Comparative study of Nd:KGW lasers pumped at 808 nm and 877 nm

NASA Astrophysics Data System (ADS)

Huang, Ke; Ge, Wen-Qi; Zhao, Tian-Zhuo; He, Jian-Guo; Feng, Chen-Yong; Fan, Zhong-Wei

2015-10-01

The laser performance and thermal analysis of Nd:KGW laser continuously pumped by 808 nm and 877 nm are comparatively investigated. Output power of 670 mW and 1587 mW, with nearly TEM00 mode, are achieved respectively at 808 nm pump and 877 nm pump. Meanwhile, a high-power passively Q-switched Nd:KGW/Cr4+:YAG laser pumped at 877 nm is demonstrated. An average output power of 1495 mW is obtained at pump power of 5.22 W while the laser is operating at repetition of 53.17 kHz. We demonstrate that 877 nm diode laser is a more potential pump source for Nd:KGW lasers.

Diode-pumped dual-wavelength Nd:LSO laser at 1059 and 1067  nm with nearly diffraction-limited beam quality.

PubMed

Huang, Xiaoxu; Lan, Jinglong; Lin, Zhi; Wang, Yi; Xu, Bin; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Zhang, Jian; Xu, Jun

2016-04-10

We report a diode-pumped continuous-wave simultaneous dual-wavelength Nd:LSO laser at 1059 and 1067 nm. By employing a specially coated output coupler with relatively high transmissions at high-gain emission lines of 1075 and 1079 nm, the two low-gain emission lines, 1059 and 1067 nm, can be achieved, for the first time to our knowledge, with maximum output power of 1.27 W and slope efficiency of about 29.2%. The output power is only limited by the available pump power. Output beam quality is also measured to be about 1.19 and 1.21 of the beam propagation factors in the x and y directions, respectively.

Power scaling of diode-pumped neodymium yttrium aluminum borate laser

NASA Technical Reports Server (NTRS)

Hemmati, Hamid

1991-01-01

Preliminary results are presented of the efficient diode-pumped operation of a neodymium yttrium aluminum borate (NYAB) laser at 531.5 nm using two 1-W diode-laser arrays for the pump. With 1380 mW of CW power incident on the crystal, as much as 51 mW of 532.5-nm laser radiation was obtained with the unoptimized cavity. The corresponding optical-to-optical conversion efficiency was 3.7 percent. A plot of the output 531.5 nm vs incident 807 nm pump power is shown. The crystal output power was critically dependent on the rotational and translational adjustment of the NYAB crystal inside the cavity. It is suggested that a crystal cut at the exact phase matching angle, placed in a cavity with proper optimal reflection and transmission mirror coatings, and pumped at proper wavelength can result in higher output power. Thus, the NYAB output power approaches that of a CW intracavity frequency doubled Nd:YAG laser.

The effects of TGG crystal length on output power and beam quality of a unidirectional ring Nd:YVO4 laser with and without second harmonic generation

NASA Astrophysics Data System (ADS)

Ahmadi, A.; Avazpour, A.; Nadgaran, H.; Mousavi, M.

2018-04-01

The effect of terbium gallium garnet (TGG ) crystal length on 1064 and 532 nm output powers and beam quality of a unidirectional ring Nd:YVO4 laser is investigated. In the case of 1064 nm (without nonlinear crystal), the laser output power without considerating the effect of TGG crystal was computed theoretically. Then three TGG crystals with different lengths were placed in the laser setup one by one. A systematic decrease in output power was observed by increasing the TGG crystal length. The experiment was repeated in the case of 532 nm. It was found that in a 532 nm laser, higher laser efficiency and small beam quality degradation can be achieved by increasing the TGG crystal length leading to a 5.7 W green laser with 27 W pump power. The power stability and beam quality were 0.8% for 30 min and less than 1.3, respectively.

Continuous-wave and passively Q-switched Nd:YVO4 laser at 1085 nm

NASA Astrophysics Data System (ADS)

Lin, Hongyi; Liu, Hong; Huang, Xiaohua; Zhang, Jiyan

2017-11-01

An admirable and efficient Nd:YVO4 laser at 1085 nm is demonstrated with a compact 35 mm plano-plano cavity. A chosen narrow bandpass filter with high-transmittance (HT) coating at 1064 nm (T=96%) and optimized part-reflection (PR) coating at 1085 nm (T=15%) is used as the output coupler. In the continuous-wave (CW) regime, the maximum output power reaches 3110 mW at the pump power of 11.41 W. Based on a Cr:YAG crystal with initial-transmittance of 91%, the first passively Q-switched Nd:YVO4 laser at 1085 nm is achieved. When the pump power is changed from the threshold of 4.50 to 6.08 W, the dual-wavelength lines at 1064 and 1085 nm are generated simultaneously. However, at the pump power of above 6.08 W, the single-wavelength line at 1085 nm is achieved. The largest output power, the highest peak power, and the narrowest pulse width are 1615 mW, 878 W and 26.2 ns, respectively.

926 nm laser operation in Nd:GdNbO4 crystal based on 4F3/2 → 4I9/2 transition

NASA Astrophysics Data System (ADS)

Yan, Renpeng; Li, Xudong; Yao, Wenming; Shen, Yingjie; Zhou, Zhongxiang; Peng, Fang; Zhang, Qingli; Dou, Renqing; Gao, Jing

2018-05-01

926 nm laser operation in a Nd:GdNbO4 crystal based on quasi-three-level 4F3/2 → 4I9/2 transition is reported, for the first time to our best knowledge. An average output power of 393 mW at 926 nm under 879 nm LD pumping is obtained with a slope efficiency of 33.3% and an optical-to-optical efficiency of 26.0%. The slope efficiency with respect to absorbed pump power is estimated to be 47.7%. Comparison between output characters of 926 nm laser under direct and indirect pumping is conducted. The average output power at 926 nm under 808 nm LD pumping reaches 305 mW with an optical-to-optical efficiency of 16.1%.

A 250 MHz, high power mode-locked Nd:GdVO4 oscillator with low timing jitter under 879 nm direct pumping

NASA Astrophysics Data System (ADS)

Zhang, F. F.; Zuo, J. W.; Wang, Z. M.; Yang, J.; Cheng, H. L.; Zong, N.; Yang, F.; Peng, Q. J.; Xu, Z. Y.

2013-04-01

We developed a high power mode-locked Nd:GdVO4 oscillator with low timing jitter directly pumped by an 879 nm diode. Under the absorbed pump power of 13.8 W, a maximum output power of 5.68 W at 1063 nm was obtained with a repetition rate of ˜250 MHz, corresponding to a slope efficiency of 78.7%. The measured pulse width and root mean square timing jitter at the output power of 5.35 W were 7.4 ps and 286 fs, respectively. To the best of our knowledge, this is the highest output power for a picosecond Nd:GdVO4 oscillator with low timing jitter.

Diode-end-pumped solid-state lasers with dual gain media for multi-wavelength emission

NASA Astrophysics Data System (ADS)

Cho, C. Y.; Chang, C. C.; Chen, Y. F.

2015-01-01

We develop a theoretical model for designing a compact efficient multi-wavelength laser with dual gain media in a shared resonator. The developed model can be used to analyze the optimal output reflectivity for each wavelength to achieve maximum output power for multi-wavelength emission. We further demonstrate a dual-wavelength laser at 946 nm and 1064 nm with Nd:YAG and Nd:YVO4 crystals to confirm the numerical analysis. Under optimum conditions and at incident pump power of 17 W, output power at 946 nm and 1064 nm was up to 2.51 W and 2.81 W, respectively.

