA Astrophysics Data System (ADS)

    Lin, J.-H.; Wang, D.; Lin, K.-H.

    2011-01-01

    Robust passively mode-locked pulse generation with low pulse repetition rate and giant spectrum bandwidth in an all-fiber, all-normal-dispersion ytterbium-doped fiber laser has been experimentally demonstrated using nonlinear polarization evolution technique. The highest pulse energy over 20 nJ with spectrum bandwidth over 50 nm can be experimentally obtained at 175 mW pump power. The mode-locked pulses reveal broadened 3-dB pulsewidth about several nanosecond and widened pedestal in time trace that is resulted from enormous dispersion in laser cavity and gain dynamics. At certain mode-locking state, a spectrum gap around 1056 nm are observed between the three and four energy levels of Yb-doped fiber laser. By properly rotating the polarization controller, the gap can be eliminated due to four-wave mixing to produce more flattened spectrum output.

  18. High-order harmonic noise-like pulsing of a passively mode-locked double-clad Er/Yb fibre ring laser

    NASA Astrophysics Data System (ADS)

    Pottiez, O.; Hernández-García, J. C.; Ibarra-Escamilla, B.; Kuzin, E. A.; Durán-Sánchez, M.; González-García, A.

    2014-11-01

    In this paper, we study noise-like pulse generation in a km-long fibre ring laser including a double-clad erbium-ytterbium fibre and passively mode-locked through nonlinear polarization evolution. Although single noise-like pulsing is only observed at moderate pump power, pulse energies as high as 120 nJ are reached in this regime. For higher pump power, the pulse splits into several noise-like pulses, which then rearrange into a stable and periodic pulse train. Harmonic mode locking from the 2nd to the 48th orders is readily obtained. At pump powers close to the damage threshold of the setup, much denser noise-like pulse trains are demonstrated, reaching harmonic orders beyond 1200 and repetition frequencies in excess of a quarter of a GHz. The mechanisms leading to noise-like pulse breaking and stable high-order harmonic mode locking are discussed.

  19. Passive mode-locking characteristics from the Nd:Gd0.19Y0.81VO4 laser at 1.34 μm

    NASA Astrophysics Data System (ADS)

    Qiao, Wenchao; Chu, Hongwei; Zhao, Shengzhi; Li, Guiqiu; Yang, Kejian; Li, Tao; Zhao, Jia

    2016-08-01

    We report a passively continuous-wave mode-locked (CWML) Nd:Gd0.19Y0.81VO4 laser oscillating at 1342.3 nm for the first time in this paper. Stable mode-locked pulse cluster with a pulse width of 7.2 ps and a pulse repetition frequency of 32.8 MHz has been realized with a semiconductor saturable absorber mirror (SESAM). The highest output power was 880 mW when the incident pump power was 7.1 W, corresponding to an optical conversion efficiency of 12.4%. The mode-locked pulse energy was about 26.83 nJ, while the peak power was 3.73 kW.

  20. Single-walled carbon nanotube saturable absorber for a diode-pumped passively mode-locked Nd,Y:SrF2 laser

    NASA Astrophysics Data System (ADS)

    Li, Chun; Cai, Wei; Liu, Jie; Su, Liangbi; Jiang, Dapeng; Ma, Fengkai; Zhang, Qian; Xu, Jun; Wang, Yonggang

    2016-08-01

    A reflective single-walled carbon nanotube as saturable absorber has been firstly adopted to a passively mode-locked Nd,Y:SrF2 crystal. Without any dispersion compensation, the stably mode-locked laser delivers pulses with pulse width as short as 1.7 ps, repetition rate of 107.8 MHz and center wavelength of 1056 nm. The oscillator produces maximum average output power of 319 mW corresponding with a high slope efficiency of 20.2%. The single pulse energy and the peak power are 2.96 nJ and 1.74 kW, respectively. The experimental results show that single-walled carbon nanotube is an excellent saturable absorber for mode-locked lasers.

  1. Yb:YAG thin disk laser passively Q-switched by a hydro-thermal grown molybdenum disulfide saturable absorber

    NASA Astrophysics Data System (ADS)

    Zhan, Yi; Wang, Li; Wang, Jie Yu; Li, Hong Wei; Yu, Zhen Huang

    2015-02-01

    We demonstrate a passively Q-switched Yb:YAG thin disk solid-state laser based on nanoflake MoS2 as a saturable absorber. MoS2 is synthesized by a hydro-thermal process. The prepared MoS2 is transferred onto the BK7 glass for ease-of-use in the solid-state laser as a saturable absorber. The average output power could reach up to 250 mW, center wavelength 1030 nm corresponding to a pulse width, a pulse repetition rate, and a per pulse energy of 12 μs, 17 kHz, and 15 μJ, respectively. Our results show that nanoflake MoS2 could be a promising saturable absorber for Q-switching solid-state lasers. The over saturation of the MoS2 saturable absorber at a high pump strength limit in a solid-state laser could be also effective for high power operation.

  2. Passively Q-switched dual-wavelength Yb:LSO laser based on tungsten disulphide saturable absorber

    NASA Astrophysics Data System (ADS)

    Jing-Hui, Liu; Jin-Rong, Tian; He-Yang, Guoyu; Run-Qin, Xu; Ke-Xuan, Li; Yan-Rong, Song; Xin-Ping, Zhang; Liang-Bi, Su; Jun, Xu

    2016-03-01

    We demonstrate a passively Q-switched Yb:LSO laser based on tungsten disulphide (WS2) saturable absorber operating at 1034 nm and 1056 nm simultaneously. The saturable absorbers were fabricated by spin coating method. With low speed, the WS2 nanoplatelets embedded in polyvinyl alcohol could be coated on a BK7 glass substrate coated with high-refractive-index thin polymer. The shortest pulse width of 1.6 μs with a repetition rate of 76.9 kHz is obtained. As the pump power increases to 9 W, the maximum output power is measured to be 250 mW, corresponding to a single pulse energy of 3.25 μJ. To the best of our knowledge, this is the first time to obtain dual-wavelength Q-switched solid-state laser using few-layer WS2 nanoplatelets. Project supported by the National Scientific Research Project of China (Grant No. 61177047), Beijing Municipal Natural Science Foundation, China (Grant No. 1102005), and the Basic Research Foundation of Beijing University of Technology, China (Grant No. X3006111201501).

  3. Third-order nonlinearity and passive Q-switching of Cr⁴⁺:YGG garnet crystal.

    PubMed

    Wang, Shuxian; Zhang, Yuxia; Wu, Kui; Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Zhang, Guanghui; Xiong, Qihua

    2015-05-15

    We demonstrate the third-order nonlinear optical properties of Cr(4+):Y(3)Ga(5)O(12) (Cr(4+):YGG) and Q-switched lasers with Cr(4+):YGG as the saturable absorber for the first time to our knowledge. The third-order nonlinear properties, including the optical Kerr nonlinearity and saturable absorption, were systematically measured and analyzed in detail by using a Z-scan technique. The measured data show that Cr(4+):YGG has a large nonlinear refractive index, ground-state absorption cross section, and excited-state absorption cross section in contrast to Cr(4+):Y(3)Al(5)O(12) (Cr(4+):YAG). With a Nd:YGG crystal as the gain medium and a Cr(4+):YGG crystal as the saturable absorber, the passively Q-switched laser was performed. The shortest pulse width and largest pulse energy were achieved at the absorbed pump power of 8 W with the values of 9.1 ns and 26.1 μJ, respectively, corresponding to the average output power of 0.87 W and peak power of 2.9 kW. The results indicate that Cr(4+):YGG is an available and promising optical switcher for pulsed lasers. PMID:26393755

  4. MoS2 nanoflowers as high performance saturable absorbers for an all-fiber passively Q-switched erbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Wei, Rongfei; Zhang, Hang; Tian, Xiangling; Qiao, Tian; Hu, Zhongliang; Chen, Zhi; He, Xin; Yu, Yongze; Qiu, Jianrong

    2016-03-01

    Strong saturable absorption was observed in MoS2 nanoflowers, which were synthesized by a facile solvothermal method. A MoS2 nanoflower-based saturable absorber with a high modulation depth of 51.8% and a large saturable intensity of 275.5 GW cm-2 was introduced to the application of passively Q-switched fiber laser generation. Stable passively Q-switched fiber laser pulses at 1.56 μm with a low threshold power of 16.10 mW, high signal-to-noise ratio of 52.5 dB and short pulse duration of 1.9 μs were obtained. More importantly, a high output power of 3.10 mW related to a large pulse energy of about 51.84 nJ can be attained at a very low pump power. The efficiency of the laser reaches 4.71%, which is larger than that of the prepared layered MoS2 and recently reported MoS2-based passively Q-switching operations. Such results imply that the MoS2 nanoflowers are an excellent candidate for a saturable absorber in passively Q-switched fiber lasers at a low pump intensity.Strong saturable absorption was observed in MoS2 nanoflowers, which were synthesized by a facile solvothermal method. A MoS2 nanoflower-based saturable absorber with a high modulation depth of 51.8% and a large saturable intensity of 275.5 GW cm-2 was introduced to the application of passively Q-switched fiber laser generation. Stable passively Q-switched fiber laser pulses at 1.56 μm with a low threshold power of 16.10 mW, high signal-to-noise ratio of 52.5 dB and short pulse duration of 1.9 μs were obtained. More importantly, a high output power of 3.10 mW related to a large pulse energy of about 51.84 nJ can be attained at a very low pump power. The efficiency of the laser reaches 4.71%, which is larger than that of the prepared layered MoS2 and recently reported MoS2-based passively Q-switching operations. Such results imply that the MoS2 nanoflowers are an excellent candidate for a saturable absorber in passively Q-switched fiber lasers at a low pump intensity. Electronic supplementary

  5. LD-pumped passively Q-switched Nd:GGG laser at 1062 nm with a GaAs saturable absorber

    NASA Astrophysics Data System (ADS)

    Zhang, H. N.; Li, P.; Wang, Q. P.; Chen, X. H.

    2011-11-01

    we have experimentally studied the passively Q-switched performance of a diode-pumped Nd:GGG laser at 1062 nm with a GaAs saturable absorber, in the experiment when the pumped power was 9.8 W, the maximum CW output power of 5.1 W was obtained. The optical conversion efficiency and the slop efficiency were 52 and 53%, respectively. The threshold was 0.9 W. In the passively Q-switched regime, we get the average output power of 0.93 W. The shortest pulse width and pulse repetition rate were 7 ns and 188 kHz, respectively.

  6. Passively Q-switched 2 μm Tm:YAP laser based on graphene saturable absorber mirror.

    PubMed

    Hou, Jia; Zhang, Baitao; He, Jingliang; Wang, Zhaowei; Lou, Fei; Ning, Jian; Zhao, Ruwei; Su, Xiancui

    2014-08-01

    Using high-quality single-layer graphene as a saturable absorber, Tm:YAlO₃ (Tm:YAP) crystal as the gain medium, we demonstrated a laser-diode-pumped, compact, passively Q-switched (PQS) solid-state laser in the 2 μm region. The maximum average output power was 362 mW, with the corresponding largest pulse repetition rate and pulse energy of 42.4 kHz and 8.5 μJ, respectively. Under the same pump power, the pulse width of 735 ns was obtained, which is, to our best knowledge, the shortest pulse width among Tm-doped solid-state PQS lasers using graphene saturable absorber mirrors. PMID:25090328

  7. Passively Q-switched 1617-nm polycrystalline ceramic Er:YAG laser using a Cr:ZnSe saturable absorber

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoqi; Shen, Deyuan; Huang, Haitao; Liu, Jun; Zhang, Jian; Tang, Dingyuan; Fan, Dianyuan

    2015-08-01

    We report on a passively Q-switched polycrystalline ceramic Er:YAG laser by using a Cr:ZnSe crystal as a saturable absorber. When pumped by a 1532-nm Er-, Yb-doped fiber laser with the maximum power of 12.4 W, the laser yielded pulses of 28.8 ns duration at 1617 nm by using a saturable absorber with an initial transmission of 80 %. The corresponding peak power was up to 11.3 kW at a repetition rate of 2.17 kHz. The dependence of the pulse duration and repetition rate on the pump power was experimentally studied. The numerical and experimental results both show that the pulse duration was mainly determined by the initial transmission of the saturable absorber and slightly affected by the transmission of the output coupler. At last, we give some prospects for further narrowing down the pulse duration.

  8. Analytical solution of the transient temperature profile in gain medium of passively Q-switched microchip laser.

    PubMed

    Han, Xiahui; Li, Jianlang

    2014-11-01

    The transient temperature evolution in the gain medium of a continuous wave (CW) end-pumped passively Q-switched microchip (PQSM) laser is analyzed. By approximating the time-dependent population inversion density as a sawtooth function of time and treating the time-dependent pump absorption of a CW end-pumped PQSM laser as the superposition of an infinite series of short pumping pulses, the analytical expressions of transient temperature evolution and distribution in the gain medium for four- and three-level laser systems, respectively, are given. These analytical solutions are applied to evaluate the transient temperature evolution and distribution in the gain medium of CW end-pumped PQSM Nd:YAG and Yb:YAG lasers. PMID:25402922

  9. CW and passively Q-switched laser performance of Nd:Lu2SiO5 crystal

    NASA Astrophysics Data System (ADS)

    Xu, Xiaodong; Di, Juqing; Zhang, Jian; Tang, Dingyuan; Xu, Jun

    2016-01-01

    We demonstrated an efficient and controllable dual-wavelength continuous-wave (CW) laser of Nd:Lu2SiO5 (Nd:LSO) crystal. The maximum output power was 3.02 W at wavelength of 1075 nm and 1079 nm, and with increasing of absorbed pump power, the ratio of 1079 nm laser rose. The slope efficiency of 65.6% and optical-to-optical conversion efficiency of 63.3% were obtained. The passively Q-switched laser properties of Nd:LSO were investigated for the first time. The shortest pulse, maximum pulse energy and peak power were 11.58 ns, 29.05 μJ and 2.34 kW, respectively.

  10. Narrow-band 1 W source at 257 nm using frequency quadrupled passively Q-switched Yb:YAG laser.

    PubMed

    Goldberg, Lew; Cole, Brian; McIntosh, Chris; King, Vernon; Hays, A D; Chinn, Stephen R

    2016-07-25

    We describe generation of 1.1 W of 257 nm emission by frequency quadrupling the 1030 nm emission from a compact passively Q-switched Yb:YAG laser. The laser utilized a volume Bragg grating to achieve a 0.1 nm linewidth required for UV-Raman spectroscopic applications, generated 100 kW peak power, 250 μJ pulses and 3.6 W of average power at 1030 nm. Fourth harmonic generation (FHG) was carried out using a 10 mm lithium triborate (LBO) crystal to generate 515 nm second harmonic with 70% conversion efficiency, followed by a 7 mm beta-barium borate (BBO) crystal to generate 257 nm fourth harmonic with 45% efficiency, resulting in an overall nonlinear conversion efficiency of 31%. Far-field and near-field of the FHG emission were characterized. PMID:27464186

  11. High-damage-resistant tungsten disulfide saturable absorber mirror for passively Q-switched fiber laser.

    PubMed

    Chen, Hao; Chen, YuShan; Yin, Jinde; Zhang, Xuejun; Guo, Tuan; Yan, Peiguang

    2016-07-25

    In this paper, we demonstrate a high-damage-resistant tungsten disulfide saturable absorber mirror (WS2-SAM) fabricated by magnetron sputtering technique. The WS2-SAM has an all-fiber-integrated configuration and high-damage-resistant merit because the WS2 layer is protected by gold film so as to avoid being oxidized and destroyed at high pump power. Employing the WS2-SAM in an Erbium-doped fiber laser (EDFL) with linear cavity, the stable Q-switching operation is achieved at central wavelength of 1560 nm, with the repetition rates ranging from 29.5 kHz to 367.8 kHz and the pulse duration ranging from 1.269 μs to 154.9 ns. For the condition of the maximum pump power of 600 mW, the WS2-SAM still works stably with an output power of 25.2 mW, pulse energy of 68.5 nJ, and signal-noise-ratio of 42 dB. The proposed WS2-SAM configuration provides a promising solution for advanced pulsed fiber lasers with the characteristics of high damage resistance, high output energy, and wide tunable frequency. PMID:27464082

  12. High-power passively mode-locked Nd:YVO(4) laser using SWCNT saturable absorber fabricated by dip coating method.

    PubMed

    Tang, Chun Yin; Chai, Yang; Long, Hui; Tao, Lili; Zeng, Long Hui; Tsang, Yuen Hong; Zhang, Ling; Lin, Xuechun

    2015-02-23

    Passive mode locked laser is typically achieved by the Semiconductor Saturable absorber Mirror, SESAM, saturable absorber, which is produced by expensive and complicated metal organic chemical vapor deposition method. Carbon based single wall carbon nanotube (SWCNT), saturable absorber, is a promising material which is capable to produce stable passive mode-locking in the high power laser cavity over a wide operational wavelength range. This study has successfully demonstrated the high power mode locking laser system operating at 1 micron by using SWCNT based absorbers fabricated by dip coating method. The proposed fabrication method is practical, simple and cost effective for fabricating SWCNT saturable absorber. The demonstrated high power Nd:YVO(4) mode-locked laser operating at 1064nm have maximum output power up to 2.7W,with the 167MHz repetition rate and 3.1 ps pulse duration, respectively. The calculated output pulse energy and peak power are 16.1nJ and 5.2kW, respectively. PMID:25836523

  13. Efficient passive Q-switching operation of a diode-pumped Nd:GdVO4 laser with a Cr4+:YAG saturable absorber

    NASA Astrophysics Data System (ADS)

    Liu, Junhai; Ozygus, Bernd; Yang, Suhui; Erhard, Jürgen; Seelig, Ute; Ding, Adalbert; Weber, Horst; Meng, Xianlin; Zhu, Li; Qin, Lianjie; Du, Chenlin; Xu, Xinguang; Shao, Zongshu

    2003-04-01

    A diode-pumped highly efficient Cr4+:YAG passively Q-switched Nd:GdVO4 laser formed by a plano-concave resonator has been demonstrated. At the highest attainable absorbed pump power of 11.4 W, 4.05 W of average output power, which was two thirds of the maximum corresponding cw output, was achieved with an optical conversion efficiency of 35.5%, and the slope efficiency was determined to be 46.8%, reaching 85% of the magnitude of its cw counterpart. The resulting shortest pulse duration, single-pulse energy, and peak power were found to be 13 ns, 90 μJ, and 7 kW, respectively, with a pulse repetition frequency (PRF) of 45 kHz. Two particularly modified resonator configurations were employed; the largest pulse energy and the highest peak power reached were, respectively, 154 μJ and 11.2 kW at 8.5 W of absorbed pump power. An analytical relation between the PRF and the absorbed pump power is given for a passively Q-switched laser, showing good consistency with experiment with a Nd:GdVO4 laser. The dependence of the operational parameters on the pump power and on the output coupling was also investigated experimentally. Issues involving the criterion for passive Q switching are discussed in some detail for Cr4+:YAG passively Q-switched neodymium-doped vanadate lasers.

  14. MoS2 nanoflowers as high performance saturable absorbers for an all-fiber passively Q-switched erbium-doped fiber laser.

    PubMed

    Wei, Rongfei; Zhang, Hang; Tian, Xiangling; Qiao, Tian; Hu, Zhongliang; Chen, Zhi; He, Xin; Yu, Yongze; Qiu, Jianrong

    2016-04-14

    Strong saturable absorption was observed in MoS2 nanoflowers, which were synthesized by a facile solvothermal method. A MoS2 nanoflower-based saturable absorber with a high modulation depth of 51.8% and a large saturable intensity of 275.5 GW cm(-2) was introduced to the application of passively Q-switched fiber laser generation. Stable passively Q-switched fiber laser pulses at 1.56 μm with a low threshold power of 16.10 mW, high signal-to-noise ratio of 52.5 dB and short pulse duration of 1.9 μs were obtained. More importantly, a high output power of 3.10 mW related to a large pulse energy of about 51.84 nJ can be attained at a very low pump power. The efficiency of the laser reaches 4.71%, which is larger than that of the prepared layered MoS2 and recently reported MoS2-based passively Q-switching operations. Such results imply that the MoS2 nanoflowers are an excellent candidate for a saturable absorber in passively Q-switched fiber lasers at a low pump intensity. PMID:26997036

  15. Passive q-switching of CO/sub 2/ TEA laser using sulfur hexafluoride (SF/sub 6/). Report for April-August 1986

    SciTech Connect

    Pastel, R.

    1986-10-01

    Passive Q-switching of a CO/sub 2/ TEA laser using sulfur hexafluoride (SF/sub 6/) was demonstrated at 10.2 micron. There is minimum loss of peak power, narrowing of the pulse, and elimination of the tail. Q-switching at 9.6 micron was not observed. Also discussed is the use of SF/sub 6/ to frequency the laser to the strong gain lines of the 10.2-m and 9.6-m branch of the CO/sub 2/ emission. Both theory and experimental results are given.

  16. Diode-pumped CW and passively Q-switched lasers of Nd:GdLuAG mixed garnet at 1123 nm

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Liu, Zhaojun; Zhang, Sasa; Xia, Jinbao; Zhang, Yanmin; Guan, Chen

    2016-03-01

    Diode-pumped CW and passively Q-switched lasers of Nd:GdLuAG mixed garnet at 1123 nm were demonstrated. The maximum average output power of CW operation was 4.13 W. For Q-switched operation, the average output power was 800 mW, the corresponding single pulse energy was 133.8 μJ. The Nd:GdLuAG laser emitting at 1123 nm was obtained for the first time to the best of our knowledge, which proves that the Nd:GdLuAG mixed garnet has a better ability of energy storage than Nd:YAG in 1123 nm oscillation.

  17. Gold nanobipyramids as saturable absorbers for passively Q-switched laser generation in the 1.1  μm region.

    PubMed

    Zhang, Huanian; Liu, Jie

    2016-03-15

    We demonstrated that gold nanobipyramids (Au-NBPs) can be used as saturable absorbers for ultrafast pulsed-laser application, for the first time. Au-NBPs are prepared through a seed-mediated growth method, and performance is investigated in a passively Q-switched Nd:YVO4 laser. In the Q-switched operation the maximum average output power that can be achieved is 151 mW. The minimum pulse width is 396 ns at a pulse repetition rate of 90.6 kHz. PMID:26977656

  18. Nanosecond pulse generation in a passively Q-switched Nd:GGG laser at 1331 nm by CVD graphene saturable absorber

    NASA Astrophysics Data System (ADS)

    Xu, Bin; Wang, Yi; Cheng, Yongjie; Yang, Han; Xu, Huiying; Cai, Zhiping

    2015-10-01

    We report on a nanosecond pulse generation in a diode end-pumped passively Q-switched Nd:GGG laser at the low-gain transition line of 1331 nm. A three-layer CVD graphene thin film was transferred from Cu foil to a BK7 glass substrate for the use of saturable absorber. A stable Q-switching laser operation was obtained with maximum average output power of 0.69 W and slope efficiency of about 11.0% with respect to the absorbed pump power. The shortest pulse duration and the maximum repetition rate of the pulse trains were registered to be 556 ns and 166.7 kHz with corresponding maximum pulse energy 4.14 μJ and pulse peak power 7.45 W. This is the first demonstration of CVD-graphene-based Q-switched laser operation at 1.3 μm, to the best of our knowledge.

  19. Passively mode-locking erbium-doped fiber lasers with 0.3 nm Single-Walled Carbon Nanotubes

    PubMed Central

    Xu, Xintong; Zhai, Jianpang; Li, Ling; Chen, Yanping; Yu, Yongqin; Zhang, Min; Ruan, Shuangchen; Tang, Zikang

    2014-01-01

    We demonstrate a passively mode-locked erbium-doped fiber laser (EDFL) by using the smallest single-walled carbon nanotubes (SWNTs) with a diameter of 0.3 nm as the saturable absorber. These ultrasmall SWNTs are fabricated in the elliptical nanochannels of a ZnAPO4-11 (AEL) single crystal. By placing an AEL crystal into an EDFL cavity pumped by a 980 nm laser diode, stable passive mode-locking is achieved for a threshold pump power of 280 mW, and 73 ps pulses at 1563.2 nm with a repetition rate of 26.79 MHz. PMID:25342292

  20. Generation of more than 40  W of average output power from a passively Q-switched Yb-doped fiber laser.

    PubMed

    Chakravarty, Usha; Kuruvilla, Antony; Singh, Ravindra; Upadhyaya, B N; Bindra, K S; Oak, S M

    2016-01-10

    We report on the generation of 41.6 W of average output power from a passively Q-switched ytterbium-doped fiber laser using Cr4+:YAG crystal as a saturable absorber (SA). This is the highest average power from passively Q-switched fiber lasers reported so far in the literature, to our knowledge, and it has been achieved by using a specially designed T-type double-end pumping configuration. Variation in average output power, pulse energy, pulse duration, pulse frequency, and pulse-to-pulse stability has also been studied using SAs of different linear transmissions. The effect of an intracavity SA on self-pulsing dynamics was also investigated and it was observed that, at lower input pump power near threshold, the presence of an SA enhances the peak power of relaxation oscillations to trigger the generation of stimulated Raman scattering in the gain fiber. With an increase in pump power, when the passive Q-switching threshold is reached, high peak power random self-pulses regenerate into low amplitude regular Q-switched pulses. The effect of the length of the gain medium on dual-wavelength generation at very low input pump power and broadband generation at sufficiently higher pump power has also been explored. PMID:26835764

  1. Determination of topological parameters of a laser with passive mode-locking on the basis of InGaAlAs/InGaAs/InP heterostructures

    NASA Astrophysics Data System (ADS)

    Mikhailovskii, G. A.; Polukhin, I. S.; Rybalko, D. A.; Solov'ev, Yu. V.; Odnoblyudov, M. A.

    2016-05-01

    Topological parameters of a strip-geometry laser with passive mode-locking on the basis of an InGaAlAs/InGaAs/InP heterostructure are determined from the condition for the existence of one transverse mode in a strip waveguide. The strip width was 1.5 μm, the mesa etch depth was 1.32 μm, and the thickness of the dielectric layer was 0.36 μm.

  2. Single- and double-walled carbon nanotube based saturable absorbers for passive mode-locking of an erbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Cheng, Kuang-Nan; Lin, Yung-Hsiang; Lin, Gong-Ru

    2013-04-01

    The passive mode-locking of an erbium-doped fiber laser (EDFL) with a medium gain is demonstrated and compared by using three different types of carbon nanotubes (CNTs) doped in polyvinyl alcohol (PVA) films. Nano-scale clay is used to disperse the CNTs doped in the PVA polymer aqueous solution to serve as a fast saturable absorber to initiate passive mode-locking. The three types of CNT based saturable absorbers, namely single-walled (SW), double-walled (DW) and multi-walled (MW), are characterized by Raman scattering and optical absorption spectroscopy. The SW-CNTs with a diameter of 1.26 nm have two absorption peaks located around 1550 ± 70 and 860 ± 50 nm. In contrast, the DW-CNTs with a diameter of 1.33 nm reveal two absorption peaks located at 1580 ± 40 and 920 ± 50 nm. By using the SW-CNT based saturable absorber, the passively mode-locked EDFL exhibits a pulsewidth of 1.28 ps and a spectral linewidth of 1.99 nm. Due to the increased linear absorption of the DW-CNT based saturable absorber, the intra-cavity net gain of the EDFL is significantly attenuated to deliver an incompletely mode-locked pulsewidth of 6.8 ps and a spectral linewidth of 0.62 nm. No distinct pulse-train is produced by using the MW-CNT film as the saturable absorber, which is attributed to the significant insertion loss of the EDFL induced by the large linear absorption of the MW-CNT film.

  3. Thulium/holmium-doped fiber laser passively mode locked by black phosphorus nanoplatelets-based saturable absorber.

    PubMed

    Yu, Hao; Zheng, Xin; Yin, Ke; Cheng, Xiang'ai; Jiang, Tian

    2015-12-01

    By coupling black phosphorus (BP) nanoplatelets (NPs) with a fiber-taper evanescent light field, a saturable absorber (SA) based on the BP NPs has been successfully fabricated and used in a thulium/holmium-doped fiber laser as the mode locker. The SA had a modulation depth of ∼9.8% measured at 1.93 μm. A stable mode-locking operation at 1898 nm was achieved with a pulse width of 1.58 ps and a fundamental mode-lock repetition rate of 19.2 MHz. By increasing the pump intensity, phenomena of multi-pulsing operations, including harmonic mode-locked states and soliton bunches, were obtained in the experiment, showing that the BP NPs possess an ultrafast optical response time. This work suggests that the BP NPs-based SA is potentially useful for ultrashort, pulsed laser operations in the eye-safe region of 2 μm. PMID:26836690

  4. All-fiber passively mode-locked Tm-doped NOLM-based oscillator operating at 2-μm in both soliton and noisy-pulse regimes.

    PubMed

    Li, Jianfeng; Zhang, Zuxing; Sun, Zhongyuan; Luo, Hongyu; Liu, Yong; Yan, Zhijun; Mou, Chengbo; Zhang, Lin; Turitsyn, Sergei K

    2014-04-01

    A self-starting all-fiber passively mode-locked Tm(3+)-doped fiber laser based on nonlinear loop mirror (NOLM) is demonstrated. Stable soliton pulses centered at 2017.33 nm with 1.56 nm FWHM were produced at a repetition rate of 1.514 MHz with pulse duration of 2.8 ps and pulse energy of 83.8 pJ. As increased pump power, the oscillator can also operate at noise-like (NL) regime. Stable NL pulses with coherence spike width of 341 fs and pulse energy of up to 249.32 nJ was achieved at a center wavelength of 2017.24 nm with 21.33 nm FWHM. To the best of our knowledge, this is the first 2 µm region NOLM-based mode-locked fiber laser operating at two regimes with the highest single pulse energy for NL pulses. PMID:24718163

  5. Noise-like femtosecond pulse in passively mode-locked Tm-doped NALM-based oscillator with small net anomalous dispersion

    NASA Astrophysics Data System (ADS)

    Liu, Shuo; Yan, Feng-Ping; Zhang, Lu-Na; Han, Wen-Guo; Bai, Zhuo-Ya; Zhou, Hong

    2016-01-01

    A passively mode-locked thulium-doped fiber laser (TDFL) based on a nonlinear amplifying loop mirror (NALM) is presented. By adjusting the polarization controllers, stable noise-like (NL) mode-locked femtosecond pulse operation is obtained at the 2 μm band. In the experimental period of 200 min, the output power fluctuation is less than 0.06 dB and the 3 dB spectral bandwidth variation is less than 0.02 nm, indicating that the pulsed TDFL possesses good long-term stability. To the best of our knowledge, this is the first 2 μm band NALM-based TDFL with small net anomalous dispersion for a NL femtosecond pulse. At the maximum pump power of 3.52 W, the emitting laser has a NL pulse width of 460 fs, the repetition rate of 9.1 MHz, and the NL pulse energy of 32.72 nJ.

  6. Generation of high energy square-wave pulses in all anomalous dispersion Er:Yb passive mode locked fiber ring laser.

    PubMed

    Semaan, Georges; Ben Braham, Fatma; Salhi, Mohamed; Meng, Yichang; Bahloul, Faouzi; Sanchez, François

    2016-04-18

    We have experimentally demonstrated square pulses emission from a co-doped Er:Yb double-clad fiber laser operating in anomalous dispersion DSR regime using the nonlinear polarization evolution technique. Stable mode-locked pulses have a repetition rate of 373 kHz with 2.27 µJ energy per pulse under a pumping power of 30 W in cavity. With the increase of pump power, both the duration and the energy of the output square pulses broaden. The experimental results demonstrate that the passively mode-locked fiber laser operating in the anomalous regime can also realize a high-energy pulse, which is different from the conventional low-energy soliton pulse. PMID:27137277

  7. Compression mechanism of subpicosecond pulses by malachite green dye in passively mode-locked rhodamine 6G/DODCI CW dye lasers

    SciTech Connect

    Watanabe, A.; Hara, M.; Kobayashi, H.; Takemura, H.; Tanaka, S.

    1983-04-01

    The pulse width compression effect of a malachite green (MG) dye upon subpicosecond pulses has been experimentally investigated in a CW passively mode-locked rhodamine 6G/DODCI dye laser. The pulse width reduces as MG concentration increases, and reaches 0.34 ps at 1.5 X 10/sup -6/ M. By adding the MG dye, good mode locking is achieved in a rather wide pumping-power range. A computer simulation of pulse growth has also been carried out by using simple rate equations, in which the fast-recovery component of loss due to the MG dye is taken into account. The simulated results can explain some experimental results qualitatively such as pulse width compression and pumping-power restriction. The pulse width compression results essentially from the fast recovery of cavity loss caused by the MG dye.

  8. Modeling of beam width in passively Q-switched end-pumped lasers.

    PubMed

    Jabczyński, Jan; Kwiatkowski, Jacek; Zendzian, Waldemar

    2003-03-24

    An iterative model based on the LambertW function was developed for estimating the fundamental mode parameters of resonators with saturable gain guiding. The process of pulse buildup in passively Qswitched, end-pumped lasers was analyzed. The effective ABCD cavity matrix for consecutive round-trips was calculated, taking into account spatially variable saturated gain in an active medium and absorption bleaching in a saturable absorber. The twofold decrease in beam width, as compared with the fundamental mode of the bare cavity, was demonstrated. The application of such a model for resonators with other nonlinear elements is feasible. PMID:19461764

  9. Free-standing nano-scale graphite saturable absorber for passively mode-locked erbium doped fiber ring laser Free-standing nano-scale graphite saturable absorber

    NASA Astrophysics Data System (ADS)

    Lin, Y.-H.; Lin, G.-R.

    2012-05-01

    The free-standing graphite nano-particle located between two FC/APC fiber connectors is employed as the saturable absorber to passively mode-lock the ring-type Erbium-doped fiber laser (EDFL). The host-solvent-free graphite nano-particles with sizes of 300 - 500 nm induce a comparable modulation depth of 54%. The interlayer-spacing and lattice fluctuations of polished graphite nano-particles are observed from the weak 2D band of Raman spectrum and the azimuth angle shift of -0.32° of {002}-orientation dependent X-ray diffraction peak. The graphite nano-particles mode-locked EDFL generates a 1.67-ps pulsewidth at linearly dispersion-compensated regime with a repetition rate of 9.1 MHz. The time-bandwidth product of 0.325 obtained under a total intra-cavity group-delay-dispersion of -0.017 ps2 is nearly transform-limited. The extremely high stability of the nano-scale graphite saturable absorber during mode-locking is observed at an intra-cavity optical energy density of 7.54 mJ/cm2. This can be attributed to its relatively high damage threshold (one order of magnitude higher than the graphene) on handling the optical energy density inside the EDFL cavity. The graphite nano-particle with reduced size and sufficient coverage ratio can compete with other fast saturable absorbers such as carbon nanotube or graphene to passively mode-lock fiber lasers with decreased insertion loss and lasing threshold.

  10. Evaluation of a commercially available passively Q-switched Nd:YAG laser with LiF: F2- saturable absorber for laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Carson, Cantwell G.; Goueguel, Christian L.; Sanghapi, Hervé; Jain, Jinesh; McIntyre, Dustin

    2016-05-01

    Interest in passively Q-switched microchip lasers as a means for miniaturization of laser-induced breakdown spectroscopy (LIBS) apparatus has rapidly grown in the last years. To explore the possibility of using a comparatively UV-vis transparent absorber, we herein present the first report on the evaluation of a commercially available flash lamp-pumped passively Q-switched Nd:YAG laser with LiF: F2- saturable absorber as an excitation source in LIBS. Quantitative measurements of barium, strontium, rubidium and lithium in granite, rhyolite, basalt and syenite whole-rock glass samples were performed. Using a gated intensified benchtop spectrometer, limits of detection of 0.97, 23, 37, and 144 ppm were obtained for Li, Sr, Rb, and Ba, respectively. Finally, we discuss the advantages of using such a laser unit for LIBS applications in terms of ablation efficiency, analytical performances, output energy, and standoff capabilities.

  11. Performance enhancement of sub-nanosecond diode-pumped passively Q-switched Yb:YAG microchip laser with diamond surface cooling.

    PubMed

    Zhuang, W Z; Chen, Yi-Fan; Su, K W; Huang, K F; Chen, Y F

    2012-09-24

    We experimentally confirm that diamond surface cooling can significantly enhance the output performance of a sub-nanosecond diode-end-pumped passively Q-switched Yb:YAG laser. It is found that the pulse energy obtained with diamond cooling is approximately 1.5 times greater than that obtained without diamond cooling, where a Cr(4+):YAG absorber with the initial transmission of 84% is employed. Furthermore, the standard deviation of the pulse amplitude peak-to-peak fluctuation is found to be approximately 3 times lower than that measured without diamond cooling. Under a pump power of 3.9 W, the passively Q-switched Yb:YAG laser can generate a pulse train of 3.3 kHz repetition rate with a pulse energy of 287 μJ and with a pulse width of 650 ps. PMID:23037409

  12. Nanosecond pulse passively Q-switched Yb-doped fiber laser with Cr4+: YAG as saturable absorber

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Liu, Jiang; Wang, Pu

    2011-06-01

    We report a passively Q-switched Yb-doped fiber laser with Cr4+:YAG saturable absorber and get stable nanosecond pulse trains. Three kinds of laser cavity configurations, including a cladding-pumped ring cavity, a cladding-pumped linear cavity and a core-pumped linear cavity were studied, and they all can effectively restrain the generation of Stimulated Brillouin scattering and the generation of self-pulse. Cladding-pumped ring-avity fiber laser with Cr4+:YAG as saturable absorber inside is established for the first time to obtain stable 1 μs pulse trains. The amplitude fluctuation and timing jitter are below 5% (rms). Further more, we can also get stable pulse trains by using a high reflective fiber Bragging grating as a resonator mirror in a cladding-pumped linear cavity and a core-pumped linear cavity fiber laser respectively. In the cladding-pumped linear cavity fiber laser, the tunable pulse repetition rate is from 9.1 kHz to 30.3 kHz and the minimum pulse duration is 156 ns. And in the core-pumped linear cavity fiber laser, the tunable pulse repetition rate is from 15 kHz to 33 kHz and the minimum pulse duration is 24 ns which much less than those reported before. Although the average output power is only hundreds milli-Watts now, the laser uses a fiber coupler as the output of pulse trains, it is convinient to boost the power with a stage of fiber amplifier. This kind of pulse laser can be used as a seed source, and amplified to tens of Watts for practical applications in the future.