Passively mode-locked Nd:YVO4 laser operating at 1073 nm and 1085 nm

NASA Astrophysics Data System (ADS)

Waritanant, Tanant; Major, Arkady

2018-02-01

A passively mode-locked Nd:YVO4 laser operating at 1073 nm and 1085 nm was demonstrated with an intracavity birefringent filter as the wavelength selecting element. The average output powers achieved were 2.17 W and 2.18 W with optical-to-optical efficiency of 19.6% and 19.7%, respectively. The slope efficiencies were more than 31% at both output wavelengths. The pulse durations at the highest average output power were 10.3 ps and 8.4 ps, respectively. We believe that this is the first report of mode locking of a Nd:YVO4 laser operating at 1073 nm or 1085 nm lines.

A continuous-wave, widely tunable, intra-cavity, singly resonant, magnesium-doped, periodically poled lithium niobate optical parametric oscillator

NASA Astrophysics Data System (ADS)

Li, Z. P.; Duan, Y. M.; Wu, K. R.; Zhang, G.; Zhu, H. Y.; Wang, X. L.; Chen, Y. H.; Xue, Z. Q.; Lin, Q.; Song, G. C.; Su, H.

2013-05-01

We report a continuous-wave (CW), intra-cavity singly resonant optical parametric oscillator (OPO), based on periodically poled MgO:LiNbO3 pumped by a diode-end-pumped CW Nd:YVO4 laser, and calculate the gain of optical parametric amplification as a function of pump beam waist (at 1064 nm) in the singly resonant OPO (SRO) cavity, to balance the mode-matching and the intensity for the higher gain of a signal wave in the operation of the SRO. In order to achieve maximum gain, we use a convex lens to limit the 1064 nm beam waist. In the experiment, a tunable signal output from 1492 to 1614 nm and an idler output from 3122 to 3709 nm are obtained. For an 808 nm pump power of 11.5 W, a maximum signal output power of up to 2.48 W at 1586 nm and an idler output power of 1.1 W at 3232 nm are achieved with a total optical-to-optical conversion efficiency of 31%.

High-Power Single- and Dual-Wavelength Nd:GdVO4 Lasers with Potential Application for the Treatment of Telangiectasia

NASA Astrophysics Data System (ADS)

Chen, Lijuan; Wang, Zhengping; Yu, Haohai; Zhuang, Shidong; Han, Shuo; Zhao, Yongguang; Xu, Xinguang

2012-11-01

Diode-end-pumped high-power Nd:GdVO4 lasers at 1083 nm are presented. The maximum continuous-wave output power was 10.1 W with an optical conversion efficiency of 31.3%. For acoustooptic (AO) Q-switched operation, the largest pulse energy, shortest pulse width, and highest peak power were 111 µJ, 77 ns, and 1.44 kW, respectively. By decreasing the 1063 nm transmission of the output coupler, we also achieved efficient CW dual-wavelength operation at 1083 and 1063 nm. Their total output power reached 6.7 W, and the optical conversion efficiency reached 31.6%. These lasers have special requirements in the treatment of facial telangiectasia.

Diode-pumped continuous-wave Nd:Gd3Ga5O12 lasers at 1406, 1415 and 1423 nm

NASA Astrophysics Data System (ADS)

Lin, Haifeng; Zhu, Wenzhang; Xiong, Feibing; Ruan, Jianjian

2018-05-01

We report a diode-pumped continuous-wave Nd:Gd3Ga5O12 (GGG) laser operating at 1.4 μm spectral region. A dual-wavelength laser at 1423 and 1406 nm is achieved with output power of about 2.59 W at absorbed pump power of 13.4 W. Further increasing the pump power, simultaneous tri-wavelength laser at 1423, 1415 and 1406 nm is also obtained with a maximum output power of 3.96 W at absorbed pump power of 18.9 W. Single-wavelength lasing is also realized at the three emission lines using an intracavity etalon. The laser result is believed to be the highest output power achieved in Nd:GGG crystal, at present, to the best of our knowledge.

Fully automated 1.5 MHz FDML laser with more than 100mW output power at 1310 nm

NASA Astrophysics Data System (ADS)

Wieser, Wolfgang; Klein, Thomas; Draxinger, Wolfgang; Huber, Robert

2015-07-01

While FDML lasers with MHz sweep speeds have been presented five years ago, these devices have required manual control for startup and operation. Here, we present a fully self-starting and continuously regulated FDML laser with a sweep rate of 1.5 MHz. The laser operates over a sweep range of 115 nm centered at 1315 nm, and provides very high average output power of more than 100 mW. We characterize the laser performance, roll-off, coherence length and investigate the wavelength and phase stability of the laser output under changing environmental conditions. The high output power allows optical coherence tomography (OCT) imaging with an OCT sensitivity of 108 dB at 1.5 MHz.

Researching the 915 nm high-power and high-brightness semiconductor laser single chip coupling module

NASA Astrophysics Data System (ADS)

Wang, Xin; Wang, Cuiluan; Wu, Xia; Zhu, Lingni; Jing, Hongqi; Ma, Xiaoyu; Liu, Suping

2017-02-01

Based on the high-speed development of the fiber laser in recent years, the development of researching 915 nm semiconductor laser as main pumping sources of the fiber laser is at a high speed. Because the beam quality of the laser diode is very poor, the 915 nm laser diode is generally based on optical fiber coupling module to output the laser. Using the beam-shaping and fiber-coupling technology to improve the quality of output beam light, we present a kind of high-power and high-brightness semiconductor laser module, which can output 13.22 W through the optical fiber. Based on 915 nm GaAs semiconductor laser diode which has output power of 13.91 W, we describe a thoroughly detailed procedure for reshaping the beam output from the semiconductor laser diode and coupling the beam into the optical fiber of which the core diameter is 105 μm and the numerical aperture is 0.18. We get 13.22 W from the output fiber of the module at 14.5 A, the coupling efficiency of the whole module is 95.03% and the brightness is 1.5 MW/cm2 -str. The output power of the single chip semiconductor laser module achieves the advanced level in the domestic use.

Continuous-wave broadly tunable Cr 2+:ZnSe laser pumped by a thulium fiber laser

NASA Astrophysics Data System (ADS)

Sennaroglu, Alphan; Demirbas, Umit; Vermeulen, Nathalie; Ottevaere, Heidi; Thienpont, Hugo

2006-12-01

We describe a compact, broadly tunable, continuous-wave (cw) Cr 2+:ZnSe laser pumped by a thulium fiber laser at 1800 nm. In the experiments, a polycrystalline ZnSe sample with a chromium concentration of 9.5 × 10 18 cm -3 was used. Free-running laser output was around 2500 nm. Output couplers with transmissions of 3%, 6%, and 15% were used to characterize the power performance of the laser. Best power performance was obtained with a 15% transmitting output coupler. In this case, as high as 640 mW of output power was obtained with 2.5 W of pump power at a wavelength of 2480 nm. The stimulated emission cross-section values determined from laser threshold data and emission measurements were in good agreement. Finally, broad, continuous tuning of the laser was demonstrated between 2240 and 2900 nm by using an intracavity Brewster cut MgF 2 prism and a single set of optics.

High-power diode laser modules from 410 nm to 2200 nm

NASA Astrophysics Data System (ADS)

Köhler, Bernd; Kissel, Heiko; Flament, Marco; Wolf, Paul; Brand, Thomas; Biesenbach, Jens

2010-02-01

In this work we report on high-power diode laser modules covering a wide spectral range from 410 nm to 2200 nm. Driven by improvements in the technology of diode laser bars with non-standard wavelengths, such systems are finding a growing number of applications. Fields of application that benefit from these developments are direct medical applications, printing industry, defense technology, polymer welding and pumping of solid-sate lasers. Diode laser bars with standard wavelengths from 800 - 1000 nm are based on InGaAlAs, InGaAlP, GaAsP or InGaAs semiconductor material with an optical power of more than 100 W per bar. For shorter wavelengths from 630 - 690 nm InGaAlP semiconductor material is used with an optical power of about 5 W per bar. Extending the wavelength range beyond 1100 nm is realized by using InGaAs on InP substrates or with InAs quantum dots embedded in GaAs for wavelengths up to 1320 nm and (AlGaIn)(AsSb) for wavelengths up to 2200 nm. In these wavelength ranges the output power per bar is about 6 - 20 W. In this paper we present a detailed characterization of these diode laser bars, including measurements of power, spectral data and life time data. In addition, we will show different fiber coupled modules, ranging from 638 nm with 13 W output power (400 μm fiber, NA 0.22) up to 1940 nm with more than 50 W output power (600 μm fiber NA 0.22).

Efficient dual-wavelength laser at 946 and 1064 nm with compactly combined Nd:YAG and Nd:YVO4 crystals

NASA Astrophysics Data System (ADS)

Cho, C. Y.; Chang, C. C.; Chen, Y. F.

2013-04-01

We originally employ a compact combination of a Nd:YAG crystal and a Nd:YVO4 crystal to develop an efficient dual-wavelength laser operating at 946 and 1064 nm. We exploit a short Nd:YAG crystal to generate 946 nm laser by reducing the reabsorption loss and a follow-up Nd:YVO4 crystal to generate a 1064 nm laser by absorbing the residual pump light. The output power ratio between the 946 and 1064 nm emissions can be flexibly adjusted from 0.3 to 0.9 by varying the separation between the two output couplers. At an incident pump power of 17 W, the total output power is generally higher than 5.2 W, with an overall optical-to-optical efficiency greater than 30%.

Simultaneous dual-wavelength lasing at 1047 and 1053 nm and wavelength tuning to 1072 nm in a diode-pumped a-cut Nd : LiYF4 laser

NASA Astrophysics Data System (ADS)

Lin, Zhi; Wang, Yi; Xu, Bin; Cheng, Yongjie; Xu, Huiying; Cai, Zhiping

2015-12-01

We report on diode-end-pumped a-cut Nd:YLF laser on F→I transition. In a free-running regime, using an output coupler with a radius of curvature of 1000 mm, we obtain dual-wavelength laser operation at both π-polarized 1047 nm and σ-polarized 1053 nm with maximum output power of about 1.25 W and the highest slope efficiency of about 50.9% at pump power of 5.77 W at room temperature, for the first time to our knowledge. Furthermore, using a 0.1-mm glass plate as a wavelength selector, a dual-wavelength laser at 1047 and 1072 nm can also be yielded with the maximum output power of 0.34 W, which has not been reported before.

Generation of 14  W at 589  nm by frequency doubling of high-power CW linearly polarized Raman fiber laser radiation in MgO:sPPLT crystal.

PubMed

Surin, A A; Borisenko, T E; Larin, S V

2016-06-01

We introduce an efficient, single-mode, linearly polarized continuous wave (CW) Raman fiber laser (RFL), operating at 1178 nm, with 65 W maximum output power and a narrow linewidth of 0.1 nm. Single-pass second-harmonic generation was demonstrated using a 20 mm long MgO-doped stoichiometric periodically polled lithium tantalate (MgO:sPPLT) crystal pumped by RFL radiation. Output power of 14 W at 589 nm with 22% conversion efficiency was achieved. The possibility of further power scaling is considered, as no crystal degradation was observed at these power levels.

Visible high power fiber coupled diode lasers

NASA Astrophysics Data System (ADS)

Köhler, Bernd; Drovs, Simon; Stoiber, Michael; Dürsch, Sascha; Kissel, Heiko; Könning, Tobias; Biesenbach, Jens; König, Harald; Lell, Alfred; Stojetz, Bernhard; Löffler, Andreas; Strauß, Uwe

2018-02-01

In this paper we report on further development of fiber coupled high-power diode lasers in the visible spectral range. New visible laser modules presented in this paper include the use of multi single emitter arrays @ 450 nm leading to a 120 W fiber coupled unit with a beam quality of 44 mm x mrad, as well as very compact modules with multi-W output power from 405 nm to 640 nm. However, as these lasers are based on single emitters, power scaling quickly leads to bulky laser units with a lot of optical components to be aligned. We also report on a new approach based on 450 nm diode laser bars, which dramatically reduces size and alignment effort. These activities were performed within the German government-funded project "BlauLas": a maximum output power of 80 W per bar has been demonstrated @ 450 nm. We show results of a 200 μm NA0.22 fiber coupled 35 W source @ 450 nm, which has been reduced in size by a factor of 25 compared to standard single emitter approach. In addition, we will present a 200 μm NA0.22 fiber coupled laser unit with an output power of 135 W.

Tuneable powerful UV laser system with UV noise eater

NASA Astrophysics Data System (ADS)

Kobtsev, Sergey; Radnatarov, Daba; Khripunov, Sergey; Zarudnev, Yurii

2018-02-01

The present work for the first time presents the study of a laser system delivering into the fibre up to 250 mW of CW radiation tuneable across the 275-310-nm range with the output line width less than 5 GHz and stability of UV output power within 1%. This system can automatically set the output radiation wavelength within the range of 275-310 nm to the precision of 2 pm. UV output power stabilisation is provided by a newly proposed by the authors noise eating technology. This paper discusses details of the developed technology and the results of its application.

940  mW 1564  nm multi-longitudinal-mode and 440  mW 1537  nm single-longitudinal-mode continuous-wave Er:Yb:Lu2Si2O7 microchip lasers.

PubMed

Huang, Jianhua; Chen, Yujin; Lin, Yanfu; Gong, Xinghong; Luo, Zundu; Huang, Yidong

2018-04-15

An Er:Yb:Lu 2 Si 2 O 7 microchip laser was constructed by placing a 1.2 mm thick, Y-cut Er:Yb:Lu 2 Si 2 O 7 microchip between two 1.2 mm thick sapphire crystals, in which input and output mirrors were directly deposited onto one face of each crystal. End-pumped by a continuous-wave 975.4 nm diode laser, a 1564 nm multi-longitudinal-mode laser with a maximum output power of 940 mW and slope efficiency of 20% was realized at an absorbed pump power of 5.5 W when the transmission of output mirror was 2.2%. When the transmission of the output mirror was increased to 6%, a 1537 nm single-longitudinal-mode laser with a maximum output power of 440 mW and slope efficiency of 12% was realized at an absorbed pump power of 4.3 W. The results indicate that the Er:Yb:Lu 2 Si 2 O 7 crystal is a promising microchip gain medium to realize a single-longitudinal-mode laser.

Diode-pumped Nd:GAGG-LBO laser at 531 nm

NASA Astrophysics Data System (ADS)

Zou, J.; Chu, H.; Wang, L. R.

2012-03-01

We report a green laser at 531 nm generation by intracavity frequency doubling of a continuous wave (cw) laser operation of a 1062 nm Nd:GAGG laser under in-band diode pumping at 808 nm. A LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 18.5 W, as high as 933 mW of cw output power at 531 nm is achieved. The fluctuation of the green output power was better than 3.5% in the given 4 h.

An intra-cavity pumped dual-wavelength laser operating at 946 nm and 1064 nm with Nd:YAG  +  Nd:YVO4 crystals

NASA Astrophysics Data System (ADS)

He-Dong, Xiao; Yuan, Dong; Yu, Liu; Shu-Tao, Li; Yong-Ji, Yu; Guang-Yong, Jin

2016-09-01

We adopt a compact intra-cavity pumped structure of Nd:YAG and Nd:YVO4 crystals to develop an efficient dual-wavelength laser that operates at 946 nm and 1064 nm. A 808 nm laser diode is used to pump the Nd:YAG crystal, which emits at 946 nm, and the Nd:YVO4 crystal, which emits at 1064 nm, is intra-cavity pumped at 946 nm. In order to avoid unnecessary pump light passing though the Nd:YAG crystal, reaching the Nd:YVO4 crystal and having an impact on the cavity pump, the two crystals are placed as far from one another as possible in this experiment. The output power at 1064 nm can be adjusted from 1 W-2.9 W by varying the separation between the two crystals. A total output power of 4 W at the dual-wavelengths is achieved at an incident pump power of 30.5 W, where the individual output powers for the 946 nm and 1064 nm emissions are 1.1 W and 2.9 W, respectively.