  13. Wall paper single-walled carbon nanotubes absorber for passively mode-locked Nd: GdVO4 laser

    NASA Astrophysics Data System (ADS)

    Wang, Yong Gang; Chen, Hou Ren; Wen, Xiao Min; Hsieh, Wen Feng; Tang, Jau

    2012-04-01

    A novel and low-cost wall paper single-walled carbon nanotubes (SWCNTs) absorber was fabricated by high viscosity of polyvinyl alcohol (PVA) aqueous solution and vertical evaporation technique. Sandwich structure wall paper SWCNT (SSWA-SWCNT) absorber was constructed by a piece of wall paper SWCNT absorber, a piece of round quartz and an output coupler mirror. We exploited it to realize mode locking operation in a diode-pumped Nd: GdVO4 laser. A pulse duration of 9.6 ps was produced with an average power of 870 mW. The stable mode locking operation was obtained when the average power is less than 300 mW.

  14. Passively mode-locked pulse generation in a c-cut Nd:LuVO4 laser at 1086 nm with a semiconductor saturable-absorber mirror

    NASA Astrophysics Data System (ADS)

    Lin, Ja-Hon; Yang, Pao-Keng; Lin, Wei-Cheng

    2012-04-01

    We demonstrate a diode-pumped passively mode-locked (ML) c-cut Nd:LuVO4 laser with central wavelength at 1086 nm by shifting the reflectance band of the SESAM into a longer wavelength to result in larger loss around 1068 nm. At 15 W absorbed pump power, the highest output power of the ML pulse was about 2.6 W that corresponded to the 17.3% optical-to-optical conversion efficiency and the slope efficiency of laser was about 22.9%. Using our ML laser as the light source, we have also successfully measured the saturation fluence of the SESAM at 1086 nm.

  15. Efficiency of non-linear frequency conversion of double-scale pico-femtosecond pulses of passively mode-locked fiber laser.

    PubMed

    Smirnov, Sergey V; Kobtsev, Sergey M; Kukarin, Sergey V

    2014-01-13

    For the first time we report the results of both numerical simulation and experimental observation of second-harmonic generation as an example of non-linear frequency conversion of pulses generated by passively mode-locked fiber master oscillator in different regimes including conventional (stable) and double-scale (partially coherent and noise-like) ones. We show that non-linear frequency conversion efficiency of double-scale pulses is slightly higher than that of conventional picosecond laser pulses with the same energy and duration despite strong phase fluctuations of double-scale pulses. PMID:24515065

  16. High-power 880-nm diode-directly-pumped passively mode-locked Nd:YVO₄ laser at 1342 nm with a semiconductor saturable absorber mirror.

    PubMed

    Li, Fang-Qin; Liu, Ke; Han, Lin; Zong, Nan; Bo, Yong; Zhang, Jing-Yuan; Peng, Qin-Jun; Cui, Da-Fu; Xu, Zu-Yan

    2011-04-15

    A high-power 880-nm diode-directly-pumped passively mode-locked 1342 nm Nd:YVO₄ laser was demonstrated with a semiconductor saturable absorber mirror (SESAM). The laser mode radii in the laser crystal and on the SESAM were optimized carefully using the ABCD matrix formalism. An average output power of 2.3 W was obtained with a repetition rate of 76 MHz and a pulse width of 29.2 ps under an absorbed pump power of 12.1 W, corresponding to an optical-optical efficiency of 19.0% and a slope efficiency of 23.9%, respectively. PMID:21499398

  17. Passive mode locking of an in-band-pumped Ho:YLiF4 laser at 2.06 μm.

    PubMed

    Coluccelli, Nicola; Lagatsky, Alexander; Di Lieto, Alberto; Tonelli, Mauro; Galzerano, Gianluca; Sibbett, Wilson; Laporta, Paolo

    2011-08-15

    We demonstrate the passive mode-locking operation of an in-band-pumped Ho:YLiF(4) laser at 2.06 μm using a semiconductor saturable absorber mirror based on InGaAsSb quantum wells. A transform-limited pulse train with minimum duration of 1.1 ps and average power of 0.58 W has been obtained at a repetition frequency of 122 MHz. A maximum output power of 1.7 W has been generated with a corresponding pulse duration of 1.9 ps. PMID:21847210

  18. High-efficiency 17 W, 80 MHz repetition rate, passively mode-locked TEM00 Nd:YAG oscillator pumped at 885 nm

    NASA Astrophysics Data System (ADS)

    Zhang, X.-F.; Li, F.-Q.; Zong, N.; Le, X.-Y.; Cui, D.-F.; Xu, Z.-Y.

    2011-03-01

    We report on a passively mode-locked TEM00 Nd:YAG oscillator with the beam quality at M 2 = 1.1 by a semiconductor saturable absorber mirror under 885 nm laser diode direct pumping for the first time. A maximum average output power of 17 W at a repetition rate of 80 MHz with 39 ps pulse width was obtained under the absorbed pump power of 38 W, corresponding to an optical-optical efficiency of 44% and the slope efficiency of 69%, respectively.

  19. PVP-Assisted Solvothermal Synthesis of High-Yielded Bi2Te3 Hexagonal Nanoplates: Application in Passively Q-Switched Fiber Laser

    NASA Astrophysics Data System (ADS)

    He, Xin; Zhang, Hang; Lin, Wei; Wei, Rongfei; Qiu, Jianrong; Zhang, Mei; Hu, Bin

    2015-10-01

    High-yielded Bi2Te3 hexagonal nanoplates were fabricated via a facile solvothermal method with the assistance of poly (vinyl pyrrolidone) (PVP). Effects of PVP molecular weight and concentration on the morphology and size distribution of the products were illustrated in this study. Molecular weight of PVP is significant for determining the morphology of Bi2Te3. The hexagonal nanoplates with high yield were obtained in the presence of PVP with molecular weight of 40000-45000. The average size and size distribution of Bi2Te3 nanoplates can be slightly varied by controlling concentration of PVP. High-yielded Bi2Te3 nanoplates exhibit characteristics of saturable absorption, identified by open-aperture Z-scan technique. The synthesized Bi2Te3 nanoplates with large saturation intensity of 4.6 GW/cm2 and high modulation depth of 45.95% generated a stable passively Q-switched fiber laser pulse at 1.5 μm. In comparison with recently reported Q-switched fiber lasers utilizing exfoliated Bi2Te3 nanosheets, our passive Q-switching operations could be conducted at a relatively low threshold power of 30.2 mW or a quite high output power of 99.45 mW by tuning the cavity parameters.

  20. PVP-Assisted Solvothermal Synthesis of High-Yielded Bi2Te3 Hexagonal Nanoplates: Application in Passively Q-Switched Fiber Laser.

    PubMed

    He, Xin; Zhang, Hang; Lin, Wei; Wei, Rongfei; Qiu, Jianrong; Zhang, Mei; Hu, Bin

    2015-01-01

    High-yielded Bi2Te3 hexagonal nanoplates were fabricated via a facile solvothermal method with the assistance of poly (vinyl pyrrolidone) (PVP). Effects of PVP molecular weight and concentration on the morphology and size distribution of the products were illustrated in this study. Molecular weight of PVP is significant for determining the morphology of Bi2Te3. The hexagonal nanoplates with high yield were obtained in the presence of PVP with molecular weight of 40000-45000. The average size and size distribution of Bi2Te3 nanoplates can be slightly varied by controlling concentration of PVP. High-yielded Bi2Te3 nanoplates exhibit characteristics of saturable absorption, identified by open-aperture Z-scan technique. The synthesized Bi2Te3 nanoplates with large saturation intensity of 4.6 GW/cm(2) and high modulation depth of 45.95% generated a stable passively Q-switched fiber laser pulse at 1.5 μm. In comparison with recently reported Q-switched fiber lasers utilizing exfoliated Bi2Te3 nanosheets, our passive Q-switching operations could be conducted at a relatively low threshold power of 30.2 mW or a quite high output power of 99.45 mW by tuning the cavity parameters. PMID:26511763

  1. PVP-Assisted Solvothermal Synthesis of High-Yielded Bi2Te3 Hexagonal Nanoplates: Application in Passively Q-Switched Fiber Laser

    PubMed Central

    He, Xin; Zhang, Hang; Lin, Wei; Wei, Rongfei; Qiu, Jianrong; Zhang, Mei; Hu, Bin

    2015-01-01

    High-yielded Bi2Te3 hexagonal nanoplates were fabricated via a facile solvothermal method with the assistance of poly (vinyl pyrrolidone) (PVP). Effects of PVP molecular weight and concentration on the morphology and size distribution of the products were illustrated in this study. Molecular weight of PVP is significant for determining the morphology of Bi2Te3. The hexagonal nanoplates with high yield were obtained in the presence of PVP with molecular weight of 40000–45000. The average size and size distribution of Bi2Te3 nanoplates can be slightly varied by controlling concentration of PVP. High-yielded Bi2Te3 nanoplates exhibit characteristics of saturable absorption, identified by open-aperture Z-scan technique. The synthesized Bi2Te3 nanoplates with large saturation intensity of 4.6 GW/cm2 and high modulation depth of 45.95% generated a stable passively Q-switched fiber laser pulse at 1.5 μm. In comparison with recently reported Q-switched fiber lasers utilizing exfoliated Bi2Te3 nanosheets, our passive Q-switching operations could be conducted at a relatively low threshold power of 30.2 mW or a quite high output power of 99.45 mW by tuning the cavity parameters. PMID:26511763

  2. High-power CW and passively Q-switched laser operation of Yb:GdCa4O(BO3)3 crystal

    NASA Astrophysics Data System (ADS)

    Chen, Xiaowen; Wang, Lisha; Liu, Junhai; Guo, Yunfeng; Han, Wenjuan; Xu, Honghao; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    We demonstrate efficient high-power CW and passively Q-switched operations of Yb:GdCa4O(BO3)3 lasers. An output power of 18.2 W is generated at 1031.5 nm in CW mode, with optical-to-optical and slope efficiencies being respectively 55% and 70%, with respect to incident pump power. In passively Q-switched operation with a Cr4+:YAG crystal as saturable absorber, a maximum average output power of 15.6 W is produced at a pulse repetition rate of 91 kHz, with an optical-to-optical efficiency of 44%. Low-repetition-rate Q-switched action is also realized, generating an average output power of 4.2 W at 5.7 kHz, the resulting pulse energy and duration are 737 μJ and 3.6 ns, leading to a peak power amounting to 205 kW.

  3. Passive Q-switching of a Tm,Ho:KLu(WO4)2 microchip laser by a Cr:ZnS saturable absorber.

    PubMed

    Serres, J M; Loiko, P; Mateos, X; Jambunathan, V; Yasukevich, A S; Yumashev, K V; Petrov, V; Griebner, U; Aguiló, M; Díaz, F

    2016-05-10

    A diode-pumped Tm,Ho:KLu(WO4)2 microchip laser passively Q-switched with a Cr:ZnS saturable absorber generated an average output power of 131 mW at 2063.6 nm with a slope efficiency of 11% and a Q-switching conversion efficiency of 58%. The pulse characteristics were 14  ns/9  μJ at a pulse repetition frequency of 14.5 kHz. With higher modulation depth of the saturable absorber, 9  ns/10.4  μJ/8.2  kHz pulses were generated at 2061.1 nm, corresponding to a record peak power extracted from a passively Q-switched Tm,Ho laser of 1.15 kW. A theoretical model is presented, predicting the pulse energy and duration. The simulations are in good agreement with the experimental results. PMID:27168288

  4. Bi2Te3 based passively Q-switched fiber laser with cylindrical vector beam emission.

    PubMed

    Yan, Ke; Lin, Jian; Zhou, Yong; Gu, Chun; Xu, Lixin; Wang, Anting; Yao, Peijun; Zhan, Qiwen

    2016-04-10

    We report a passively Q-switched fiber laser with cylindrical vector beam output modes using a few-mode fiber Bragg grating as a polarization-selective output coupler and Bi2Te3 as the saturable absorber. Both radially and azimuthally polarized beams can be readily generated, and the output polarization can be switchable by tuning the polarization controllers inside the laser cavity. The repetition rate of the Q-switched laser can be tuned from 31.54 to 49.40 kHz when the pump power increases from 103.5 to 139.5 mW. The fiber laser operates at a single wavelength of 1557.5 nm with a 3 dB linewidth of <0.04  nm. PMID:27139870

  5. 2.78 μm passively Q-switched Er3+-doped ZBLAN fiber laser based on PLD-Fe2+:ZnSe film

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Feng, Guoying; Zhang, Hong; Yang, Xianheng; Dai, Shenyu; Zhou, Shouhuan

    2016-07-01

    Based on the pulsed laser deposition (PLD) method, we first fabricated a mid-infrared Fe2+:ZnSe film saturable absorber (SA). By employing the PLD Fe2+:ZnSe film SA, we have demonstrated a passively Q-switched double-clad Er3+-doped ZBLAN fiber laser operating at a wavelength of 2.78 μm. Stable Q-switched pulses with pulse energy of 7.98 μJ and pulse duration of 0.742 μs, corresponding to a peak power of 10.76 W, were obtained at a repetition rate of 102.94 kHz. The maximum average output power is 822 mW. Our results demostrate that the PLD-Fe2+:ZnSe film SA is promising for high power pulse generation in compact mid-infrared fiber lasers.

  6. 808-nm diode-pumped dual-wavelength passively Q-switched Nd:LuLiF4 laser with Bi-doped GaAs

    NASA Astrophysics Data System (ADS)

    Li, S. X.; Li, T.; Li, D. C.; Zhao, S. Z.; Li, G. Q.; Hang, Y.; Zhang, P. X.; Li, X. Y.; Qiao, H.

    2015-09-01

    Diode-pumped CW and passively Q-switched Nd:LuLiF4 lasers with stable, synchronous dual-wavelength operations near 1047 and 1053 nm were demonstrated for the first time. The maximal CW output power of 821 mW was obtained at an incident pump power of 6.52 W. Employing high quality Bi-doped GaAs as saturable absorber, stable dual-wavelength Q-switched operation was realized. Under 6.52 W incident pump power, the minimal pulse duration of 1.5 ns, the largest single pulse energy of 11.32 μJ, and the highest peak power of 7.25 kW were achieved.

  7. High-peak-power flashlamp-pumped passively Q-switched Nd:YAG laser with AlGaInAs quantum wells as a saturable absorbers

    NASA Astrophysics Data System (ADS)

    Liang, H. C.; Huang, J. Y.; Huang, S. C.; Su, K. W.; Chen, Y. F.; Huang, K. F.

    2008-02-01

    We demonstrate an AlGaInAs saturable absorber with a periodic quantum wells (QWs)/barrier structure that can be used to achieve an efficient high-peak-power and high-pulse-energy passively flashlamp-pumped Q-switched Nd:YAG laser at 1.06 um. The barrier layers are designed to locate the QW groups in the region of the nodes of the lasing standing wave to avoid damage. With an incident pump voltage of 14.5 J, a single pulse was generated with a pulse energy of 14 mJ and a Q-switched pulse width of 13 ns. The maximum peak power was greater than 1.08 MW.

  8. Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

    DOEpatents

    Woodruff, Steven D.; Mcintyre, Dustin L.

    2016-03-29

    A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

  9. Experimental study on the self-mode-locked Ti:sapphire laser

    NASA Astrophysics Data System (ADS)

    Qi-rong, Xing; Wei-li, Zhang; Wei, Lu; Yoo, K. M.; Lueng, J.

    1996-01-01

    The role of gain aperture in self-mode-locked Ti:sapphire laser was verified in our experiments. The observation of self-Q switching of self-mode-locked Ti:sapphire laser is reported. And tuning pulse duration from 50 fs to 14.5 ps was achieved.

  10. Numerical analysis of a broadband spectrum generated in a standard fiber by noise-like pulses from a passively mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Hernandez-Garcia, J. C.; Pottiez, O.; Estudillo-Ayala, J. M.; Rojas-Laguna, R.

    2012-04-01

    This paper covers a numerical analysis of supercontinuum spectrum generation in a piece of standard fiber by using as the pump noise-like pulses produced by a passively mode-locked fiber laser. An experimental study was also carried out, yielding results that support the numerical results. In the numerical study we estimated that the spectral extension of the generated supercontinuum reaches ~ 1000 nm, and that it presents a high flatness over a region of ~ 220 nm (1630 nm-1850 nm) when we use as the pump noise-like pulses with a wide optical bandwidth (~ 50 nm) and a peak power of ~ 2 kW. Experimentally, the output signal spectrum extends from ~ 1530 nm to at least 1750 nm and presents a high flatness over a region of 1640 nm to 1750 nm for the same value of numerical input power, 1750 nm being the upper limit of the optical spectrum analyzer. The numerical analysis presented here is thus an essential part to overcome the severe limitation in measuring capabilities and to understand the phenomena of supercontinuum generation, which is mainly related to Raman self-frequency shift. Finally, this work demonstrates the potential of noise-like pulses from a passively mode-locked fiber laser for broadband spectrum generation.

  11. Widely-tunable, passively Q-switched erbium-doped fiber laser with few-layer MoS2 saturable absorber.

    PubMed

    Huang, Yizhong; Luo, Zhengqian; Li, Yingyue; Zhong, Min; Xu, Bin; Che, Kaijun; Xu, Huiying; Cai, Zhiping; Peng, Jian; Weng, Jian

    2014-10-20

    We propose and demonstrate a MoS2-based passively Q-switched Er-doped fiber laser with a wide tuning range of 1519.6-1567.7 nm. The few-layer MoS2 nano-platelets are prepared by the liquid-phase exfoliation method, and are then made into polymer-composite film to construct the fiber-compatible MoS2 saturable absorber (SA). It is measured at 1560 nm wavelength, that such MoS2 SA has the modulation depth of ∼ 2% and the saturable optical intensity of ∼ 10 MW/cm(2). By further inserting the filmy MoS2-SA into an Er-doped fiber laser, stable Q-switching operation with a 48.1 nm continuous tuning from S- to C-waveband is successfully achieved. The shortest pulse duration and the maximum pulse energy are 3.3 μs and 160 nJ, respectively. The repetition rate and the pulse duration under different operation conditions have been also characterized. To the best of our knowledge, it is the first demonstration of MoS2 Q-switched, widely-tunable fiber laser. PMID:25401559

  12. Erbium-doped fiber laser passively mode locked with few-layer WSe2/MoSe2 nanosheets

    NASA Astrophysics Data System (ADS)

    Mao, Dong; She, Xiaoyang; Du, Bobo; Yang, Dexing; Zhang, Wending; Song, Kun; Cui, Xiaoqi; Jiang, Biqiang; Peng, Tao; Zhao, Jianlin

    2016-03-01

    Few-layer transition-metal dichalcogenide WSe2/MoSe2 nanosheets are fabricated by a liquid exfoliation technique using sodium deoxycholate bile salt as surfactant, and their nonlinear optical properties are investigated based on a balanced twin-detector measurement scheme. It is demonstrated that both types of nanosheets exhibit nonlinear saturable absorption properties at the wavelength of 1.55 μm. By depositing the nanosheets on side polished fiber (SPF) or mixing the nanosheets with polyvinyl alcohol (PVA) solution, SPF-WSe2 saturable absorber (SA), SPF-MoSe2 SA, PVA-WSe2 SA, and PVA-MoSe2 SA are successfully fabricated and further tested in erbium-doped fiber lasers. The SPF-based SA is capable of operating at the high pump regime without damage, and a train of 3252.65 MHz harmonically mode-locked pulses are obtained based on the SPF-WSe2 SA. Soliton mode locking operations are also achieved in the fiber laser separately with other three types of SAs, confirming that the WSe2 and MoSe2 nanosheets could act as cost-effective high-power SAs for ultrafast optics.

  13. Erbium-doped fiber laser passively mode locked with few-layer WSe2/MoSe2 nanosheets

    PubMed Central

    Mao, Dong; She, Xiaoyang; Du, Bobo; Yang, Dexing; Zhang, Wending; Song, Kun; Cui, Xiaoqi; Jiang, Biqiang; Peng, Tao; Zhao, Jianlin

    2016-01-01

    Few-layer transition-metal dichalcogenide WSe2/MoSe2 nanosheets are fabricated by a liquid exfoliation technique using sodium deoxycholate bile salt as surfactant, and their nonlinear optical properties are investigated based on a balanced twin-detector measurement scheme. It is demonstrated that both types of nanosheets exhibit nonlinear saturable absorption properties at the wavelength of 1.55 μm. By depositing the nanosheets on side polished fiber (SPF) or mixing the nanosheets with polyvinyl alcohol (PVA) solution, SPF-WSe2 saturable absorber (SA), SPF-MoSe2 SA, PVA-WSe2 SA, and PVA-MoSe2 SA are successfully fabricated and further tested in erbium-doped fiber lasers. The SPF-based SA is capable of operating at the high pump regime without damage, and a train of 3252.65 MHz harmonically mode-locked pulses are obtained based on the SPF-WSe2 SA. Soliton mode locking operations are also achieved in the fiber laser separately with other three types of SAs, confirming that the WSe2 and MoSe2 nanosheets could act as cost-effective high-power SAs for ultrafast optics. PMID:27010509

  14. Erbium-doped fiber laser passively mode locked with few-layer WSe2/MoSe2 nanosheets.

    PubMed

    Mao, Dong; She, Xiaoyang; Du, Bobo; Yang, Dexing; Zhang, Wending; Song, Kun; Cui, Xiaoqi; Jiang, Biqiang; Peng, Tao; Zhao, Jianlin

    2016-01-01

    Few-layer transition-metal dichalcogenide WSe2/MoSe2 nanosheets are fabricated by a liquid exfoliation technique using sodium deoxycholate bile salt as surfactant, and their nonlinear optical properties are investigated based on a balanced twin-detector measurement scheme. It is demonstrated that both types of nanosheets exhibit nonlinear saturable absorption properties at the wavelength of 1.55 μm. By depositing the nanosheets on side polished fiber (SPF) or mixing the nanosheets with polyvinyl alcohol (PVA) solution, SPF-WSe2 saturable absorber (SA), SPF-MoSe2 SA, PVA-WSe2 SA, and PVA-MoSe2 SA are successfully fabricated and further tested in erbium-doped fiber lasers. The SPF-based SA is capable of operating at the high pump regime without damage, and a train of 3252.65 MHz harmonically mode-locked pulses are obtained based on the SPF-WSe2 SA. Soliton mode locking operations are also achieved in the fiber laser separately with other three types of SAs, confirming that the WSe2 and MoSe2 nanosheets could act as cost-effective high-power SAs for ultrafast optics. PMID:27010509

  15. Applications of single-walled carbon nanotubes and type-II quantum dots in photovoltaics and passive mode-locking saturable absorbers

    NASA Astrophysics Data System (ADS)

    Tang, Jau; Wang, Yong-Gang; Cheng, Shin-Min; Yu, Pyng; Huang, Kuo-Yen; Yuan, Chi-Tsu

    2012-10-01

    Using single-molecule confocal imaging techniques combined with time-correlated single-photon counting we investigated the electron transfer (ET) rates to the single-walled carbon nanotubes from various types of semiconductor hetero-nanocrystals of type-I or type-II band alignment. We observed significantly larger ET rate for type-II ZnSe/CdS dot-in-rod nanostructures as compared to type-I spherical CdSe/ZnS core/shell quantum-dots, and to CdSe/CdS dot-in-rod structures. We demonstrated that such rapid ET dynamics can compete with both Auger and radiative recombination processes, leading to potentially more effective photovoltaic operation. In another work, we used aligned single-walled carbon nanotubes as saturable absorbers for ps laser pulse generation. Using the vertical evaporation technique we fabricated saturable absorbers by transferring the water-soluble single wall carbon nanotubes onto a hydrophilic quartz substrate. The fast recovery times of the absorber were measured to be 136 fs and 790 fs. The modulation depth of the absorber was about 1.5%. Passive mode-locked Nd: GdVO4 laser using such an absorber was demonstrated. The continuous wave mode-locked pulses with the pulse duration of 12.4 ps and the repetition of 120 MHz were achieved. The maximum average output power of the mode-locked laser is 2.4 W at the pump power of 13 W. Such a kind of absorbers has potential to be put into practical use.

  16. Optical frequency comb generator based on a monolithically integrated passive mode-locked ring laser with a Mach-Zehnder interferometer.

    PubMed

    Corral, V; Guzmán, R; Gordón, C; Leijtens, X J M; Carpintero, G

    2016-05-01

    We report the demonstration of an optical-frequency comb generator based on a monolithically integrated ring laser fabricated in a multiproject wafer run in an active/passive integration process in a generic foundry using standardized building blocks. The device is based on a passive mode-locked ring laser architecture, which includes a Mach-Zehnder interferometer to flatten the spectral shape of the comb output. This structure allows monolithic integration with other optical components, such as optical filters for wavelength selection, or dual wavelength lasers for their stabilization. The results show a -10  dB span of the optical comb of 8.7 nm (1.08 THz), with comb spacing of 10.16 GHz. We also obtain a flatness of 44 lines within a 1.8 dB power variation. PMID:27128043

  17. High-peak-power, short-pulse-width, LD end-pumped, passively Q-switched Nd:YAG 946 nm laser

    NASA Astrophysics Data System (ADS)

    Yan, Renpeng; Yu, Xin; Ma, Yufei; Li, Xudong; Chen, Deying; Yu, Junhua

    2012-10-01

    High-peak-power, short-pulse-width diode pumped 946 nm Nd:YAG laser in passively Q-switching operation with Cr4+:YAG is reported. The highest average output power reaches 3.4 W using the Cr4+:YAG with initial transmissivity T0=95%. When the T0=90% Cr4+:YAG is employed, the maximum peak power of 31.4 kW with a pulse width of 8.3 ns at 946 nm is generated.

  18. Diode-pumped Nd:YAG ceramic laser at 946 nm passively Q-switched with a Cr 4+:YAG saturable absorber

    NASA Astrophysics Data System (ADS)

    Li, Ping; Zhang, Huanian; Chen, Xiaohan; Wang, Qingpu

    2012-04-01

    We demonstrate a diode-pumped Nd:YAG ceramic laser with emission at 946 nm that is passively Q-switched by single-crystal Cr 4+:YAG saturable absorber. An average output power of 1.7 W is measured under 18.4 W of incident power using an output mirror with transmission T=4%. The corresponding optical-to-optical efficiency is 9.2%. The laser runs at a pulse repetition rate of 120 kHz and delivers pulses with energy of 14 μJ and duration of 80 ns, which corresponds to a peak power of 175 W.

  19. Generation of high-peak power 532-nm green pulses from composite, all-ceramics, passively Q-switched Nd:YAG/Cr4+:YAG laser

    NASA Astrophysics Data System (ADS)

    Salamu, Gabriela; Ionescu, Alina; Brandus, Catalina; Grigore, Oana; Pavel, Nicolaie; Dascalu, Traian

    2013-06-01

    Laser pulses at 1.06 μm with 2.5-mJ energy and 3.1-MW peak power have been obtained from a composite, all polycrystalline ceramics, passively Q-switched 1.1-at.% Nd:YAG/Cr4+:YAG laser that was quasi-continuous-wave pumped with diode lasers. Single-pass frequency doubling with LiB3O5 nonlinear crystal at room temperature yielded green laser pulses at 532 nm with energy of 0.36-mJ and 0.45-MW peak power; the infrared-to-green conversion efficiency was 0.27.

  20. Diode-pumped passively Q-switched Nd:YVO4 green laser with a periodically poled KTP and Cr4+:YAG saturable absorber.

    PubMed

    Li, Guiqiu; Zhao, Shengzhi; Yang, Kejian; Li, Dechun

    2006-03-10

    A diode-pumped passively Q-switched Nd:YVO4 green laser with a periodically poled KTP and Cr4+:YAG saturable absorber is realized. The dependences of pulse repetition rate, pulse energy, pulse width, and peak power on incident pump power are measured for the generated green-light pulses. A rate-equation model is introduced to theoretically analyze the results obtained in the experiment, in which the spatial distribution of the intracavity photon density is taken into account. The numerical solutions of the rate equations agree with the experimental results. PMID:16572700

  1. Lean-Burn Stationary Natural Gas Reciprocating Engine Operation with a Prototype Miniature Diode Side Pumped Passively Q-switched Laser Spark Plug

    SciTech Connect

    McIntyre, D.L.; Woodruff, S.D.; McMillian, M.H.; Richardson, S.W.; Gautam, Mridul

    2008-04-01

    To meet the ignition system needs of large bore lean burn stationary natural gas engines a laser diode side pumped passively Q-switched laser igniter was developed and used to ignite lean mixtures in a single cylinder research engine. The laser design was produced from previous work. The in-cylinder conditions and exhaust emissions produced by the miniaturized laser were compared to that produced by a laboratory scale commercial laser system used in prior engine testing. The miniaturized laser design as well as the combustion and emissions data for both laser systems was compared and discussed. It was determined that the two laser systems produced virtually identical combustion and emissions data.

  2. All solid-state mode-locked flashlamp pumped Nd:YAG laser system with selectable pulse duration

    NASA Astrophysics Data System (ADS)

    Kubecek, Vaclav; Diels, Jean-Claude; Stintz, Andreas; Jelinkova, Helena; Dombrovsky, Andrej; Cech, Miroslav

    2005-04-01

    All solid state mode-locked flashlamp pumped Nd:YAG laser system with selectable pulse duration was developed based on the oscillator where a single semiconductor structure containing a multiple-quantum-well was used as a saturable absorber for mode-locking, and energy limiter for passive negative feedback. Single pulse selection from various parts of extended 200 ns long Q-switched pulse train enables the changing of pulse duration before entering into three stages of laser amplifiers. Using of additional acousto-optic mode-locker, stability enhancement of the output pulses was obtained and the amplitude fluctuations were reduced below 5%. The exploitation of the solid state saturable absorber and limiter integrated in the single element improved significantly the long term characteristics of the laser system which can be therefore used for various applications as a satellite laser ranging, spectroscopy, or medicine.

  3. Pump beam waist-dependent pulse energy generation in Nd:YAG/Cr4+:YAG passively Q-switched microchip laser

    NASA Astrophysics Data System (ADS)

    Li, Chao-yu; Dong, Jun

    2016-08-01

    The incident pump beam waist-dependent pulse energy generation in Nd:YAG/Cr4+:YAG composite crystal passively Q-switched microchip laser has been investigated experimentally and theoretically by moving the Nd:YAG/Cr4+:YAG composite crystal along the pump beam direction. Highest pulse energy of 0.4 mJ has been generated when the Nd:YAG/Cr4+:YAG composite crystal is moved about 6 mm away from the focused pump beam waist. Laser pulses with pulse width of 1.7 ns and peak power of over 235 kW have been achieved. The theoretically calculated effective laser beam area at different positions of Nd:YAG/Cr4+:YAG composite crystal along the pump beam direction is in good agreement with the experimental results. The highest peak power can be generated by adjusting the pump beam waist incident on the Nd:YAG/Cr4+:YAG composite crystal to optimize the effective laser beam area in passively Q-switched microchip laser.

  4. Continuous wave and passively Q-switched laser performance of Nd:LuxGd3-xGa5O12 crystal at 1062 nm

    NASA Astrophysics Data System (ADS)

    Fu, X. W.; Jia, Z. T.; Yang, H.; Li, Y. B.; Yuan, D. S.; Zhang, B. T.; Dong, C. M.; He, J. L.; Tao, X. T.

    2012-12-01

    Continuous wave (CW) and passively Q-switched (PQS) laser properties at 1062 nm of the Nd:LuxGd3-xGa5O12 (Nd:LGGG) disordered crystal have been demonstrated. The doping concentrations of Nd3+ and Lu3+ in the as obtained crystal were measured to be 0.96 and 0.66 at.%, respectively. In the CW regime, the output power of 9.73 W was obtained with an optical-to-optical efficiency as high as 60.7% and slope efficiency of 61.2%. During the passively Q-switched operation, the maximum output power of 1.24 W was achieved under the absorbed pump power of 6.86 W. The maximum peak power of 14.20 kW and single pulse energy of 148 μJ were obtained with the Toc = 10% under the absorbed pump power of 6.36 W. The results are much better than those obtained with Nd:LGGG crystal doped with 13.6 at.% Lu3+ and 0.53 at.% Nd3+ ions.

  5. Experimental and theoretical study of passively Q-switched Yb:YAG laser with GaAs saturable absorber near 1050 nm

    NASA Astrophysics Data System (ADS)

    Chu, Hongwei; Zhao, Shengzhi; Yang, Kejian; Li, Yuefei; Li, Dechun; Li, Guiqiu; Zhao, Jia; Qiao, Wenchao; Xu, Xiaodong; Di, Juqing; Zheng, Lihe; Xu, Jun

    2014-03-01

    A diode-end-pumped passively Q-switched ytterbium-doped yttrium aluminum garnet (Yb:YAG) laser with gallium arsenide (GaAs) wafer as saturable absorber has been realized. In the experiment, two pieces of GaAs wafers with respective thicknesses of 400 and 700 μm were used respectively. The output laser characteristics such as the pulse duration, single pulse energy and peak power, have been measured. By using thicker GaAs wafer as saturable absorber, a minimum pulse duration of 3.5 ns was obtained with an average output power of 361 mW and a pulse repetition rate (PRR) of 25 kHz, corresponding to a single pulse energy of 19.6 μJ and a peak power of 5.7 kW. With a 400 μm-thick GaAs wafer as saturable absorber, a maximum output power of 469 mW was achieved. The central wavelength of the laser was measured to be 1050.4 nm at pump power of 7.8 W and dual wavelength operation peaked at 1049.3 nm and 1051.6 nm was observed at a high pump power of 10 W. By considering Gaussian spatial distribution and the thermal effects in the gain medium, the coupled rate equations for passively Q-switched Yb:YAG laser with GaAs saturable absorber were given.

  6. Passively mode-locked Yb:YAG thin-disk laser with pulse energies exceeding 13 microJ by use of an active multipass geometry.

    PubMed

    Neuhaus, Joerg; Kleinbauer, Jochen; Killi, Alexander; Weiler, Sascha; Sutter, Dirk; Dekorsy, Thomas

    2008-04-01

    We demonstrate the generation of high-energy picosecond pulses directly from a thin-disk laser oscillator by employing a self-imaging active multipass geometry. Stable single-pulse operation has been obtained with an average output power in excess of 50 W, excluding a cw background of 8%, at a repetition rate of 3.8 MHz. Self-starting passive mode locking was accomplished using a semiconductor saturable absorber mirror. The maximum pulse energy was 13.4 microJ at a pulse duration of 1.36 ps with a time-bandwidth product of 0.34. Single-pass external frequency doubling with a conversion efficiency of 60% yielded >28 W of average power at 515 nm. PMID:18382531

  7. The formation of various multi-soliton patterns and noise-like pulse in a fiber laser passively mode-locked by a topological insulator based saturable absorber

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Wu, Man; Tang, Pinghua; Chen, Shuqing; Du, Juan; Jiang, Guobao; Li, Ying; Zhao, Chujun; Zhang, Han; Wen, Shuangchun

    2014-05-01

    We experimentally investigated the formation of various multi-soliton patterns and noise-like (NL) pulses in an erbium-doped fiber laser passively mode-locked by a new type of saturable absorber: topological insulator. With the increase of pump power, various multi-soliton operation states—ordered, chaotic and bunched multiple-soliton—were subsequently obtained. Once the pump power exceeds 401 mW, an NL pulse state emerged, with a maximum 3 dB bandwidth of about 9.3 nm. This systematic study clearly demonstrated that a topological insulator could be an effective saturable absorber for the formation of various soliton operation states in a fiber laser cavity.

  8. Passive synchronization between a self-similar pulse and a bound-soliton bunch in a two-color mode-locked fiber laser.

    PubMed

    Hsiang, Wei-Wei; Chang, Chia-Hao; Cheng, Chien-Po; Lai, Yinchieh

    2009-07-01

    We report the first (to our knowledge) experimental observation of passive synchronization between a 1.03 microm self-similar pulse and a 1.56 microm bound-soliton bunch in a two-color mode-locked fiber laser. The self-similar pulse can form an effective potential well of several picoseconds to trap the copropagating bound solitons in the shared-fiber section. Such synchronization mechanism is supported by the experimental evidence of smaller time separation between the bound solitons under synchronization. In addition, the self-similar pulse and bound solitons can still remain locked under the periodic collision of another 1.56 microm unlocked pulse train. PMID:19571968

  9. Generation of "gigantic" ultra-short microwave pulses based on passive mode-locking effect in electron oscillators with saturable absorber in the feedback loop

    NASA Astrophysics Data System (ADS)

    Ginzburg, N. S.; Denisov, G. G.; Vilkov, M. N.; Zotova, I. V.; Sergeev, A. S.

    2016-05-01

    A periodic train of powerful ultrashort microwave pulses can be generated in electron oscillators with a non-linear saturable absorber installed in the feedback loop. This method of pulse formation resembles the passive mode-locking widely used in laser physics. Nevertheless, there is a specific feature in the mechanism of pulse amplification when consecutive energy extraction from different fractions of a stationary electron beam takes place due to pulse slippage over the beam caused by the difference between the wave group velocity and the electron axial velocity. As a result, the peak power of generated "gigantic" pulses can exceed not only the level of steady-state generation but also, in the optimal case, the power of the driving electron beam.

  10. Compact diode-directly-pumped passively mode-locked TEM00 Nd:GdVO4 laser at 1341 nm using a semiconductor saturable absorber mirror

    NASA Astrophysics Data System (ADS)

    Liu, K.; Li, F. Q.; Liu, Y.; Cao, D.; Bo, Y.; Peng, Q. J.; Cui, D. F.; Zhang, J. Y.; Xu, Z. Y.

    2011-11-01

    We report on a compact 880-nm diode-directly-pumped passively mode-locked TEM00 Nd:GdVO4 laser at 1341 nm with a semiconductor saturable absorber mirror (SESAM) for the first time. Under the absorbed pump power of 14.6 W, the maximum output power of 1.27 W was obtained at the repetition rate of 85.3 MHz with the pulse width of 45.3 ps, corresponding to an optical-optical efficiency of 8.8% and the slope efficiency of 33.3%, respectively. The beam quality factor was measured to be M 2 = 1.18, indicating a TEM00 mode.

  11. Megawatt-level peak-power from a passively Q-switched hybrid fiber-bulk amplifier and its applications

    NASA Astrophysics Data System (ADS)

    Reiser, Axel; Bdzoch, Juraj; Höfer, Sven; Scholz-Riecke, Sina; Seitz, Daniel; Kugler, Nicolas; Genter, Peter

    2016-03-01

    A novel laser system with optical parameters that fill the gap between Q-switched and modelocked lasers has been developed. It consists of a high gain hybrid fiber-bulk amplifier seeded by a low power SESAM Q-switched oscillator. The mW level output power of the seed oscillator is preamplified by a single mode fiber which is limited by SRS effects. The final amplification stage is realized by a longitudinal pumped Nd:YVO4 crystal in a double pass setup. This MOPA configuration delivers sub-300ps pulses at repetition rates up to 1 MHz with an output power exceeding 60W. Nonlinear frequency conversion to 532nm and 355nm is achieved with efficiencies of >75% and >45%, respectively. Due to the high peak power, high repetition rate and high beam quality of this system, applications formerly only addressable at lower pulse repetition frequencies or with complex modelocked laser systems are now possible with high speed and lower cost of ownership. Application results that take benefit from these new laser parameters will be shown. Furthermore, the reduction of the pulse duration to sub-100ps and power scaling to output powers <100W by the use of the Innoslab concept are being presented.