Green high-power tunable external-cavity GaN diode laser at 515  nm.

PubMed

Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

2016-09-15

A 480 mW green tunable diode laser system is demonstrated for the first time to our knowledge. The laser system is based on a GaN broad-area diode laser and Littrow external-cavity feedback. The green laser system is operated in two modes by switching the polarization direction of the laser beam incident on the grating. When the laser beam is p-polarized, an output power of 50 mW with a tunable range of 9.2 nm is achieved. When the laser beam is s-polarized, an output power of 480 mW with a tunable range of 2.1 nm is obtained. This constitutes the highest output power from a tunable green diode laser system.

Single frequency 1560nm Er:Yb fiber amplifier with 207W output power and 50.5% slope efficiency

NASA Astrophysics Data System (ADS)

Creeden, Daniel; Pretorius, Herman; Limongelli, Julia; Setzler, Scott D.

2016-03-01

High power fiber lasers/amplifiers in the 1550nm spectral region have not scaled as rapidly as Yb-, Tm-, or Ho-doped fibers. This is primarily due to the low gain of the erbium ion. To overcome the low pump absorption, Yb is typically added as a sensitizer. Although this helps the pump absorption, it also creates a problem with parasitic lasing of the Yb ions under strong pumping conditions, which generally limits output power. Other pump schemes have shown high efficiency through resonant pumping of erbium only without the need for Yb as a sensitizer [1-2]. Although this can enable higher power scaling due to a decrease in the thermal loading, resonant pumping methods require long fiber lengths due to pump bleaching, which may limit the power scaling which can be achieved for single frequency output. By using an Er:Yb fiber and pumping in the minima of the Yb pump absorption at 940nm, we have been able to simultaneously generate high power, single frequency output at 1560nm while suppressing the 1-micron ASE and enabling higher efficiency compared to pumping at the absorption peak at 976nm. We have demonstrated single frequency amplification (540Hz linewidth) to 207W average output power with 49.3% optical efficiency (50.5% slope efficiency) in an LMA Er:Yb fiber. We believe this is the highest reported efficiency from a high power 9XXnm pumped Er:Yb-doped fiber amplifier. This is significantly more efficient that the best-reported efficiency for high power Er:Yb doped fibers, which, to-date, has been limited to ~41% slope efficiency [3].

Diode-side-pumped intracavity frequency-doubled Nd:YAG/BaWO4 Raman laser generating average output power of 3.14 W at 590 nm.

PubMed

Li, Shutao; Zhang, Xingyu; Wang, Qingpu; Zhang, Xiaolei; Cong, Zhenhua; Zhang, Huaijin; Wang, Jiyang

2007-10-15

We report a linear-cavity high-power all-solid-state Q-switched yellow laser. The laser source comprises a diode-side-pumped Nd:YAG module that produces 1064 nm fundamental radiation, an intracavity BaWO(4) Raman crystal that generates a first-Stokes laser at 1180 nm, and a KTP crystal that frequency doubles the first-Stokes laser to 590 nm. A convex-plane cavity is employed in this configuration to counteract some of the thermal effect caused by high pump power. An average output power of 3.14 W at 590 nm is obtained at a pulse repetition frequency of 10 kHz.

Dual-wavelength tunable fibre laser with a 15-dBm peak power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latif, A A; Awang, N A; Zulkifli, M Z

2011-08-31

A high-power dual-wavelength tunable fibre laser (HP-DWTFL) operating in the C-band at wavelengths from 1536.7 nm to 1548.6 nm is proposed and demonstrated. The HP-DWTFL utilises an arrayed waveguide grating (AWG) (1 x 16 channels) and is capable of generating eight different dual-wavelength pairs with eight possible wavelength spacings ranging from 0.8 nm (the narrowest spacing) to 12.0 nm (the widest spacing). The average output power and side mode suppression ratio (SMSR) of the HP-DWTFL are measured to be 15 dBm and 52.55 dB, respectively. The proposed HP-DWTFL is highly stable with no variations in the chosen output wavelengths andmore » has minimal changes in the output power. Such a laser has good potential for use in measurements, communications, spectroscopy and terahertz applications. (control of radiation parameters)« less

Continuous-wave Nd:GYSGG laser at 1.1 μm

NASA Astrophysics Data System (ADS)

Lin, Hongyi; Liu, Hong; Huang, Xiaohua; Copner, Nigel; Sun, Dong

2018-02-01

We demonstrated a compact and simple continuous-wave (CW) Nd:GYSGG laser with triple-wavelength lines at 1105, 1107 and 1110 nm based on R2 → Y6, R1 → Y5 and R1 → Y6 of the 4F3/2 → 4I11/2 transition. The total output power of the triple-wavelength lines was 480 mW. Moreover, we obtained an efficient CW Nd:GYSGG laser at 1110 nm with the output power of 1560 mW at the pump power of 11.05 W. Those lines at 1058 and 1062 nm were suppressed completely by the simple output mirror of high transmission at 1.06 μm.

Miniature solid-state lasers for pointing, illumination, and warning devices

NASA Astrophysics Data System (ADS)

Brown, D. C.; Singley, J. M.; Yager, E.; Kowalewski, K.; Lotito, B.; Guelzow, J.; Hildreth, J.; Kuper, J. W.

2008-04-01

In this paper we review the current status of and progress towards higher power and more wavelength diverse diode-pumped solid-state miniature lasers. Snake Creek Lasers now offers unprecedented continuous wave (CW) output power from 9.0 mm and 5.6 mm TO type packages, including the smallest green laser in the world, the MicroGreen TM laser, and the highest density green laser in the world, the MiniGreen TM laser. In addition we offer an infrared laser, the MiniIR TM, operating at 1064 nm, and have just introduced a blue Mini laser operating at 473 nm in a 9.0 mm package. Recently we demonstrated over 1 W of output power at 1064 nm from a 12 mm TO type package, and green output power from 300-500 mW from the same 12 mm package. In addition, the company is developing a number of other innovative new miniature CW solid-state lasers operating at 750 nm, 820 nm, 458 nm, and an eye-safe Q-switched laser operating at 1550 nm. We also review recently demonstrated combining volume Bragg grating (VBG) technology has been combined with automatic power control (APC) to produce high power MiniGreen TM lasers whose output is constant to +/- 10 % over a wide temperature range, without the use of a thermoelectric cooler (TEC). This technology is expected to find widespread application in military and commercial applications where wide temperature operation is particularly important. It has immediate applications in laser pointers, illuminators, and laser flashlights, and displays.

High-efficient Nd:YAG microchip laser for optical surface scanning

NASA Astrophysics Data System (ADS)

Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

2017-12-01

A CW operating, compact, high-power, high-efficient diode pumped 1064nm laser, based on Nd:YAG active medium, was developed for optical surface scanning and mapping applications. To enhance the output beam quality, laser stability, and compactness, a microchip configuration was used. In this arrangement the resonator mirrors were deposited directly on to the laser crystal faces. The Nd-doping concentration was 1 at.% Nd/Y. The Nd:YAG crystal was 5mm long. The laser resonator without pumping radiation recuperation was investigated {the output coupler was transparent for pumping radiation. For the generated laser radiation the output coupler reflectivity was 95%@1064 nm. The diameter of the samples was 5 mm. For the laser pumping two arrangements were investigated. Firstly, a fibre coupled laser diode operating at wavelength 808nm was used in CW mode. The 400 ¹m fiber was delivering up to 14W of pump power amplitude to the microchip laser. The maximum CW output power of 7.2W @ 1064nm in close to TEM00 beam was obtained for incident pumping power 13.7W @ 808 nm. The differential efficiency in respect to the incident pump power reached 56 %. Secondly, a single-emitter, 1W laser diode operating at 808nm was used for Nd:YAG microchip pumping. The laser pumping was directly coupled into the microchip laser using free-space lens optics. Slope efficiency up to 70% was obtained in stable, high-quality, 1064nm laser beam with CW power up to 350mW. The system was successfully used for scanning of super-Gaussian laser mirrors reflectivity profile.

Passively mode-locked high power Nd:GdVO4 laser with direct in-band pumping at 912 nm

NASA Astrophysics Data System (ADS)

Nadimi, Mohammad; Waritanant, Tanant; Major, Arkady

2018-01-01

We report on the first semiconductor saturable absorber mirror mode-locked Nd:GdVO4 laser directly diode-pumped at 912 nm. The laser generated 10.14 W of averaged output power at 1063 nm with the pulse width of 16 ps at the repetition rate of 85.2 MHz. The optical-to-optical efficiency and slope efficiency in the mode-locked regime were calculated to be 49.6% and 67.4% with respect to the absorbed pump power, respectively. Due to the low quantum defect pumping the output power was limited only by the available pump power.

High-Power Nd:GdVO4 Innoslab Continuous-Wave Laser under Direct 880 nm Pumping

NASA Astrophysics Data System (ADS)

Deng, Bo; Zhang, Heng-Li; Xu, Liu; Mao, Ye-Fei; He, Jing-Liang; Xin, Jian-Guo

2014-11-01

A high-power cw end-pumped laser device is demonstrated with a slab crystal of Nd:GdVO4 operating at 1063 nm. Diode laser stacks at 880 nm are used to pump Nd:GdVO4 into emitting level 4F3/2. The 149 W output power is presented when the absorbed pump power is 390 W and the optical-to-optical conversion efficiency is 38.2%. When the output power is 120 W, the M2 factors are 2.3 in both directions. Additionally, mode overlap inside the resonator is analyzed to explain the beam quality deterioration.

End-pumped continuous-wave intracavity yellow Raman laser at 590 nm with SrWO4 Raman crystal

NASA Astrophysics Data System (ADS)

Yang, F. G.; You, Z. Y.; Zhu, Z. J.; Wang, Y.; Li, J. F.; Tu, C. Y.

2010-01-01

We present an end-pumped continuous-wave intra-cavity yellow Raman laser at 590 nm with a 60 mm long pure crystal SrWO4 and an intra-cavity LiB3O5 frequency doubling crystal. The highest output power of yellow laser at 590 nm was 230 mW and the output power and threshold were found to be correlative with the polarized directions of pure single crystal SrWO4 deeply. Along different directions, the minimum and maximum thresholds of yellow Raman laser at 590 nm were measured to be 2.8 W and 14.3 W with respect to 808 nm LD pump power, respectively.

A frequency doubled pressure-tunable oscillator-amplifier dye laser system

NASA Technical Reports Server (NTRS)

Moriarty, A.; Heaps, W.; Davis, D. D.

1976-01-01

A tunable high-repetition-rate oscillator-amplifier dye-laser system is reported. The dye laser described was longitudinally pumped with the second harmonic of a Nd-YAG laser operating at 10 Hz. Using three Faraday-Perot etalons and pressure tuning, a maximum fundamental output power of the order of 6 MW with a corresponding spectral width of less than 0.003 nm at 564 nm was obtained. The fundamental at 564 nm was frequency doubled to give a maximum power level of 0.6 MW of second-harmonic output power with a spectral width less than 0.0015 nm at 282 nm. Frequency stability could be maintained to within approximately 15% of the line-width.

16.7 W 885 nm diode-side-pumped actively Q-switched Nd:YAG/YVO4 intracavity Raman laser at 1176 nm

NASA Astrophysics Data System (ADS)

Jiang, Pengbo; Zhang, Guizhong; Liu, Jian; Ding, Xin; Sheng, Quan; Yu, Xuanyi; Sun, Bing; Shi, Rui; Wu, Liang; Wang, Rui; Yao, Jianquan

2017-11-01

We proposed and experimentally demonstrated the generation of high-power 1176 nm Stokes wave by frequency shifting of a 885 nm diode-side-pumped Nd:YAG laser using a YVO4 crystal in a Z-shaped cavity configuration. Employing the 885 nm diode-side-pumped scheme and the Z-shaped cavity, for the first time to our knowledge, we realized the thermal management effectively, achieving excellent 1176 nm Stokes wave consequently. With an incident pump power of ~190.0 W, a maximum average output power of 16.7 W was obtained at the pulse repetition frequency of 10 kHz. The pulse duration and spectrum linewidth of the Stokes wave at the maximum output power were 20.3 ns and ~0.08 nm, respectively.

Power-ratio tunable dual-wavelength laser using linearly variable Fabry-Perot filter as output coupler.

PubMed

Wang, Xiaozhong; Wang, Zhongfa; Bu, Yikun; Chen, Lujian; Cai, Guoxiong; Huang, Wencai; Cai, Zhiping; Chen, Nan

2016-02-01

For a linearly variable Fabry-Perot filter, the peak transmission wavelengths change linearly with the transverse position shift of the substrate. Such a Fabry-Perot filter is designed and fabricated and used as an output coupler of a c-cut Nd:YVO₄ laser experimentally in this paper to obtain a 1062 and 1083 nm dual-wavelength laser. The peak transmission wavelengths are gradually shifted from 1040.8 to 1070.8 nm. The peak transmission wavelength of the Fabry-Perot filter used as the output coupler for the dual-wavelength laser is 1068 nm and resides between 1062 and 1083 nm, which makes the transmissions of the desired dual wavelengths change in opposite slopes with the transverse shift of the filter. Consequently, powers of the two wavelengths change in opposite directions. A branch power, oppositely tunable 1062 and 1083 nm dual-wavelength laser is successfully demonstrated. Design principles of the linear variable Fabry-Perot filter used as an output coupler are discussed. Advantages of the method are summarized.

Concepts and performance of solid state RGB laser sources for large-frame laser projection displays

NASA Astrophysics Data System (ADS)

Nebel, Achim; Wallenstein, Richard E.

2000-04-01

We report on concepts and the performance of diode pumped solid state laser systems which generate simultaneously red (R), green (G) and blue (B) laser light with output powers of up to 7.1 W at 629 nm, 6.9 W at 532 nm and 5.0 W at 446 nm. The superposition of this RGB radiation provides white light with a power of 19 W. In respect to the diode pump power of 110 W the RGB output corresponds to an optical efficiency of 17%.

Near-IR, blue, and UV generation by frequency conversion of a Tm:YAP laser

NASA Astrophysics Data System (ADS)

Cole, Brian; Goldberg, Lew; Chinn, Steve

2018-02-01

We describe generation of near-infrared (944nm, 970nm), blue (472nm, 485nm), and UV (236 nm) light by frequency up-conversion of 2 μm output of a compact and efficient passively Q-switched Tm:YAP laser. The Tm:YAP laser source was near diffraction limited with maximum Q-switched pulse peak power of 190 kW. For second harmonic generation (SHG) of NIR, both periodically poled lithium niobate (PPLN) and lithium tri-borate (LBO) were evaluated, with 58% conversion efficiency and 3.1 W of 970 nm power achieved with PPLN. The PPLN 970nm emission was frequency doubled in 20mm long type I LBO, generating 1.1 W at 485nm with a conversion efficiency of 34%. With LBO used for frequency doubling of 2.3 W of 1888 nm Tm:YAP output to 944nm, 860mW was generated, with 37% conversion efficiency. Using a second LBO crystal to generate the 4th harmonic, 545mW of 472nm power was generated, corresponding to 64% conversion efficiency. To generate the 8th harmonic of Tm:YAP laser emission, the 472nm output of the second LBO was frequency doubled in a 7mm long BBO crystal, generating 110 mW at 236nm, corresponding to 21% conversion efficiency.