  12. A random Q-switched fiber laser.

    PubMed

    Tang, Yulong; Xu, Jianqiu

    2015-01-01

    Extensive studies have been performed on random lasers in which multiple-scattering feedback is used to generate coherent emission. Q-switching and mode-locking are well-known routes for achieving high peak power output in conventional lasers. However, in random lasers, the ubiquitous random cavities that are formed by multiple scattering inhibit energy storage, making Q-switching impossible. In this paper, widespread Rayleigh scattering arising from the intrinsic micro-scale refractive-index irregularities of fiber cores is used to form random cavities along the fiber. The Q-factor of the cavity is rapidly increased by stimulated Brillouin scattering just after the spontaneous emission is enhanced by random cavity resonances, resulting in random Q-switched pulses with high brightness and high peak power. This report is the first observation of high-brightness random Q-switched laser emission and is expected to stimulate new areas of scientific research and applications, including encryption, remote three-dimensional random imaging and the simulation of stellar lasing. PMID:25797520

  13. Effect of beam expansion loss in a carbon nanotube-doped PVA film on passively mode-locked erbium-doped fiber lasers with different feedback ratios

    NASA Astrophysics Data System (ADS)

    Cheng, Kuang-Nan; Chi, Yu-Chieh; Cheng, Chih-Hsien; Lin, Yung-Hsiang; Lo, Jui-Yung; Lin, Gong-Ru

    2014-10-01

    The effect of beam expansion induced divergent loss in a single-wall carbon nanotube (SWCNT) doped polyvinyl alcohol (PVA) based ultrafast saturable absorber (SA) film thickness on the passive mode-locking (PML) performances of erbium-doped fiber lasers are demonstrated. The variation on the PML pulsewidth of the EDFL is discussed by changing the SWCNT-PVA SA film thicknesses, together with adjusting the pumping power and the intra-cavity feedback ratio. An almost 6 dB increment of divergent loss when enlarging the SWCNT-PVA based SA film thickness from 30-130 µm is observed. When shrinking the SA thickness to 30 µm at the largest pumping power of 52.5 mW, the optical spectrum red-shifts to 1558.8 nm with its 3 dB spectral linewidth broadening up to 2.7 nm, while the pulse has already entered the soliton regime with multi-order Kelly sidebands aside the spectral shoulder. The soliton pulsewidth is as short as 790 fs, which is much shorter than those obtained with other thicker SWCNT doped PVA polymer film based SAs; therefore, the peak power from the output of the PML-EDFL is significantly enlarged accompanied by a completely suppressed residual continuous-wave level to achieve the largest on/off extinction ratio. The main mechanism of pulse shortening with reducing thickness of SWCNT doped PVA polymer film based SA is attributed to the limited beam expansion as well as the enlarged modulation depth, which results in shortened soliton pulsewidth with a clean dc background, and broadened spectrum with enriched Kelly sidebands. The increase of total SWCNT amount in the thicker SA inevitably causes a higher linear absorption; hence, the mode-locking threshold also rises accordingly. By enlarging pumping power from 38.5-52.5 mW, the highest ascent on pulse extinction of up to 32 dB is observed among all kinds of feedback conditions. Nevertheless, the enlargement on the extinction slightly decays with increasing the feedback ratio from 30-90%, as

  14. Generation and evolution of mode-locked noise-like square-wave pulses in a large-anomalous-dispersion Er-doped ring fiber laser.

    PubMed

    Liu, Jun; Chen, Yu; Tang, Pinghua; Xu, Changwen; Zhao, Chujun; Zhang, Han; Wen, Shuangchun

    2015-03-01

    In a passively mode-locked Erbium-doped fiber laser with large anomalous-dispersion, we experimentally demonstrate the formation of noise-like square-wave pulse, which shows quite different features from conventional dissipative soliton resonance (DSR). The corresponding temporal and spectral characteristics of a variety of operation states, including Q-switched mode-locking, continuous-wave mode-locking and Raman-induced noise-like pulse near the lasing threshold, are also investigated. Stable noise-like square-wave mode-locked pulses can be obtained at a fundamental repetition frequency of 195 kHz, with pulse packet duration tunable from 15 ns to 306 ns and per-pulse energy up to 200 nJ. By reducing the linear cavity loss, stable higher-order harmonic mode-locking had also been observed, with pulse duration ranging from 37 ns at the 21st order harmonic wave to 320 ns at the fundamental order. After propagating along a piece of long telecom fiber, the generated square-wave pulses do not show any obvious change, indicating that the generated noise-like square-wave pulse can be considered as high-energy pulse packet for some promising applications. These experimental results should shed some light on the further understanding of the mechanism and characteristics of noise-like square-wave pulses. PMID:25836862

  15. Compact high-pulse-energy passively Q-switched Nd:YLF laser with an ultra-low-magnification unstable resonator: application for efficient optical parametric oscillator.

    PubMed

    Cho, C Y; Huang, Y P; Huang, Y J; Chen, Y C; Su, K W; Chen, Y F

    2013-01-28

    We exploit an ultra-low-magnification unstable resonator to develop a high-pulse-energy side-pumped passively Q-switched Nd:YLF/Cr⁴⁺:YAG laser with improving beam quality. A wedged laser crystal is employed in the cavity to control the emissions at 1047 nm and 1053 nm independently through the cavity alignment. The pulse energies at 1047 nm and 1053 nm are found to be 19 mJ and 23 mJ, respectively. The peak powers for both wavelengths are higher than 2 MW. Furthermore, the developed Nd:YLF lasers are employed to pump a monolithic optical parametric oscillator for confirming the applicability in nonlinear wavelength conversions. PMID:23389131

  16. Diode end-pumped passively Q-switched Tm:YAP laser with 1.85-mJ pulse energy.

    PubMed

    Sebbag, Daniel; Korenfeld, Arik; Ben-Ami, Udi; Elooz, David; Shalom, Eran; Noach, Salman

    2015-04-01

    Passive Q switching of a Tm:YAP solid-state laser at 1935 nm with Cr:ZnSe and Cr:ZnS polycrystalline saturable absorbers is demonstrated for the first time, to the best of our knowledge. With Cr:ZnS, a maximum pulse energy of 1.85 mJ is obtained for a pulse duration of 35.8 ns, resulting in a peak power of 51.7 kW. With Cr:ZnSe, the achieved pulse energy of 1.55 mJ with a pulse duration of 42.2 ns leads to 36.7-kW peak power. These high pulse energies, together with the unique lasing wavelength at 1935 nm, make this laser a promising tool for biomedical and microsurgery applications. PMID:25831305

  17. Widely tunable eye-safe laser by a passively Q-switched photonic crystal fiber laser and an external-cavity optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Chang, H. L.; Zhuang, W. Z.; Huang, W. C.; Huang, J. Y.; Huang, K. F.; Chen, Y. F.

    2011-09-01

    We report on a widely tunable passively Q-switched photonic crystal fiber (PCF) laser with wavelength tuning range up to 80 nm. The PCF laser utilizes an AlGaInAs quantum well/barrier structure as a saturable absorber and incorporates an external-cavity optical parametric oscillator (OPO) to achieve wavelength conversion. Under a pump power of 13.1 W at 976 nm, the PCF laser generated 1029-nm radiation with maximum output energy of 750 μJ and was incident into an external-cavity OPO. The output energy and peak power of signal wave was found to be 138 μJ and 19 kW, respectively. By tuning the temperature of nonlinear crystal, periodically poled lithium niobate (PPLN), in the OPO, the signal wavelength in eye-safe regime from 1513 to 1593 nm was obtained.

  18. High-order Stokes generation in a KTP Raman laser pumped by a passively Q-switched ND:YLF laser

    NASA Astrophysics Data System (ADS)

    Wang, Maorong; Zhong, Kai; Mei, Jialin; Guo, Shibei; Xu, Degang; Yao, Jianquan

    2015-12-01

    High-order Stokes wave was observed in an x-cut KTP crystal based on stimulated Raman scattering (SRS) pumped by a passively Q-switched Nd:YLF laser with a Cr4+:YAG saturable absorber. Output spectra including the fundamental wave at 1047 nm and six Stokes wavelengths at 1077 nm, 1110 nm, 1130 nm, 1143 nm, 1164 nm, 1180 nm based on two Raman frequency shift at 267.4 cm-1 and 693.0 cm-1 were obtained simultaneously. We also detected green light generation with output power of 12 mW from self frequency mixing in the KTP crystal. The maximum total output power reached 452 mW at the repetition frequency of 8.1 kHz, corresponding to the optical-to-optical conversion efficiency of 4.61% and pump-to-Raman conversion efficiency of 3.6%.

  19. Compact KTA-based intracavity optical parametric oscillator driven by a passively Q-switched Nd:GdVO4 laser.

    PubMed

    Miao, Jieguang; Peng, Jiying; Wang, Baoshan; Tan, Huiming

    2008-08-10

    We present a compact and efficient KTA-based intracavity optical parametric oscillator (IOPO) driven by a diode-end-pumped Nd:GdVO(4)/Cr:YAG passively Q-switched laser. At the incident diode pump power of 9.2 W, signal (1.53 microm) and idler (3.47 microm) average output powers of up to 744 and 356 mW, respectively, have been obtained. The total (signal+idler) optical-to-optical conversion efficiency is as high as 12%. By using the knife-edge method, near-diffraction-limited signal and idler beams have been detected, and the M(2) factors are well within 1.2. In addition, based on the ABCD matrix theory, the impact of mode matching and the thermal lens effect on the OPO output have been analyzed. PMID:18690272

  20. Influence of focal point properties on energy transfer and plasma evolution during laser ignition process with a passively q-switched laser.

    PubMed

    Bärwinkel, Mark; Lorenz, Sebastian; Stäglich, Robert; Brüggemann, Dieter

    2016-07-11

    Miniaturized passively q-switched laser ignition systems are a promising alternative to conventional ignition sources to ensure a reliable ignition under difficult conditions. In this study the influences of focal point properties on energy transfer from laser to plasma as well as plasma formation and propagation are investigated as the first steps of the laser induced ignition process. Maximum fluence and fluence volume are introduced to characterize focal point properties for varying laser pulse energies and focusing configurations. The results show that the transferred laser energy increases with increasing maximum fluence. During laser emission plasma propagates along the beam path of the focused laser beam. Rising maximum fluence results in increased plasma volume, but expansion saturates when fluence volume reaches its maximum. PMID:27410797

  1. Diode-pumped short pulse passively Q-switched 912 nm Nd:GdVO4/Cr:YAG laser at high repetition rate operation

    NASA Astrophysics Data System (ADS)

    Chen, F.; Yu, X.; Wang, C.; Yan, R. P.; Li, X. D.; Gao, J.; Zhang, Z. H.; Yu, J. H.

    2010-06-01

    A diode-end-pumped passively Q-switched 912 nm Nd:GdVO4/Cr:YAG laser is demonstrated for the first time. In a concave-piano cavity, pulsed 912 nm laser performance is investigated using two kinds of Cr:YAG crystal with different unsaturated transmission ( T U) of 95% and 90% at 912 nm as the saturable absorbers. When the T U = 90% Cr:YAG is used, as much as 2.6 W average output power for short pulsed 912 nm laser is achieved at an absorbed pump power of 34.0 W, corresponding to an optical efficiency of 7.6% and a slope efficiency of 20.3%. Moreover, 10.5 ns duration pulses and up to 2.3 kW peak power is obtained at the repetition rate around 81.6 kHz.

  2. Isolas of periodic passive Q-switching self-pulsations in the three-level:two-level model for a laser with a saturable absorber.

    PubMed

    Doedel, Eusebius J; Pando, Carlos L L

    2011-11-01

    We show that a fundamental feature of the three-level:two-level model, used to describe molecular monomode lasers with a saturable absorber, is the existence of isolas of periodic passive Q-switching (PQS) self-pulsations. A common feature of these closed families of periodic solutions is that they contain regions of stability of the PQS self-pulsation bordered by period-doubling and fold bifurcations, when the control parameter is either the incoherent external pump or the cavity frequency detuning. These findings unveil the fundamental solution structure that is at the origin of the phenomenon known as "period-adding cascades" in our system. Using numerical continuation techniques we determine these isolas systematically, as well as the changes they undergo as secondary parameters are varied. PMID:22181484

  3. 10 W mid-IR optical parametric oscillator pumped by a passively Q-switched Ho:YAG ceramic laser

    NASA Astrophysics Data System (ADS)

    Yuan, Jin-He; Duan, Xiao-Ming; Yao, Bao-Quan; Li, Jiang; Li, Chao-Yu; Pan, Yu-Bai

    2016-02-01

    We report on a ZnGeP2 (ZGP) optical parametric oscillator (OPO) pumped by a Cr2+:ZnS saturable absorbed passively Q-switched (PQS) Ho:YAG ceramic laser. The maximum output power of the ZGP OPO was 10 W at a 27.4 W incident PQS Ho:YAG ceramic laser, corresponding to a slope efficiency of 41.3% with respect to the incident pump power. The minimum mid-IR pulse width of 21 ns in 3.8 and 4.6 μm was obtained from the ZGP OPO. The beam quality was measured to be M 2  <  3.22.

  4. Large-energy, narrow-bandwidth laser pulse at 1645 nm in a diode-pumped Er:YAG solid-state laser passively Q-switched by a monolayer graphene saturable absorber.

    PubMed

    Zhou, Rong; Tang, Pinghua; Chen, Yu; Chen, Shuqing; Zhao, Chujun; Zhang, Han; Wen, Shuangchun

    2014-01-10

    Nonlinear transmission parameters of monolayer graphene at 1645 nm were obtained. Based on the monolayer graphene saturable absorber, a 1532 nm LD pumped 1645 nm passively Q-switched Er:YAG laser was demonstrated. Under the pump power of 20.8 W, a 1645 nm Q-switched pulse with FWHM of 0.13 nm (without the use of etalon) and energy of 13.5 μJ per pulse can be obtained. To the best of our knowledge, this is the highest pulse energy for graphene-based passively Q-switched Er:YAG laseroperating at 1645 nm, suggesting the potentials of graphene materials for high-energy solid-state laser applications. PMID:24514058

  5. Diode-Pumped Soliton and Non-Soliton Mode-Locked Yb:GYSO Lasers

    NASA Astrophysics Data System (ADS)

    He, Jin-Ping; Liang, Xiao-Yan; Li, Jin-Feng; Zheng, Li-He; Su, Liang-Bi; Xu, Jun

    2011-08-01

    Diode-pumped soliton and non-soliton mode-locked Yb:(Gd1-x Yx)2SiO5(x = 0.5) lasers are demonstrated. Pulses as short as 1.4 ps are generated for the soliton mode-locked operation, with a pair of SF10 prisms as the negative dispersion elements. The central wavelength is 1056 nm and the repetition rate is 48 MHz. For the non-soliton mode locking, the output power could achieve ~1.2 W, and the pulse width is about 20 ps. The critical pulse energy in the soliton-mode locked operation against the Q-switched mode locking is much lower than the critical pulse energy in the non-soliton mode-locked operation.

  6. Integration of mode-locked diode lasers

    NASA Astrophysics Data System (ADS)

    Coleman, A. Catrina; Hou, Lianping; Marsh, John H.

    2016-03-01

    Monolithic mode-locked semiconductor lasers are attractive sources of short optical pulses with advantages over more conventional sources in compactness, robustness, performance stability, power consumption, and cost savings. The use of quantum well intermixing (QWI) to integrate passive sections and surface etched distributed Bragg reflectors (DBR) into monolithic laser cavity will be described. The performance of the devices will be presented.

  7. Mode-locked silicon evanescent lasers.

    PubMed

    Koch, Brian R; Fang, Alexander W; Cohen, Oded; Bowers, John E

    2007-09-01

    We demonstrate electrically pumped lasers on silicon that produce pulses at repetition rates up to 40 GHz. The mode locked lasers generate 4 ps pulses with low jitter and extinction ratios above 18 dB, making them suitable for data and telecommunication transmitters and for clock generation and distribution. Results of both passive and hybrid mode locking are discussed. This type of device could enable new silicon based integrated technologies, such as optical time division multiplexing (OTDM), wavelength division multiplexing (WDM), and optical code division multiple access (OCDMA). PMID:19547478

  8. Flashlamp pumped oscillator-amplifier Nd:YAG system mode-locked using multiple quantum well saturable absorber

    NASA Astrophysics Data System (ADS)

    Kubecek, Vaclav; Jelinkova, Helena; Dombrovsky, Andrej; Diels, Jean-Claude; Stintz, Andreas

    2004-09-01

    We report on flashlamp pumped oscillator - three amplifiers Nd:YAG picosecond laser system in which the liquid saturable dye used for passive mode locking is replaced by semiconductor saturable absorber with multiple quantum well (MQW) structure. This element placed at Brewster angle inside a laser resonator had 100 layers of absorber and therefore it has high nonlinearity and is suitable for high power Q-switched and mode locked operation. The short pulse train from oscillator contained only 5-6 pulses with total energy of 3 mJ in single transversal mode, the pulse duration was 80 ps. After amplification, the maximum energy of the pulse train was 180 mJ. In the regime of the amplification of a single selected pulse the energy on the output of the third amplifier was 50 mJ. Operation of the oscillator in active-passive regime of mode locking using an additional acousto-optic mode-locker leads to improvement of reproducibility and stability of output parameters.

  9. Eye-safe 1.55  μm passively Q-switched Er,Yb:GdAl3(BO3)4 diode-pumped laser.

    PubMed

    Gorbachenya, K N; Kisel, V E; Yasukevich, A S; Maltsev, V V; Leonyuk, N I; Kuleshov, N V

    2016-03-01

    We report for the first time, to the best of our knowledge, on a diode-pumped passively Q-switched Er,Yb:GdAl3(BO3)4 laser. By using a Co2+:MgAl2O4 crystal as a saturable absorber, Q-switched laser pulses with a duration of 12 ns and a maximum energy of 18.7 μJ at a repetition rate of 32 kHz corresponding to an average output power of 0.6 W were obtained at 1550 nm under continuous-wave pumping. In the burst mode of operation, Q-switched laser pulses with the highest energy up to 44 μJ were realized with a pulse repetition rate of 6.5 kHz. PMID:26974080

  10. Different pulse pattern generation by frequency detuning in pulse modulated actively mode-locked ytterbium doped fiber laser

    NASA Astrophysics Data System (ADS)

    Chen, He; Chen, Sheng-Ping; Si, Lei; Zhang, Bin; Jiang, Zong-Fu

    2015-10-01

    We report the results of our recent experimental investigation of the modulation frequency detuning effect on the output pulse dynamics in a pulse modulated actively mode-locked ytterbium doped fiber laser. The experimental study shows the existence of five different mode-locking states that mainly depend on the modulation frequency detuning, which are: (a) amplitude-even harmonic/fundamental mode-locking, (b) Q-switched harmonic/fundamental mode-locking, (c) sinusoidal wave modulation mode, (d) pulses bundle state, and (e) noise-like state. A detailed experimental characterization of the output pulses dynamics in each operating mode is presented.

  11. A 2 μm continuous wave and passively Q-switched fiber laser in thulium-doped germanate glass fibers

    NASA Astrophysics Data System (ADS)

    Fan, Xiaokang; Kuan, Peiwen; Li, Kefeng; Zhang, Lei; Li, Wentao; Hu, Lili

    2014-08-01

    In this study, we designed and fabricated a Tm3+-doped germanate glass fiber by using a rod-in-tube technique. The fiber has a core diameter of ~13.5 μm with a cladding of 125 μm. The Tm3+ doping concentration reached ~13 500 ppm, and the propagation loss of the fiber was less than 0.03 dB cm - 1 at 1310 nm. Pumping with a 1590 nm fiber laser constructed in-house, a 44.7 mW continuous-wave fiber laser at 1940 nm was achieved in a 22 cm-long germanate fiber, with a slope efficiency of 26%. The passively Q-switched pulse output was first demonstrated by using a carbon nanotube saturable absorber in the germanate fiber. The germanate fiber laser generates approximately 1.5 μs pulses with a maximum pulse energy of 110 nJ, and the repetition rate varies from 15 to 84 kHz, depending on pump power.

  12. Multi-wavelength passively Q-switched c-cut Nd:YVO4 self-Raman laser with Cr4+:YAG saturable absorber

    NASA Astrophysics Data System (ADS)

    Lin, H. Y.; Pan, X.; Huang, X. H.; Xiao, M.; Liu, X.; Sun, D.; Zhu, W. Z.

    2016-06-01

    A multi-wavelength passively Q-switched self-Raman laser with a c-cut Nd:YVO4 both as laser and Raman medium is reported. With the increasing pump power, the multi-wavelength laser including the fundamental line at 1067.4 nm, 1st-Stokes at 1097.9 nm, 2nd-Stokes at 1130.1 nm, and 3rd-Stokes at 1163.6 nm is generated sequentially. At a pump power of 5.0 W, the maximum output power of the four discrete lines are 186.8 mW, 246.5 mW, 158.4 mW and 63.6 mW, with corresponding optical conversion efficiencies of 3.7%, 4.9%, 3.2% and 1.3% respectively. The total stimulated Raman scattering conversion efficiency is 9.4%. To our best knowledge, this is the first report of the 2nd-Stokes at 1130.1 nm and 3rd-Stokes at 1163.6 nm.

  13. 763 fs Passively mode-locked Yb:Y2SiO5 laser with a graphene oxide absorber mirror

    NASA Astrophysics Data System (ADS)

    Zhu, Hongtong; Cai, Wei; Wei, Jiafeng; Liu, Jie; Zheng, Lihe; Su, Liangbi; Xu, Jun; Wang, Yonggang

    2015-05-01

    Based on a graphene oxide absorber mirror, the laser-diode pumped mode-locked Yb:Y2SiO5 (Yb:YSO) laser was demonstrated for the first time. The laser generated pulses with pulse duration as short as ~763 fs and average output power of 700 mW at the central wavelength of 1059 nm. The corresponding peak power and energy of a single pulse were ~8.6 kW and ~7.4 nJ, respectively. To our best knowledge, this is the shortest bulk mode-locked laser based on graphene oxide.

  14. Compact passively mode-locked fiber laser at 1.55 μm with low timing jitter of 8 fs

    NASA Astrophysics Data System (ADS)

    Wu, Kan; Shum, Perry Ping

    2013-05-01

    Mode-locked fiber lasers with low timing jitter and high repetition rate is desired for various applications including photonics analog-to-digital conversion, microwave synthesis and high-precision clock distribution. We demonstrate a compact all fiber laser mode locked by semiconductor saturable absorber mirror with linear cavity. The laser is operating near 1.55 μm. It has a repetition rate of 250 MHz and the root-mean-square timing jitter is 8 fs integrated from 100 Hz to 1 MHz measured at the third harmonic frequency of 750 MHz.

  15. High-energy passively Q-switched operation of Yb:GdCa(4)O(BO(3))(3) laser with a GaAs semiconductor saturable absorber.

    PubMed

    Chen, Xiaowen; Wang, Lisha; Han, Wenjuan; Guo, Yunfeng; Xu, Honghao; Yu, Haohai; Zhang, Huaijin; Liu, Junhai

    2015-11-16

    High-energy passively Q-switched operation of a Yb:GdCa(4)O(BO(3))(3) laser is demonstrated, with a GaAs crystal plate acting as saturable absorber. An average output power of 1.31 W at 1027 nm is produced at a pulse repetition rate of 1.92 kHz, the resulting pulse energy, duration, and peak power being respectively 0.68 mJ, 9.0 ns, and 75.6 kW. The shortest pulse duration obtained is 4.9 ns; whereas the maximum pulse energy achievable amounts to 0.83 mJ, which proves to be nearly one order of magnitude higher than ever generated from Yb or Nd lasers passively Q-switched by a GaAs saturable absorber. PMID:26698515

  16. Compact and efficient passively Q-switched laser at 473  nm with an Nd:YAG/YAG/Cr4+:YAG/YAG multifunctional composite crystal.

    PubMed

    Zhu, Siqi; Zhou, Haiqiong; Jiang, Wei; Li, Zhen; Yin, Hao; Zhang, Ge; Chen, Zhenqiang

    2016-05-20

    An Nd:YAG/YAG/Cr4+:YAG/YAG composite crystal and an LBO crystal were used to generate a passively Q-switched frequency-doubling 473 nm blue laser for the first time, to the best of our knowledge. The result demonstrated that the slope efficiency of this system reaches 18%, which is the highest in all the passively Q-switched 473 nm laser systems reported, to the best of our knowledge. Under the pumped power of 8.64 W, the maximum average output power of 0.93 W was obtained with a pulsewidth of 78 ns, and the repetition rate of 18.5 kHz. PMID:27411146

  17. Evaluation of a commercially available passively Q-switched Nd:YAG laser with LiF:F-2 saturable absorber for laser-induced breakdown spectroscopy

    SciTech Connect

    Carson, Cantwell; Goueguel, Christian; Sanghapi, Herve; Jinesh, Jain; McIntyre, Dustin

    2015-12-11

    Interest in passively Q-switched microchip lasers as a means for miniaturization of laser-induced breakdown spectroscopy (LIBS) apparatus has rapidly grown in the last years. To explore the possibility of using a comparatively UV–vis transparent absorber, we herein present the first report on the evaluation of a commercially available flash lamp-pumped passively Q-switched Nd:YAG laser with LiF: saturable absorber as an excitation source in LIBS. Quantitative measurements of barium, strontium, rubidium and lithium in granite, rhyolite, basalt and syenite whole-rock glass samples were performed. Using a gated intensified benchtop spectrometer, limits of detection of 0.97, 23, 37, and 144 ppm were obtained for Li, Sr, Rb, and Ba, respectively. Finally, we discuss the advantages of using such a laser unit for LIBS applications in terms of ablation efficiency, analytical performances, output energy, and standoff capabilities.

  18. High-average-power actively-mode-locked Tm3+ fiber lasers

    NASA Astrophysics Data System (ADS)

    Eckerle, Michael; Kieleck, Christelle; Hübner, Philipp; Świderski, Jacek; Jackson, Stuart D.; Mazé, Gwenael; Eichhorn, Marc

    2012-02-01

    Fiber lasers emitting in the 2 μm wavelength range doped with thulium ions can be used as highly efficient pump sources for nonlinear converters to generate mid-infrared radiation. For spectroscopic purposes, illumination and countermeasures, a broad mid-infrared emission spectrum is advantageous. This can be reached by supercontinuum generation in fibers, e.g. fluoride fibers, which up to now has, however, only been presented with either low average power, complex Raman-shifted 1.55 μm pump sources or multi-stage amplifier pump schemes. Here we present recent results of a new actively-mode-locked single-oscillator scheme that can provide the high-repetition rate sub-ns pump pulses needed for pumping supercontinuum generators. A thulium-doped silica fiber laser is presented that provides > 11 W of average power CW-mode-locked pulses at 38 MHz repetition rate at ~ 38 ps pulse width. Upgrading the setup to allow Q-switched mode-locked operation yields mode-locked 40 MHz pulses arranged in 60 kHz bunched Q-switch envelopes and thus increases further the available peak power. In this Q-switched mode-locked regime over 5 W of average power has been achieved.

  19. Switchable Q-switched and modelocked operation in ytterbium doped fiber laser under all-normal-dispersion configuration

    SciTech Connect

    Mukhopadhyay, Pranb K. Gupta, Pradeep K.; Singh, Chandra Pal; Singh, Amarjeet; Sharma, Sunil K.; Bindra, Kushvinder S.; Oak, Shrikant M.

    2015-03-15

    We have constructed an Yb-doped fiber laser in all-normal-dispersion configuration which can be independently operated in Q-switched or modelocked configuration with the help of a simple fiber optic ring resonator (FORR). In the presence of FORR, the laser operates in Q-switched mode producing stable pulses in the range of 1 μs-200 ns with repetition rate in the range of 45 kHz-82 kHz. On the other hand, the laser can be easily switched to mode-locked operation by disjoining the FORR loop producing train of ultrashort pulses of ∼5 ps duration (compressible to ∼150 fs) at ∼38 MHz repetition rate. The transmission characteristics of FORR in combination with the nonlinear polarization rotation for passive Q-switching operation is numerically investigated and experimentally verified. The laser can serve as a versatile seed source for power amplifier which can be easily configured for application in the fields that require different pulsed fiber lasers.

  20. Switchable Q-switched and modelocked operation in ytterbium doped fiber laser under all-normal-dispersion configuration.

    PubMed

    Mukhopadhyay, Pranb K; Gupta, Pradeep K; Singh, Chandra Pal; Singh, Amarjeet; Sharma, Sunil K; Bindra, Kushvinder S; Oak, Shrikant M

    2015-03-01

    We have constructed an Yb-doped fiber laser in all-normal-dispersion configuration which can be independently operated in Q-switched or modelocked configuration with the help of a simple fiber optic ring resonator (FORR). In the presence of FORR, the laser operates in Q-switched mode producing stable pulses in the range of 1 μs-200 ns with repetition rate in the range of 45 kHz-82 kHz. On the other hand, the laser can be easily switched to mode-locked operation by disjoining the FORR loop producing train of ultrashort pulses of ∼5 ps duration (compressible to ∼150 fs) at ∼38 MHz repetition rate. The transmission characteristics of FORR in combination with the nonlinear polarization rotation for passive Q-switching operation is numerically investigated and experimentally verified. The laser can serve as a versatile seed source for power amplifier which can be easily configured for application in the fields that require different pulsed fiber lasers. PMID:25832207

  1. Mode-locked fiber laser based on chalcogenide microwires.

    PubMed

    Al-Kadry, Alaa; El Amraoui, Mohammed; Messaddeq, Younès; Rochette, Martin

    2015-09-15

    We report the first mode-locked fiber laser using a chalcogenide microwire as the nonlinear medium. The laser is passively mode-locked with nonlinear polarization rotation and can be adjusted for the emission of solitons or noise-like pulses. The use of the microwire leads to a mode-locking threshold at the microwatt level and shortens the cavity length by 4 orders of magnitude with respect to other lasers of its kind. The controlled birefringence of the microwire, combined with a linear polarizer in the cavity, enables multiwavelength laser operation with tunable central wavelength, switchable wavelength separation, and a variable number of laser wavelengths. PMID:26371923

  2. Broadband tuning in a passively Q-switched erbium doped fiber laser (EDFL) via multiwall carbon nanotubes/polyvinyl alcohol (MWCNT/PVA) saturable absorber

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Hassan, S. N. M.; Ahmad, F.; Zulkifli, M. Z.; Harun, S. W.

    2016-04-01

    An MWCNT/PVA-based Q-switched erbium-doped fiber laser (EDFL) that uses a tunable bandpass filter (TBPF) as the wavelength tuning and filtering mechanism to achieve a broadband tuning range is proposed and demonstrated. The tuning range of the generated Q-switched pulses covered a wide wavelength range of 50 nm, which spanned from 1519 nm to 1569 nm and corresponded to the S- and C-band regions. In addition, the lasing and Q-switching operations had low thresholds of 8.9 mW and 22.4 mW respectively. The highest pulse energy of 52.13 nJ was obtained at an output wavelength of 1569 nm, with a corresponding repetition rate of 26.53 kHz and pulse width of 6.10 μs, at the maximum power of 114.8 mW.

  3. Neodymium laser with negative feedback: Suppression of self-mode-locking, control of mode-locking regime

    NASA Astrophysics Data System (ADS)

    Kozlova, M. V.; Smirnov, A. M.; Al-Khuzheyri, R. M.; Mantsevich, V. N.; Dneprovskii, V. S.

    2015-08-01

    A simple way of suppression of self-mode-locking in a nanosecond Q-switched Nd3+:YAlO3 laser by placing an element introducing a negative feedback into the laser cavity, which consists of a plate of singlecrystal GaAs exhibiting two-photon absorption (complete suppression) or a cell containing colloidal solution of CdSe/ZnS quantum dots (partial suppression), is implemented. Placing the element introducing the negative feedback into the cavity of a pulsed picosecond mode-locked Nd3+:Y3Al5O12 laser allowed an increase in the number of pulses in the pulse train and a change in the energy distribution between the pulses. Specificities of laser oscillation regimes in the presence of a nonlinear absorbing element in the cavity were analyzed by numerically solving the set of balance equations describing the population inversion density and the photon flux density in the cavity.

  4. Fast wavelength-tunable picosecond pulses from a passively mode-locked Er fiber laser using a galvanometer-driven intracavity filter.

    PubMed

    Ozeki, Yasuyuki; Tashiro, Daigo

    2015-06-15

    We experimentally investigate fast wavelength-tuning characteristics of a polarization-maintaining Er fiber laser, which is mode-locked with a semiconductor saturable absorber mirror. Wavelength tuning was accomplished with an intracavity filter incorporating a galvanometer mirror and a diffraction grating. Within the tunability of 30 nm, we achieved a wavelength-tuning speed of <5 ms. We also show that the variation of repetition rates can be suppressed to <200 Hz by simply shifting the position of the grating. The presented scheme for generating wavelength-tunable pulses will be potentially useful for coherent Raman spectral imaging. PMID:26193501

  5. Diverse output states from an all-normal dispersion ytterbium-doped fiber laser: Q-switch, dissipative soliton resonance, and noise-like pulse

    NASA Astrophysics Data System (ADS)

    Xu, Z. W.; Zhang, Z. X.

    2013-06-01

    An all-normal-dispersion ytterbium-doped fiber ring laser has been demonstrated, with different operation regimes: Q-switch, CW mode-locking and noise-like pulses, depending on the pump power and suitable orientation of the polarization controllers. As a transition between Q-switch and CW mode-locking, Q-switched mode-locking has also been observed. Moreover, our experiment shows that the CW mode-locking operation is the result of dissipative soliton resonance in the all-normal-dispersion fiber laser without external filter, which is a new way to generate high-energy pulses. This fiber laser with diverse outputs has many potential applications, and is helpful to investigate laser dynamics.

  6. Reduction of timing jitter and intensity noise in normal-dispersion passively mode-locked fiber lasers by narrow band-pass filtering.

    PubMed

    Qin, Peng; Song, Youjian; Kim, Hyoji; Shin, Junho; Kwon, Dohyeon; Hu, Minglie; Wang, Chingyue; Kim, Jungwon

    2014-11-17

    Fiber lasers mode-locked with normal cavity dispersion have recently attracted great attention due to large output pulse energy and femtosecond pulse duration. Here we accurately characterized the timing jitter of normal-dispersion fiber lasers using a balanced cross-correlation method. The timing jitter characterization experiments show that the timing jitter of normal-dispersion mode-locked fiber lasers can be significantly reduced by using narrow band-pass filtering (e.g., 7-nm bandwidth filtering in this work). We further identify that the timing jitter of the fiber laser is confined in a limited range, which is almost independent of cavity dispersion map due to the amplifier-similariton formation by insertion of the narrow bandpass filter. The lowest observed timing jitter reaches 0.57 fs (rms) integrated from 10 kHz to 10 MHz Fourier frequency. The rms relative intensity noise (RIN) is also reduced from 0.37% to 0.02% (integrated from 1 kHz to 5 MHz Fourier frequency) by the insertion of narrow band-pass filter. PMID:25402069

  7. Small acousto-optic modulation for active mode locking in the iodine photodissociation laser and the effect of supplementary saturable absorber

    SciTech Connect

    Kim, Y.S.; Lee, S.S.

    1985-02-01

    Active, passive, and active--passive mode locking of the iodine photodissociation laser are investigated. The peak-to-background ratio (PBR) of the acousto-optically mode-locked pulse is 85% for rf power of 5 W. Passive mode locking using BDN dye gives PBR of 75% and has inferior reproducibility. The active--passive mode locking using the two methods simultaneously is useful for the pressure broadened iodine laser line and gives a PBR of 91%. In this case the rf power required for complete mode locking is calculated to be 7 W which is much less than the required power of 11 W in using active mode locking alone.

  8. Investigation of the laser pumping power impact on the operating regimes of a laser passively Q-switched by a saturated absorber

    NASA Astrophysics Data System (ADS)

    Benarab, Mustapha; Mokdad, Rabah; Djellout, Hocine; Benfdila, Arezki; Lamrous, Omar; Meyrueis, Patrick

    2011-09-01

    We have adapted the point model for the study of an all-fiber laser doped with Nd3+ and Q-switched by a saturable fiber absorber doped with Cr4+. Calculations of the output power of the 1084 nm laser are considered as a function of the pump power supplied by a 790 nm laser diode. The analysis of the simulation results reveals the existence of pulsed, sinusoidal, and dc operating regimes.

  9. Compact diode-pumped continuous-wave and passively Q-switched Nd:GYSO laser at 1.07 μm

    NASA Astrophysics Data System (ADS)

    Lin, Zhi; Huang, Xiaoxu; Lan, Jinglong; Cui, Shengwei; Wang, Yi; Xu, Bin; Luo, Zhengqian; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Zhang, Xiaoyan; Wang, Jun; Xu, Jun

    2016-08-01

    We report diode-pumped continuous-wave (CW) and Q-switched Nd:GYSO lasers using a compact two-mirror linear laser cavity. Single-wavelength laser emissions at 1074.11 nm with 4.1-W power and at 1058.27 nm with 1.47-W power have been obtained in CW mode. The slope efficiencies with respect to the absorbed pump powers are 48.5% and 22.9%, respectively. Wavelength tunability is also demonstrated with range of about 8 nm. Using a MoS2 saturable absorber, maximum average output power up to 410 mW at 1074 nm can be yielded with absorbed pump power 6.41 W and the maximum pulse energy reaches 1.20 μJ with pulse repetition rate of 342.5 kHz and shortest pulse width of 810 ns. The CW laser results represent the best laser performance and the Q-switching also present the highest output power for Q-switched Nd3+ lasers with MoS2 as saturable absorber.

  10. High-energy passively Q-switched laser operation of Yb:Ca3La2(BO3)4 disordered crystal.

    PubMed

    Wang, Lisha; Han, Wenjuan; Pan, Zhongben; Xu, Honghao; Chen, Xiaowen; Liu, Junhai; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    Efficient high-energy passively Q-switched laser operation was demonstrated with Yb:Ca3La2(BO3)4 disordered crystal, producing an average output power of 3.0 W at 1018.7 nm, at a pulse repetition frequency of 5.0 kHz; the resulting pulse energy, duration, and peak power were 600 μJ, 5.3 ns, and 113.2 kW, respectively. PMID:27140354

  11. Monolithic hybrid mode-locked 1. 3. mu. m semiconductor lasers

    SciTech Connect

    Morton, P.A.; Bowers, J.E. ); Koszi, L.A.; Soler, M.; Lopata, J.; Wilt, D.P. )

    1990-01-08

    We describe the first results of hybrid mode locking combining both active and passive mode locking of a semiconductor laser. These functions are integrated into a monolithic device with a 1.3 {mu}m GaInAsP gain region, an active waveguide, and a saturable absorber. The devices have low threshold currents, and exhibit hysteresis in their light/current characteristics. The long integrated waveguides allow mode locking at a repetition rate of 15 GHz without the need for an external cavity. Pulse widths as short as 1.4 ps have been demonstrated using the combined effects of active and passive mode locking.