High-power narrow-linewidth quasi-CW diode-pumped TEM00 1064 nm Nd:YAG ring laser.

PubMed

Liu, Yuan; Wang, Bao-shan; Xie, Shi-yong; Bo, Yong; Wang, Peng-yuan; Zuo, Jun-wei; Xu, Yi-ting; Xu, Jia-lin; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

2012-04-01

We demonstrated a high average power, narrow-linewidth, quasi-CW diode-pumped Nd:YAG 1064 nm laser with near-diffraction-limited beam quality. A symmetrical three-mirror ring cavity with unidirectional operation elements and an etalon was employed to realize the narrow-linewidth laser output. Two highly efficient laser modules and a 90° quartz rotator for birefringence compensation were used for the high output power. The maximum average output power of 62.5 W with the beam quality factor M(2) of 1.15 was achieved under a pump power of 216 W at a repetition rate of 500 Hz, corresponding to the optical-to-optical conversion efficiency of 28.9%. The linewidth of the laser at the maximum output power was measured to be less than 0.2 GHz.

Several hundred kHz repetition rate nanosecond pulses amplification in Er-Yb co-doped fiber amplifier

NASA Astrophysics Data System (ADS)

Yang, Weiqiang; Yin, Ke; Zhang, Bin; Xue, Guanghui; Hou, Jing

2014-07-01

We have experimentally investigated several hundred kHz repetition rate 1,550-nm nanosecond pulses amplification in Er-Yb co-doped fiber amplifier (EYDFA). The experimental setup has three stage fiber amplifiers. At the output of the second stage EYDFA, Yb3+ ions induced amplified spontaneous emission (Yb-ASE) is not observed owing to the low pump power. In the third stage EYDFA, a simultaneously seeded 1,064-nm continuous-wave laser is used to control Yb-ASE. Without any additional 1,064-nm signal, significantly backward Yb-ASE which caused loss-induced heat accumulation at the input port of the pump combiner can be observed. The monitored temperature at the input port of the pump combiner rapidly grows from 30 to 80 °C when the pump power is turned from 20 to 32 W. When a 196-mW forward 1,064-nm laser is added, the monitored backward Yb-ASE power is significantly declined, and the monitored temperature is kept below 35 °C. But, the additional signal caused a large power fraction at 1,064 nm in the output laser. In our experiment at the maximum pump power of 48.5 W, the total output power is 20 W with ~6.4-W 1,550-nm pulsed laser and ~13-W 1,064-nm continuous-wave laser.

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%.

20-W 1952-nm tandem hybrid single and double clad TDFA

NASA Astrophysics Data System (ADS)

Romano, Clément; Tench, Robert E.; Delavaux, Jean-Marc

2018-02-01

A simple engineering design is important for achieving high Thulium-doped amplifier (TDFA) performance such as good power conversion, low noise figure (NF), scalable output power, high gain, and stable operation over a large dynamic range. In this paper we report the design, performance, and simulation of two stage high-power 1952 nm hybrid single and double clad TDFAs. The first stage of our hybrid amplifier is a single clad design, and the second stage is a double clad design. We demonstrate TDFAs with an output power greater than 20 W with single-frequency narrow linewidth (i.e. MHz) input signals at both 1952 and 2004 nm. An optical 10 dB bandwidth of 80 nm is derived from the ASE spectrum. The power stage is constructed with 10 μm core active fibers showing a maximum optical slope efficiency greater than 50 %. The experimental results lead to a 1 dB agreement with our simulation tool developed for single clad and double clad TDFAs. Overall this hybrid amplifier offers versatile features with the potential of much higher output power.

A fiber-laser-pumped four-wavelength continuous-wave mid-infrared optical parametric oscillator

NASA Astrophysics Data System (ADS)

Wang, Peng; Shang, Yaping; Li, Xiao; Xu, Xiaojun

2017-10-01

In this paper, a four-wavelength continuous-wave mid-infrared optical parametric oscillator was demonstrated for the first time. The pump source was a home-built linearly polarized Yb-doped fiber laser and the maximum output power was 72.5 W. The pump source had three central wavelengths locating at 1060 nm, 1065 nm and 1080 nm. Four idler emissions with different wavelengths were generated which were 3132 nm, 3171 nm, 3310 nm and 3349 nm under the maximum pump power. The maximum idler output reached 8.7 W, indicating a 15% pump-to-idler slope efficiency. The signal wave generated in the experiment had two wavelengths which were 1595 nm and 1603 nm under the maximum pump power. It was analyzed that four nonlinear progresses occurred in the experiment, two of them being optical parametric oscillation and the rest two being intracavity difference frequency generation.

Single-mode oscillation of a diode-pumped Nd:YAG microchip laser at 1835 nm

NASA Astrophysics Data System (ADS)

Lan, Jinglong; Cui, Qin; Wang, Yi; Xu, Bin; Xu, Huiying; Cai, Zhiping

2016-10-01

Single-mode oscillation of a diode-pumped conventional Nd:YAG laser at 1835 nm is demonstrated, for the first time to our knowledge, in the form of microchip configuration. The achieved maximum output power reaches 189 mW with slope efficiency of about 5.5% with respect to absorbed pump power. The laser spectra are measured with linewidth less than 0.08 nm indicating a single longitudinal mode. The output laser beam is also measured to be near diffraction-limited with M2 factors of about 1.2 and 1.5 in x and y directions. Using a mechanical chopper with 50% duty cycle, the maximum output power is improved to 253 mW with slope efficiency of about 9.7%.

Orange fiber laser for ophthalmology

NASA Astrophysics Data System (ADS)

Adachi, M.; Kojima, K.; Hayashi, K.

2007-02-01

For the light source of photocoagulators for ophthalmology, orange laser is more suitable than green laser because of low scattering loss by the crystalline lens, and low absorption by xanthophylls in the retina. We developed two orange fiber lasers (580 nm and 590 nm) to investigate the effect depending on the difference in the range of orange. The 580nm laser is composed of a 1160 nm fiber laser and a Periodically Polled Lithium Niobate (PPLN) crystal for second harmonic generation. The 1160 nm fiber laser beam is focused into the MgO-doped PPLN crystal whose length is 30 mm with 3-pass configuration. Continuous-wave 1.3 W output power of 580 nm was obtained with 5.8 W input power of 1160nm for the first time. The conversion efficiency was 22%. The band width of the second harmonic was 0.006 nm (FWHM). The 590 nm laser is almost the same as 580 nm laser source. In this case we used a Raman shift fiber to generate 1180 nm, and the output power of 590 nm was 1.4 W. We developed an evaluation model of photocoagulator system using these two laser sources. A 700 mW coagulation output power was obtained with this orange fiber laser photocoagulator system. This is enough power for the eye surgery. We have the prospect of the maintenance-free, long-life system that is completely air-cooled. We are planning to evaluate this photocoagulator system in order to investigate the difference between the two wavelengths at the field test.

250W continuous-tunable all-fiberized single-frequency polarization-maintained amplifiers with wavelength spanning from 1065 nm to 1090 nm

NASA Astrophysics Data System (ADS)

Liu, Yakun; Su, Rongtao; Wang, Xiaolin; Ma, Pengfei; Zhang, Hanwei; Si, Lei

2017-10-01

In this manuscript, we demonstrate an all-fiberized, single-frequency and polarization-maintained (PM) amplifiers with wavelength tuned from 1065 nm to 1090 nm. The ASE is suppressed by a signal to noise ratio of higher than 27 dB, and each wavelengths can be amplified to be 250 W output power. The stimulated Brillouin scattering (SBS) effect in such high power amplifiers is suppressed by employing a high dopant fiber (10 dB/m). The polarization extinction ratio (PER) of the amplifier is over 20 dB at the maximum output power. It should be noted that although the experiments are conducted at the wavelength from 1065 nm to 1090 nm with a step of 5 nm, the wavelength can also be continuously tuned.

High-energy directly diode-pumped Q-switched 1617 nm Er:YAG laser at room temperature.

PubMed

Wang, Mingjian; Zhu, Liang; Chen, Weibiao; Fan, Dianyuan

2012-09-01

We describe high-energy Erbium-doped yttrium aluminum garnet (Er:YAG) lasers operating at 1617 nm, resonantly pumped using 1532 nm fiber-coupled laser diodes. A maximum continuous wave output power of 4.3 W at 1617 nm was achieved with an output coupler of 20% transmission under incident pump power of 29.7 W, resulting in an optical conversion of 14% with respect to the incident pump power. In Q-switched operation, the pulse energy of 11.8 mJ at 100 Hz pulse repetition frequency and 81 ns pulse duration was obtained. This energy is the highest pulse energy reported for a directly diode-pumped Q-switched Er:YAG laser operating at 1617 nm.

High-power linearly-polarized operation of a cladding-pumped Yb fibre laser using a volume Bragg grating for wavelength selection.

PubMed

Jelger, P; Wang, P; Sahu, J K; Laurell, F; Clarkson, W A

2008-06-23

In this work a volume Bragg grating is used as a wavelength selective element in a high-power cladding-pumped Yb-doped silica fiber laser. The laser produced 138 W of linearly-polarized single-spatial-mode output at 1066 nm with a relatively narrow linewidth of 0.2 nm for approximately 202 W of launched pump power at 976 nm. The beam propagation factor (M(2)) for the output beam was determined to be 1.07. Thermal limitations of volume Bragg gratings are discussed in the context of power scaling for fiber lasers.

Realization of a mW-level 10.7-eV (λ = 115.6 nm) laser by cascaded third harmonic generation of a Yb:fiber CPA laser at 1-MHz.

PubMed

Zhao, Zhigang; Kobayashi, Yohei

2017-06-12

We demonstrate a 10.7-eV (λ = 115.6 nm) laser with mW levels of average power and a 1-MHz repetition rate, which was driven by the third harmonic radiation (THG), at 347 nm, of an Yb:fiber chirped pulse amplifier (CPA) laser. The 347 nm ultraviolet radiation was obtained by frequency conversion of the high power output of a 1-MHz Yb:fiber CPA, using beta barium borate (BBO) nonlinear crystals. The frequency converted output was focused down into a gas cell filled with a mixture of Ar and Xe, and was subjected to a second THG frequency conversion. The generated 10.7-eV laser was separated from the fundamental beam using a LiF prism and no further separation from other harmonic waves was required. The highest measured output power was ~80 μW, which corresponded to an average power of ~1.25 mW inside the gas cell when the transmission coefficients of the LiF optics were taken into account. The corresponding conversion efficiency from 347 nm down to 115.6 nm was ~2.5 × 10 -4 .

Diode-pumped Kerr-lens mode-locked Yb:CaGdAlO4 laser with tunable wavelength

NASA Astrophysics Data System (ADS)

Gao, Ziye; Zhu, Jiangfeng; Wang, Junli; Wang, Zhaohua; Wei, Zhiyi; Xu, Xiaodong; Zheng, Lihe; Su, Liangbi; Xu, Jun

2016-01-01

We experimentally demonstrated a wavelength tunable Kerr-lens mode-locked femtosecond laser based on an Yb:CaGdAlO4 (Yb:CGA) crystal. The Kerr-lens mode-locked wavelength tuning range was from 1043.5 to 1076 nm, as broad as 32.5 nm, by slightly tilting the end mirror. Pulses as short as 60 fs were generated at the central wavelength of 1043.8 nm with an average output power of 66 mW. By using an output coupler with 1.5% transmittance, the Kerr-lens mode-locked average output power reached 127 mW with a pulse duration of 81 fs at a central wavelength of 1049.5 nm.

Compact 2100 nm laser diode module for next-generation DIRCM

NASA Astrophysics Data System (ADS)

Dvinelis, Edgaras; Greibus, Mindaugas; TrinkÅ«nas, Augustinas; NaujokaitÄ--, Greta; Vizbaras, Augustinas; Vizbaras, Dominykas; Vizbaras, Kristijonas

2017-10-01

Compact high-power 2100 nm laser diode module for next-generation directional infrared countermeasure (DIRCM) systems is presented. Next-generation DIRCM systems require compact, light-weight and robust laser modules which could provide intense IR light emission capable of disrupting the tracking sensor of heat-seeking missile. Currently used solid-state and fiber laser solutions for mid-IR band are bulky and heavy making them difficult to implement in smaller form-factor DIRCM systems. Recent development of GaSb laser diode technology greatly improved optical output powers and efficiencies of laser diodes working in 1900 - 2450 nm band [1] while also maintaining very attractive size, weight, power consumption and cost characteristics. 2100 nm laser diode module presented in this work performance is based on high-efficiency broad emitting area GaSb laser diode technology. Each laser diode emitter is able to provide 1 W of CW output optical power with working point efficiency up to 20% at temperature of 20 °C. For output beam collimation custom designed fast-axis collimator and slow-axis collimator lenses were used. These lenses were actively aligned and attached using UV epoxy curing. Total 2 emitters stacked vertically were used in 2100 nm laser diode module. Final optical output power of the module goes up to 2 W at temperature of 20 °C. Total dimensions of the laser diode module are 35 x 25 x 16 mm (L x W x H) with a weight of 28 grams. Finally output beam is bore-sighted to mechanical axes of the module housing allowing for easy integration into next-generation DIRCM systems.

650-nm-band high-power and highly reliable laser diodes with a window-mirror structure

NASA Astrophysics Data System (ADS)

Shima, Akihiro; Hironaka, Misao; Ono, Ken-ichi; Takemi, Masayoshi; Sakamoto, Yoshifumi; Kunitsugu, Yasuhiro; Yamashita, Koji

1998-05-01

An active layer structure with 658 nm-emission at 25 degrees Celsius has been optimized in order to reduce the operating current of the laser diodes (LD) under high temperature condition. For improvement of the maximum output power and the reliability limited by mirror degradation, we have applied a zinc-diffused-type window-mirror structure which prevents the optical absorption at the mirror facet. As a result, the CW output power of 50 mW is obtained even at 80 degrees Celsius for a 650 micrometer-long window-mirror LD. In addition, the maximum light output power over 150 mW at 25 degrees Celsius has been realized without any optical mirror damage. In the aging tests, the LDs have been operating for over 2,500 - 5,000 hours under the CW condition of 30 - 50 mW at 60 degrees Celsius. The window-mirror structure also enables reliable 60 degree Celsius, 30 mW, CW operation of the LDs with 651 nm- emission at 25 degrees Celsius. Moreover, the maximum output power of around 100 mW even at 80 degrees Celsius and reliable 2,000-hour operation at 60 degrees Celsius, 70 mW have been realized for the first time by 659 nm LDs with a long cavity length of 900 micrometers.

High-power single-stage thulium-doped superfluorescent fiber source

NASA Astrophysics Data System (ADS)

Hu, Z. Y.; Yan, P.; Liu, Q.; Ji, E. C.; Xiao, Q. R.; Gong, M. L.

2015-01-01

In this paper, we report a high-power thulium (Tm)-doped superfluorescent fiber source (SFS) in the 2-μm spectral region. The SFS is based on double angle-cleaved facet operation and uses a simple single-stage geometry. The copropagating amplified spontaneous emission (ASE) yields a maximum output of 20.7 W at a center wavelength of 1,960.7 nm, with a full width at half maximum (FWHM) of ~45 nm. The counterpropagating ASE yields a maximum output of 25.2 W at a center wavelength of 1,948.2 nm, with a FWHM of ~50 nm. The maximum combined output of the SFS is as much as 45.9 W, which corresponds to a slope efficiency of 38.9 %. In addition, a model of the ~2 μm SFS in Tm-doped silica fibers pumped at ~790 nm is developed, and the influence of fiber length and end-facet reflectivity on the ASE output performance and the parasitic lasing threshold are studied numerically.