  12. Solitary pulse-on-demand production by optical injection locking of passively Q-switched InGaN diode laser near lasing threshold

    SciTech Connect

    Zeng, X. E-mail: dmitri.boiko@csem.ch; Stadelmann, T.; Grossmann, S.; Hoogerwerf, A. C.; Boïko, D. L. E-mail: dmitri.boiko@csem.ch; Sulmoni, L.; Lamy, J.-M.; Grandjean, N.

    2015-02-16

    In this letter, we investigate the behavior of a Q-switched InGaN multi-section laser diode (MSLD) under optical injection from a continuous wave external cavity diode laser. We obtain solitary optical pulse generation when the slave MSLD is driven near free running threshold, and the peak output power is significantly enhanced with respect to free running configuration. When the slave laser is driven well above threshold, optical injection reduces the peak power. Using standard semiconductor laser rate equation model, we find that both power enhancement and suppression effects are the result of partial bleaching of the saturable absorber by externally injected photons.

  13. Solitary pulse-on-demand production by optical injection locking of passively Q-switched InGaN diode laser near lasing threshold

    NASA Astrophysics Data System (ADS)

    Zeng, X.; Sulmoni, L.; Lamy, J.-M.; Stadelmann, T.; Grossmann, S.; Hoogerwerf, A. C.; Grandjean, N.; Boïko, D. L.

    2015-02-01

    In this letter, we investigate the behavior of a Q-switched InGaN multi-section laser diode (MSLD) under optical injection from a continuous wave external cavity diode laser. We obtain solitary optical pulse generation when the slave MSLD is driven near free running threshold, and the peak output power is significantly enhanced with respect to free running configuration. When the slave laser is driven well above threshold, optical injection reduces the peak power. Using standard semiconductor laser rate equation model, we find that both power enhancement and suppression effects are the result of partial bleaching of the saturable absorber by externally injected photons.

  14. Carbon nanotube mode-locked optically-pumped semiconductor disk laser.

    PubMed

    Seger, K; Meiser, N; Choi, S Y; Jung, B H; Yeom, D-I; Rotermund, F; Okhotnikov, O; Laurell, F; Pasiskevicius, V

    2013-07-29

    An optically pumped semiconductor disk laser was mode-locked for the first time by employing a single-walled carbon nanotube saturable absorber. Stable passive fundamental mode-locking was obtained at a repetition rate of 613 MHz with a pulse length of 1.23 ps. The mode-locked semiconductor disk laser in a compact geometry delivered a maximum average output power of 136 mW at 1074 nm. PMID:23938653

  15. Optical parametric oscillator of quasi-phasematched LiNbO 3 pumped by a compact high repetition rate single-frequency passively Q-switched Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Bäder, U.; Bartschke, J.; Klimov, I.; Borsutzky, A.; Wallenstein, R.

    1998-02-01

    We report on an efficient diode pumped compact source of pulsed tunable infrared radiation based on a high repetition rate single frequency passively Q-switched Nd:YAG laser and an optical parametric oscillator (OPO) of quasi-phase matched LiNbO 3. When pumped by 5.4 W of 810 nm cw diode laser radiation the Nd:YAG laser (which is passively Q-switched by a Cr 4+:GSGG saturable absorber) oscillates on a single-longitudinal mode and emits in a diffraction limited beam light pulses with duration of 2 ns, pulse energy of 100 μJ, repetition rate of 1.1 kHz and average power of 110 mW. This radiation excites an OPO of quasi-phase matched LiNbO 3. The OPO generates signal and idler radiation which is tunable in the range of 1.46-1.61 μm and 3.13-3.92 μm, respectively. Tuning is achieved by using 8 different poling periods ( Λ=28.5-29.9 μm) and by changing the crystal's temperature in the range of 80-160°C. The measured signal pulse energy is ES =22 μJ, the average signal output power PS =24 mW, the measured idler power PI =2.5 mW and the pump depletion 33%.

  16. Continuous-wave and passively Q-switched laser performance of Nd:(LaxGd1-x)3Ga5O12 crystal at 1062 nm CW and PQS laser performance of Nd:LaGGG crystal at 1062 nm

    NASA Astrophysics Data System (ADS)

    Yang, H.; Fu, X.-W.; Jia, Z.-T.; He, J.-L.; Yang, X.-Q.; Zhang, B.-T.; Wang, R.-H.; Liu, X.-M.; Hou, J.; Lou, F.; Wang, Z.-W.; Yang, Y.

    2012-10-01

    The performance of diode-pumped continuous-wave (CW) and passively Q-switched (PQS) Nd:(LaxGd1-x)3Ga5O12 lasers at 1062 nm were demonstrated for the first time to our knowledge. The highest CW output power of 9.9 W was obtained, corresponding to an optical-to-optical efficiency of 42.9%. For the passive Q-switching operation, when the output coupler of Toc = 27% was adopted, the maximum output power of 3.97 W was obtained by a Cr4+:YAG saturable absorber with the initial transmission of T0 = 89.9%.While at T0 = 81.4% and Toc = 27%, the output power of 2.83 W, with pulse width of 7.4 ns and the repetition rate of 13.87 kHz, was obtained, corresponding to the maximum peak power of 27.6 kW and single pulse energy of 0.2 mJ, respectively.

  17. 7.6  W 1342  nm passively mode-locked picosecond composite Nd:YVO4/YVO4 laser with a semiconductor saturable absorber mirror.

    PubMed

    Tu, Wei; Chen, Ying; Zong, Nan; Liu, Ke; Wang, Zhi-Min; Zhang, Feng-Feng; Zhang, Shen-Jin; Yang, Feng; Yuan, Lei; Bo, Yong; Peng, Qin-Jun; Cui, Da-Fu; Xu, Zu-Yan

    2015-04-10

    A high average power 1342 nm passively CW mode-locked picoseconds (ps) composite Nd:YVO4 laser was demonstrated with a semiconductor saturable absorber mirror (SESAM). The oscillator cavity was carefully designed to optimize the laser beam radii in the crystal and on the SESAM. The combination of composite bonded laser crystal, direct pumping, and dual end-pumped configuration was adopted to reduce the thermal effect and produce high output power with high beam quality. A maximum average output power of 7.63 W was obtained with a repetition rate of 77 MHz and a pulse duration of 24.2 ps under an absorbed pump power of 38.6 W, corresponding to an optical-optical efficiency of 19.7% and a slope efficiency of 25.9%, respectively. The beam quality factor M(2) was measured to be 1.49. PMID:25967328

  18. All-normal dispersion passively mode-locked Yb-doped fiber laser using MoS2-PVA saturable absorber

    NASA Astrophysics Data System (ADS)

    Sathiyan, S.; Velmurugan, V.; Senthilnathan, K.; Babu, P. Ramesh; Sivabalan, S.

    2016-05-01

    We demonstrate the generation of a dissipative soliton in an all-normal dispersion ytterbium (Yb)-doped fiber laser using few-layer molybdenum disulfide (MoS2) as a saturable absorber. The saturable absorber is prepared by mixing few-layer MoS2 solution with polyvinyl alcohol (PVA) to form a free-standing composite film. The modulation depth and saturation intensity of the MoS2-PVA film are 11% and 5.86 MW cm-2, respectively. By incorporating the MoS2 saturable absorber in the fiber laser cavity, the mode-locked pulses are generated with a pulse width of 1.55 ns and a 3 dB spectral bandwidth of 0.9 nm centered at 1037.5 nm. The fundamental repetition rate and the average power are measured as 15.43 MHz and 1.5 mW, respectively. These results reveal the feasibility of deploying liquid-phase exfoliated few-layer MoS2 nanosheets for dissipative soliton generation in the near-IR region.

  19. Theory and Engineering Design Aspects of a Mini Diode-Pumped Q-Switch Er: Glass Laser for Space Applications

    NASA Astrophysics Data System (ADS)

    Sankar, N. Siva; Ramalingam, A.; Raja, V. L. N. Sridhar; Laxmiprasad, A. S.

    2011-10-01

    The invention of the laser, with its precise wavelength and beam divergence characteristics, coupled with the techniques like q-switching, mode locking to produce ultra-short pulses has been influencing the era of space technology. Space agencies worldwide are equipping satellites with laser transmitters in the hope of achieving crucial and vital tasks. Though, both laser technology and space operations have matured substantially in the recent decades, offering synergistic possibilities of using lasers from space-based platforms, development of a reliable laser sources meeting the space mission types and constraints is still the current quest. This paper especially focuses on the conceptualization and engineering design aspects of developing a miniaturized diode pumped, passive q-switch Er: Glass laser capable of delivering pulses of energy 3 mJ, pulse width of 7 ns at a repetition rate of 1 Hz and operating wavelength of 1535 nm. This paper sheds the light also on the selected resonator configurations, pump geometries and theoretical estimations that were performed in selection of the resonator elements keeping the miniaturization as the prime concern. Simulations of the non-linear effects like pump energy distribution, thermal lensing of the configured laser resonator design are done by employing various laser cavity and design analysis software.

  20. Continuous wave and passively Q-switched Nd:Lu0.15Y0.85VO4 laser with 885 nm direct pumping

    NASA Astrophysics Data System (ADS)

    Li, Qi-nan; Zhao, Bin; Zhang, Tao; Li, Rei; Liu, Xiang-mei; Zheng, Ya-hui; Liu, Xiao-jun

    2015-05-01

    The 885 nm direct pumping directly into the 4F3/2 emitting level of Nd3+ is applied on an Nd:Lu0.15Y0.85VO4 crystal. The maximum output power of 2.8 W for continuous wave (CW) operation is obtained. For Q-switched operation, the maximum average output power is 1.2 W with pulse repetition of 23.69 kHz and pulse width of 35 ns at the pump power of 27.9 W. The high-quality fundamental transverse mode can be observed owing to the reduction of thermal effect for Nd:Lu0.15Y0.85VO4 crystal by 885 nm direct pumping.

  1. Subharmonic Fourier domain mode locking.

    PubMed

    Eigenwillig, Christoph M; Wieser, Wolfgang; Biedermann, Benjamin R; Huber, Robert

    2009-03-15

    We demonstrate a subharmonically Fourier domain mode-locked wavelength-swept laser source with a substantially reduced cavity fiber length. In contrast to a standard Fourier domain mode-locked configuration, light is recirculated repetitively in the delay line with the optical bandpass filter used as switch. The laser has a fundamental optical round trip frequency of 285 kHz and can be operated at integer fractions thereof (subharmonics). Sweep ranges up to 95 nm full width centred at 1317 nm are achieved at the 1/5th subharmonic. A maximum sensitivity of 116 dB and an axial resolution of 12 microm in air are measured at an average sweep power of 12 mW. A sensitivity roll-off of 11 dB over 4 mm and 25 dB over 10 mm is observed and optical coherence tomography imaging is demonstrated. Besides the advantage of a reduced fiber length, subharmonic Fourier domain mode locking (shFDML) enables simple scaling of the sweep speed by extracting light from the delay part of the resonator. A sweep rate of 570 kHz is achieved. Characteristic features of shFDML operation, such as power leakage during fly-back and cw breakthrough, are investigated. PMID:19282912

  2. 1000-1400-nm partially mode-locked pulse from a simple all-fiber cavity.

    PubMed

    Wei, Xiaoming; Xu, Yiqing; Wong, Kenneth K Y

    2015-07-01

    We demonstrate a partially mode-locked pulse laser delivering ultra-wideband optical spectrum, i.e., 1000-1400 nm at 30 dB, from a simple all-fiber short cavity with all-normal dispersion. Examined by both real-time temporal and spectral analyzers, the partially mode-locked pulse exhibits double-scale noise-like characteristics-the fast L-shaped mode-locked pulse modulated by slow free-running Q-switched envelopes. Moreover, the statistical analysis as a function of its optical bandwidth shows that the spectral tuning does not compromise the temporal stability, but affects the pulsing periodicity. It is believed that the wide spectrum of knowledge obtained here would enrich the field of noise-like pulse, such as being beneficial to the rogue wave generation. PMID:26125353

  3. Actively mode-locked GaInAsP laser with subpicosecond output

    SciTech Connect

    Corzine, S.W.; Bowers, J.E.; Przybylek, G.; Koren, U.; Miller, B.I.; Soccolich, C.E.

    1988-02-01

    We actively mode lock a high-frequency GaInAsP laser at a rate of 16 GHz to obtain nearly transform-limited hyperbolic secant pulses with a pulse width of 0.58 ps. This is the shortest pulse width yet demonstrated for either passively or actively mode-locked semiconductor lasers.

  4. Pulsed actively mode-locked laser based on Nd{sup 3+}-doped disordered garnet and LiF:F{sub 2}{sup {minus}} crystal

    SciTech Connect

    Basiev, T.; Fedorov, V.; Karasik, A.; Senatorov, A.; Shubochkin, R.; Sobol, A.; Grudinin, A.

    1994-12-31

    It is well known that neodymium glasses are widely used as active media in powerful picosecond laser system. However, low thermal conductivity of glasses with broad bands of absorption and luminescence limits their use in pulsed lasers with high repetition rate. At the same time, disordered crystals having broad inhomogeneous bands of active ions and combining properties of both glasses and crystals may be reckoned as active media for ultrashort pulse lasers with high repetition rate. The aim of this work is to investigate the operation of actively mode-locked with LiNbO{sub 3} AOM laser on a calcium-lithium-niobium-gallium disordered garnet crystal doped with Nd{sup 3+} ions (CLNGG:Nd{sup 3+}) and a LiF:F{sub 2}{sup {minus}} passive Q-switch.

  5. Passively Q-switched Nd:YAG/Cr(4+):YAG bonded crystal microchip laser operating at 1112  nm and its application for second-harmonic generation.

    PubMed

    Fu, S G; Ouyang, X Y; Liu, X J

    2015-10-10

    A passively Q-switched Nd:YAG/Cr4+:YAG microchip laser operating at 1112 nm is demonstrated. Under a pump power of 5.5 W, a maximum average output power of 623 mW was obtained with T=6% output coupler, corresponding to an optical-to-optical conversion efficiency of 11.3% and a slope efficiency of 19.5%. The minimum pulse width was 2.8 ns, the pulse energy and peak power were 39.3 μJ and 14 kW, respectively. Additionally, based on the 1112 nm laser, a 230 mW 556 nm green-yellow laser was achieved within an LBO crystal. PMID:26479822

  6. Compact, passively Q-switched, all-solid-state master oscillator-power amplifier-optical parametric oscillator (MOPA-OPO) system pumped by a fiber-coupled diode laser generating high-brightness, tunable, ultraviolet radiation.

    PubMed

    Peuser, Peter; Platz, Willi; Fix, Andreas; Ehret, Gerhard; Meister, Alexander; Haag, Matthias; Zolichowski, Paul

    2009-07-01

    We report on a compact, tunable ultraviolet laser system that consists of an optical parametric oscillator (OPO) and a longitudinally diode-pumped Nd:YAG master oscillator-power amplifier (MOPA). The pump energy for the whole laser system is supplied via a single delivery fiber. Nanosecond pulses are produced by an oscillator that is passively Q-switched by a Cr(4+):YAG crystal. The OPO is pumped by the second harmonic of the Nd:YAG MOPA. Continuously tunable radiation is generated by an intracavity sum-frequency mixing process within the OPO in the range of 245-260 nm with high beam quality. Maximum pulse energies of 1.2 mJ were achieved, which correspond to an optical efficiency of 3.75%, relating to the pulse energy of the MOPA at 1064 nm. PMID:19571944

  7. Experimental and theoretical study of a laser-diode-pumped passively Q-switched intracavity-frequency-doubled Nd:GdVO4/KTP red laser with V:YAG saturable absorber.

    PubMed

    Xu, Chao; Li, Guiqiu; Zhao, Shengzhi; Li, Xin; Du, Guolong; Yin, Lei

    2011-09-10

    A laser-diode-pumped passively Q-switched intracavity-frequency-doubled Nd:GdVO4/KTP red laser with V:YAG saturable absorber is realized in a V-type resonator. The dependences of the pulse repetition rate, pulse width, single-pulse energy, and peak power on the incident pump power are measured and contrasted. By assuming the intracavity photon density and the initial population-inversion density to be Gaussian spatial distributions, the space-dependent rate equations of this laser are given. The numerical solutions of the rate equations are consistent with the experimental results. In order to optimize the described system, the variations of the pulse width, peak power, single-pulse energy, and laser efficiency with the initial transmission of the saturable absorber and the ratio of the laser beam radius to the pump beam radius are also calculated, respectively. PMID:21946991

  8. Improvement of stability and efficiency in diode-pumped passively Q-switched intracavity optical parametric oscillator with a monolithic cavity Improvement of stability and efficiency

    NASA Astrophysics Data System (ADS)

    Huang, J. Y.; Zhuang, W. Z.; Huang, Y. P.; Huang, Y. J.; Su, K. W.; Chen, Y. F.

    2012-07-01

    We improve the performance of intracavity optical parametric oscillator (IOPO) pumped by a diode-pumped Q-switched Nd:YVO4/Cr4+:YAG laser. The IOPO cavity is formed independently by a monolithic KTP crystal that the mirrors are directly deposited on top of the nonlinear crystal. We study the performances of this IOPO cavity with different reflectivity of the output coupler at 1.5 μm (Rs) of 80 and 50%. The average power of 1.5 μm is up to 3.3 W at the maximum pump power of 16.8 W for both cases. The diode-to-signal conversion efficiency is up to 20%, which is the highest one for IOPOs to our best knowledge. At the maximum pump power, the pulse energies are 41 μJ with the pulse width of 3 ns at a pulse repetition rate (PRR) of 80 kHz for Rs = 80% and 51 μJ with the pulse width of 1.2 ns at a PRR of 65 kHz for Rs = 50%, respectively. The pulse amplitude fluctuations in standard deviation are 2.6% for Rs = 80% and 4% for Rs = 50%, respectively.

  9. Dual-wavelength operation of continuous-wave and mode-locked erbium-doped fiber lasers

    NASA Astrophysics Data System (ADS)

    Pottiez, O.; Martinez-Rios, A.; Monzon-Hernandez, D.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernandez-Garcia, J. C.

    2012-06-01

    We study numerically and experimentally multiple-wavelength operation of an erbium-doped figure-eight fiber laser including a multiple-bandpass optical filter formed by two concatenated fiber tapers. Both continuous-wave and pulsed operations are considered. In the continuous-wave regime, stable long-term operation at multiple closely spaced wavelengths is only obtained if fine adjustments of the cavity losses are performed. Under these conditions, simultaneous lasing at up to four wavelengths separated by 1.5 nm was observed experimentally. Tunable single-wavelength operation over more than 20 nm is also observed in the continuous-wave regime. In the passive mode locking regime, numerical simulations indicate that mechanisms involving the filter losses and the nonlinear transmission characteristic of the NOLM contribute in principle to stabilize dual-wavelength operation, allowing less demanding cavity loss adjustments. In this regime, the problem of synchronization between the pulse trains generated at each wavelength adds an additional dimension to the problem. In presence of cavity dispersion, the pulses at each wavelength tend to be asynchronous if the wavelength separation is large, however they can be synchronous in the case of closely spaced wavelengths, if cross-phase modulation is able to compensate for the dispersion-induced walkoff. Experimentally, fundamental and 2nd-order harmonic mode locking was observed, characterized by the generation of noise-like pulses. Finally, a regime of multi-wavelength passive Q-switching was also observed. We believe that this work will be helpful to guide the design of multiple-wavelength fiber laser sources, which are attractive for a wide range of applications including Wavelength Division Multiplexing transmissions, signal processing and sensing.

  10. Simulation of tunable Cr:YSO Q-switched Cr:LiSAF laser

    NASA Astrophysics Data System (ADS)

    Chen, Hsiu-Fen; Hsieh, Shang-Wei; Kuo, Yen-Kuang

    2005-01-01

    In this work, we numerically investigate the passive Q-switching performance of the tunable Cr:YSO Q-switched Cr:LiSAF laser over its entire tuning range. Specifically, the optical performance of the Cr:YSO Q-switched Cr:LiSAF laser as functions of the initial population in the ground state of the Cr:YSO saturable absorber, the pumping rate, the reflectivity of the output coupler, and the dissipative loss inside the laser cavity are studied. Simulation results show that the Cr:YSO is an effective saturable absorber Q switch for the Cr:LiSAF laser over its entire tuning range. Unlike the Cr:YSO Q-switched alexandrite laser and the Cr:YSO Q-switched Cr:LiCAF laser, the Cr:YSO Q-switched Cr:LiSAF laser has similar passive Q-switching performance when the laser polarization is along each of the three principal axes of the Cr:YSO. The results obtained numerically in this work are in good agreement with those obtained experimentally by other researchers. Our simulation results indicate that, a Q-switched laser pulse with an output energy of 10 mJ and a pulse width of 17 ns may be obtained at 850 nm, the peak of its tuning spectrum.

  11. Rate equations for ruby and alexandrite Q-switched lasers

    NASA Astrophysics Data System (ADS)

    Sulc, Jan; Jelinkova, Helena

    2003-07-01

    To have a complex view on giant pulse generation, a more precise computer model of the build up Q-switch pulse in solid-state laser was realized. As a time starting point of the rate equation calculation, the moment of a flashlamp trigger was chosen. A system of three or four main differential rate equations describes the energy transfer from a pumping source - capacitor to an output giant pulse. Two laser active media, i.e. ruby and alexandrite, were examined with this model. A passive Q-switch ruby laser needs solving of the system of four differential equations; three differential equations gave the computer results for electro-optically Q-switched alexandrite laser.

  12. Actively Q-switched Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. G.; Podivilov, E. V.; Babin, S. A.

    2015-03-01

    A new scheme providing actively Q-switched operation of a Raman fiber laser (RFL) has been proposed and tested. The RFL consists of a 1 km single-mode fiber with a switchable loop mirror at one end and an angled cleaved output end. An 1080 nm pulse with microsecond duration is generated at the output by means of acousto-optic switching of the mirror at ~30 kHz in the presence of 6 W backward pumping at 1030 nm. In the proposed scheme, the generated pulse energy is defined by the pump energy distributed along the passive fiber, which amounts to 30 μJ in our case. The available pump energy may be increased by means of fiber lengthening. Pulse shortening is also expected.

  13. Electro-optic Q-switch

    NASA Technical Reports Server (NTRS)

    Zou, Yingyin (Inventor); Chen, Qiushui (Inventor); Zhang, Run (Inventor); Jiang, Hua (Inventor)

    2006-01-01

    An electro-optic Q-switch for generating sequence of laser pulses was disclosed. The Q-switch comprises a quadratic electro-optic material and is connected with an electronic unit generating a radio frequency wave with positive and negative pulses alternatively. The Q-switch is controlled by the radio frequency wave in such a way that laser pulse is generated when the radio frequency wave changes its polarity.

  14. High power L-band mode-locked fiber laser based on topological insulator saturable absorber.

    PubMed

    Meng, Yichang; Semaan, Georges; Salhi, Mohamed; Niang, Alioune; Guesmi, Khmaies; Luo, Zhi-Chao; Sanchez, Francois

    2015-09-01

    We demonstrate a passive mode-locked Er:Yb doped double-clad fiber laser using a microfiber-based topological insulator (Bi(2)Se(3)) saturable absorber (TISA). By optimizing the cavity loss and output coupling ratio, the mode-locked fiber laser can operate in L-band with high average output power. With the highest pump power of 5 W, 91st harmonic mode locking of soliton bunches with average output power of 308 mW was obtained. This is the first report that the TISA based erbium-doped fiber laser operating above 1.6 μm and is also the highest output power yet reported in TISA based passive mode-locked fiber laser. PMID:26368409

  15. Versatile mode-locked fiber laser with switchable operation states of bound solitons.

    PubMed

    Zou, Xin; Qiu, Jifang; Wang, Xiaodong; Ye, Zi; Shi, Jindan; Wu, Jian

    2016-06-01

    Bound states of two solitons are among the typical forms of bound states and can be observed in various operation states of mode-locked fiber lasers. We experimentally investigated bound solitons (BSs) in a passively mode-locked erbium-doped fiber laser based on a semiconductor saturable absorber mirror, whose operation states can be switched among multiple pulses, passively harmonic mode-locking, and "giant pulses" by simply adjusting the in-line polarization controller with the pump power fixed. Up to four pulses, fourth-order harmonic mode-locking (HML), and a "giant pulse" with four BSs were obtained with increasing pump power. Experimental results showed a correlative relationship among those operation states (N pulses/Nth-order HML/"giant pulses" of N bound solitons) at different pump power levels. The birefringence induced by the erbium-doped fiber inside the laser cavity played a vital role in the transitions of those operation states. PMID:27411182

  16. Oscillatory phenomena and Q switching in a model for laser with a saturable absorber

    SciTech Connect

    Antoranz, J.C.; Gea, J.; Velarde, M.G.

    1981-12-28

    Sufficiently long population decay times and sufficiently short dipole decay times in a single-mode laser with saturable absorber permit passive Q switching in the form of a hard-mode sustained relaxation oscillation.

  17. Self-mode-locking semiconductor disk laser.

    PubMed

    Gaafar, Mahmoud; Richter, Philipp; Keskin, Hakan; Möller, Christoph; Wichmann, Matthias; Stolz, Wolfgang; Rahimi-Iman, Arash; Koch, Martin

    2014-11-17

    The development of mode-locked semiconductor disk lasers received striking attention in the last 14 years and there is still a vast potential of such pulsed lasers to be explored and exploited. While for more than one decade pulsed operation was strongly linked to the employment of a saturable absorber, self-mode-locking emerged recently as an effective and novel technique in this field - giving prospect to a reduced complexity and improved cost-efficiency of such lasers. In this work, we highlight recent achievements regarding self-mode-locked semiconductor devices. It is worth to note, that although nonlinear effects in the active medium are expected to give rise to self-mode-locking, this has to be investigated with care in future experiments. However, there is a controversy whether results presented with respect to self-mode-locking truly show mode-locking. Such concerns are addressed in this work and we provide a clear evidence of mode-locking in a saturable-absorber-free device. By using a BBO crystal outside the cavity, green light originating from second-harmonic generation using the out-coupled laser beam is demonstrated. In addition, long-time-span pulse trains as well as radiofrequency-spectra measurements are presented for our sub-ps pulses at 500 MHz repetition rate which indicate the stable pulse operation of our device. Furthermore, a long-time-span autocorrelation trace is introduced which clearly shows absence of a pedestal or double pulses. Eventually, a beam-profile measurement reveals the excellent beam quality of our device with an M-square factor of less than 1.1 for both axes, showing that self-mode-locking can be achieved for the fundamental transverse mode. PMID:25402081

  18. 70-fs mode-locked erbium-doped fiber laser with topological insulator.

    PubMed

    Liu, Wenjun; Pang, Lihui; Han, Hainian; Tian, Wenlong; Chen, Hao; Lei, Ming; Yan, Peiguang; Wei, Zhiyi

    2016-01-01

    Femtosecond optical pulses have applications in optical communication, astronomical frequency combs, and laser spectroscopy. Here, a hybrid mode-locked erbium-doped fiber (EDF) laser with topological insulator (TI) is proposed, for the first time to our best knowledge. The pulsed laser deposition (PLD) method is employed to fabricate the fiber-taper TI saturable absorber (TISA). By virtue of the fiber-taper TISA, the hybrid EDF laser is passively mode-locked using the nonlinear polarization evolution (NPE), and emits 70 fs pulses at 1542 nm, whose 3 dB spectral width is 63 nm with a repetition rate and transfer efficiency of 95.4 MHz and 14.12%, respectively. Our experiments indicate that the proposed hybrid mode-locked EDF lasers have better performance to achieve shorter pulses with higher power and lower mode-locking threshold in the future. PMID:26813439

  19. 70-fs mode-locked erbium-doped fiber laser with topological insulator

    NASA Astrophysics Data System (ADS)

    Liu, Wenjun; Pang, Lihui; Han, Hainian; Tian, Wenlong; Chen, Hao; Lei, Ming; Yan, Peiguang; Wei, Zhiyi

    2016-01-01

    Femtosecond optical pulses have applications in optical communication, astronomical frequency combs, and laser spectroscopy. Here, a hybrid mode-locked erbium-doped fiber (EDF) laser with topological insulator (TI) is proposed, for the first time to our best knowledge. The pulsed laser deposition (PLD) method is employed to fabricate the fiber-taper TI saturable absorber (TISA). By virtue of the fiber-taper TISA, the hybrid EDF laser is passively mode-locked using the nonlinear polarization evolution (NPE), and emits 70 fs pulses at 1542 nm, whose 3 dB spectral width is 63 nm with a repetition rate and transfer efficiency of 95.4 MHz and 14.12%, respectively. Our experiments indicate that the proposed hybrid mode-locked EDF lasers have better performance to achieve shorter pulses with higher power and lower mode-locking threshold in the future.

  20. 70-fs mode-locked erbium-doped fiber laser with topological insulator

    PubMed Central

    Liu, Wenjun; Pang, Lihui; Han, Hainian; Tian, Wenlong; Chen, Hao; Lei, Ming; Yan, Peiguang; Wei, Zhiyi

    2016-01-01

    Femtosecond optical pulses have applications in optical communication, astronomical frequency combs, and laser spectroscopy. Here, a hybrid mode-locked erbium-doped fiber (EDF) laser with topological insulator (TI) is proposed, for the first time to our best knowledge. The pulsed laser deposition (PLD) method is employed to fabricate the fiber-taper TI saturable absorber (TISA). By virtue of the fiber-taper TISA, the hybrid EDF laser is passively mode-locked using the nonlinear polarization evolution (NPE), and emits 70 fs pulses at 1542 nm, whose 3 dB spectral width is 63 nm with a repetition rate and transfer efficiency of 95.4 MHz and 14.12%, respectively. Our experiments indicate that the proposed hybrid mode-locked EDF lasers have better performance to achieve shorter pulses with higher power and lower mode-locking threshold in the future. PMID:26813439

  1. On the Q-switched operation of Titanium:Sapphire lasers using a graphene-based saturable absorber mirror

    NASA Astrophysics Data System (ADS)

    Weigand, R.; Pinto, T.; Crespo, H. M.; Guerra, J. M.

    2015-09-01

    We numerically demonstrate Q-switched operation of Titanium:Sapphire lasers using mono and multilayer graphene, deposited on a totally reflecting end mirror as a saturable absorber. Output energies, pulse duration and repetition frequencies of the Q-switched pulse trains are given as a function of the pump intensity for different number of graphene layers and cavity lengths. For the geometries studied, pulses from 17 to 491 ns can be achieved, with energies ranging from 11 to 74 μJ and repetition rates from 0.06 to 2.5 MHz. These results can be useful for designing and building laser cavities for Q-switched and mode-locked operation in laser media with short lifetimes as Titanium:Sapphire.

  2. Actively mode-locked semiconductor lasers

    SciTech Connect

    Bowers, J.E.; Morton, P.A.; Mar, A.; Corzine, S.W.

    1989-06-01

    Measurements of actively mode-locked semiconductor lasers are described and compared to calculations of the mode-locking process using three coupled traveling wave rate equations for the electron and photon densities. The dependence of pulse width on the modulation current and frequency are described. A limitation to minimum achievable pulse widths in mode-locked semiconductor lasers is shown to be dynamic detuning due to gain saturation. Techniques to achieve subpicosecond pulses are described, together with ways to reduce multiple pulse outputs. The amplitude and phase noise of linear and ring cavity semiconductor lasers were measured and found to be tens of dB smaller than YAG and argon lasers and limited by the noise from the microwave oscillator. High-frequency phase noise is only measurable in detuned cavities, and is below -110 dBc (1 Hz) in optimally tuned cavities. The prospects for novel ways to achieve even shorter pulses are discussed.

  3. Optical performance of Ho:YLF Q-switched Tm:YAG laser system

    NASA Astrophysics Data System (ADS)

    Chang, Yi-An; Kuo, Yen-Kuang

    2002-09-01

    The absorption cross-section of the Ho:YLF crystal is close to the emission cross-section of the Tm:YAG laser. According to the passive Q-switching theory, a giant laser pulse cannot be generated from the Ho:YLF Q-switched Tm:YAG laser system unless an internal focusing lens is utilized. In a previous work we experimentally demonstrated that passive Q-switching of the 2017-nm, flashlamp pumped Tm,Cr:YAG laser with a Ho:YLF saturable absorber could be obtained with an internal focusing lens. In this paper, we theoretically investigate the optical performance of the Ho:YLF Q-switched Tm:YAG laser system by solving the coupled rate equations. The simulation results indicate that the results obtained numerically are in good agreement with that obtained experimentally. Moreover, we study the passive Q-switching performance of the Ho:YLF Q-switched Tm:YAG laser system as functions of the reflectivity of the output coupler, the initial population of the saturable absorber ground state, the laser pumping rate, and the loss inside the laser resonator. On the other hand, assuming that a polarizer is utilized inside the laser cavity, we explore the passive Q-switching performance of the Ho:YLF Q-switched Tm:YAG laser system when the polarization of the laser light is along different direction between the two saturable absorber principal axes. Effect of the relative position between the saturable absorber and the output coupler is also investigated.

  4. SESAM mode-locked red praseodymium laser.

    PubMed

    Gaponenko, Maxim; Metz, Philip Werner; Härkönen, Antti; Heuer, Alexander; Leinonen, Tomi; Guina, Mircea; Südmeyer, Thomas; Huber, Günter; Kränkel, Christian

    2014-12-15

    We present the first semiconductor saturable absorber mirror (SESAM) mode-locked praseodymium solid-state laser. The laser is based on a Pr(3+):LiYF(4) crystal as gain medium and a GaInP-quantum well-based SESAM. Self-starting continuous-wave mode-locked laser operation with an average output power of 16 mW is achieved at a center wavelength of 639.5 nm. The laser operates at a repetition rate of ∼85.55  MHz and emits pulses with a duration of ∼18  ps. PMID:25503035

  5. III-V-on-silicon anti-colliding pulse-type mode-locked laser.

    PubMed

    Keyvaninia, S; Uvin, S; Tassaert, M; Wang, Z; Fu, X; Latkowski, S; Marien, J; Thomassen, L; Lelarge, F; Duan, G; Lepage, G; Verheyen, P; Van Campenhout, J; Bente, E; Roelkens, G

    2015-07-01

    An anti-colliding pulse-type III-V-on-silicon passively mode-locked laser is presented for the first time based on a III-V-on-silicon distributed Bragg reflector as outcoupling mirror implemented partially underneath the III-V saturable absorber. Passive mode-locking at 4.83 GHz repetition rate generating 3 ps pulses is demonstrated. The generated fundamental RF tone shows a 1.7 kHz 3 dB linewidth. Over 9 mW waveguide coupled output power is demonstrated. PMID:26125366

  6. Soliton mode locking by nonlinear Faraday rotation

    NASA Astrophysics Data System (ADS)

    Wabnitz, S.; Westin, E.; Frey, R.; Flytzanis, C.

    1996-11-01

    We propose nonlinear Faraday rotation as a mechanism for achieving stable polarization mode locking of a soliton laser. We analyze by perturbation theory and beam-propagation simulations the interplay between bandwidth-limited gain, gain dichroism, and linear and nonlinear Faraday rotation. .

  7. Investigation of mechanically Q-switched lasers

    NASA Astrophysics Data System (ADS)

    Cole, Brian; Goldberg, Lew; Hough, Nathaniel; Nettleton, John

    2015-02-01

    Using a resonant scanner mirror Q-switch to provide a time varying change in cavity alignment, 1535nm lasers based on Er/Yb-doped glass and 1064nm lasers based on Nd:YAG were evaluated. Using a side pumping architecture, the Er/Yb glass laser used a compact mechanical Q-switch with a mirror rotation rate of 330 Rad/s, enabling generation of <3 mJ pulses with a pulse width of 16ns. The laser output was a diffraction limited TEM00 mode. A mechanical Q-switch based on a MEMS tilting mirror was also used; its performance in a laser cavity was found to be similar to the resonant mirror. The technique of mechanical Q-switching was also extended to a side pumped Nd:YAG laser (mirror sweep rate of 1300 Rad/s), enabling generation of Q-switched pulses of <30mJ and 25ns duration. The far-field divergence showed this laser to be highly multi-moded within the pump plane, with a measured beam-product-parameter greater than 30 mm-mRad.

  8. Characterization of mode-locking in an all-fiber, all normal dispersion ytterbium based fiber oscillator

    NASA Astrophysics Data System (ADS)

    Cserteg, András.; Sági, Veronika; Drozdy, András.; Varallyay, Zoltán.; Gajdátsy, Gábor

    2015-03-01

    An ytterbium based all fiber, all normal dispersion fiber oscillator with integrated SESAM can have several operation modes like mode-locked, Q-switched and noise-like. To know and to control the quality of the mode-locking is essential for the application of such laser oscillators, otherwise the whole laser setup can be damaged or the expected operation characteristics of the oscillator driven systems cannot be achieved. Usually the two-photon signal generated by the short pulses is used to indicate the mode locked operation, however such detection can be misleading in certain cases and not always able to predict the forthcoming degradation or vanishing of mode locking. The characterization method that we propose uses only the radio frequency spectrum of the oscillator output and can identify the different operation regimes of our laser setup. The optical spectra measured simultaneously with the RF signals proves the reliability of our method. With this kind of characterization stable mode locking can be initiated and maintained during the laser operation. The method combined with the ability to align the polarization states automatically in the laser cavity leads to the possibility to record a polarization map where the stability domains can be identified and classified. With such map the region where the mode locking is self starting and maintainable with minimal polarization alignment can be selected. The developed oscillator reported here with its compact setup and self alignment ability can be a reliable source with long term error free operation without the need of expensive monitoring tools.

  9. Mode-locking via dissipative Faraday instability

    PubMed Central

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-01-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin–Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system—spectrally dependent losses—achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin–Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering. PMID:27503708

  10. Mode-locking via dissipative Faraday instability.

    PubMed

    Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K

    2016-01-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering. PMID:27503708

  11. Actively mode-locked Raman fiber laser.

    PubMed

    Yang, Xuezong; Zhang, Lei; Jiang, Huawei; Fan, Tingwei; Feng, Yan

    2015-07-27

    Active mode-locking of Raman fiber laser is experimentally investigated for the first time. An all fiber connected and polarization maintaining loop cavity of ~500 m long is pumped by a linearly polarized 1120 nm Yb fiber laser and modulated by an acousto-optic modulator. Stable 2 ns width pulse train at 1178 nm is obtained with modulator opening time of > 50 ns. At higher power, pulses become longer, and second order Raman Stokes could take place, which however can be suppressed by adjusting the open time and modulation frequency. Transient pulse evolution measurement confirms the absence of relaxation oscillation in Raman fiber laser. Tuning of repetition rate from 392 kHz to 31.37 MHz is obtained with harmonic mode locking. PMID:26367642

  12. Mode-locking via dissipative Faraday instability

    NASA Astrophysics Data System (ADS)

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-08-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system--spectrally dependent losses--achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  13. Whispering-Gallery Mode-Locked Lasers

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey; Iltchenko, Vladimir; Savchenkov, Anatoly; Maleki, Lute

    2003-01-01

    Mode-locked lasers of a proposed type would incorporate features of the design and operation of previously demonstrated miniature electro-optical modulators and erbium-doped glass lasers that contain whispering-gallery-mode (WGM) resonators. That is to say, WGM lasers and WGM electro-optical modulators would be integrated into monolithic units that, when suitably excited with pump light and microwaves, would function as mode-locked lasers. The proposed devices are intended to satisfy an anticipated demand for compact, low-power devices that could operate in the optical-communication wavelength band centered at a wavelength of 1.55 m and could generate pulses as short as picoseconds at repetition rates of multiple gigahertz.

  14. Femtosecond mode-locked holmium fiber laser pumped by semiconductor disk laser.

    PubMed

    Chamorovskiy, A; Marakulin, A V; Ranta, S; Tavast, M; Rautiainen, J; Leinonen, T; Kurkov, A S; Okhotnikov, O G

    2012-05-01

    We report on a 2085 nm holmium-doped silica fiber laser passively mode-locked by semiconductor saturable absorber mirror and carbon nanotube absorber. The laser, pumped by a 1.16 μm semiconductor disk laser, produces 890 femtosecond pulses with the average power of 46 mW and the repetition rate of 15.7 MHz. PMID:22555700

  15. Carbon nanotube mode-locked vertical external-cavity surface-emitting laser

    NASA Astrophysics Data System (ADS)

    Seger, K.; Meiser, N.; Choi, S. Y.; Jung, B. H.; Yeom, D.-I.; Rotermund, F.; Okhotnikov, O.; Laurell, F.; Pasiskevicius, V.

    2014-03-01

    Mode-locking an optically pumped semiconductor disk laser has been demonstrated using low-loss saturable absorption containing a mixture of single-walled carbon nanotubes in PMM polymer. The modulator was fabricated by a simple spin-coating technique on fused silica substrate and was operating in transmission. Stable passive fundamental modelocking was obtained at a repetition rate of 613 MHz with a pulse length of 1.23 ps. The mode-locked semiconductor disk laser in a compact geometry delivered a maximum average output power of 136 mW at 1074 nm.

  16. High-power diode-pumped mode-locked Yb:YAG ceramic laser

    NASA Astrophysics Data System (ADS)

    Nakamura, Shinki; Hikita, Yuto; Sone, Hiroyasu; Ogawa, Takayo; Wada, Satoshi

    2014-05-01

    A high-power diode-pumped passively mode-locked Yb:YAG ceramic laser was demonstrated. An average output power of 3.80W with a pulse duration of 433 fs at a repetition rate of 90.9MHz was obtained at a wavelength of 1050 nm using a 2% output coupler. A peak power of 96.5kW was also obtained. To the best of our knowledge, these are the highest reported average power and peak power for a diode-pumped mode-locked Yb:YAG ceramic laser.

  17. Broadly tunable mode-locked Ho:YAG ceramic laser around 2.1 µm.

    PubMed

    Wang, Yicheng; Lan, Ruijun; Mateos, Xavier; Li, Jiang; Hu, Chen; Li, Chaoyu; Suomalainen, Soile; Härkönen, Antti; Guina, Mircea; Petrov, Valentin; Griebner, Uwe

    2016-08-01

    A passively mode-locked Ho:YAG ceramic laser around 2.1 µm is demonstrated using GaSb-based near-surface SESAM as saturable absorber. Stable and self-starting mode-locked operation is realized in the entire tuning range from 2059 to 2121 nm. The oscillator operated at 82 MHz with a maximum output power of 230 mW at 2121 nm. The shortest pulses with duration of 2.1 ps were achieved at 2064 nm. We also present spectroscopic properties of Ho:YAG ceramics at room temperature. PMID:27505767

  18. A 12.1-W SESAM mode-locked Yb:YAG thin disk laser

    NASA Astrophysics Data System (ADS)

    Yingnan, Peng; Zhaohua, Wang; Dehua, Li; Jiangfeng, Zhu; Zhiyi, Wei

    2016-05-01

    Pumped by a 940 nm fiber-coupled diode laser, a passively mode-locked Yb:YAG thin disk oscillator was demonstrated with a semiconductor saturable absorber mirror (SESAM). 12.1 W mode-locked pulses were obtained with pulse duration of 698 fs at the repetition rate of 57.43 MHz. Measurement showed that the beam quality was close to the diffraction limit. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB922402), the National Major Instrument Program of China (Grant No. 2012YQ120047), and the National Natural Science Foundation of China (Grant No. 61210017).

  19. High-pulse-energy mode-locked picosecond oscillator

    NASA Astrophysics Data System (ADS)

    Chao, Yang; Chen, Meng; Li, Gang

    2014-02-01

    We report on a high-pulse-energy solid-state picosecond Nd:YVO4 oscillator with cavity-dumping. The laser is end-pumped by an 808 nm laser diode and passively mode-locked with a semiconductor saturable absorption mirror (SESAM). In pure cw-mode-locking, this laser produced 2.5 W of average power at a pulse repetition rate of 40 MHz and pulse duration around 12 ps. A cavity dumping technique using an intra-cavity BBO electro-optic crystal to which bidirectional voltage was applied was adopted, effectively improving the cavity-dumping rate. Tunable high repetition rate from 100 kHz to 1 MHz was achieved. With electro-optic cavity dumper working at 1 MHz repetition rate, we achieved average power 594 mW. The laser includes a 5 mm long, a-cut, 0.5% doped Nd:YVO4 crystal with a 5-degree angle at one end face. Laser radiation is coupled out from the crystal end face with a 5-degree angle, without requiring insertion of a thin-film polarizer (TFP), thus simplifying the laser structure. This picosecond laser system has the advantages of compact structure and high stability, providing a good oscillator for regenerative amplifiers.

  20. Deep-red semiconductor monolithic mode-locked lasers

    SciTech Connect

    Kong, L.; Bajek, D.; White, S. E.; Forrest, A. F.; Cataluna, M. A.; Wang, H. L.; Pan, J. Q.; Wang, X. L.; Cui, B. F.; Ding, Y.

    2014-12-01

    A deep-red semiconductor monolithic mode-locked laser is demonstrated. Multi-section laser diodes based on an AlGaAs multi-quantum-well structure were passively mode-locked, enabling the generation of picosecond optical pulses at 752 nm, at pulse repetition rates of 19.37 GHz. An investigation of the dependence of the pulse duration as a function of reverse bias revealed a predominantly exponential decay trend of the pulse duration, varying from 10.5 ps down to 3.5 ps, which can be associated with the concomitant reduction of absorption recovery time with increasing applied field. A 30-MHz-tunability of the pulse repetition rate with bias conditions is also reported. The demonstration of such a compact, efficient and versatile ultrafast laser in this spectral region paves the way for its deployment in a wide range of applications such as biomedical microscopy, pulsed terahertz generation as well as microwave and millimeter-wave generation, with further impact on sensing, imaging and optical communications.

  1. Graphene Q-switched, tunable fiber laser

    NASA Astrophysics Data System (ADS)

    Popa, D.; Sun, Z.; Hasan, T.; Torrisi, F.; Wang, F.; Ferrari, A. C.

    2011-02-01

    We demonstrate a wideband-tunable Q-switched fiber laser exploiting a graphene saturable absorber. We get ˜2 μs pulses, tunable between 1522 and 1555 nm with up to ˜40 nJ energy. This is a simple and low-cost light source for metrology, environmental sensing, and biomedical diagnostics.

  2. Q-Switching in a Neodymium Laser

    ERIC Educational Resources Information Center

    Holgado, Warein; Sola, Inigo J.; Jarque, Enrique Conejero; Jarabo, Sebastian; Roso, Luis

    2012-01-01

    We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the Q-switching regime is…

  3. All-fiber widely tunable mode-locked thulium-doped laser using a curvature multimode interference filter

    NASA Astrophysics Data System (ADS)

    Li, N.; Liu, M. Y.; Gao, X. J.; Zhang, L.; Jia, Z. X.; Feng, Y.; Ohishi, Y.; Qin, G. S.; Qin, W. P.

    2016-07-01

    We demonstrated a widely tunable mode-locked thulium doped fiber laser (TDFL) by using a homemade multimode interference filter (MMIF). The MMIF had a structure of single mode fiber (SMF)—multimode fiber (MMF)—SMF and three main transmission peaks at 1901.2, 1957.2 and 2043.2 nm. By mechanically bending the MMIF, the three main transmission peaks were tuned in the range of 1860–2024 nm due to multimode interference effect. By inserting the MMIF into a passively mode-locked TDFL cavity pumped by a 1570 nm fiber laser, a tunable mode-locked TDFL with a tuning range of 1919.6–2014.9 nm was achieved by adjusting the MMIF. To the best of our knowledge, such a tunable range is the largest among all-fiber tunable mode-locked TDFLs.

  4. Integrated-optical q-switching and mode-locking of a Nd3+-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Geister, G.

    1990-07-01

    RareEarth doped silica fibers are interesting light sources for optical communications and sensor applications. Their broad fluorescence linewidth and the long spontaneous lifetime of the upper laser level otter the possibility to produce short and intense light pulses. We demonstrate pulsed operation of a Nddoped fiber laser with an asymmetric switched directional coupler operating as an intracavity intensity . modulator. 1 . Fiberlaser configuration The fiberlaser arrangement is shown in Fig. 1 . The prepared modulator is an xcut LiNbO3substrate with a pair of indiffused Tistripe waveguides of 5 pm width which are singlemode at the lasing wavelength A 1088 nm. The minimum waveguide separation is 2 im and has 8 mm length. One single pair of 8 mm long Alelectrodes with a 10 pm gap deposited onto the substrate surface is placed asymmetrically relative to the waveguides. This electrode arrangement provides electrooptic modulation of the phase mismatch between the two waveguides via the strong electrooptic coefficient rss of the LiNbO3 crystal. The modulator chip is Lw 20 mm long. The singlemode Ndfiber with LF 3. 485 m is pumped at a wavelength A 825 nm and butt coupled to the modulator. At the buttjoint the faces are angledcut with angles Yr 1 1. and yp. 7. 5 so no residual cavities exist within the laser resonator. The laser cavity is defined by dielectric coatings on the free ends of

  5. Electro-optic Q-switch driver design specifics

    NASA Astrophysics Data System (ADS)

    Melnikov, Konstantin

    2010-07-01

    Different schematic designs of Q-Switch Drivers for Pockels Cell based optical arrangement are considered. Schematic solutions of Q-Switch driver design are analyzed. Marx Bank based Generator and High Voltage Switch Schematics are compared. Parameters of constructed Q-Switch Drivers are presented.

  6. Electro-optic Q-switch driver design specifics

    NASA Astrophysics Data System (ADS)

    Melnikov, Konstantin

    2011-03-01

    Different schematic designs of Q-Switch Drivers for Pockels Cell based optical arrangement are considered. Schematic solutions of Q-Switch driver design are analyzed. Marx Bank based Generator and High Voltage Switch Schematics are compared. Parameters of constructed Q-Switch Drivers are presented.

  7. Multiple acousto-optic q-switch

    DOEpatents

    Deason, Vance A.

    1993-01-01

    An improved dynamic moire interferometer comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event.

  8. Multiple acousto-optic q-switch

    DOEpatents

    Deason, Vance A.

    1993-12-07

    An improved dynamic moire interferometer comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event.

  9. Q-switching of a thulium-doped fibre laser using a holmium-doped fibre saturable absorber

    SciTech Connect

    Sadovnikova, Ya E; Kamynin, V A; Kurkov, A S; Medvedkov, O I; Marakulin, A V; Minashina, L A

    2014-01-31

    We have proposed and demonstrated a new passively Q-switched thulium-doped fibre laser configuration. A distinctive feature of this configuration is the use of a heavily holmium-doped fibre for Q-switching. Lasing was obtained at 1.96 μm, with a pulse energy of 3 μJ and pulse duration of 600 ns. The highest pulse repetition rate was 80 kHz. (control of laser radiation parameters)

  10. Circuit Stops Prelasing In A Q-Switched Laser

    NASA Technical Reports Server (NTRS)

    Lockard, George E.

    1995-01-01

    Protective shutdown circuit stops prelasing in Q-switched laser operating at pulse-repetition rate of about 10 Hz. During normal operation, Q-switch prevents emission of light from laser cavity during application of Q-switch-trigger pulse. When circuit detects prelasing, it triggers relay turning off laser power supply. Circuit integrated into almost any Q-switched-laser system, provided one gains access to laser light, Q-switch-trigger pulse, and safety-interlock line of laser power supply.

  11. Gold nanoparticles as a saturable absorber for visible 635 nm Q-switched pulse generation.

    PubMed

    Wu, Duanduan; Peng, Jian; Cai, Zhiping; Weng, Jian; Luo, Zhengqian; Chen, Nan; Xu, Huiying

    2015-09-01

    Gold nanoparticle (GNP) possesses saturable absorption bands in the visible region induced by surface plasmon resonance (SPR). We firstly applied the GNP as a visible saturable absorber (SA) for the red Q-switched pulse generation. The GNPs were embedded in polyvinyl alcohol (PVA) for film-forming and inserted into a praseodymium (Pr(3+))-doped fiber laser cavity to achieve 635 nm passive Q-switching. The visible 635 nm Q-switched fiber laser has a wide range of pulse-repetition-rate from 285.7 to 546.4 kHz, and a narrow pulse width of 235 ns as well as the maximum output power of 11.1 mW. The results indicate that the GNPs-based SA is available for pulsed operation in the visible spectral range. PMID:26368498

  12. High power VCSEL array pumped Q-switched Nd:YAG lasers

    NASA Astrophysics Data System (ADS)

    Xiong, Yihan; Van Leeuwen, Robert; Watkins, Laurence S.; Seurin, Jean-Francois; Xu, Guoyang; Miglo, Alexander; Wang, Qing; Ghosh, Chuni

    2012-03-01

    Solid-state lasers pumped by high-power two-dimensional arrays of vertical-cavity surface-emitting lasers (VCSELs) were investigated. Both end-pumping and side-pumping schemes of Nd:YAG lasers with high power kW-class 808 nm VCSEL pump modules were implemented. For one application 10 mJ blue laser pulses were obtained from a frequencydoubled actively Q-switched VCSEL-array dual side-pumped Nd:YAG laser operating at 946 nm. For another application 10 mJ green laser pulses were obtained from a frequency-doubled passively Q-switched VCSEL-array endpumped Nd:YAG laser operating at 1064 nm. Both QCW and CW pumping schemes were investigated to achieve high average Q-switched power.

  13. 980-nm Q-switched photonic crystal fiber laser by MoS2 saturable absorber

    NASA Astrophysics Data System (ADS)

    Li, Pingxue; Liang, Boxing; Su, Meng; Zhang, Yuefei; Zhao, Yan; Zhang, Mengmeng; Ma, Chunmei; Su, Ning

    2016-05-01

    We demonstrate a 980-nm Q-switch Yb-doped photonic crystal fiber laser by a multilayer molybdenum sulfide polymer composite as the broadband saturable absorber which is prepared by the chemical vapor deposition method. We achieve passively Q-switching operations at 978 nm with the pulse width of 2.7 and 0.63 μs, corresponding to the repetition rate of 212 and 221 kHz, respectively. The maximum output power is 127 mW. It is the first time that MoS2 Q-switched Yb-doped photonic crystal fiber laser at 980 nm is demonstrated. The experimental results show that few-layer MoS2 is a promising broadband saturable absorber material.

  14. Tungsten disulphide based all fiber Q-switching cylindrical-vector beam generation

    SciTech Connect

    Lin, J.; Yan, K.; Zhou, Y.; Xu, L. X. Gu, C.; Zhan, Q. W.

    2015-11-09

    We proposed and demonstrated an all fiber passively Q-switching laser to generate cylindrical-vector beam, a two dimensional material, tungsten disulphide (WS{sub 2}), was adopted as a saturable absorber inside the laser cavity, while a few-mode fiber Bragg grating was used as a transverse mode-selective output coupler. The repetition rate of the Q-switching output pulses can be varied from 80 kHz to 120 kHz with a shortest duration of 958 ns. Attributed to the high damage threshold and polarization insensitivity of the WS{sub 2} based saturable absorber, the radially polarized beam and azimuthally polarized beam can be easily generated in the Q-switching fiber laser.

  15. Mode-Locked Laser Arrays for WDM Applications

    NASA Technical Reports Server (NTRS)

    Forouhar, S.

    1997-01-01

    Colliding pulse mode-locked laser arrays are being developed at 20 GHz for WDM applications. Arrays with 5 wavelengths in the EDFA gain bandwidth have already been demonstrated, with the final goal being a packaged, 10 wavelength mode-locked laser array.

  16. Spatial filter for Q-switched lasers

    NASA Technical Reports Server (NTRS)

    Wuerker, R. F.; Heflinger, L. O. (Inventor)

    1977-01-01

    A spatial filtered Q-switched laser system is reported that prevents ionization of air in close proximity to the aperture of the spatial filter. A compound lens system having an astigmatic focus is positioned between the laser and the spatial filter for defocusing the light beam emanating from the laser in the vicinity of the aperture of the spatial filter to an intensity below that which produces ionization of air. The preferred construction of the compound lens system as viewed from the laser comprises a cylindrical lens and a pair of positive lenses.

  17. Q-switched laser prelase detection circuit

    NASA Technical Reports Server (NTRS)

    Lockard, George E.

    1991-01-01

    A compact electronic circuit was developed to detect prelasing in Q-swithed pulsed laser systems and once detected to shut down the laser before the next laser pulse occurs. The circuit is small, compact, and uses a minimum of components which makes it quite economical, thus readily lending itself to commercial applications. It can easily be incorporated into virtually any Q-switched laser system or reliability of a laser system by reducing a source of possible costly optical damage. The circuit operation and instrument requirements necessary to incorporate the circuit into a laser system are discussed.

  18. Multi-pulses dynamic patterns in a topological insulator mode-locked ytterbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Peiguang, Yan; Rongyong, Lin; Han, Zhang; Zhiteng, Wang; Han, Chen; Shuangchen, Ruan

    2015-01-01

    Multi-pulse dynamic patterns have been experimentally observed in an Ytterbium-doped fiber laser passively mode locked by a topological insulator (TI) Bi2Te3 saturable absorber (SA). The fundamental mode-locking operation with a repetition rate of ~1.10 MHz was achieved under a pump power of ~160 mW with an appropriate setting of the polarization controller (PC). It was found that through either changing the pump power or rotating the orientation of intra-cavity PC, several characteristic modes have been experimentally observed, including disordered multi-pulses, bunch of pulses, and soliton rains. Simultaneously, quasi-square pulses have also been observed in the laser cavity. Our systematic study clearly demonstrated that TI could be developed as an effective SA for the generation of different pulse operation states in a passively mode-locked all-normal-dispersion Ytterbium-doped fiber laser.

  19. Short pulse fiber lasers mode-locked by carbon nanotubes and graphene

    NASA Astrophysics Data System (ADS)

    Yamashita, Shinji; Martinez, Amos; Xu, Bo

    2014-12-01

    One and two dimensional forms of carbon, carbon nanotubes and graphene, have interesting and useful, not only electronic but also photonic, properties. For fiber lasers, they are very attractive passive mode lockers for ultra-short pulse generation, since they have saturable absorption with inherently fast recovery time (<1 ps). In this paper, we review the photonic properties of graphene and CNT and our recent works on fabrication of fiber devices and applications to ultra-short pulse mode-locked fiber lasers.

  20. Large repetitively Q-switched oscillators

    NASA Astrophysics Data System (ADS)

    Epstein, H. M.; Dulaney, J. L.; O'Loughlin, J. F.; Altman, W. P.

    A versatile waveform laser which can operate in bursts from 5 to 160 ms long and deliver up to 30 kJ power burst has been constructed. This Nd:glass laser system consists of four oscillators in parallel. Each oscillator can be varied in length from about 3 to 10 m, and contains two pump heads 670 mm long by 64 mm in diameter phosphate glass laser rods. When trains of Q-switched pulses are required, 70 mm diameter Pockels cells and dielectric polarizers are added to the oscillator cavity. The basic burst duration of 5 ms can be stretched to 10, 20, 40, 80,and 160 ms by sequencing the firing of flashlamps, with the longest pulse length attained by sequentially firing 1/4 heads. Trains of Q-switched pulses up to 10 kHz in repetition rate and 50 to 900 ns wide can be obtained by varying the cavity configuration and Pockels cell firing rate. Spatial distributions are flat-topped within about 10 percent. Overall efficiency for the oscillator with a CW waveform can exceed 4.8 percent.

  1. Dispersion measurements of mode-locked fiber laser components

    NASA Astrophysics Data System (ADS)

    Louthain, James A.; Hayduk, Michael J.; Erdmann, Reinhard K.

    2000-07-01

    Precise control of the dispersion within mode-locked laser cavities can lead to optical pulse compression and reduced timing jitter of mode-locked lasers. Two simple measurement techniques are used to provide a complete picture of the dispersion within an erbium doped mode-locked fiber laser cavity. We measured the optical dispersion of erbium-doped fiber, standard single mode fiber, and chirped Bragg gratings. We built a Michelson interferometer with a wideband LED source to measure the dispersion of fiber lengths of less than 1 meter. Next, we measured the dispersion of chirped Bragg gratings using a network analyzer and a tunable laser in a differential phase measurement technique.

  2. Timing stability enhancement of an Erbium Doped mode locked Fiber Laser using SESAM mirror

    NASA Astrophysics Data System (ADS)

    Afifi, G.; Khedr, M. Atta; Badr, Y.; Danailov, M.; Sigalotti, P.; Cinquegrana, P.; Alsous, M. B.; Galaly, A. R.

    2016-05-01

    We report on an examination of pulse timing stability of a home built Erbium Doped Fiber Laser (EDFL) passively mode locked via nonlinear polarization rotation by inserting semiconductor saturable absorber mirror (SESAM) in laser cavity. A very low root mean square (RMS) timing jitter (less than 27 fsec) and faster self-starting mode locking have been established. In order to get clear, low noise signal for time resolving measurements, synchronization of EDFL laser with an external high precision electronic oscillator have been established. Subsequently, it is synchronized and optically cross-correlated with a Ti:Sapphire laser source (Micra). The measured relative timing jitter was found to be less than 65 fsec. In this way, the two, well synchronized Ti:Sapphire and EDFL laser pulses prove to be a powerful tool for time resolving measurements.

  3. 11-GHz waveguide Nd:YAG laser CW mode-locked with single-layer graphene

    PubMed Central

    Okhrimchuk, Andrey G.; Obraztsov, Petr A.

    2015-01-01

    We report stable, passive, continuous-wave (CW) mode-locking of a compact diode-pumped waveguide Nd:YAG laser with a single-layer graphene saturable absorber. The depressed cladding waveguide in the Nd:YAG crystal is fabricated with an ultrafast laser inscription method. The saturable absorber is formed by direct deposition of CVD single-layer graphene on the output coupler. The few millimeter-long cavity provides generation of 16-ps pulses with repetition rates in the GHz range (up to 11.3 GHz) and 12 mW average power. Stable CW mode-locking operation is achieved by controlling the group delay dispersion in the laser cavity with a Gires–Tournois interferometer. PMID:26052678

  4. 11-GHz waveguide Nd:YAG laser CW mode-locked with single-layer graphene.

    PubMed

    Okhrimchuk, Andrey G; Obraztsov, Petr A

    2015-01-01

    We report stable, passive, continuous-wave (CW) mode-locking of a compact diode-pumped waveguide Nd:YAG laser with a single-layer graphene saturable absorber. The depressed cladding waveguide in the Nd:YAG crystal is fabricated with an ultrafast laser inscription method. The saturable absorber is formed by direct deposition of CVD single-layer graphene on the output coupler. The few millimeter-long cavity provides generation of 16-ps pulses with repetition rates in the GHz range (up to 11.3 GHz) and 12 mW average power. Stable CW mode-locking operation is achieved by controlling the group delay dispersion in the laser cavity with a Gires-Tournois interferometer. PMID:26052678

  5. Diode-pumped femtosecond mode-locked Nd, Y-codoped CaF2 laser

    NASA Astrophysics Data System (ADS)

    Zhu, Jiangfeng; Zhang, Lijuan; Gao, Ziye; Wang, Junli; Wang, Zhaohua; Su, Liangbi; Zheng, Lihe; Wang, Jingya; Xu, Jun; Wei, Zhiyi

    2015-03-01

    A passively mode-locked femtosecond laser based on an Nd, Y-codoped CaF2 disordered crystal was demonstrated. The Y3+-codoping in Nd : CaF2 markedly suppressed the quenching effect and improved the fluorescence quantum efficiency and emission spectra. With a fiber-coupled laser diode as the pump source, the continuous wave tuning range covering from 1042 to 1076 nm was realized, while the mode-locked operation generated 264 fs pulses with an average output power of 180 mW at a repetition rate of 85 MHz. The experimental results show that the Nd, Y-codoped CaF2 disordered crystal has potential in a new generation diode-pumped high repetition rate chirped pulse amplifier.

  6. Mid-infrared mode-locked pulse generation with multilayer black phosphorus as saturable absorber.

    PubMed

    Qin, Zhipeng; Xie, Guoqiang; Zhao, Chujun; Wen, Shuangchun; Yuan, Peng; Qian, Liejia

    2016-01-01

    A mid-infrared saturable absorber mirror is successfully fabricated by transferring the mechanically exfoliated black phosphorus onto the gold-coated mirror. With the as-prepared black phosphorus saturable absorber mirror, a continuous-wave passively mode-locked Er:ZBLAN fiber laser is demonstrated at the wavelength of 2.8 μm, which delivers a maximum average output power of 613 mW, a repetition rate of 24 MHz, and a pulse duration of 42 ps. To the best of our knowledge, this is the first time a black phosphorus mode-locked laser at 2.8 μm wavelength has been demonstrated. Our results demonstrate the feasibility of black phosphorus flake as a new two-dimensional material for application in mid-infrared ultrafast photonics. PMID:26696157

  7. Saturable absorber mode-locked femtosecond Cr4+:YAG laser

    NASA Astrophysics Data System (ADS)

    Hayduk, Michael J.; Johns, Steven T.; Krol, Mark F.

    1997-07-01

    We have demonstrated self-starting passive mode-locking of a chromium-doped:YAG (Cr4+:YAG) laser using a saturable absorber mirror (SAM) structure. Highly stable femtosecond pulses tunable from 1488 to 1535 nm were generated. Average TEM00 output powers ranged from 40 to 80 mW with a minimum pulse width of 120 fs measured at 1488 nm. The generation of ultrashort pulses in solid-state lasers using the Kerr lens modelocking (KLM) technique has been the center of much attention in recent years. Sub 100 fs pulses have been produced using many different laser systems. However, the KLM process is very sensitive to cavity alignment and is easily perturbed by mechanical vibrations and pump power fluctuations. A more reliable process makes use of a saturable absorber to start and stabilize the soliton formation process. The saturable absorber eliminates the need for critical cavity alignment. The femtosecond pulse train produced by the SAM structure in the Cr4+:YAG laser system is highly stable over very long periods of time. The wide tunability of the Cr4+:YAG laser throughout the 1.5 micrometer transmission window of optical fiber makes it an ideal spectroscopic source for the characterization and development of novel materials and devices for ultrafast optical interconnects.

  8. An Analytic Technique for Investigating Mode-Locked Lasers

    SciTech Connect

    Usechak, N.G.; Agrawal, G.P.

    2005-09-30

    We present an analytic theory capable of predicting pulse parameters in mode-locked lasers in the presence of dispersion and nonlinearity. Excellent agreement is obtained between this approach and full numerical solutions.

  9. Dual-wavelength synchronous mode-locked Yb:LSO laser using a double-walled carbon nanotube saturable absorber.

    PubMed

    Feng, Chao; Hou, Wei; Yang, Jimin; Liu, Jie; Zheng, Lihe; Su, Liangbi; Xu, Jun; Wang, Yonggang

    2016-05-01

    A dual-wavelength, passively mode-locked Yb:LSO laser was demonstrated using a double-walled carbon nanotube as a saturable absorber. The maximum average output power of the laser was 1.34 W at the incident pump power of 9.94 W. The two central wavelengths were 1057 and 1058 nm. The corresponding pulse duration of the autocorrelation interference pattern was about 15 ps, while the beat pulse repetition rate was 0.17 THz and the width of one beat pulse about 2 ps. When the incident pump power was above 10.25 W, a multiwavelength mode-locked oscillation phenomenon was observed. After employing a pair of SF10 prisms, a 1058.7 nm single-wavelength mode-locked laser was obtained with a pulse width of 7 ps. PMID:27140382

  10. 59 fs mode-locked Yb:KGW oscillator pumped by a single-mode laser diode

    NASA Astrophysics Data System (ADS)

    Kowalczyk, M.; Sotor, J.; Abramski, K. M.

    2016-03-01

    In this letter we present a passively mode-locked Yb:KGW oscillator pumped by a low power single-mode laser diode. Contrary to high power operation, single-mode pumping enabled us to suppress parasitic thermal effects, while keeping the setup compact and its alignment straightforward. Undisturbed mode-locking (ML) stability was achieved without active cooling of the gain medium and the laser was entirely self-starting. Pulses 59 fs in duration were obtained in a semiconductor saturable absorber mirror (SESAM)-assisted Kerr-lens mode-locked regime. The corresponding spectrum was 20.2 nm broad at a central wavelength of 1036 nm approaching the performance limit of the crystal. To the best of our knowledge, these are the shortest pulses generated from a Yb:KGW laser.

  11. Femtosecond Kerr-lens mode-locked Alexandrite laser.

    PubMed

    Ghanbari, Shirin; Akbari, Reza; Major, Arkady

    2016-06-27

    The generation of 170 fs pulses at 755 nm from a Kerr-lens mode-locked Alexandrite laser was demonstrated. The laser was pumped at 532 nm and produced 780 mW of average output power with 9.8% of optical-to-optical efficiency. To the best of our knowledge, these are the shortest pulses that have been produced from a mode-locked Alexandrite laser to date. PMID:27410635

  12. Subpicosecond solitons in an actively mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Jones, D. J.; Haus, H. A.; Ippen, E. P.

    1996-11-01

    Experimental results are presented for a study of the stability regime of an actively mode-locked polarization-maintaining fiber ring laser used as a memory. Observations indicate that the pulse widths in the memory can be reduced (by soliton effects) by a factor of approximately 4.4 below the pulse widths predicted by standard active mode-locking theory. Stability regions for the solitons are mapped and compared with theoretical predictions.

  13. Injection Seeding Of A Q-Switched Alexandrite Laser

    NASA Technical Reports Server (NTRS)

    Zukowski, Barbara J. K.; Glesne, Thomas R.; Schwemmer, Geary; Czechanski, James P.; Kay, Richard B.

    1992-01-01

    Experiment demonstrates that standing-wave, Q-switched, tunable alexandrite laser can be injection-seeded to increase stability of output frequency and significantly reduce bandwidth from 750 GHz to 180 MHz. Injecting laser acts as oscillator or master, while Q-switched laser into which ouput of seed laser injected acts as amplifier or slave.

  14. Power scalable semiconductor disk lasers for frequency conversion and mode-locking

    SciTech Connect

    Okhotnikov, O G

    2008-12-31

    The semiconductor disk laser, a relatively novel type of light oscillators, is now under intensive development. These lasers produce an excellent beam quality in conjunction with a scalable output power. This paper presents recent achievements in power scalability, mode-locking and frequency conversion with optically-pumped semiconductor disk lasers. A novel concept for power scaling described here allows the thermal load of the gain material to be reduced, increasing the threshold of rollover and extending the capability for boosting the output power without degradation in the beam quality. The proposed technique is based on the multiple gain scheme. The total power of over 8 W was achieved in dual-gain configuration, while one-gain lasers could produce separately up to 4 W, limited by the thermal rollover of the output characteristics. The results show that the reduced thermal load to a gain element in a dual-gain cavity allows extending the range of usable pump powers boosting the laser output. Orange-red radiation required for a number of challenging applications can be produced through frequency-doubling using a GaInNAs/GaAs laser. Using such a disk laser operating at a fundamental wavelength of 1224 nm, we demonstrate an output power of 2.68 W in the visible region with an optical-to-optical conversion efficiency of 7.4%. The frequency-converted signal could be launched into a single-mode optical fibre with 70%-78% coupling efficiency, demonstrating good beam quality for the visible radiation. Using a Fabry-Perot glass etalon, the emission wavelength could be tuned over an 8-nm spectral range. We report on optically-pumped disk lasers passively mode-locked with a semiconductor saturable-absorber mirror. The potential of harmonic mode-locking in producing pulse trains at multigigahertz repetition rates has been explored. The mode-locked disk laser is investigated for different designs of the gain medium that allow bistable mode-locking to be controlled. An

  15. High-energy mode-locked fiber lasers using multiple transmission filters and a genetic algorithm.

    PubMed

    Fu, Xing; Kutz, J Nathan

    2013-03-11

    We theoretically demonstrate that in a laser cavity mode-locked by nonlinear polarization rotation (NPR) using sets of waveplates and passive polarizer, the energy performance can be significantly increased by incorporating multiple NPR filters. The NPR filters are engineered so as to mitigate the multi-pulsing instability in the laser cavity which is responsible for limiting the single pulse per round trip energy in a myriad of mode-locked cavities. Engineering of the NPR filters for performance is accomplished by implementing a genetic algorithm that is capable of systematically identifying viable and optimal NPR settings in a vast parameter space. Our study shows that five NPR filters can increase the cavity energy by approximately a factor of five, with additional NPRs contributing little or no enhancements beyond this. With the advent and demonstration of electronic controls for waveplates and polarizers, the analysis suggests a general design and engineering principle that can potentially close the order of magnitude energy gap between fiber based mode-locked lasers and their solid state counterparts. PMID:23482223

  16. Quantum dot based mode-locked AlGaInP-VECSEL

    NASA Astrophysics Data System (ADS)

    Bek, Roman; Kersteen, Grizelda; Kahle, Hermann; Schwarzbäck, Thomas; Jetter, Michael; Michler, Peter

    2015-03-01

    We present passive mode locking of a vertical external-cavity surface-emitting laser (VECSEL) in the red spectral range with quantum dots (QDs) as active material in the gain and in the absorber structure. Both semiconductor samples are fabricated by metal-organic vapor-phase epitaxy (MOVPE) in a near-anti-resonant design. A vshaped cavity is used to tightly focus onto the semiconductor saturable absorber mirror (SESAM), producing pulses with a duration of less than 1 ps and a repetition rate of 852MHz. In order to increase the field enhancement inside the absorber structure, some SESAM samples were additionally coated with a fused silica layer. The pulse duration as well as the mode locking stability were investigated for different thicknesses of the SiO2 layer. The most stable mode locking operation is observed for a 97 nm SiO2 layer, while the disadvantage of this overall near-resonant SESAM structure is an increased pulse duration of around 2 ps. Due to the improved stability, the transmission of the outcoupling mirror could be increased resulting in an average output power of 10mW at an emission wavelength of 651 nm.

  17. Measuring a Fiber-Optic Delay Line Using a Mode-Locked Laser

    NASA Technical Reports Server (NTRS)

    Tu, Meirong; McKee, Michael R.; Pak, Kyung S.; Yu, Nan

    2010-01-01

    The figure schematically depicts a laboratory setup for determining the optical length of a fiber-optic delay line at a precision greater than that obtainable by use of optical time-domain reflectometry or of mechanical measurement of length during the delay-line-winding process. In this setup, the delay line becomes part of the resonant optical cavity that governs the frequency of oscillation of a mode-locked laser. The length can then be determined from frequency-domain measurements, as described below. The laboratory setup is basically an all-fiber ring laser in which the delay line constitutes part of the ring. Another part of the ring - the laser gain medium - is an erbium-doped fiber amplifier pumped by a diode laser at a wavelength of 980 nm. The loop also includes an optical isolator, two polarization controllers, and a polarizing beam splitter. The optical isolator enforces unidirectional lasing. The polarization beam splitter allows light in only one polarization mode to pass through the ring; light in the orthogonal polarization mode is rejected from the ring and utilized as a diagnostic output, which is fed to an optical spectrum analyzer and a photodetector. The photodetector output is fed to a radio-frequency spectrum analyzer and an oscilloscope. The fiber ring laser can generate continuous-wave radiation in non-mode-locked operation or ultrashort optical pulses in mode-locked operation. The mode-locked operation exhibited by this ring is said to be passive in the sense that no electro-optical modulator or other active optical component is used to achieve it. Passive mode locking is achieved by exploiting optical nonlinearity of passive components in such a manner as to obtain ultra-short optical pulses. In this setup, the particular nonlinear optical property exploited to achieve passive mode locking is nonlinear polarization rotation. This or any ring laser can support oscillation in multiple modes as long as sufficient gain is present to overcome

  18. An 885-nm Direct Pumped Nd:CNGG 1061 nm Q-Switched Laser

    NASA Astrophysics Data System (ADS)

    Li, Qi-Nan; Zhang, Tao; Feng, Bao-Hua; Zhang, Zhi-Guo; Zhang, Huai-Jin; Wang, Ji-Yang

    2014-07-01

    The 885 nm direct pumping method, directly into the 4F3/2 emitting level of Nd3+ ion, is used to a Nd:CNGG crystal to product passive Q-switched 1061 nm laser pulses, for the first time to the best of our knowledge. A maximum average output power of 1.16 W for 1061 nm Q-switched pulses and a repetition rate of 12.54 kHz are obtained. The pulse width is measured to be 24 ns and the peak power is 3.843 kW. A high-quality fundamental transverse mode can be observed owing to the reduction of the thermal effect for Nd:CNGG crystal by 885 nm direct pumping.

  19. Tunable Q-switched fiber laser using zinc oxide nanoparticles as a saturable absorber.

    PubMed

    Ahmad, H; Lee, C S J; Ismail, M A; Ali, Z A; Reduan, S A; Ruslan, N E; Harun, S W

    2016-06-01

    Nanomaterials have ignited new interest due to their distinctive electronic, mechanical, and optical properties. Zinc oxide nanostructures are fabricated into thin film and then inserted between two fiber ferrules to act as a saturable absorber (SA). The modulation depth and insertion loss of the SA are 5% and 3.5 dB, respectively. When the ZnO-SA is incorporated into the laser cavity, a stable Q-switched pulse tunable from 1536 to 1586 nm (50 nm range) with pulse energy up to 46 nJ was observed. Our result suggests that ZnO is a promising broadband SA to generate passively Q-switched fiber lasers. PMID:27411175

  20. Large energy laser pulses with high repetition rate by graphene Q-switched solid-state laser.

    PubMed

    Li, Xian-lei; Xu, Jin-long; Wu, Yong-zhong; He, Jing-liang; Hao, Xiao-peng

    2011-05-01

    We demonstrated that the graphene could be used as an effective saturable absorber for Q-switched solid-state lasers. A graphene saturable absorber mirror was fabricated with large and high-quality graphene sheets deprived from the liquid phase exfoliation. Using this mirror, 105-ns pulses and 2.3-W average output power are obtained from a passively Q-switched Nd:GdVO(4) laser. The maximum pulse energy is 3.2 μJ. The slope efficiency is as high as 37% approximating to 40% of the continue-wave laser, indicating a low intrinsic loss of the graphene. PMID:21643251

  1. Pulse shaping mechanism in mode-locked lasers

    NASA Astrophysics Data System (ADS)

    Horikis, Theodoros P.; Bakırtaş, İlkay; Antar, Nalan

    2016-06-01

    A pulse shaping mechanism applied to mode-locked lasers is proposed. By adding a linear (forcing) term in the power energy saturation model, we are able to control the resulting pulses in both energy and shape. In fact, this term also provides a focusing effect keeping most of the pulse’s energy confined within the width of the forcing. The appropriate condition for which mode-locking occurs is also derived and links the physical parameters of the system (gain, loss, filtering) to those of the pulse (amplitude, width, energy). Thus, given the desired pulse one only needs to fix the laser’s parameters accordingly, so as to obey this condition, and mode-locking will occur.

  2. Raman rogue waves in a partially mode-locked fiber laser.

    PubMed

    Runge, Antoine F J; Aguergaray, Claude; Broderick, Neil G R; Erkintalo, Miro

    2014-01-15

    We report on an experimental study of spectral fluctuations induced by intracavity Raman conversion in a passively partially mode-locked, all-normal dispersion fiber laser. Specifically, we use dispersive Fourier transformation to measure single-shot spectra of Raman-induced noise-like pulses, demonstrating that for low cavity gain values Raman emission is sporadic and follows rogue-wave-like probability distributions, while a saturated regime with Gaussian statistics is obtained for high pump powers. Our experiments further reveal intracavity rogue waves originating from cascaded Raman dynamics. PMID:24562136

  3. 1700 nm dispersion managed mode-locked bismuth fiber laser

    NASA Astrophysics Data System (ADS)

    Noronen, Teppo; Firstov, Sergei; Dianov, Evgeny; Okhotnikov, Oleg G.

    2016-04-01

    We demonstrate the first 1.7 μm bismuth-doped fiber laser generating ultrashort pulses via passive mode-locking. Pulse operation has been achieved for both anomalous and normal dispersion of the laser cavity owing to broadband characteristics of carbon nanotube saturable absorber. The laser delivered 1.65 ps pulses in net anomalous dispersion regime. In normal dispersion regime, the laser delivered 14 ps pulses which could be compressed to 1.2 ps using external fiber compressor.

  4. 1700 nm dispersion managed mode-locked bismuth fiber laser.

    PubMed

    Noronen, Teppo; Firstov, Sergei; Dianov, Evgeny; Okhotnikov, Oleg G

    2016-01-01

    We demonstrate the first 1.7 μm bismuth-doped fiber laser generating ultrashort pulses via passive mode-locking. Pulse operation has been achieved for both anomalous and normal dispersion of the laser cavity owing to broadband characteristics of carbon nanotube saturable absorber. The laser delivered 1.65 ps pulses in net anomalous dispersion regime. In normal dispersion regime, the laser delivered 14 ps pulses which could be compressed to 1.2 ps using external fiber compressor. PMID:27097798

  5. 1700 nm dispersion managed mode-locked bismuth fiber laser

    PubMed Central

    Noronen, Teppo; Firstov, Sergei; Dianov, Evgeny; Okhotnikov, Oleg G.

    2016-01-01

    We demonstrate the first 1.7 μm bismuth-doped fiber laser generating ultrashort pulses via passive mode-locking. Pulse operation has been achieved for both anomalous and normal dispersion of the laser cavity owing to broadband characteristics of carbon nanotube saturable absorber. The laser delivered 1.65 ps pulses in net anomalous dispersion regime. In normal dispersion regime, the laser delivered 14 ps pulses which could be compressed to 1.2 ps using external fiber compressor. PMID:27097798

  6. Kerr-lens mode locking without dispersion compensation.

    PubMed

    Gatz, S; Herrmann, J; Müller, M

    1996-10-01

    We propose and theoretically investigate a novel operating regime of femtosecond Kerr-lens mode-locked solidstate lasers that avoids group-velocity dispersion compensation by use of a nonresonant semiconductor plate in the focused resonator section that provides an overall negative nonlinear refractive index per round trip. The saturable loss of the laser resonator with an effective self-defocusing nonlinearity is derived from a generalized ABCD matrix formalism, and the correspondingly calculated steady-state pulse parameters show that a Kerrlens mode-locked laser with an overall negative nonlinear refractive index generates stable femtosecond pulses without any dispersion compensation. PMID:19881729

  7. Resolving the build-up of femtosecond mode-locking with single-shot spectroscopy at 90 MHz frame rate

    NASA Astrophysics Data System (ADS)

    Herink, G.; Jalali, B.; Ropers, C.; Solli, D. R.

    2016-05-01

    Mode-locked lasers have enabled some of the most precise measurements ever performed, from attosecond time-domain spectroscopy to metrology with frequency combs. However, such extreme precision belies the complexity of the underlying mode-locking dynamics. This complexity is particularly evident in the emergence of the mode-locked state, an intrinsically singular, non-repetitive transition. Many details of mode-locking are well understood, yet conventional spectroscopy cannot resolve the nascent dynamics in passive mode-locking on their natural nanosecond timescale, the single pulse period. Here, we capture the pulse-resolved spectral evolution of a femtosecond pulse train from the initial fluctuations, recording ∼900,000 consecutive periods. We directly observe critical phenomena on timescales from tens to thousands of roundtrips, including the birth of the broadband spectrum, accompanying wavelength shifts and transient interference dynamics described as auxiliary-pulse mode-locking. Enabled by the time-stretch transform, the results may impact laser design, ultrafast diagnostics and nonlinear optics.

  8. All-optical Q-switching limiter for high-power gigahertz modelocked diode-pumped solid-state lasers.

    PubMed

    Klenner, Alexander; Keller, Ursula

    2015-04-01

    Passively modelocked diode-pumped solid-state lasers (DPSSLs) with pulse repetition rates in the gigahertz regime suffer from an increased tendency for Q-switching instabilities. Low saturation fluence intracavity saturable absorbers - such as the semiconductor saturable absorber mirrors (SESAMs) - can solve this problem up to a certain average output power limited by the onset of SESAM damage. Here we present a passive stabilization mechanism, an all-optical Q-switching limiter, to reduce the impact of Q-switching instabilities and increase the potential output power of SESAM modelocked lasers in the gigahertz regime. With a proper cavity design a Kerr lens induced negative saturable absorber clamps the maximum fluence on the SESAM and therefore limits the onset of Q-switching instabilities. No critical cavity alignment is required because this Q-switching limiter acts well within the cavity stability regime. Using a proper cavity design, a high-power diode-pumped Yb:CALGO solid-state laser generated sub-100 fs pulses with an average output power of 4.1 W at a pulse repetition rate of 5 GHz. With a pulse duration of 96 fs we can achieve a peak power as high as 7.5 kW directly from the SESAM modelocked laser oscillator without any further external pulse amplification and/or pulse compression. We present a quantitative analysis of this Kerr lens induced Q-switching limiter and its impact on modelocked operation. Our work provides a route to compact high-power multi-gigahertz frequency combs based on SESAM modelocked diode-pumped solid-state lasers without any additional external amplification or pulse compression. PMID:25968691

  9. Towards monolithic integration of mode-locked vertical cavity surface emitting laser

    NASA Astrophysics Data System (ADS)

    Aldaz, Rafael I.

    2007-12-01

    The speed and performance of today's high end computing and communications systems have placed difficult but still feasible demands on off-chip electrical interconnects. However, future interconnect systems may need aggregate bandwidths well into the terahertz range thereby making electrical bandwidth, density, and power targets impossible to meet. Optical interconnects, and specifically compact semiconductor mode-locked lasers, could alleviate this problem by providing short pulses in time at 10s of GHz repetition rates for Optical Time Division Multiplexing (OTDM) and clock distribution applications. Furthermore, the characteristic spectral comb of frequencies of these lasers could also serve as a multi-wavelength source for Wavelength Division Multiplexing (WDM) applications. A fully integrated mode-locked Vertical Cavity Surface Emitting Laser (VCSEL) is proposed as a low-cost high-speed source for these applications. The fundamental laser platform for such a device has been developed and a continuous-wave version of these lasers has been fabricated and demonstrated excellent results. Output powers close to 60mW have been obtained with very high beam quality factor of M2 < 1.07. The mode-locked laser utilizes a passive mode-locking region provided by a semiconductor saturable absorber integrated together with the gain region. Such an aggressive integration forces the resonant beam in the cavity to have the same area on the gain and absorber sections, placing high demands on the saturation fluence and absorption coefficient for the saturable absorber. Quantum Wells (QWs), excitons in QWs and Quantum Dots (QDs) have been investigated as possible saturable absorbers for the proposed device. QDs have been found to have the lowest saturation fluence and total absorption, necessary to meet the mode-locking requirements for this configuration. The need to further understand QDs as saturable absorbers has led to the development of a theoretical model on the dynamics of

  10. On-Chip Colliding Pulse Mode-locked laser diode (OCCP-MLLD) using multimode interference reflectors.

    PubMed

    Gordón, Carlos; Guzmán, Robinson; Corral, Vinicio; Leijtens, Xaveer; Carpintero, Guillermo

    2015-06-01

    We report the achievement of colliding pulse mode-locked (CPM) regimes on a novel on-chip mode locked laser diode (OCCP-MLLD). The advantage of the resonator structure that we present is that the end-mirrors are defined through multimode interference reflectors (MIRs), which provide precise control of the cavity length avoiding the need for cleaved facets. This simplifies positioning the saturable absorber at the center of the resonator to achieve the colliding pulse mode-locked regime and double the repetition rate, reaching the millimeter wave frequency range. An additional advantage is that the pulsed output is delivered within the Photonic Integrated Circuit chip for further processing (i.e. modulation). We demonstrate a colliding pulse passive mode locked regime with pulse widths below a picosecond (Δτ = 0.64 ps), timing jitter σT = 75 fs and amplitude noise NAM = 0.012 dBc. The samples were fabricated in a generic InP foundry service through multi-project wafer (MPW) runs. PMID:26072826

  11. Graphene mode-locked femtosecond Cr2+:ZnS laser with ~300 nm tuning range.

    PubMed

    Cho, Won Bae; Choi, Sun Young; Zhu, Chunhui; Kim, Mi Hye; Kim, Jun Wan; Kim, Jin Sun; Park, Hyung Ju; Shin, Dong Ho; Jung, Moon Youn; Wang, Fengqiu; Rotermund, Fabian

    2016-09-01

    Graphene has proved to be an excellent broadband saturable absorber for mode-locked operation of ultrafast lasers. However, for the mid-infrared (mid-IR) range where broadly tunable sources are in great needs, graphene-based broadly tunable ultrafast mid-IR lasers have not been demonstrated so far. Here, we report on passive mode-locking of a mid-IR Cr:ZnS laser by utilizing a transmission-type monolayer graphene saturable absorber and broad spectral tunability between 2120 nm and 2408 nm, which is the broadest tuning bandwidth ever reported for graphene mode-locked mid-IR solid-state lasers. The recovery time of the saturable absorber is measured to be ~2.4 ps by pump-probe technique at a wavelength of 2350 nm. Stably mode-locked Cr:ZnS laser delivers Fourier transform-limited 220-fs pulses with a pulse energy of up to 7.8 nJ. PMID:27607680

  12. Flexibly controllable multi-pulse mode-locked MOPA Yb-doped fiber laser in all normal dispersion regime

    NASA Astrophysics Data System (ADS)

    Bu, Chenxi; Wang, Chinhua

    2013-09-01

    A Controllable, high energy, all normal dispersion (ANDi), passively mode-locked Yb-doped fiber laser is demonstrated with a Master Oscillator Power-Amplifier (MOPA) structure. The mode-locking is achieved by nonlinear polarization evolution (NPE). different types of laser pulse are achieved from fundamental mode-locked (FML) single pulse to twin pulse and then to harmonically mode-locked (HML) pulses (the maximum order is 7 times) by adjusting quarter-wave plates (QWPS) and a half-wave plate (HWP) in our system. Using a cascaded long-period fiber grating as the spectral filter, the center wavelength of our laser is fixed at 1034nm.The repetition frequency rate of the FML pulse is 1.53MHz with a pulse width of 817ps. The maximum average energy is 450 mW and the maximum pulse energy of FML single pulse is 294 nJ. Besides, the 517nm green laser output is also achieved by using a LiB3O5 (LBO) crystal as the frequency doubling crystal. The maximum average of the green pulse is 4.71mW.

  13. Dynamics of Fourier domain mode-locked lasers.

    PubMed

    Slepneva, S; Kelleher, B; O'Shaughnessy, B; Hegarty, S P; Vladimirov, A G; Huyet, G

    2013-08-12

    An analysis of the dynamical features in the output of a Fourier Domain Mode Locked laser is presented. An experimental study of the wavelength sweep-direction asymmetry in the output of such devices is undertaken. A mathematical model based on a set of delay differential equations is developed and shown to agree well with experiment. PMID:23938841

  14. Multiwavelength pulse generation using a SESAM-based mode-locked fiber laser together with Fabry-Perot filter

    NASA Astrophysics Data System (ADS)

    Chen, Changxiu; Wu, Zhichao; Fu, Songnian; Luo, Yiyang; Liu, Bin; Liu, Deming

    2015-09-01

    A simple and compact configuration of multiwavelength pulse generator is proposed and experimentally demonstrated, using a SESAM-based passively mode-locked fiber laser together with fiber Fabry-Perot filter. By optimizing the dispersion of fiber ring cavity, a flat rectangular optical spectrum with 3 dB bandwidth of 8.1 nm is obtained, with power fluctuation of <0.5 dB. Inserting a fiber Fabry-Perot filter at the output of passively mode-locked fiber laser, we can simultaneously obtain 40 channels with 0.2 nm wavelength spacing, under the condition of <3 dB power uniformity. After wavelength-division demultiplexing and optic-to-electronic conversion, the full width at half maximum (FWHM) of single channel pulse is measured to be 30 ps while the repetition rate of pulse train is 20.3 MHz.

  15. Coexistence and interaction of vector and bound vector solitons in a dispersion-managed fiber laser mode locked by graphene.

    PubMed

    Song, Y F; Zhang, H; Zhao, L M; Shen, D Y; Tang, D Y

    2016-01-25

    We report on the experimental observation of vector and bound vector solitons in a fiber laser passively mode locked by graphene. Localized interactions between vector solitons, vector soliton with bound vector solitons, and vector soliton with a bunch of vector solitons are experimentally investigated. We show that depending on the soliton interactions, various stable and dynamic multiple vector soliton states could be formed. PMID:26832559

  16. Narrow-linewidth Q-switched random distributed feedback fiber laser.

    PubMed

    Xu, Jiangming; Ye, Jun; Xiao, Hu; Leng, Jinyong; Wu, Jian; Zhang, Hanwei; Zhou, Pu

    2016-08-22

    A narrow-linewidth Q-switched random fiber laser (RFL) based on a half-opened cavity, which is realized by narrow-linewidth fiber Bragg grating (FBG) and a section of 3 km passive fiber, has been proposed and experimentally investigated. The narrow-linewidth lasing is generated by the spectral filtering of three FBGs with linewidth of 1.21 nm, 0.56 nm, and 0.12 nm, respectively. The Q switching of the distributed cavity is achieved by placing an acousto-optical modulator (AOM) between the FBG and the passive fiber. The maximal output powers of the narrow-linewidth RFLs with the three different FBGs are 0.54 W, 0.27 W, and 0.08 W, respectively. Furthermore, the repetition rates of the output pulses are 500 kHz, and the pulse durations are about 500 ns. The corresponding pulse energies are about 1.08 μJ, 0.54 μJ, and 0.16 μJ, accordingly. The linewidth of FBG can influence the output characteristics in full scale. The narrower the FBG, the higher the pump threshold; the lower the output power at the same pump level, the more serious the linewidth broadening; and thus the higher the proportion of the CW-ground exists in the output pulse trains. Thanks to the assistance of the band-pass filter (BPF), the proportion of the CW-ground of narrow-linewidth Q-switched RFL under the relative high-pump-low-output condition can be reduced effectively. The experimental results indicate that it is challenging to demonstrate a narrow-linewidth Q-switched RFL with high quality output. But further power scaling and linewidth narrowing is possible in the case of operating parameters, optimization efforts, and a more powerful pump source. To the best of our knowledge, this is the first demonstration of narrow-linewidth generation in a Q-switched RFL. PMID:27557200

  17. Length characterization of a piezoelectric actuator travel with a mode-locked femtosecond laser

    NASA Astrophysics Data System (ADS)

    Pravdová, Lenka; Lešundák, Adam; Hucl, Václav; Čížek, Martin; Mikel, Břetislav; Hrabina, Jan; Řeřucha, Šimon; Číp, Ondřej; Lazar, Josef

    2015-05-01

    The development of absolute distance measurement methods have been enabled by new kind of lasers, special digital signal processing electronics, algorithms and new materials for optics. The phenomenon of the mode-lock of the femtosecond pulse laser increased a number of potential applications with distance surveying where that stable generator of very short and periodically repeated coherent pulses can be used. The main aim of the work is a description of precise measuring method with absolute scale which is able to determine the length of unknown distance with direct traceability to a time standard. The principle of the method is based on a passive optical cavity with mirrors keeping measured distance, in our case a piezoelectric actuator. Time spacing of short femtosecond pulses generated by mode-locked laser is optically phase locked to the cavity free spectral range. A value of the repetition frequency of the laser determines the measured distance. The exact value of the frequency/period of the femtosecond pulse train is detected by a frequency counter. The counting gate of the counter is synchronized with a highly stable oscillator disciplined by H-maser or GPS received signal from atomic clocks. The work shows methods how to overcome problems with dispersive optics in the passive cavity and a way of phase lock of the femtosecond laser repetition rate to free spectral range of the cavity. This measuring technique is demonstrated on length characterization of the piezoelectric transducer which belongs to ultra-precise positioning actuators.

  18. Narrow-band tunable alexandrite laser with passive Q switching

    SciTech Connect

    Tyryshkin, I S; Ivanov, N A; Khulugurov, V M

    1998-06-30

    An alexandrite laser with a self-injection of narrow-band radiation into its cavity was developed. A Fabry - Perot interferometer and a diffraction grating were used as dispersive components in an additional cavity. The cavity was switched by an LiF crystal with F{sub 3}{sup -} colour centres. The laser generated a single pulse of {approx} 180 ns duration and of 1.5 mJ energy, and with a spectrum 5 x 10{sup -3} cm{sup -1} wide. The laser emitted in the spectral range 720 - 780 nm. (lasers, active media)

  19. Mode locking of fiber lasers at high repetition rates

    NASA Astrophysics Data System (ADS)

    Usechak, Nicholas G.

    Mode-locked fiber lasers have become indispensable tools in many fields as their use is no longer relegated to the optics community. In the future, their size will decrease and their applications will become far more prevalent than they are today. At present, the field is undergoing a cardinal shift as these devices have become commercially available in the last decade. This has put an emphasis on long-term performance and reliability as these devices are beginning to be integrated into complex systems in areas as diverse as medical optics, micro-machining, forensics, and tracking as well as their obvious use as laboratory tools or sources in telecommunications. This is also resulting in a transition from research to engineering. Since the field of mode-locked lasers has been extensively studied for over forty years, one may expect that little has been overlooked. However, since the mode-locking phenomena is governed by nonlinear partial differential equations, a rich degree of effects exist and the field has not yet been exhausted. During the past two decades, the main emphasis has been on short-pulse generation; however, the main thrust of research is likely to change to producing high-power devices, which will result in limiting effects and thermal issues that are currently ignored for low-power sources. Finally, detailed studies have generally been performed numerically as analytic solutions only exist in limiting cases. In this thesis, mode-locked fiber lasers are studied experimentally, numerically, and theoretically. The experimental work focuses on high-repetition rate, mode-locked cavities, which are then modeled numerically. A semi-analytic tool, which goes beyond the prior theories and includes all of the effects experienced by steady-state, mode-locked pulses as they propagate in a laser cavity, is also derived. The only caveats to this approach are an assumption of the pulse shape and the requirement that it not change during propagation through the

  20. Q-switched Nd:YAG optical vortex lasers.

    PubMed

    Kim, D J; Kim, J W; Clarkson, W A

    2013-12-01

    Q-switched operation of a high-quality Nd:YAG optical vortex laser with the first order Laguerre-Gaussian mode and well-determined helical wavefronts using a fiber-based pump beam conditioning scheme is reported. A simple two-mirror resonator incorporating an acousto-optic Q-switch was employed, along with an etalon and a Brewster plate to enforce the particular helicity of the output. The laser yielded Q-switched pulses with ~250 μJ pulse energy and ~33 ns pulse duration (FWHM) at a 0.1 kHz repetition rate for 5.1 W of absorbed pump power. The handedness of the helical wavefronts was preserved regardless of the repetition rates. The prospects of further power scaling and improved laser performance are discussed. PMID:24514499

  1. Terahertz generation and detection using femtosecond mode-locked Yb-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Kong, Moon Sik; Kim, Ji Su; Han, Sang-Pil; Kim, Namje; Moon, Ki Won; Park, Kyung Hyun; Jeon, Min Yong

    2016-02-01

    We successfully demonstrate a THz generation using an ytterbium (Yb)-doped mode-locked femtosecond fiber laser and a home-made low-temperature grown (LTG) InGaAs Photoconductive antenna (PCA) module for THz Time-domain spectroscopy (TDS) systems. The Yb-doped fiber ring laser consists of a pump laser diode (PLD), a wavelength division multiplexer (WDM) coupler, a single-mode fiber (SMF), a 25 cm-long highly Yb-doped fiber, two collimators, two quarter wave plates (QWPs), a half-wave plate (HWP), a 10 nm broadband band pass filter, an isolator, and a polarizing beam splitter (PBS). In order to achieve the passively mode-locked optical short pulse, the nonlinear polarization rotation (NPR) effect is used. The achieved center wavelength and the 3 dB bandwidth of the modelocked fiber laser are 1.03 μm and ~ 15.6 nm, respectively. It has 175 fs duration after pulse compression with 66.2 MHz repetition rate. The average output power of mode-locked laser has more than 275 mW. The LTG-InGaAs PCA modules are used as the emitter and receiver in order to achieve the THz radiation. The PCA modules comprise a hyper-hemispherical Si lens and a log-spiral antenna-integrated LTG-InGaAs PCA chip electronically contacted on a printed circuit board (PCB). An excitation optical average pumping and probing power were ~ 6.3 mW and 5 mW, respectively. The free-space distance between the emitter and the receiver in the THz-TDS system was 70 mm. The spectrum of the THz radiation is achieved higher than 1.5 THz.

  2. A highly efficient graphene oxide absorber for Q-switched Nd:GdVO4 lasers

    NASA Astrophysics Data System (ADS)

    Wang, Yong Gang; Chen, Hou Ren; Wen, Xiao Ming; Hsieh, Wen Feng; Tang, Jau

    2011-11-01

    We demonstrated that graphene oxide material could be used as a highly efficient saturable absorber for the Q-switched Nd:GdVO4 laser. A novel and low-cost graphene oxide (GO) absorber was fabricated by a vertical evaporation technique and high viscosity of polyvinyl alcohol (PVA) aqueous solution. A piece of GO/PVA absorber, a piece of round quartz, and an output coupler mirror were combined to be a sandwich structure passive component. Using such a structure, 104 ns pulses and 1.22 W average output power were obtained with the maximum pulse energy at 2 µJ and a slope efficiency of 17%.

  3. Q-switching in the electron backward-wave oscillator

    SciTech Connect

    Denisov, G. G.; Kuzikov, S. V.; Savilov, A. V.

    2011-10-15

    The use of Q-switching (periodical modulation of the feedback factor) is proposed for the electron backward-wave oscillator (BWO). This can be a way to realize regimes of a stable generation of periodical short high-power rf pulses with relatively high averaged efficiency. As compared to the conventional regime of the stable generation of a BWO with no feedback, in the Q-switched BWO the averaged electronic efficiency can be increased by an order of magnitude, whereas the peak power of output rf pulses is 40-50 times higher.

  4. Self-induced transparency mode locking, and area theorem.

    PubMed

    Arkhipov, R M; Arkhipov, M V; Babushkin, I; Rosanov, N N

    2016-02-15

    Self-induced transparency mode locking (or coherent mode locking, CML), which is based on intracavity self-induced transparency soliton dynamics, potentially allows achievement of nearly single-cycle intracavity pulse durations, much below the phase relaxation time T2 in a laser which, despite having great promise, has not yet been realized experimentally. We develop a diagram technique which allows us to predict the main features of CML regimes in a generic two-section laser far from the single-cycle limit. We show that CML can arise directly at the first laser threshold if the phase relaxation time is large enough. Furthermore, we discuss the stability of the corresponding mapping. We also predict the existence of "super-CML regimes," with a pulse coupled to several Rabi oscillations in the nonlinear medium. PMID:26872176

  5. Kerr-lens mode locking without dispersion compensation

    SciTech Connect

    Gatz, S.; Herrmann, J.; Mueller, M.

    1996-10-01

    We propose and theoretically investigate a novel operating regime of femtosecond Kerr-lens mode-locked solid-state lasers that avoids group-velocity dispersion compensation by use of a nonresonant semiconductor plate in the focused resonator section that provides an overall negative nonlinear refractive index per round trip. The saturable loss of the laser resonator with an effective self-defocusing nonlinearity is derived from a generalized {ital ABCD} matrix formalism, and the correspondingly calculated steady-state pulse parameters show that a Kerr-lens mode-locked laser with an overall negative nonlinear refractive index generates stable femtosecond pulses without any dispersion compensation. {copyright} {ital 1996 Optical Society of America.}

  6. Mode-locked solid state lasers using diode laser excitation

    DOEpatents

    Holtom, Gary R.

    2012-03-06

    A mode-locked laser employs a coupled-polarization scheme for efficient longitudinal pumping by reshaped laser diode bars. One or more dielectric polarizers are configured to reflect a pumping wavelength having a first polarization and to reflect a lasing wavelength having a second polarization. An asymmetric cavity provides relatively large beam spot sizes in gain medium to permit efficient coupling to a volume pumped by a laser diode bar. The cavity can include a collimation region with a controlled beam spot size for insertion of a saturable absorber and dispersion components. Beam spot size is selected to provide stable mode locking based on Kerr lensing. Pulse durations of less than 100 fs can be achieved in Yb:KGW.

  7. Pulsed FM mode locking of a Nd:BEL laser.

    PubMed

    Godil, A A; Li, K D; Bloom, D M

    1991-08-15

    A novel but simple and practical mode locker was built and demonstrated for a diode-pumped Nd:BEL laser. Fast electrical pulses from a comb generator drive a LiNbO(3) crystal, which produces pulsed electro-optic phase modulation in the laser cavity. Stable mode-locked pulses of 7.5-ps duration were obtained at a repetition rate of 250 MHz. PMID:19776932

  8. Nonlinear high-order mode locking in stochastic sensory neurons

    NASA Astrophysics Data System (ADS)

    Rowe, Michael; Afghan, Muhammad; Neiman, Alexander

    2004-03-01

    Excitable systems demonstrate various mode locking regimes when driven by periodic external signals. With noise taken into account, such regimes represent complex nonlinear responses which depend crucially on the frequency and amplitude of the periodic drive as well as on the noise intensity. We study this using a computational model of a stochastic Hodgkin-Huxley neuron in combination with the turtle vestibular sensory system as an experimental model. A bifurcation analysis of the model is performed. Extracellular recordings from primary vestibular afferent neurons with two types of stimuli are used in the experimental study. First, mechanical stimuli applied to the labyrinth allow us to study the responses of the entire system, including transduction by the hair cells and spike generation in the primary afferents. Second, a galvanic stimuli applied directly to an afferent are used to study the responses of afferent spike generator directly. The responses to galvanic stimuli reveal multiple high-order mode locking regimes which are well reproduced in numerical simulation. Responses to mechanical stimulation are characterized by larger variability so that fewer mode-locking regimes can be observed.

  9. Modeling of ultrashort pulse generation in mode-locked VECSELs

    NASA Astrophysics Data System (ADS)

    Kilen, I.; Koch, S. W.; Hader, J.; Moloney, J. V.

    2016-03-01

    We present a study of various models for the mode-locked pulse dynamics in a vertical external-cavity surface emitting laser with a saturable absorber. The semiconductor Bloch equations are used to model microscopically the light-matter interaction and the carrier dynamics. Maxwell's equations describe the pulse propagation. Scattering contributions due to higher order correlation effects are approximated using effective rates that are found from a comparison to solving the microscopic scattering equations on the second Born-Markov level. It is shown that the simulations result in the same mode-locked final state whether the system is initialized with a test pulse close to the final mode-locked pulse or the full field build-up from statistical noise is considered. The influence of the cavity design is studied. The longest pulses are found for a standard V-cavity while a linear cavity and a V-cavity with an high reflectivity mirror in the middle are shown to produce similar, much shorter pulses.

  10. 2.3-ps pulses from a Kerr-lens mode-locked lamp-pumped Nd:YLF laser with a microdot mirror.

    PubMed

    Ramaswamy, M; Gouveia-Neto, A S; Negus, D K; Izatt, J A; Fujimoto, J G

    1993-11-01

    Pulses as short as 2.3 ps have been generated by passive mode locking of a lamp-pumped Nd:YLF laser with a microdot mirror mode locker for Kerr-lens mode-locking (KLM) saturable absorber action and a compact Gires-Tournois interferometer for dispersion compensation. KLM was initiated with an acousto-optic modulator. Average output powers of 800 mW have been achieved. This result demonstrates the potential use of KLM for generating near-bandwidth-limited pulses from high-power lamp-pumped sources. PMID:19829417

  11. Mode-locked InGaAs-AlGaAs disk laser generating sub-200-fs pulses, pulse picking and amplification by a tapered diode amplifier.

    PubMed

    Klopp, Peter; Griebner, Uwe; Zorn, Martin; Klehr, Andreas; Liero, Armin; Weyers, Markus; Erbert, Götz

    2009-06-22

    Almost chirp-free pulses with a duration of 190 fs were achieved from a mode-locked semiconductor disk laser (SDL) emitting at approximately 1045 nm. Pulse shaping was different from the soliton-like mode-locking process known from lasers using dielectric gain media; passive amplitude modulation provided by a fast saturable absorber was essential. The spectrum of the absorber had to be matched to the gain spectrum within a few nm. A tapered diode amplifier was demonstrated to be a device for both picking and amplifying SDL pulses. The pulse repetition rate of the SDL output was reduced from 3 GHz to 47 MHz. PMID:19550482

  12. High power (130 mW) 40 GHz 1.55 μm mode-locked distributed Bragg reflector lasers with integrated optical amplifiers.

    PubMed

    Akbar, Jehan; Hou, Lianping; Haji, Mohsin; Strain, Michael J; Marsh, John H; Bryce, A Catrina; Kelly, Anthony E

    2012-02-01

    High output power 40 GHz 1.55 μm passively mode-locked surface-etched distributed Bragg reflector (DBR) lasers with monolithically integrated semiconductor optical amplifiers are reported. These are based on an optimized AlGaInAs/InP epitaxial structure with a three quantum well active layer and an optical trap layer. The device produces near transform limited Gaussian pulses with a pulse duration of 3.3 ps. An average output power during mode-locked operation of 130 mW was achieved with a corresponding peak power of >1 W. PMID:22297347

  13. Dual-wavelength asynchronous and synchronous mode-locking operation by a Nd:CLTGG disordered crystal

    NASA Astrophysics Data System (ADS)

    Xu, J.-L.; Guo, S.-Y.; He, J.-L.; Zhang, B.-Y.; Yang, Y.; Yang, H.; Liu, S.-D.

    2012-04-01

    We have developed a diode-pumped passively mode-locked Nd3+:CLTGG laser operated at 1059 and 1061 nm with a semiconductor saturable absorber mirror (SESAM). The relative intensity of the two spectrum wavelengths is adjustable, allowing asynchronous and synchronous generation of the dual-wavelength pulses. In synchronous mode-locking regime, a total average output power of 383 mW was obtained with pulse duration of 3.5 ps and repetition rate of 42 MHz. The two spectral bands of 1059 and 1061 nm had the same intensities and areas, indicating 1:1 for the pulse energy ratio. It is desirable for efficiently generating a terahertz wave by difference-frequency generation.

  14. Mode-locked fiber laser using the Sagnac interferometer and the nonlinear polarization rotation

    NASA Astrophysics Data System (ADS)

    Ibarra-Escamilla, Baldeamr; Kuzin, Evgueni A.; Haus, Joseph W.; Pottiez, Olivier; Gomez-Garcia, Dario E.; Gutierrez-Zainos, Francisco; Mendoza-Vazquez, Sergio; Grajales-Coutico, Ruben

    2003-07-01

    In figure-eight lasers (F8L) mode locking is achieved through a nonlinear fiber amplifier loop mirror (NALM) or an asymmetrical nonlinear optical loop mirror (NOLM). Recently, we have theoretically shown that the symmetrical NOLM with a twisted fiber is useful for passive mode locking of fiber lasers. In this work we experimentally demonstrate the operation of a F8L based on the symmetrical NOLM with a twisted low-birefringence fiber in the loop. The modelocking operation is achieved by nonlinear polarization rotation. We found that the counter-propagating beams accumulate a differential nonlinear phase shift when they have different As (where As is the Stokes parameter). At the input NOLM, we used a polarizer controller to adjust the clockwise beam to be circularly polarized, As=1. In the loop of the NOLM, we used a quarter-wave retarder to transform the counter-clockwise beam to linear polarization, As=0. The quarter-wave retarder was the only element that we adjust to achieve modelocking. The pulse repetition frequency was 0.8 MHz. The FWHM of the autocorrelation function was 0.7 ps. We used a pump power of 80 mW to get the modelocking operation. The modelocked laser ran in stable operation for hours. Even in this first experiments the laser shown several advantages. The adjustment procedure was straightforward. The laser shows stable operation and exhibits high pulse energy. We achieved stable generation of subpicosecond pulses with milliwatts of average output power.

  15. Mode locked Nd:YVO 4 laser with intracavity synchronously pumped optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Zavadilova, Alena; Kubeček, Václav; Čech, Miroslav; Hiršl, Petr; Jelínkova, Helena; Diels, Jean-Claude

    2006-02-01

    The motivation of this work is the development of laser sensor and gyroscope based on short pulse solid state ring laser. In comparison with regular ring laser containing the gain medium and saturable absorber, where counterpropagating pulses overlap, a ring synchronously pumped optical parametric oscillator, in which the pulse crossing point is controlled externally by the time of arrival of the pump pulses, is the ideal source for short pulse laser sensor. The optimum configuration is a synchronously pumped parametric oscillator inserted inside the optical resonator of the diode pumped mode-locked solid state laser. We are developing a such system, as a first step we have demonstrated operation of a diode pumped Nd:YVO 4 passively mode-locked laser using semiconductor saturable absorber with synchronously pumped intracavity optical parametric oscillator in linear configuration. The repetition rate of the pump laser was 132 MHz and the pulse duration of 15 ps. Parametric oscillator was based on 20 mm long Brewster cut single grating (with poling periode of 30.3 μm) periodically poled magnesium doped lithium niobate (MgO:PPLN) crystal. The temperature tuning of parametric luminescence from the crystal with peak wavelength at 1537 nm - 1550 nm for temperature variation from 30 °C to 57 °C was observed.

  16. Characterization and modeling of a dispersive cavity mode-locked erbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Hayduk, Michael J.; Haus, Joseph W.; Kaechele, Walter; Shaulov, Gary; Teegarden, Kenneth J.; Theimer, James P.; Wicks, Gary W.

    1999-07-01

    A novel, compact, polarization insensitive mode-locked erbium-doped fiber laser producing 2 ps pulses was constructed. The laser was passively mode-locked using a 75 period InGaAs/InAlAs multiple quantum well saturable absorber grown lattice matched on an InP substrate. The laser was constructed in a linear cavity, Fabry-Perot configuration with the saturable absorber at one end of the cavity and a chirped fiber Bragg grating at the other end. The output pulses are chirped and were further characterized by varying their energies and propagating them down different lengths of standard optical fiber. The laser cavity was modeled using the complex Ginzburg-Landau equation derived under the condition that nonlinear changes to the pulse must be small per round-trip. The contribution of the semiconductor saturable absorber was modeled using a two-level rate equation. The free carrier absorption within the semiconductor contributes to the refractive index which was shown numerically to result in an additional frequency shift. The modeling is in close agreement with the pulse propagation experiments.

  17. Power-scalable 1.57 microm mode-locked semiconductor disk laser using wafer fusion.

    PubMed

    Saarinen, Esa J; Puustinen, Janne; Sirbu, Alexei; Mereuta, Alexandru; Caliman, Andrei; Kapon, Eli; Okhotnikov, Oleg G

    2009-10-15

    We report the first (to our knowledge) wafer-fused high-power passively mode-locked semiconductor disk laser operating at 1.57 microm wavelength. An InP-based active medium was fused with GaAs/AlGaAs distributed Bragg reflector on a 2 inch wafer level, resulting in an integrated monolithic gain mirror. An intracavity wedged diamond heat-spreader capillary bonded to the gain chip provides efficient heat removal from the gain structure without disturbing the spectrum of the mode-locked laser. The laser produces over 0.6 W of average output power at 15 degrees C with 16 ps pulse width. The total output power accounting for all output beams emerging from the cavity was 0.86 W. The results reveal an essential advantage of wafer fusion processing of disparate materials over monolithically grown InP-based gain structures and demonstrate the high potential of this technique for power scaling of long-wavelength semiconductor disk lasers. PMID:19838252

  18. Short-pulse fiber lasers mode-locked by carbon nanotube and graphene

    NASA Astrophysics Data System (ADS)

    Yamashita, Shinji; Set, Sze Y.; Xu, Bo

    2014-09-01

    We review the optical properties of carbon nanotubes (CNTs) and graphene and describe how those properties have been used for the implementation of various nonlinear fiber optic applications. Early studies on the optical properties of CNTs in the late 90s revealed that these materials exhibit high third order susceptibility and a broadband saturable absorption with a sub-picosecond response time. Recent discovery of similar nonlinear optical properties in graphene attracts much attention in this field. Such ultrafast, highly nonlinear optical response means that they can be employed for noise suppression and for the mode-locking of fiber lasers, and in addition, their high third order nonlinearity holds great promise for the implementation of various other nonlinear fiber optic devices such as wavelength converters based on four wave mixing. In this paper, we will discuss the various methods that have been considered thus far for the integration of CNTs and graphene in optical systems and highlight the advantages and limitations of using the saturable absorption of CNTs and graphene for the passive mode-locking of fiber lasers, and the current status of CNT and graphene saturable absorbers in the state of art fiber laser technologies.

  19. Digital-wavelength ytterbium fiber laser mode-locked with MoS2

    NASA Astrophysics Data System (ADS)

    Wang, Shiwei; Zhou, Yan; Wang, Yao; Yan, Shuo; Li, Yue; Zheng, Wanguo; Deng, Ying; Zhu, Qihua; Xu, Jianqiu; Tang, Yulong

    2016-05-01

    In this letter, we report a digital-wavelength ytterbium-doped fiber laser passively mode-locked with layered molybdenum disulfide (MoS2). The MoS2 based saturable absorber (SA) is made by solution coating the MoS2 solution on a gold mirror, showing modulation depth and saturation intensity of 11.4% and 1.37 MW cm‑2, respectively. The output pulse has duration of ~300 ps, 3 dB spectral width of ~0.5 nm and maximum output power of 2.6 mW. The mode-locked fundamental frequency is 2.67 MHz with a ~36 dB signal-to-noise ratio. Through tuning the polarization controller (PC) and squeezing/stretching the single mode fiber in the ring cavity, four-bit digital wavelength emission is achieved. It is proposed that the digital-wavelength tuning feature of fiber lasers can be employed in coding and signal processing.

  20. Dual-wavelength synchronous operation of a mode-locked 2-μm Tm:CaYAlO4 laser.

    PubMed

    Kong, L C; Qin, Z P; Xie, G Q; Xu, X D; Xu, J; Yuan, P; Qian, L J

    2015-02-01

    We experimentally demonstrated dual-wavelength synchronous operation of a high-power passively mode-locked 2-μm Tm:CaYAlO4 (Tm:CYA) disordered crystal laser with semiconductor saturable absorber mirror (SESAM) as mode locker. The mode-locked laser emitted an average output power as high as 830 mW with pulse duration of 35.3 ps and repetition rate of 145.4 MHz. The mode-locking dual wavelengths were centered at 1958.9 nm and 1960.6 nm, respectively. Autocorrelation trace clearly shows beating pulses with pulse width of 3.5 ps and repetition rate of 0.13 THz. PMID:25680046

  1. Dual-wavelength synchronously Q-switched solid-state laser with multi-layered graphene as saturable absorber.

    PubMed

    Zhao, Yongguang; Li, Xianlei; Xu, Miaomiao; Yu, Haohai; Wu, Yongzhong; Wang, Zhengping; Hao, Xiaopeng; Xu, Xinguang

    2013-02-11

    Using multilayered graphene as the saturable absorber (SA), Nd:LYSO crystal as the laser material, we demonstrated a laser-diode (LD) pumped, dual-wavelength passively Q-switched solid-state laser. The maximum average output power is 1.8 W, the largest pulse energy and highest peak power is 11.3 μJ, 118 W, respectively. As we have known, they are the best results for passively Q-switched operation of graphene. The pulse laser is strong enough to realize extra-cavity frequency conversions. With a KTP crystal as the sum-frequency generator, the dual wavelengths are proved to be well time overlapped, which manifests the synchronous modulation to the dual-wavelength with multi-layered graphene. PMID:23481809

  2. Solid state saturable absorbers for Q-switching at 1 and 1.3μm: investigation and modeling

    NASA Astrophysics Data System (ADS)

    Šulc, Jan; Arátor, Pavel; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav; Kokta, Milan R.

    2008-02-01

    Yttrium and Lutecium garnets (YAG and LuAG) doped by Chromium or Vanadium ions (Cr 4+ or V 3+) were investigated as saturable absorbers potentially useful for passive Q-switching at wavelengths 1 μm and/or 1.3 μm. For comparison also color center saturable absorber LiF:F - II and Cobalt doped spinel (Co:MALO) were studied. Firstly, low power absorption spectra were recorded for all samples. Next, absorbers transmission in dependence on incident energy/power density was measured using the z-scan method. Crystals Cr:YAG, Cr:LuAG, V:YAG, and LiF:F - II were tested at wavelength 1064 nm. Therefore Alexandrite laser pumped Q-switched Nd:YAG laser was used as a radiation source (pulse length 6.9 ns, energy up to 1.5 mJ). Crystals V:YAG, V:LuAG, and Co:MALO were tested at wavelength 1338 nm. So diode pumped Nd:YAG/V:YAG microchip laser was used as a radiation source (pulse length 6.2 ns, energy up to 0.1 mJ). Using measured data fitting, and by their comparison with numerical model of a "thick" saturable absorber transmission for Q-switched Gaussian laser beam, following parameters were estimated: saturable absorber initial transmission T 0, saturation energy density w s, ground state absorption cross-section σ GSA, saturated absorber transmission T s, excited state absorption cross-section σ ESA, ratio γ = σ GSA/σ ESA, and absorbing ions density. For V:YAG crystal, a polarization dependence of T s was also investigated. With the help of rate equation numerical solution, an impact of saturable absorber parameters on generated Q-switched pulse properties was studied in plane wave approximation. Selected saturable absorbers were also investigated as a Q-switch and results were compared with the model.

  3. Fabrication, optimization, and characterization of monolithic semiconductor mode-locked lasers and colliding, pulse mode-locked lasers at millimeter-wave frequencies

    NASA Astrophysics Data System (ADS)

    Passerini, Marco; Sorel, Marc; Laybourn, Peter J.; Giuliani, Guido; Donati, Silvano

    2004-09-01

    This work reports on the fabrication, optimisation and characterisation of monolithic mode-locked lasers (MLLs) and colliding-pulse mode-locked (CPM) lasers with repetition rate in the range 10-60 GHz. The devices consist of double section split-contact ridge waveguide lasers fabricated in GaAs/AlGaAs double quantum well (DQW) material. For CPM devices, the saturable absorber section was fabricated with a coplanar ground-signal-ground (G-S-G) pad structure. The optimum saturable absorber size for efficient mode-locking is found experimentally. The fabricated devices are characterised in terms of operating regimes (Continuous Wave, Self-Pulsation, Mode-Locking) and the mode-locking signals were observed in the frequency domain using an external fast photodiode. In the case of CPM devices a mm-wave signal could also be extracted directly from the saturable absorber section of the laser using a microwave probe.

  4. Inter-comb synchronization by mode-to-mode locking

    NASA Astrophysics Data System (ADS)

    Chun, Byung Jae; Kim, Young-Jin; Kim, Seung-Woo

    2016-08-01

    Two combs of fiber femtosecond lasers are synchronized through the optical frequency reference created by injection-locking of a diode laser to a single comb mode. Maintaining a mHz-level narrow linewidth, the optical frequency reference permits two combs to be stabilized by mode-to-mode locking with a relative stability of 1.52  ×  10‑16 at 10 s with a frequency slip of 2.46 mHz. This inter-comb synchronization can be utilized for applications such as dual-comb spectroscopy or ultra-short pulse synthesis without extra narrow-linewidth lasers.

  5. Picosecond Measurements with Mode-Locked CW Lasers.

    NASA Astrophysics Data System (ADS)

    Mosaad, Neamat Roushdy M.

    Available from UMI in association with The British Library. Requires signed TDF. The characteristics of output pulses from a synchronously and hybridly mode-locked CW Rhodamine 6G dye laser were studied in detail by both spectral and temporal measurements. In a synchronous system, the observed spectrum was found to change from deeply channelled to nearly smooth according to the position of the birefringent filter. The output pulses were nearly transform-limited and believed to have a single-sided exponential shape. Hybridly CW mode-locked dye laser was a more reliable source for generating broadly tunable subpicosecond pulses, compared to a synchronously mode-locked laser. With carefull adjustment of the dye laser and the saturable absorber concentration (DQOCI) mixed with R6G in a single dye jet stream, pulses as short as 0.21 ps have been obtained with a compression factor of 5. The observed spectrum showed asymmetric broadening at the long-wavelength side alone. The SHG autocorrelation traces showed broad wings with exponential-like shape. The time-bandwidth product for these pulses were about three to seven times larger than that for the transform-limited pulse with single-sided exponential shape. This suggest that the pulse is largely frequency-chirped which can consistently be explained by taking into account the nonlinear process of self-phase modulation due to optical Kerr effect in a mixed dye jet stream. The timing pulse jitter was reduced by a factor of 2.4 due to mode-locking stabilization. Optical pulse compression utilizing nonlinear propagation in single-mode fibres was studied. The propagation in the fibre broadens and chirps the pulse due to the combined action of group velocity dispersion and self-phase modulation. The channelled spectrum disappeared completely and a smooth Gaussian shape was observed with the same overall width. The pulse can then be compressed by passage through a suitable dispersive delay line. Short pulses were obtained with a

  6. A practical topological insulator saturable absorber for mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Yan, Peiguang; Lin, Rongyong; Ruan, Shuangchen; Liu, Aijiang; Chen, Hao; Zheng, Yuequn; Chen, Sifan; Guo, Chunyu; Hu, Juguang

    2015-03-01

    A novel saturable absorber (SA) was fabricated by coating the topological insulator (TI) film on microfiber using pulsed laser deposition (PLD) method. The TISA device had an insertion loss of ~1.25 dB, a saturable intensity of 26.7 MW/cm2, a modulation depth of ~5.7%, and a nonsaturable loss of 20.5%. Upon employing this SA device, we established a passively mode-locked EDFL and achieved nearly free-chirped soliton pulse with 286 fs of pulse duration and >73 dB of signal to noise ratio (SNR). This result clearly evidences that the PLD is an effective scheme for practical SA device fabrication.

  7. A practical topological insulator saturable absorber for mode-locked fiber laser

    PubMed Central

    Yan, Peiguang; Lin, Rongyong; Ruan, Shuangchen; Liu, Aijiang; Chen, Hao; Zheng, Yuequn; Chen, Sifan; Guo, Chunyu; Hu, Juguang

    2015-01-01

    A novel saturable absorber (SA) was fabricated by coating the topological insulator (TI) film on microfiber using pulsed laser deposition (PLD) method. The TISA device had an insertion loss of ~1.25 dB, a saturable intensity of 26.7 MW/cm2, a modulation depth of ~5.7%, and a nonsaturable loss of 20.5%. Upon employing this SA device, we established a passively mode-locked EDFL and achieved nearly free-chirped soliton pulse with 286 fs of pulse duration and >73 dB of signal to noise ratio (SNR). This result clearly evidences that the PLD is an effective scheme for practical SA device fabrication. PMID:25732598

  8. A practical topological insulator saturable absorber for mode-locked fiber laser.

    PubMed

    Yan, Peiguang; Lin, Rongyong; Ruan, Shuangchen; Liu, Aijiang; Chen, Hao; Zheng, Yuequn; Chen, Sifan; Guo, Chunyu; Hu, Juguang

    2015-01-01

    A novel saturable absorber (SA) was fabricated by coating the topological insulator (TI) film on microfiber using pulsed laser deposition (PLD) method. The TISA device had an insertion loss of ~1.25 dB, a saturable intensity of 26.7 MW/cm(2), a modulation depth of ~5.7%, and a nonsaturable loss of 20.5%. Upon employing this SA device, we established a passively mode-locked EDFL and achieved nearly free-chirped soliton pulse with 286 fs of pulse duration and >73 dB of signal to noise ratio (SNR). This result clearly evidences that the PLD is an effective scheme for practical SA device fabrication. PMID:25732598

  9. Intra-cavity frequency-doubled mode-locked semiconductor disk laser at 325 nm.

    PubMed

    Bek, Roman; Baumgärtner, Stefan; Sauter, Fabian; Kahle, Hermann; Schwarzbäck, Thomas; Jetter, Michael; Michler, Peter

    2015-07-27

    We present a passively mode-locked semiconductor disk laser (SDL) emitting at 650nm with intra-cavity second harmonic generation to the ultraviolet (UV) spectral range. Both the gain and the absorber structure contain InP quantum dots (QDs) as active material. In a v-shaped cavity using the semiconductor samples as end mirrors, a beta barium borate (BBO) crystal is placed in front of the semiconductor saturable absorber mirror (SESAM) for pulsed UV laser emission in one of the two outcoupled beams. Autocorrelation (AC) measurements at the fundamental wavelength reveal a FWHM pulse duration of 1.22ps. With a repetition frequency of 836MHz, the average output power is 10mW per beam for the red emission and 0.5mW at 325nm. PMID:26367654

  10. Stochasticity, periodicity and localized light structures in partially mode-locked fibre lasers

    NASA Astrophysics Data System (ADS)

    Churkin, D. V.; Sugavanam, S.; Tarasov, N.; Khorev, S.; Smirnov, S. V.; Kobtsev, S. M.; Turitsyn, S. K.

    2015-05-01

    Physical systems with co-existence and interplay of processes featuring distinct spatio-temporal scales are found in various research areas ranging from studies of brain activity to astrophysics. The complexity of such systems makes their theoretical and experimental analysis technically and conceptually challenging. Here, we discovered that while radiation of partially mode-locked fibre lasers is stochastic and intermittent on a short time scale, it exhibits non-trivial periodicity and long-scale correlations over slow evolution from one round-trip to another. A new technique for evolution mapping of intensity autocorrelation function has enabled us to reveal a variety of localized spatio-temporal structures and to experimentally study their symbiotic co-existence with stochastic radiation. Real-time characterization of dynamical spatio-temporal regimes of laser operation is set to bring new insights into rich underlying nonlinear physics of practical active- and passive-cavity photonic systems.

  11. Mode locking in a bismuth fibre laser by using a SESAM

    SciTech Connect

    Krylov, A A; Dvoirin, V V; Mashinsky, V M; Kryukov, P G; Okhotnikov, O G; Guina, M

    2008-03-31

    By using a semiconductor saturable-absorber mirror (SESAM) optimised for operation in the spectral range from 1100 to 1200 nm, passive mode locking is obtained in a cw bismuth-doped fibre laser. Pumping was performed by a cw ytterbium-doped fibre laser at a wavelength of 1075 nm. The operation of the laser is studied by using either a fibre Bragg grating or a loop fibre Sagnac mirror as the output resonator mirror. Stable laser pulses of duration from 50 ps to 3.5 ns, depending on the output mirror type, were generated. The pulse repetition rate was 11 MHz at a wavelength of {approx}1160 nm and the maximum spectral width of 2.1 nm. The maximum average output power was 7.8 mW upon pumping by 1140 mW. (control of laser radiation parameters)

  12. Stochasticity, periodicity and localized light structures in partially mode-locked fibre lasers

    PubMed Central

    Churkin, D. V.; Sugavanam, S.; Tarasov, N.; Khorev, S.; Smirnov, S. V.; Kobtsev, S. M.; Turitsyn, S. K.

    2015-01-01

    Physical systems with co-existence and interplay of processes featuring distinct spatio-temporal scales are found in various research areas ranging from studies of brain activity to astrophysics. The complexity of such systems makes their theoretical and experimental analysis technically and conceptually challenging. Here, we discovered that while radiation of partially mode-locked fibre lasers is stochastic and intermittent on a short time scale, it exhibits non-trivial periodicity and long-scale correlations over slow evolution from one round-trip to another. A new technique for evolution mapping of intensity autocorrelation function has enabled us to reveal a variety of localized spatio-temporal structures and to experimentally study their symbiotic co-existence with stochastic radiation. Real-time characterization of dynamical spatio-temporal regimes of laser operation is set to bring new insights into rich underlying nonlinear physics of practical active- and passive-cavity photonic systems. PMID:25947951

  13. Stochasticity, periodicity and localized light structures in partially mode-locked fibre lasers.

    PubMed

    Churkin, D V; Sugavanam, S; Tarasov, N; Khorev, S; Smirnov, S V; Kobtsev, S M; Turitsyn, S K

    2015-01-01

    Physical systems with co-existence and interplay of processes featuring distinct spatio-temporal scales are found in various research areas ranging from studies of brain activity to astrophysics. The complexity of such systems makes their theoretical and experimental analysis technically and conceptually challenging. Here, we discovered that while radiation of partially mode-locked fibre lasers is stochastic and intermittent on a short time scale, it exhibits non-trivial periodicity and long-scale correlations over slow evolution from one round-trip to another. A new technique for evolution mapping of intensity autocorrelation function has enabled us to reveal a variety of localized spatio-temporal structures and to experimentally study their symbiotic co-existence with stochastic radiation. Real-time characterization of dynamical spatio-temporal regimes of laser operation is set to bring new insights into rich underlying nonlinear physics of practical active- and passive-cavity photonic systems. PMID:25947951

  14. Optimal operating regime of saturable absorbers in mode-locked lasers

    SciTech Connect

    Narovlyanskaya, N.M.; Tikhonov, E.A.

    1982-01-01

    An investigation was made of ultrashort pulse generation by passive mode locking in a rhodamine 6G jet laser with pulsed laser pumping of up to 300 nsec duration. In order to obtain single ultrashort pulses per axial period in these systems, it was essential to reduce their time of formation to several loop passes. It was shown experimentally that the rate of formation of ultrashort pulses is influenced appreciably by the nonlinear absorber dye and, for a given intracavity intensity, the best dyes are those having a purely electronic transition near the lasing frequency. In this case, the critical bleaching intensity and relaxation time are minimized as a result of the increased role of stimulated resonance transitions in the dye modulator. Optimal types of polymethine dyes are suggested for nonlinear absorbers of tunable ultrashort-pulse rhodamine 6G lasers.

  15. Efficient diode-pumped self-mode-locking Yb:LYSO laser

    NASA Astrophysics Data System (ADS)

    Liu, J.; Wang, W. W.; Liu, C. C.; Fan, X. W.; Zheng, L. H.; Su, L. B.; Xu, J.

    2010-02-01

    We demonstrated a Kerr-lens self-mode-locked Yb:(Lu0.5Y0.5)2SiO5 (Yb:LYSO) laser for the first time, which was independent of active or passive modulators as well as hard diaphragm inside cavity. An output power of 3.08 W with a repetition rate of 99 MHz was obtained using a pump power of 16.48 W. The pulse duration estimated from this measurement was 7.8 ps at 1058 nm. Meanwhile, pulse energy of 31.1 nJ with output peak power up to 3.99 kW were generated in this system.

  16. Efficient Q-switched Tm:YAG ceramic slab laser.

    PubMed

    Zhang, Shuaiyi; Wang, Mingjian; Xu, Lin; Wang, Yan; Tang, Yulong; Cheng, Xiaojin; Chen, Weibiao; Xu, Jianqiu; Jiang, Benxue; Pan, Yubai

    2011-01-17

    Characteristics of Tm:YAG ceramic for high efficient 2-μm lasers are analyzed. Efficient diode end-pumped continuous-wave and Q-switched Tm:YAG ceramic lasers are demonstrated. At the absorbed pump power of 53.2W, the maximum continuous wave (cw) output power of 17.2 W around 2016 nm was obtained with the output transmission of 5%. The optical conversion efficiency is 32.3%, corresponding to a slope efficiency of 36.5%. For Q-switched operation, the shortest width of 69 ns was achieved with the pulse repetition frequency of 500 Hz and single pulse energy of 20.4 mJ, which indicates excellent energy storage capability of the Tm:YAG ceramic. PMID:21263612

  17. Dual-kind Q-switching of erbium fiber laser

    SciTech Connect

    Barmenkov, Yuri O. Kir'yanov, Alexander V.; Cruz, Jose L.; Andres, Miguel V.

    2014-03-03

    Two different regimes of Q-switching in the same implementation of an actively Q-switched erbium-doped fiber laser are demonstrated. Depending on the active fiber length and repetition rate of an intracavity Q-cell (acousto-optic modulator), the laser operates either in the regime of common, rather long and low-power, pulses composed of several sub-pulses or in the one of very short and powerful stimulated Brillouin scattering-induced pulses. The basic physical reason of the laser system to oscillate in one of these two regimes is the existence or absence of CW narrow-line “bad-cavity” lasing in the intervals when the Q-cell is blocked.

  18. Simple technique for sequential Q-switching of molecular lasers.

    NASA Technical Reports Server (NTRS)

    Lucht, R. A.; Allario, F.; Jarrett, O., Jr.

    1972-01-01

    A simple technique for sequentially Q-switching molecular lasers is discussed in which an optical scanner is used as an optical folding element in a laser cavity consisting of a stationary diffraction grating and partially reflecting mirror. Sequential Q-switching of a conventional CO2 laser is demonstrated in which over sixty-two transitions between 9.2 and 10.8 microns are observed. Rapid repetition rates (200 Hz) and narrow laser pulses (less than 5 microsec) allow conventional signal processing techniques to be used with this multiwavelength laser source which is a versatile tool for laser propagation studies, absorption spectroscopy, and gain measurements. Results of a preliminary experiment demonstrating the utility of measuring selective absorption of CO2 laser wavelengths by C2H4 are shown.

  19. Q-Switched Nd: YAG Laser Micro-Machining System

    SciTech Connect

    Messaoud, S.; Allam, A.; Siserir, F.; Bouceta, Y.; Kerdja, T.; Ouadjaout, D.

    2008-09-23

    In this paper, we present the design of a low cost Q-switched Nd: YAG laser micro-machining system for photo masks fabrication. It consists of: Nd:YAG laser source, beam delivery system, X-Y table, PC, The CCD camera and TV monitor. The synchronization between the laser source and the X-Y table is realised by NI PCI-7342, the two axis MID-7602 and LabVIEW based program. The first step of this work consists of engraving continuous and discontinuous lines on a thin film metal with a 100 {mu}m resolution by using the YG 980 Quantel Q-switched Nd:YAG laser.

  20. Graphene Q-switched Yb:KYW planar waveguide laser

    SciTech Connect

    Kim, Jun Wan; Young Choi, Sun; Jun Ahn, Kwang; Yeom, Dong-Il E-mail: rotermun@ajou.ac.kr; Rotermund, Fabian E-mail: rotermun@ajou.ac.kr; Aravazhi, Shanmugam; Pollnau, Markus; Griebner, Uwe; Petrov, Valentin; Bae, Sukang

    2015-01-15

    A diode-pumped Yb:KYW planar waveguide laser, single-mode Q-switched by evanescent-field interaction with graphene, is demonstrated for the first time. Few-layer graphene grown by chemical vapor deposition is transferred onto the top of a guiding layer, which initiates stable Q-switched operation in a 2.4-cm-long waveguide laser operating near 1027 nm. Average output powers up to 34 mW and pulse durations as short as 349 ns are achieved. The measured output beam profile, clearly exhibiting a single mode, agrees well with the theoretically calculated mode intensity distribution inside the waveguide. As the pump power is increased, the repetition rate and pulse energy increase from 191 to 607 kHz and from 7.4 to 58.6 nJ, respectively, whereas the pulse duration decreases from 2.09 μs to 349 ns.

  1. 100-megawatt power Q-switched Er-glass laser

    NASA Astrophysics Data System (ADS)

    Taboada, John; Taboada, John M.; Stolarski, David J.; Zohner, Justin J.; Chavey, Lucas J.; Hodnett, Harvey M.; Noojin, Gary D.; Thomas, Robert J.; Kumru, Semih S.; Cain, Clarence P.

    2006-02-01

    A very high energy Q-switched Er-glass laser is reported. We incorporated a rotating, resonant mirror/Porro-cavity reflector optical arrangement to achieve very high shutter speeds on the cavity Q of a laser designed for energetic, flashlamp-pumped, 600-μs, 1540-nm pulses. Reproducible 3.75-J, 35-ns, 1533-nm laser pulses were obtained at a repetition rate less than 1 minute. Our work shows that reliable, very high energy, Q-switched, Er-glass laser pulses at 1533 nm can be generated mechanically with no apparent damage to laser cavity components. We demonstrate the applications of this "eye safe" wavelength to energetic processes such as LIBS and materials processing. The laser could also serve as a new tool for bioeffects studies and targeting applications.

  2. 948 kHz repetition rate, picosecond pulse duration, all-PM 1.03 μm mode-locked fiber laser based on nonlinear polarization evolution

    NASA Astrophysics Data System (ADS)

    Boivinet, S.; Lecourt, J.-B.; Hernandez, Y.; Fotiadi, A.; Mégret, P.

    2014-05-01

    We present in this study a PM all-fiber laser oscillator passively mode-locked (ML) at 1.03 μm. The laser is based on Nonlinear Polarization Evolution (NPE) in polarization maintaining (PM) fibers. In order to obtain the mode-locking regime, a nonlinear reflective mirror including a fibered polarizer, a long fiber span and a fibered Faraday mirror (FM) is inserted in a Fabry-Perot laser cavity. In this work we explain the principles of operation of this original laser design that permits to generate ultrashort pulses at low repetition (lower that 1MHz) rate with a cavity length of 100 m of fiber. In this experiment, the measured pulse duration is about 6 ps. To our knowledge this is the first all-PM mode-locked laser based on the NPE with a cavity of 100m length fiber and a delivered pulse duration of few picosecondes. Furthermore, the different mode-locked regimes of the laser, i.e. multi-pulse, noise-like mode-locked and single pulse, are presented together with the ways of controlling the apparition of these regimes. When the single pulse mode-locking regime is achieved, the laser delivers linearly polarized pulses in a very stable way. Finally, this study includes numerical results which are obtained with the resolution of the NonLinear Schrodinger Equations (NLSE) with the Split-Step Fourier (SSF) algorithm. This modeling has led to the understanding of the different modes of operation of the laser. In particular, the influence of the peak power on the reflection of the nonlinear mirror and its operation are studied.

  3. WS2 mode-locked ultrafast fiber laser

    PubMed Central

    Mao, Dong; Wang, Yadong; Ma, Chaojie; Han, Lei; Jiang, Biqiang; Gan, Xuetao; Hua, Shijia; Zhang, Wending; Mei, Ting; Zhao, Jianlin

    2015-01-01

    Graphene-like two dimensional materials, such as WS2 and MoS2, are highly anisotropic layered compounds that have attracted growing interest from basic research to practical applications. Similar with MoS2, few-layer WS2 has remarkable physical properties. Here, we demonstrate for the first time that WS2 nanosheets exhibit ultrafast nonlinear saturable absorption property and high optical damage threshold. Soliton mode-locking operations are achieved separately in an erbium-doped fiber laser using two types of WS2-based saturable absorbers, one of which is fabricated by depositing WS2 nanosheets on a D-shaped fiber, while the other is synthesized by mixing WS2 solution with polyvinyl alcohol, and then evaporating them on a substrate. At the maximum pump power of 600 mW, two saturable absorbers can work stably at mode-locking state without damage, indicating that few-layer WS2 is a promising high-power flexible saturable absorber for ultrafast optics. Numerous applications may benefit from the ultrafast nonlinear features of WS2 nanosheets, such as high-power pulsed laser, materials processing, and frequency comb spectroscopy. PMID:25608729

  4. Harmonically mode-locked erbium-doped waveguide laser

    NASA Astrophysics Data System (ADS)

    Fanto, Michael L.; Malowicki, John E.; Bussjager, Rebecca J.; Johns, Steven T.; Vettese, Elizabeth K.; Hayduk, Michael J.

    2004-08-01

    The generation of ultrastable picosecond pulses in the 1550 nm range is required for numerous applications that include photonic analog-to-digital converter systems and high-bit rate optical communication systems. Mode-locked erbium-doped fiber ring lasers (EDFLs) are typically used to generate pulses at this wavelength. In addition to timing stability and output power, the physical size of the laser cavity is of primary importance to the Air Force. The length of the erbium (Er)-doped fiber used as the gain medium may be on the order of meters or even tens of meters which adds complexity to packaging. However, with the recent advancements in the production of multi-component glasses, higher doping concentrations can be achieved as compared to silicate glasses. Even more recent is the introduction of Er-doped multi-component glass waveguides, thus allowing the overall footprint of the gain medium to be reduced. We have constructed a novel harmonically mode-locked fiber ring laser using the Er-doped multi-component glass waveguide as the gain medium. The performance characteristics of this Er-doped waveguide laser (EDWL) including pulse width, spectral width, harmonic suppression, optical output power, laser stability and single sideband residual phase noise will be discussed in this paper.

  5. WS2 mode-locked ultrafast fiber laser

    NASA Astrophysics Data System (ADS)

    Mao, Dong; Wang, Yadong; Ma, Chaojie; Han, Lei; Jiang, Biqiang; Gan, Xuetao; Hua, Shijia; Zhang, Wending; Mei, Ting; Zhao, Jianlin

    2015-01-01

    Graphene-like two dimensional materials, such as WS2 and MoS2, are highly anisotropic layered compounds that have attracted growing interest from basic research to practical applications. Similar with MoS2, few-layer WS2 has remarkable physical properties. Here, we demonstrate for the first time that WS2 nanosheets exhibit ultrafast nonlinear saturable absorption property and high optical damage threshold. Soliton mode-locking operations are achieved separately in an erbium-doped fiber laser using two types of WS2-based saturable absorbers, one of which is fabricated by depositing WS2 nanosheets on a D-shaped fiber, while the other is synthesized by mixing WS2 solution with polyvinyl alcohol, and then evaporating them on a substrate. At the maximum pump power of 600 mW, two saturable absorbers can work stably at mode-locking state without damage, indicating that few-layer WS2 is a promising high-power flexible saturable absorber for ultrafast optics. Numerous applications may benefit from the ultrafast nonlinear features of WS2 nanosheets, such as high-power pulsed laser, materials processing, and frequency comb spectroscopy.

  6. Q-switched Tm3+-doped fiber laser with a micro-fiber based black phosphorus saturable absorber

    NASA Astrophysics Data System (ADS)

    Wang, Yazhou; Li, Jianfeng; Han, Lian; Lu, Rongguo; Hu, Yunxiao; Li, Zhuo; Liu, Yong

    2016-06-01

    We report a passively Q-switched Tm3+-doped fiber laser using a black phosphorus deposited micro-fiber (BPDMF) as a saturable absorption (SA) device for the first time. The BPDMF prepared by depositing black phosphorus (BP) on the micro-fiber waist with heat convention effect and optical tweezer effect has a measured modulation depth of 40.2% and a nonsaturable loss of 55.9%. By employing this device in an all-fiber ring cavity, a stable Q-switched pulse train at 1948 nm was achieved with a repetition rate from 12.5 to 28.1 kHz and a pulse width from 15.1 to 5.6 μs, respectively.

  7. Lidar-radar velocimetry using a pulse-to-pulse coherent rf-modulated Q-switched laser.

    PubMed

    Vallet, M; Barreaux, J; Romanelli, M; Pillet, G; Thévenin, J; Wang, L; Brunel, M

    2013-08-01

    An rf-modulated pulse train from a passively Q-switched Nd:YAG laser has been generated using an extra-cavity acousto-optic modulator. The rf modulation reproduces the spectral quality of the local oscillator. It leads to a high pulse-to-pulse phase coherence, i.e., phase memory, over thousands of pulses. The potentialities of this transmitter for lidar-radar are demonstrated by performing Doppler velocimetry on indoor moving targets. The experimental results are in good agreement with a model based on elementary signal processing theory. In particular, we show experimentally and theoretically that lidar-radar is a promising technique that allows discrimination between translation and rotation movements. Being independent of the laser internal dynamics, this scheme can be applied to any Q-switched laser. PMID:23913058

  8. Tunable Q-switched fiber laser based on saturable edge-state absorption in few-layer molybdenum disulfide (MoS₂).

    PubMed

    Woodward, R I; Kelleher, E J R; Howe, R C T; Hu, G; Torrisi, F; Hasan, T; Popov, S V; Taylor, J R

    2014-12-15

    We fabricate a few-layer molybdenum disulfide (MoS₂) polymer composite saturable absorber by liquid-phase exfoliation, and use this to passively Q-switch an ytterbium-doped fiber laser, tunable from 1030 to 1070 nm. Self-starting Q-switching generates 2.88 μs pulses at 74 kHz repetition rate, with over 100 nJ pulse energy. We propose a mechanism, based on edge states within the bandgap, responsible for the wideband nonlinear optical absorption exhibited by our few-layer MoS₂ sample, despite operating at photon energies lower than the material bandgap. PMID:25607060

  9. Q-Switched Alexandrite Laser-induced Chrysiasis

    PubMed Central

    Victor Ross, E.

    2015-01-01

    Background: Chyriasis is an uncommon side effect that occurs in patients who are receiving prolonged treatment with either intravenous or intramuscular gold as a distinctive blue-gray pigmentation of light-exposed skin. Laser-induced chrysiasis is a rarely described phenomenon in individuals who have received systemic gold and are subsequently treated with a Q-switched laser. Purpose: To describe the characteristics of patients with laser-induced chrysiasis. Methods: The authors describe a 60-year-old woman who developed chrysiasis at Q-switched alexandrite laser treatment sites. They also reviewed the medical literature using PubMed, searching the terms chrysiasis, gold, and laser-induced. Patient reports and previous reviews of these subjects were critically assessed and the salient features are presented. Results: Including the authors’ patient, laser-induced chrysiasis has been described in five Caucasian arthritis patients (4 women and 1 man); most of the patients had received more than 8g of systemic gold therapy during a period of 3 to 13 years. Gold therapy was still occurring or had been discontinued as long as 26 years prior to laser treatment. All of the patients immediately developed blue macules at the Q-switched laser treatment site. Resolution of the dyschromia occurred in a 70-year-old woman after two treatment sessions with a long-pulsed ruby laser and the authors’ patient after a sequential series of laser sessions using a long-pulsed alexandrite laser, followed by a nonablative fractional laser and an ablative carbon dioxide laser. Conclusion: Laser-induced chrysiasis has been observed following treatment with Q-switched lasers in patients who are receiving or have previously been treated with systemic gold. It can occur decades after treatment with gold has been discontinued. Therefore, inquiry regarding a prior history of treatment with gold—particularly in older patients with arthritis—should be considered prior to treatment with a Q-switched

  10. Self-mode-locked chromium-doped forsterite laser generates 50-fs pulses

    NASA Technical Reports Server (NTRS)

    Seas, A.; Petricevic, V.; Alfano, R. R.

    1993-01-01

    Stable transform-limited (delta nu-delta tau = 0.32) femtosecond pulses with a FWHM of 50 fs were generated from a self-mode-locked chromium-doped forsterite laser. The forsterite laser was synchronously pumped by a CW mode-locked Nd:YAG (82 MHz) laser that generated picosecond pulses (200-300 ps) and provided the starting mechanism for self-mode-locked operation. Maximum output power was 45 mW for 3.9 W of absorbed pumped power with the use of an output coupler with 1 percent transmission. The self-mode-locked forsterite laser was tuned from 1240 to 1270 nm.

  11. Development and commercialization of mode-locked VECSELs

    NASA Astrophysics Data System (ADS)

    Hempler, Nils; Bialkowski, Bartlomiej; Hamilton, Craig J.; Maker, Gareth T.; Malcolm, Graeme P. A.

    2015-03-01

    This paper will describe the current state-of-the-art in commercial mode-locked Vertical External Cavity Surface Emitting Lasers (VECSEL) and demonstrate their efficacy in key applications. Based on indium gallium arsenide quantum well gain structures, our systems operate between 920 nm - 1050 nm with >1 W output powers, 200 MHz pulse repetition rate and <1 ps pulse duration. Crucially, the development issues that have been overcome to bring this promising technology to market will be discussed. These include: thermal management challenges, electronic control system development and robust mechanical design requirements. Having the potential to replace more conventional titanium sapphire laser technology where wavelength flexibility can be traded off against a significantly lower cost point and form factor, we will discuss the use of VECSELs in key applications such as nonlinear microscopy.

  12. Dual mode-locked swept sources for SS-OCT

    NASA Astrophysics Data System (ADS)

    Stancu, Radu F.; Podoleanu, Adrian G.

    2016-03-01

    A novel dual-mode-locking mechanism was developed in order to tune an akinetic swept source (AKSS) based on dispersive cavity at a repetition rate close to, but slightly different from the inverse of the cavity roundtrip. Several optical source configurations emitting in the 1060 nm or 1550 nm wavelength region were developed, characterized and tested in OCT applications. For the 1550 nm swept source employing a Faraday rotating mirror in a dispersive cavity, sweeping rates in the range of MHz were achieved, from 782 kHz to up to 5 times this value, with proportional decrease in the tuning bandwidth. Linewidths smaller than 60 pm and output powers exceeding a few mW were measured. The 1060 nm swept source implemented was used to generate OCT images of a pressure sensitive adhesive.

  13. Mode-locked frequency doubled Nd:YAG laser

    NASA Technical Reports Server (NTRS)

    Brookman, J. S.

    1976-01-01

    The design, fabrication, test, and delivery of two mode-locked, frequency doubled Nd:YAG laser systems are described. Each system was comprised of two units, the laser head and optics on an Invar plate and the electronics control unit in a relay rack chassis panel. Laser number one operated at a repetition rate of 400 MHz and was designed for use in an optical communication system. Laser number two operated at 200 MHz repetition rate and was designed for optical ranging and target signature experiments. Both lasers had a pulse width of 200 ps at the 10% amplitude points at 1.064 micrometer wavelength (150 ps at 0.532 micrometers) with an amplitude stability of + or - 4%. Output power exceeded the design goals.

  14. Broadband Fourier-domain mode-locked lasers

    NASA Astrophysics Data System (ADS)

    Hsu, Kevin; Meemon, Panomsak; Lee, Kye-Sung; Delfyett, Peter J.; Rolland, Jannick P.

    2011-09-01

    Broadband, high-speed wavelength-swept lasers can substantially enhance applications in optical coherence tomography, chemical spectroscopy, and fiber-optic sensing. We report the demonstration of Fourier-domain mode-lock lasers operating at about 90 kHz effective sweep rate over a 158 nm sweep range using a single-band design and over a 284 nm sweep range across the 1.3 μm to 1.5 μm wavelength spectrum using a unique broadband design. A novel dual-detection full-range Fourier-domain optical coherence tomography system is developed which provides 7 μm axial resolution (in air) at about 90 kHz axial scan rate for mirror-image resolved Doppler imaging in a human finger and an African frog tadpole.

  15. Mode-locked Cr4+: YAG laser: model and experiment

    NASA Astrophysics Data System (ADS)

    Theimer, J.; Hayduk, M.; Krol, M. F.; Haus, J. W.

    1997-02-01

    A mode-locked Cr 4+:YAG laser was simulated using a complex Landau-Ginzburg equation. The pulse widths and spectrum were determined as a function of laser tuning over a range from 1470 nm to 1550 nm. Simulations exhibit the same trend as the experimental data and the magnitudes are in reasonable agreement, as well. We are able to analytically estimate the pulse width, which is controlled by the cavity dispersion and the pulse energy. We find that the absorber saturation is responsible for determining the pulse energies. The experimentally observed pulse widths widen for long wavelengths; our simulations attribute this to dispersion and to a wavelength-dependent reduction of the saturable absorber modulation combined with the effect of gain saturation.

  16. Tm:germanate Fiber Laser: Tuning And Q-switching

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; Walsh, Brian M.; Reichle, Donald J.; DeYoung, R. J.; Jiang, Shibin

    2007-01-01

    A Tm:germanate fiber laser produced >0.25 mJ/pulse in a 45 ns pulse. It is capable of producing multiple Q-switched pulses from a single p ump pulse. With the addition of a diffraction grating, Tm:germanate f iber lasers produced a wide, but length dependent, tuning range. By s electing the fiber length, the tuning range extends from 1.88 to 2.04 ?m. These traits make Tm:germanate lasers suitable for remote sensin g of water vapor.

  17. Effects of axial nonuniformity in modeling Q-switched lasers

    SciTech Connect

    Stone, D.H. )

    1992-10-01

    Generic Q-switched laser pulses are calculated using a point model and a traveling wave model. Results indicate that the point model approach commonly used in rate equation modeling is inadequate for large initial inversions, large internal losses, or large fractional outcoupling. The point model typically overestimates peak power and energy and distorts the pulse shape. A simple traveling wave model is developed which easily describes these cases. The optimum outcoupling to maximize peak power varies significantly between the two models. 9 refs.

  18. 1.55-μm mode-locked quantum-dot lasers with 300 MHz frequency tuning range

    SciTech Connect

    Sadeev, T. Arsenijević, D.; Bimberg, D.; Franke, D.; Kreissl, J.; Künzel, H.

    2015-01-19

    Passive mode-locking of two-section quantum-dot mode-locked lasers grown by metalorganic vapor phase epitaxy on InP is reported. 1250-μm long lasers exhibit a wide tuning range of 300 MHz around the fundamental mode-locking frequency of 33.48 GHz. The frequency tuning is achieved by varying the reverse bias of the saturable absorber from 0 to −2.2 V and the gain section current from 90 to 280 mA. 3 dB optical spectra width of 6–7 nm leads to ex-facet optical pulses with full-width half-maximum down to 3.7 ps. Single-section quantum-dot mode-locked lasers show 0.8 ps broad optical pulses after external fiber-based compression. Injection current tuning from 70 to 300 mA leads to 30 MHz frequency tuning.

  19. Orthogonally polarized bright-dark pulse pair generation in mode-locked fiber laser with a large-angle tilted fiber grating

    NASA Astrophysics Data System (ADS)

    Zhang, Zuxing; Mou, Chengbo; Yan, Zhijun; Sun, Zhongyuan; Zhang, Lin

    2016-06-01

    We report on the generation of orthogonally polarized bright-dark pulse pair in a passively mode-locked fiber laser with a large-angle tilted fiber grating (LA-TFG). The unique polarization properties of the LA-TFG, i.e., polarization-dependent loss and polarization-mode splitting, enable dual-wavelength mode-locking operation. Besides dual-wavelength bright pulses with uniform polarization at two different wavelengths, the bright-dark pulse pair has also been achieved. It is found that the bright-dark pulse pair is formed due to the nonlinear couplings between lights with two orthogonal polarizations and two different wavelengths. Furthermore, harmonic mode-locking of bright-dark pulse pair has been observed. The obtained bright-dark pulse pair could find potential use in secure communication system. It also paves the way to manipulate the generation of dark pulse in terms of wavelength and polarization, using specially designed fiber grating for mode-locking.

  20. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers

    NASA Astrophysics Data System (ADS)

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-04-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers.

  1. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers

    PubMed Central

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-01-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers. PMID:27126900

  2. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers.

    PubMed

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-01-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers. PMID:27126900

  3. Using a black phosphorus saturable absorber to generate dual wavelengths in a Q-switched ytterbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Rashid, F. A. A.; Azzuhri, Saaidal R.; Salim, M. A. M.; Shaharuddin, R. A.; Ismail, M. A.; Ismail, M. F.; Razak, M. Z. A.; Ahmad, H.

    2016-08-01

    Using a few-layer black phosphorus (BP) thin film that acts as a saturable absorber (SA) in an ytterbium-doped fiber laser setup, we experimentally demonstrated a passively dual-wavelength Q-switching laser operation. The setup also incorporated a D-shaped polished fiber as a wavelength selective filter. As the SA was used in the ring cavity, a dual-wavelength Q-switch produced consistent outputs at 1038.68 and 1042.05 nm. A maximum pulse energy of 2.09 nJ with a shortest pulse width of 1.16 µs was measured for the achieved pulses. In addition, the repetition rate increased from 52.52 to 58.73 kHz with the increment of the pump level. Throughout the measurement process, the results were obtained consistently and this demonstrates that the BP film is a very good candidate to produce Q-switching pulses for the 1 micron region.

  4. Kerr lens mode-locking of solid state lasers with thermal lensing

    SciTech Connect

    Huang, X.G.; Huang, F.R.; Yu, Z.X.; Lee, W.K.

    1996-12-31

    Aberrative nonlinear transfer matrices are introduced to treat the propagation of laser beam in Kerr medium with thermal lensing. The dependence of mode-locking regions on cavity symmetry and the distance between the fold mirror and the crystal, and the optimal arrangement for Kerr-lens mode-locking are discussed with ABCD matrix method.

  5. Mode-locking of thulium-doped and erbium-doped fiber lasers

    NASA Astrophysics Data System (ADS)

    Nelson, Lynn Elizabeth

    This thesis reports work on passive mode-locking of thulium-doped and erbium-doped fiber ring lasers using the technique of polarization additive pulse mode-locking (P-APM). A self-starting, mode-locked Tm+3-doped fiber laser was demonstrated with 360 to 500 fsec pulses tunable from 1.8 to 1.9 μm, the largest tuning range demonstrated from a rare-earth doped fiber. This laser operated in the soliton regime due to the large negative group-velocity dispersion (GVD) of the fiber at 1.8 μm. A possible application to optical coherence tomography on biomedical tissue was explored. A stretched-pulse Er+3-doped laser at 1.55 μm was optimized for the application of frequency-doubling to 775 nm where the pulses can be used as a seed for a Ti:Sapphire regenerative amplifier. This laser incorporated segments of fiber with positive and negative GVD to avoid operation in the soliton regime. Compressed fundamental pulses of 100 fsec and 2.7 nJ were obtained, and three nonlinear crystals, β- BaB2O4 (BBO), KNbO3 (potassium niobate), and LiB3O5 (LBO), were evaluated for frequency doubling. Near transform-limited pulses at 771 nm with average powers of 8.7 mW were obtained with a 1-cm BBO crystal, corresponding to conversion efficiencies of up to 10%. Frequency resolved optical gating (FROG) measurements were performed on both the fundamental and doubled pulses to better characterize the laser. The effect of linear birefringence on P-APM was explored through numerical simulations for the case of standard fibers, where the two are of the same order. Although reduced by the birefringence, pulse shaping still occurred and there was no inherent periodicity due to the fiber beat-length. Measurements of birefringence and temperature sensitivity of both standard and polarization maintaining (PM) fibers were also performed. Experimental work toward an environmentally stable Er+3-doped fiber laser included two different schemes. The first design was comprised of only PM-fiber, but stable

  6. Active mode locking of quantum cascade lasers in an external ring cavity.

    PubMed

    Revin, D G; Hemingway, M; Wang, Y; Cockburn, J W; Belyanin, A

    2016-01-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode-locked operation remains a challenge, despite dedicated effort. Here we report the demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents. PMID:27147409

  7. Active mode locking of quantum cascade lasers in an external ring cavity

    NASA Astrophysics Data System (ADS)

    Revin, D. G.; Hemingway, M.; Wang, Y.; Cockburn, J. W.; Belyanin, A.

    2016-05-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode-locked operation remains a challenge, despite dedicated effort. Here we report the demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents.

  8. Active mode locking of quantum cascade lasers in an external ring cavity

    PubMed Central

    Revin, D. G.; Hemingway, M.; Wang, Y.; Cockburn, J. W.; Belyanin, A.

    2016-01-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode-locked operation remains a challenge, despite dedicated effort. Here we report the demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents. PMID:27147409

  9. Repetitively Q-switched Nd:BeL lasers

    NASA Technical Reports Server (NTRS)

    Degnan, J.; Birnbaum, M.; Deshazer, L. G.

    1979-01-01

    The thermal and mechanical characteristics which will ultimately limit the performance of Nd:BeL at high average power levels were investigated. The output beam characteristics (pulse width, peak power, beam dimensions and collimation) were determined at high repetition rates for both Nd:BeL and Nd:YAG. The output of Nd:BeL was shown to exceed that of Nd:YAG by a factor of 2.7 at low Q-switched repetition rates (1 Hz). This result follows from the smaller stimulated emission cross section of x-axis Nb:BeL compared to that of NdYAG by the same factor. At high repetition rates (10 Hz) the output of Nd:Bel falls to a level of three-fifths of its low repetition rate value while under similar tests the output of Nd:YAG remains essentially constant. A comparison of the measured values of the elasto-optic coefficients, the dn/dT values and the linear expansion coefficients for BeL and YAG failed to provide an explanation for the performance of BeL; however, thermal lensing was observed in Nd:BeL. Results imply that the output of a high repetition rate Q-switched Nd:BeL laser (high thermal loading) could be dramatically increased by utilization of a resonator design to compensate for the thermal lensing effects.

  10. High order harmonic mode-locking in an all-normal-dispersion Yb-doped fiber laser with a graphene oxide saturable absorber

    NASA Astrophysics Data System (ADS)

    Huang, S. S.; Wang, Y. G.; Yan, P. G.; Zhang, G. L.; Zhao, J. Q.; Li, H. Q.; Lin, R. Y.

    2014-01-01

    A high order passive harmonic mode-locking (HML) Yb-doped all-normal-dispersion fiber laser based on a graphene oxide saturable absorber has been experimentally demonstrated. For two different pump powers and different polarization states of the laser cavity, lower order and higher order HML have been achieved. The highest 30th-order harmonic (31.86 MHz) was achieved with subnanosecond pulse duration; this is transitional from a bunched multipulse state.

  11. Diode-Pumped Mode-Locked LiSAF Laser

    SciTech Connect

    1996-02-01

    Under this contract we have developed Cr{sup 3+}:LiSrAlF{sub 6} (Cr:LiSAF, LiSAF) mode-locked lasers suitable for generation of polarized electrons for CEBAF. As 670 nm is an excellent wavelength for optical pumping of Cr:LiSAF, we have used a LIGHTWAVE developed 670 nm diode pump module that combines the output of ten diode lasers and yields approximately 2 Watts of optical power. By the use of a diffraction limited pump beam however, it is possible to maintain a small mode size through the length of the crystal and hence extract more power from Cr:LiSAF laser. For this purpose we have developed a 1 Watt, red 660nm laser (LIGHTWAVE model 240R) which serves as an ideal pump for Cr:LiSAF and is a potential replacement of costly and less robust krypton laser. This new system is to compliment LIGHTWAVE Series 240, and is currently being considered for commercialization. Partially developed under this contract is LIGHTWAVEs product model 240 which has already been in our production lines for a few months and is commercially available. This laser produces 2 Watts of output at 532 nm using some of the same technology developed for production of the 660nm red system. It is a potential replacement for argon ion lasers and has better current and cooling requirements and is an excellent pump source for Ti:Al{sub 2}O{sub 3}. Also, as a direct result of this contract we now have the capability of commercially developing a mode-locked 100MHz Cr:LiSAF system. Such a laser could be added to our 100 MHz LIGHTWAVE Series 131. The Series 131 lasers provide pico second pulses and were originally developed under another DOE SBIR. Both models of LIGHTWAVE Series 240 lasers, the fiber coupled pump module and the 100MHz LiSAF laser of Series 131 have been partially developed under this contract, and are commercially competitive products.

  12. Smart Q-switching for single-pulse generation in an erbium-doped fiber laser.

    PubMed

    Escalante-Zarate, Luis; Barmenkov, Yuri O; Kolpakov, Stanislav A; Cruz, José L; Andrés, Miguel V

    2012-02-13

    In this paper, we report an active Q-switching of an erbium-doped fiber laser with special modulation functions and novel laser geometry. We experimentally demonstrate that using such a smart Q-switch approach, Q-switch ripple-free pulses with Gaussian-like shape and 17.3 ns width can be easily obtained. The idea behind the smart Q-switch is to suppress one of two laser waves contra-propagating along the fiber cavity, which arises after Q-cell opening, and to eliminate the minor sub-pulses. PMID:22418199

  13. Phase stabilization of an actively mode-locked ring laser

    NASA Astrophysics Data System (ADS)

    Takada, Akira; Saika, Makoto; Nagano, Shigenori

    2015-03-01

    A phase-resolved system based on swept source optical coherence tomography (SS-OCT) has to incorporate a phase-stabilized wavelength-swept light source. The phase variation is induced by fluctuation of a beginning swept frequency. The conventional phase-sensitive SS-OCTs use a fiber Bragg grating (FBG) in order to avoid A-scan trigger fluctuations. However this method does not always solve the trigger fluctuation problem. In actively mode-locked ring lasers (AMLLs), the beginning swept frequency fluctuates by abrupt frequency change between the end of a sweep and the beginning of the subsequent one. To overcome this issue, we proposes a new phase stabilization method. By employing the method with an auxiliary reference configuration, the sweeping phase has successfully stabilized because the timing jitter is calculated by interference signals from the auxiliary reference path. In this research, we have proposed the phase stabilization method that has nanometer sensitivity with millisecond response. In addition, the method has successfully suppressed the depth dependence of phase instability.

  14. 456-mW graphene Q-switched Yb:yttria waveguide laser by evanescent-field interaction.

    PubMed

    Choudhary, Amol; Beecher, Stephen J; Dhingra, Shonali; D'Urso, Brian; Parsonage, Tina L; Grant-Jacob, James A; Hua, Ping; Mackenzie, Jacob I; Eason, Robert W; Shepherd, David P

    2015-05-01

    In this Letter, we present a passively Q-switched Yb:Y2O3 waveguide laser using evanescent-field interaction with an atmospheric-pressure-chemical-vapor-deposited graphene saturable absorber. The waveguide, pumped by a broad area diode laser, produced an average output power of 456 mW at an absorbed power of 4.1 W. The corresponding pulse energy and peak power were 330 nJ and 2 W, respectively. No graphene damage was observed, demonstrating the suitability of top-deposited graphene for high-power operation. PMID:25927746

  15. 0.7 MW output power from a two-arm coherently combined Q-switched photonic crystal fiber laser.

    PubMed

    Rosenstein, Boris; Shirakov, Avry; Belker, Daniel; Ishaaya, Amiel A

    2014-03-24

    We demonstrate a high peak power, Q-switched pulsed, intracavity coherently combined fiber laser system. The system is based on two Yb-doped, rod-type, photonic crystal fibers which are passively phase-locked and combined into the single output beam in a power oscillator configuration. Experimental evidence indicate that this oscillator system provides record high peak power of ∼ 0.7 MW with pulse duration of ∼ 10 ns at 1 kHz repetition rate. The measured beam quality shows near-diffraction-limited operation of the coherently combined system. PMID:24663989

  16. Diode-Pumped, Q-Switched, Frequency-Doubling Laser

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Lesh, James R.

    1993-01-01

    Experimental Q-switched, diode-pumped, intracavity-frequency-doubling laser generates pulses of radiation at wavelength of 532 nm from excitation at 810 nm. Principal innovative feature distinguishing laser from others of its type: pulsed operation of laser at pulse-repetition frequencies higher than reported previously. Folded resonator keeps most of second-harmonic radiation away from Q-switcher, laser crystal, and laser diodes. Folding mirror highly reflective at fundamental laser wavelength and highly transmissive at second-harmonic laser wavelength. By virtue of difference of about 0.6 percent between reflectivities in two polarizations at fundamental wavelength, folding mirror favors polarized oscillation at fundamental wavelength. This characteristic desirable for doubling of frequency in some intracavity crystals.

  17. Theory of the optimally coupled Q-switched laser

    NASA Technical Reports Server (NTRS)

    Degnan, John J.

    1989-01-01

    The general equations describing Q-switched laser operation are transcendental in nature and require numerical solutions, which greatly complicates the optimization of real devices. Here, it is shown that, using the mathematical technique of Lagrange multipliers, one can derive simple analytic expressions for all of the key parameters of the optimally coupled laser, i.e., one which uses an optimum reflector to obtain maximum laser efficiency for a given pump level. These parameters can all be expressed as functions of a single dimensionless variable z, defined as the ratio of the unsaturated small-signal gain to the dissipative (nonuseful) optical loss, multiplied by a few simple constants. Laser design tradeoff studies and performance projections can be accomplished quickly with the help of several graphs and a simple hand calculator. Sample calculations for a high-gain Nd:YAG and a low-gain alexandrite laser are presented as illustrations of the technique.

  18. Observation of spectral broadening in a commercial modelocked and Q-switched Nd:YLF oscillator - Wegner`s Demon

    SciTech Connect

    Wegner, P.; Feit, M.

    1994-09-14

    We have observed spectral broadening in the pulsed output of a Quantronix model 4217 modelocked and Q-switched Nd:YLF oscillator. When Q-switched, the 76-1MHz oscillator produces a nearly gaussian train of pulses with a total energy of 3 mJ and a duration of {approximately}300 ns. Between Q-switch cycles the CW-pumped oscillator lases at a low level to enable a circulating modelocked pulse to reach steady-state transform-limited conditions. With a 1-mm intracavity etalon the steady-state modelocked pulsewidth is 150 ps and the oscillating bandwidth is 3 GHz. Measurements show that at the peak of the Q-switched train the modelocked pulse bandwidth is broadened to 11 GHz, We attribute the altered spectrum to self-phase modulation (SPM) of the circulating pulse in the 3.8-cm long acousto-optic quartz modulators. SPM has been recognized as a potential problem in this type of oscillator however we did not expect to find it in a commercial product and its occurrence in the modulators rather than the rod was a surprise. Analysis of the cavity mode has determined that the spot size is small at the ends of the cavity where the modulators are located. A large mode volume in the rod coupled with a relatively small nonlinear coefficient makes intensity-dependent: phase shifts there negligible by comparison. Since the effects of SPM in this type of oscillator are not well-documented we developed a numerical model and used it to examine the spectral evolution of the circulating modelocked pulse after Q-switching. The model incorporates a rod with gain, two passive quartz blocks with nonlinear refractive index for simulating nonlinear propagation in the modulators, a time-dependent shutter to simulate the active modelocker, an etalon, and distributed Fresnel losses. The spectra that we calculate are in good agreement with that observed, confirming the source of the broadening. The oscillator has been redesigned to increase the mode size in the modulators and eliminate the SPM.

  19. Diode-pumped Kerr-lens mode-locked Yb: GSO laser generating 72 fs pulses

    NASA Astrophysics Data System (ADS)

    Tian, Wenlong; Wang, Zhaohua; Zhu, Jiangfeng; Zheng, Lihe; Xu, Xiaodong; Xu, Jun; Wei, Zhiyi

    2016-05-01

    The generation of 72 fs hyperbolic secant pulses centered at 1050 nm with 17.8 nm bandwidth from a diode pumped Kerr-lens mode-locked Yb: GSO laser is demonstrated. With the help of a semiconductor saturable absorber mirror, stable mode-locking with an average output power of 85 mW at a repetition rate of 113 MHz is realized. To the best of our knowledge, this is the first demonstration of Kerr-lens mode-locking in Yb: GSO laser.

  20. Widely tunable Tm-doped mode-locked all-fiber laser

    PubMed Central

    Yan, Zhiyu; Sun, Biao; Li, Xiaohui; Luo, Jiaqi; Shum, Perry Ping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2016-01-01

    We demonstrated a widely tunable Tm-doped mode-locked all-fiber laser, with the widest tunable range of 136 nm, from 1842 to 1978 nm. Nonlinear polarization evolution (NPE) technique is employed to enable mode-locking and the wavelength-tunable operation. The widely tunable range attributes to the NPE-induced transmission modulation and bidirectional pumping mechanism. Such kind of tunable mode-locked laser can find various applications in optical communications, spectroscopy, time-resolved measurement, and among others. PMID:27263655

  1. Mode-locking dynamics of hair cells of the inner ear.

    PubMed

    Fredrickson-Hemsing, Lea; Ji, Seung; Bruinsma, Robijn; Bozovic, Dolores

    2012-08-01

    We explore mode locking of spontaneous oscillations of saccular hair cell bundles to periodic mechanical deflections. A simple dynamic systems framework is presented that captures the main features of the experimentally observed behavior in the form of an Arnold tongue. We propose that the phase-locking transition can proceed via different bifurcations. At low stimulus amplitudes F, the transition to mode locking as a function of the stimulus frequency ω has the character of a saddle-node bifurcation on an invariant circle. At higher stimulus amplitudes, the mode-locking transition has the character of a supercritical Andronov-Hopf bifurcation. PMID:23005793

  2. Mode-Locking Dynamics of Hair Cells of the Inner Ear

    PubMed Central

    Fredrickson-Hemsing, Lea; Ji, Seung; Bruinsma, Robijn; Bozovic, Dolores

    2012-01-01

    We explore mode-locking of spontaneous oscillations of saccular hair cell bundles to periodic mechanical deflections. A simple dynamic systems framework is presented that captures the main features of the experimentally observed behavior in the form of an Arnold Tongue. We propose that the phase-locking transition can proceed via different bifurcations. At low stimulus amplitudes F, the transition to mode-locking as a function of the stimulus frequency ω has the character of a saddle-node bifurcation on an invariant circle. At higher stimulus amplitudes, the mode-locking transition has the character of a supercritical Andronov-Hopf bifurcation. PMID:23005793

  3. A wide bandwidth free-electron laser with mode locking using current modulation.

    SciTech Connect

    Kur, E.; Dunning, D. J.; McNeil, B. W. J.; Wurtele, J.; Zholents, A. A. )

    2011-01-20

    A new scheme for mode locking a free-electron laser amplifier is proposed based on electron beam current modulation. It is found that certain properties of the original concept, based on the energy modulation of electrons, are improved including the spectral brightness of the source and the purity of the series of short pulses. Numerical comparisons are made between the new and old schemes and between a mode-locked free-electron laser and self-amplified spontaneous emission free-electron laser. Illustrative examples using a hypothetical mode-locked free-electron laser amplifier are provided. The ability to generate intense coherent radiation with a large bandwidth is demonstrated.

  4. Widely tunable Tm-doped mode-locked all-fiber laser.

    PubMed

    Yan, Zhiyu; Sun, Biao; Li, Xiaohui; Luo, Jiaqi; Shum, Perry Ping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2016-01-01

    We demonstrated a widely tunable Tm-doped mode-locked all-fiber laser, with the widest tunable range of 136 nm, from 1842 to 1978 nm. Nonlinear polarization evolution (NPE) technique is employed to enable mode-locking and the wavelength-tunable operation. The widely tunable range attributes to the NPE-induced transmission modulation and bidirectional pumping mechanism. Such kind of tunable mode-locked laser can find various applications in optical communications, spectroscopy, time-resolved measurement, and among others. PMID:27263655

  5. Mode-locking dynamics of hair cells of the inner ear

    NASA Astrophysics Data System (ADS)

    Fredrickson-Hemsing, Lea; Ji, Seung; Bruinsma, Robijn; Bozovic, Dolores

    2012-08-01

    We explore mode locking of spontaneous oscillations of saccular hair cell bundles to periodic mechanical deflections. A simple dynamic systems framework is presented that captures the main features of the experimentally observed behavior in the form of an Arnold tongue. We propose that the phase-locking transition can proceed via different bifurcations. At low stimulus amplitudes F, the transition to mode locking as a function of the stimulus frequency ω has the character of a saddle-node bifurcation on an invariant circle. At higher stimulus amplitudes, the mode-locking transition has the character of a supercritical Andronov-Hopf bifurcation.

  6. Widely tunable Tm-doped mode-locked all-fiber laser

    NASA Astrophysics Data System (ADS)

    Yan, Zhiyu; Sun, Biao; Li, Xiaohui; Luo, Jiaqi; Shum, Perry Ping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2016-06-01

    We demonstrated a widely tunable Tm-doped mode-locked all-fiber laser, with the widest tunable range of 136 nm, from 1842 to 1978 nm. Nonlinear polarization evolution (NPE) technique is employed to enable mode-locking and the wavelength-tunable operation. The widely tunable range attributes to the NPE-induced transmission modulation and bidirectional pumping mechanism. Such kind of tunable mode-locked laser can find various applications in optical communications, spectroscopy, time-resolved measurement, and among others.

  7. Terahertz radiation using log-spiral-based low-temperature-grown InGaAs photoconductive antenna pumped by mode-locked Yb-doped fiber laser.

    PubMed

    Kong, Moon Sik; Kim, Ji Su; Han, Sang Pil; Kim, Namje; Moon, Kiwon; Park, Kyung Hyun; Jeon, Min Yong

    2016-04-01

    We demonstrate a terahertz (THz) radiation using log-spiral-based low-temperature-grown (LTG) InGaAs photoconductive antenna (PCA) modules and a passively mode-locked 1030 nm Yb-doped fiber laser. The passively mode-locked Yb-doped fiber laser is easily implemented with nonlinear polarization rotation in the normal dispersion using a 10-nm spectral filter. The laser generates over 250 mW of the average output power with positively chirped 1.58 ps pulses, which are dechirped to 127 fs pulses using a pulse compressor outside the laser cavity. In order to obtain THz radiation, a home-made emitter and receiver constructed from log-spiral-based LTG InGaAs PCA modules were used to generate and detect THz signals, respectively. We successfully achieved absorption lines over 1.5 THz for water vapor in free space. Therefore, we confirm that a mode-locked Yb-doped fiber laser has the potential to be used as an optical source to generate THZ waves. PMID:27136997

  8. Compact self-Q-switched green upconversion Er:ZBLAN all-fiber laser operating at 543.4  nm.

    PubMed

    Luo, Zhengqian; Ruan, Qiujun; Zhong, Min; Cheng, Yongjie; Yang, Runhua; Xu, Bin; Xu, Huiying; Cai, Zhiping

    2016-05-15

    We report the demonstration of a compact self-Q-switched green upconversion Er3+:ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber laser operating at 543.4 nm. The all-fiber green laser simply consists of a 45 cm high-concentration Er3+:ZBLAN fiber, a 976 nm pump source, and a pair of fiber end-facet mirrors. Under the strong excitation of the 976 nm pump laser, green upconversion lasing at 543.4 nm is achieved from the compact Er3+:ZBLAN fiber laser. Interestingly, the green laser exhibits stable self-Q-switching operation. As the 976 nm pump power is increased, the pulse repetition rate linearly increases from 25.9 to 50.8 kHz and the pulse width narrows from 7.2 to 1.95 μs. The Q-switched green laser has a pump threshold of 118 mW and a maximum output power of 6.9 mW with a slope efficiency of 30%. This is, to the best of our knowledge, the shortest-wavelength operation of a self-started or passively Q-switched fiber laser. PMID:27176977

  9. Q-switched 2 μm thulium bismuth co-doped fiber laser with multi-walled carbon nanotubes saturable absorber

    NASA Astrophysics Data System (ADS)

    Saidin, N.; Zen, D. I. M.; Ahmad, F.; Haris, H.; Ahmad, H.; Dimyati, K.; Harun, S. W.; Halder, A.; Paul, M. C.; Pal, M.; Bhadra, S. K.

    2016-09-01

    We report a passively Q-switched fiber laser operating at 1900 nm region using the newly developed thulium bismuth co-doped lithium-alumino-germano-silicate fiber (TBF) as a gain medium in conjunction with a multiwall carbon nanotubes (MWCNTs) based saturable absorber (SA). The TBF and MWCNTs are fabricated and prepared in-house. By increasing the 802 nm pump power from 106.6 to 160 mW, stable generation of Q-switched TBFL has been obtained at 1857.8 nm wavelength. The pulse repetition rate varies from 12.84 to 29.48 kHz while pulse width is increased from 9.6 to 6.1 μs. The performance of the laser is also compared with the Q-switched TDFL, which was obtained using a similar MWCNTs SA and pump wavelength. The Q-switched TDFL generates an optical pulse train with a repetition rate increasing from 3.8 to 4.6 kHz and pulse width reducing from 22.1 to 18.3 μs when the pump power is tuned from 187.3 to 194.2 mW. This shows that the TBFL performs better than the TDFL in terms of threshold pump power, repetition rate and pulse width.

  10. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    SciTech Connect

    Sotor, J. Sobon, G.; Abramski, K. M.; Jagiello, J.; Lipinska, L.

    2015-04-07

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (F{sub rep}) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest F{sub rep} was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  11. Thulium-doped all-fiber mode-locked laser based on NPR and 45°-tilted fiber grating.

    PubMed

    Li, Jianfeng; Yan, Zhijun; Sun, Zhongyuan; Luo, Hongyu; He, Yulian; Li, Zhuo; Liu, Yong; Zhang, Lin

    2014-12-15

    A nonlinear polarization rotation based all-fiber passively mode-locked Tm³⁺-doped fiber laser is demonstrated by using a 45° tilted fiber grating (TFG) as an in-line polarizer. The 45° TFG centered at 2000 nm with polarization dependent loss (PDL) of >12 dB at 1850 nm~2150 nm range was UV inscribed for the first time in SM28 fiber using a 244 nm Ar⁺ continuous wave laser and a phase mask with 25 mm long uniform pitch and titled period pattern of 33.7° with respect to the fiber axis. Stable soliton pulses centered at 1992.7 nm with 2.02 nm FWHM bandwidth were produced at a repetition rate of 1.902 MHz with pulse duration of 2.2 ps and pulse energy of 74.6 pJ. As increased pump power, the laser also can operate at noise-like regime with 18.1 nm FWHM bandwidth and pulse energy of up to 250.1 nJ. Using the same 45° TFG, both stable soliton and noise-like mode-locking centered at ~1970 nm and ~2050 nm, were also achieved by shortening and extending the length of Tm³⁺-doped fiber, respectively, exhibiting advantages of broadband and low insertion loss at 2 µm band. PMID:25607051

  12. Mode-locked, 1.94-μm, all-fiberized laser using WS₂ based evanescent field interaction.

    PubMed

    Jung, Minwan; Lee, Junsu; Park, June; Koo, Joonhoi; Jhon, Young Min; Lee, Ju Han

    2015-07-27

    We demonstrate the use of an all-fiberized, mode-locked 1.94 μm laser with a saturable absorption device based on a tungsten disulfide (WS2)-deposited side-polished fiber. The WS2 particles were prepared via liquid phase exfoliation (LPE) without centrifugation. A series of measurements including Raman spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) revealed that the prepared particles had thick nanostructures of more than 5 layers. The prepared saturable absorption device used the evanescent field interaction mechanism between the oscillating beam and WS2 particles and its modulation depth was measured to be ~10.9% at a wavelength of 1925 nm. Incorporating the WS2-based saturable absorption device into a thulium-holmium co-doped fiber ring cavity, stable mode-locked pulses with a temporal width of ~1.3 ps at a repetition rate of 34.8 MHz were readily obtained at a wavelength of 1941 nm. The results of this experiment confirm that WS2 can be used as an effective broadband saturable absorption material that is suitable to passively generate pulses at 2 μm wavelengths. PMID:26367658

  13. Carbon nanotube-based mode-locked wavelength-switchable fiber laser via net gain cross section alteration

    NASA Astrophysics Data System (ADS)

    Latif, A. A.; Mohamad, H.; Abu Bakar, M. H.; Muhammad, F. D.; Mahdi, M. A.

    2016-02-01

    We have proposed and demonstrated a carbon nanotube-based mode-locked erbium-doped fiber laser with switchable wavelength in the C-band wavelength region by varying the net gain cross section of erbium. The carbon nanotube is coated on a tapered fiber to form the saturable absorber for the purpose of mode-locking by exploiting the concept of evanescent field interaction on the tapered fiber with the carbon nanotube in a ring cavity configuration. The propagation loss is adjusted by inducing macrobend losses of the optical fiber in the cavity through a fiber spooling technique. Since the spooling radius can be gradually adjusted to achieve continuous tuning of attenuation, this passive tuning approach can be an alternative to optical tunable attenuator, with freedom of external device integration into the laser cavity. Based on this alteration, the net gain cross section of the laser system can be tailored to three different lasing wavelength ranges; 1533, 1560 nm and both (1533 and 1560 nm) with the minimum pulse duration of 734 fs. The proposed design is simple and stable with high beam quality and good reliability for multiple applications.

  14. Cascaded mode-locking of a spectrally controlled Yb:KYW laser

    NASA Astrophysics Data System (ADS)

    Meiser, Niels; Seger, Kai; Pasiskevicius, Valdas; Zukauskas, Andrius; Canalias, Carlota; Laurell, Fredrik

    2014-08-01

    Self-starting and stable mode-locking of an Yb:KYW laser in the picoseconds pulse regime has been achieved by exploiting a positive cascaded Kerr lens in periodically poled KTP. The use of a volume Bragg grating (VBG), for locking the output spectrum of the laser, was essential to achieve a stable mode-locked operation in this wide gain bandwidth laser material. The laser emitted stable, nearly transform-limited pulses with a duration of 16 ps, at a repetition rate of 210 MHz, and with an energy of 3.2 nJ. The mode-locked spectrum was centred at 1,029.1 nm and featured a FWHM bandwidth of 85 pm, which was effectively determined by the VBG. Combination of a large cascaded Kerr nonlinearity with spectral limiting by a VBG represents so far the best opportunity for stable mode-locking of a broadband laser to produce near-transform-limited picosecond pulses.

  15. Pulse dynamics in carbon nanotube mode-locked fiber lasers near zero cavity dispersion.

    PubMed

    Wang, Jinzhang; Cai, Zhiping; Xu, Ping; Du, Geguo; Wang, Fengqiu; Ruan, Shuangchen; Sun, Zhipei; Hasan, Tawfique

    2015-04-20

    We numerically and experimentally analyze the output characteristics and pulse dynamics of carbon nanotube mode-locked fiber lasers near zero cavity dispersion (from 0.02 to ~-0.02 ps(2)). We focus on such near zero dispersion cavities to reveal the dispersion related transition between different mode-locking regimes (such as soliton-like, stretched-pulse and self-similar regimes). Using our proposed model, we develop a nanotube-mode-locked fiber laser setup generating ~97 fs pulse which operates in the stretched-pulse regime. The corresponding experimental results and pulse dynamics are in good agreement with the numerical results. Also, the experimental results from soliton-like and self-similar regimes exhibit the same trends with simulations. Our study will aid design of different mode-locking regimes based on other new saturable absorber materials to achieve ultra-short pulse duration. PMID:25969036

  16. Method and apparatus for detection and control of prelasing in a Q-switched laser

    NASA Technical Reports Server (NTRS)

    Lockard, George E. (Inventor)

    1994-01-01

    The present invention detects prelasing in a Q-switch laser and terminates laser operation upon such detection. A detector senses the presence of light beyond a Q-switch and generates an appropriate electrical signal. A comparison stage circuit compares this detector signal with an established threshold value indicative of prelasing and generates a trigger signal if this detector signal exceeds this threshold value. A control stage circuit receives both this trigger value and a sampled Q-switch signal indicative of an opening of the Q-switch. The control stage circuit terminates operation of the laser if the trigger signal from the comparison stage is received while the sampled Q-switch signal is being received to avoid the effects of prelasing. Appropriate delays and timing sequences are established.

  17. Q-switched fiber laser based on an acousto-optic modulator with injection seeding technique.

    PubMed

    Li, Wencai; Liu, Haowei; Zhang, Ji; Long, Hu; Feng, Sujuan; Mao, Qinghe

    2016-06-10

    The operation mechanism and the pulse property of an actively Q-switched erbium-doped fiber laser based on an acousto-optic modulator (AOM) switch with the injection seeding technique are investigated. Our results show that the Q-switched pulses can be locked to oscillate near a fixed frequency higher than that of the seed laser, though the frequency-shift effect of the AOM impedes stable cavity mode oscillations. The operation mechanism of such Q-switch fiber lasers can be explained by the mutual locking-in among the shifted frequency components originated from the injected coherence seed with the help of the gain dynamics of the Q-switch cavity. Moreover, narrow-linewidth Q-switched pulses with different repetition rates can be obtained with different cavity lengths for incredibly stable output pulses without any use of cavity-stabilized techniques. PMID:27409015

  18. Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements.

    PubMed

    Olivier, Michel; Gagnon, Marc-Daniel; Habel, Joé

    2016-01-01

    When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques. PMID:26967924

  19. Mode locking of diode- and flashlamp-pumped Nd:YAG lasers using semiconductor saturable absorbers

    NASA Astrophysics Data System (ADS)

    Dombrovsky, Andrej; Kubecek, Vaclav; Zvonicek, K.; Diels, Jean-Claude M.; Stintz, Andreas

    2003-07-01

    Operation of laser diode and flash lamp pumped Nd:YAG lasers mode locked with two different types of semiconductor saturable absorbers is reported. In the first type that is used mainly in diode pumped systems the absorber layers are integrated on highly reflective Bragg mirror. The second type is for use in transmission mode inside the resonator. Different design of semiconductor elements, pumping geometries and resonator configurations were investigated and characteristics of laser operation in mode-locked regime are presented.

  20. Intermode beating mode-locking technique for O-band mixed-cascaded Raman fiber lasers.

    PubMed

    Luo, Zhengqian; Zhong, Min; Xiong, Fengfu; Wu, Duanduan; Huang, Yizhong; Li, Yingyue; Le, Lili; Xu, Bin; Xu, Huiying; Cai, Zhiping

    2015-02-15

    A novel intermode beating mode-locking (IBML) technique combined with a cascaded Raman process is proposed to mode-lock an O-band two-cascaded Raman fiber laser. Using a 980-m-long phosphosilicate fiber pumped by a 1064 nm laser, the second-order Raman oscillation at 1319 nm is generated by the mixed-cascaded Raman shifts of P2O5 and SiO2. By precisely matching the intermode beating frequencies of the 1064 nm pump laser and the second-order Raman cavity frequency, harmonic mode-locking at 1319 nm is initiated. The dynamic process of the IBML operation in the cascaded Raman laser is experimentally investigated. The 131st-order harmonic mode-locking with a repetition rate of 27.247 MHz is very stable with the radio-frequency (RF) signal-to-noise ratio of >56  dB and the RF supermode-suppression ratio of >43  dB. The mode-locked pulses with the square profile are confirmed as the noise-like pulses by an autocorrelator. The IBML technique, in combination with the cascaded Raman process, could offer an exciting new prospect for obtaining simple, compact, and arbitrary-wavelength mode-locked laser sources. PMID:25680135