Investigation of ASE and SRS effects on 1018nm short-wavelength Yb3+-doped fiber laser

NASA Astrophysics Data System (ADS)

Xie, Zhaoxin; Shi, Wei; Sheng, Quan; Fu, Shijie; Fang, Qiang; Zhang, Haiwei; Bai, Xiaolei; Shi, Guannan; Yao, Jianquan

2017-03-01

1018nm short wavelength Yb3+-doped fiber laser can be widely used for tandem-pumped fiber laser system in 1 μm regime because of its high brightness and low quantum defect (QD). In order to achieve 1018nm short wavelength Yb3+-doped fiber laser with high output power, a steady-state rate equations considering the amplified spontaneous emission (ASE) and Stimulated Raman Scattering (SRS) has been established. We theoretically analyzed the ASE and SRS effects in 1018nm short wavelength Yb3+-doped fiber laser and the simulation results show that the ASE is the main restriction rather than SRS for high power 1018nm short wavelength Yb3+-doped fiber laser, besides the high temperature of fiber is also the restriction for high output power. We use numerical solution of steady-state rate equations to discuss how to suppress ASE in 1018nm short wavelength fiber laser and how to achieve high power 1018nm short-wavelength fiber laser.

The generation of a continuous-wave Nd:YVO4/LBO laser at 543 nm by direct in-band diode pumping at 888 nm

NASA Astrophysics Data System (ADS)

Fu, S. C.; Wang, X.; Chu, H.

2013-02-01

We report the generation of a green laser at 543 nm by intracavity frequency doubling of the continuous-wave (cw) laser operation of a 1086 nm Nd:YVO4 laser under 888 nm diode pumping into the emitting level 4F3/2. An LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature, is used for the laser second-harmonic generation. At an incident pump power of 17.8 W, as high as 4.53 W cw output power at 543 nm is achieved. The optical-to-optical conversion efficiency is up to 25.4%, and the fluctuation of the green output power is better than 2.3% in a 30 min period.

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

PubMed

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

2012-03-01

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.

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

Ultimate high power operation of 9xx-nm single emitter broad stripe laser diodes

NASA Astrophysics Data System (ADS)

Kaifuchi, Yoshikazu; Yamagata, Yuji; Nogawa, Ryozaburo; Morohashi, Rintaro; Yamada, Yumi; Yamaguchi, Masayuki

2017-02-01

Design optimization of single emitter broad stripe 9xx-nm laser diodes was studied to achieve ultimate high power and high efficiency operation for a use in fiber laser pumping and other industrial applications. We tuned laser vertical layer design and stripe width in terms of optical confinement as well as electrical resistance. As a result, newly designed LDs with 4mm-long cavity and 220 μm-wide stripe successfully demonstrate maximum CW output power as high as 33 W and high efficiency operation of more than 60 % PCE even at 27 W output power. In pulse measurement, the maximum output of 68 W was obtained.

980 nm all-fiber NPR mode-locking Yb-doped phosphate fiber oscillator and its amplifier

NASA Astrophysics Data System (ADS)

Li, Pingxue; Yao, Yifei; Chi, Junjie; Hu, Haowei; Yang, Chun; Zhao, Ziqiang; Zhang, Guangju

2014-12-01

We report on a 980 nm all-fiber passively mode-locking Yb-doped phosphate fiber oscillator with the nonlinear polarization rotation (NPR) technique and its amplifier. In order to obtaining the stable self-starting mode-locking oscillator at 980 nm, a bandpass filter with 30 nm transmission bandwidth around 980 nm is inserted into the cavity. The oscillator generates the average output power of 26.1 mW with the repetition rate of 20.38 MHz, corresponding to the single pulse energy of 1.28 nJ. The pulse width is 159.48 ps. The output spectrum of the pulses is centered at 977 nm with a full width half maximum (FWHM) of 10 nm and has the characteristic steep spectral edges of dissipative soliton. No undesired ASE and harmful oscillation around 1030 nm is observed. Moreover, through two stage all-fiber-integrated amplifier by using the 980 nm oscillator as seed source, an amplified output power of 205 mW at 980 nm and pulse duration of 178.10 ps is achieved.

Cryogenic Tm:YAP microchip laser

NASA Astrophysics Data System (ADS)

Hubka, Zbyněk.; Å ulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Å koda, Václav

2016-04-01

The spectral characteristics of laser active media, and thus those of the laser output, are temperature dependent. Specifically, in almost every crystal host, cooling to low temperatures leads to better heat removal, a higher efficiency and output power, and a reduced lasing threshold. Tm-ion doped lasers have an emission wavelength around 2 μm and are important in medicine for soft tissue cutting and hemostasis, as well as in LIDAR or atmosphere sensing technology. This paper presents the performance-temperature dependency of a 4 at. % doped Tm:YAP microchip. During the experiment the Tm:YAP crystal was placed inside an evacuated liquid nitrogen cryostat on a cooling finger. As its temperature was varied from 80 K to 340 K, changes were observed in the absorption spectrum, ranging from 750 nm to 2000 nm and in the fluorescence spectrum from 1600 nm to 2050 nm. Fluorescence lifetime was seen to rise and fall with decreasing temperature. The laser was pumped by a 792 nm laser diode and at 80 K the maximum output peak power of the laser was 4.6 W with 23 % slope efficiency and 0.6 W threshold, compared to 2.4 W output peak power, 13 % slope efficiency and 3.3 W threshold when at 340 K. The laser emission wavelength changed from 1883 nm to 1993 nm for 80 K and 300 K, respectively.

High-repetition-rate widely tunable LiF : \\mathbf{\\mathsf{F}}_\\mathbf{\\mathsf{2}}^{-} color center lasers

NASA Astrophysics Data System (ADS)

Men, Shaojie; Liu, Zhaojun; Cong, Zhenhua; Rao, Han; Zhang, Sasa; Liu, Yang; Zverev, Petr G.; Konyushkin, Vasily A.; Zhang, Xingyu

2016-02-01

High-repetition-rate tunable LiF:\\text{F}2- color center lasers pumped by quasi-continuous-wave diode-side-pumped acousto-optically Q-switched Nd:YAG laser are demonstrated. Littrow-grating and Littman-grating tuning schemes are studied respectively. In the Littrow-grating scheme, the tuning range was 1085 nm to 1275 nm, and the maximal average output power was 275 mW. In the Littman-grating scheme, the tuning range was 1105.5 nm to 1215.5 nm, and the maximal average output power was 135 mW.

Continuous-wave Nd:YVO4/KTiOPO4 green laser at 542 nm under diode pumping into the emitting level

NASA Astrophysics Data System (ADS)

Liu, J. H.

2012-10-01

We report a green laser at 542 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a 1086 nm Nd:YVO4 laser under 880 nm diode pumping into the emitting level 4 F 3/2. A KTiOPO4 (KTP) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 14.5 W, as high as 1.33 W of CW output power at 542 nm is achieved. The optical-to-optical conversion efficiency is up to 9.2%, and the fluctuation of the green output power was better than 3.8% in the given 30 min.

Comparison for 1030nm DBR-tapered diode lasers with 10W central lobe output power and different grating layouts for wavelength stabilization and lateral spatial mode filtering

NASA Astrophysics Data System (ADS)

Müller, André; Zink, Christof; Fricke, Jörg; Bugge, Frank; Erbert, Götz; Sumpf, Bernd; Tränkle, Günther

2018-02-01

1030 nm DBR tapered diode lasers with different lateral layouts are presented. The layout comparison includes lasers with straight waveguide and grating, tapered waveguide and straight grating, and straight waveguide and tapered grating. The lasers provide narrowband emission and optical output powers up to 15 W. The highest diffraction-limited central lobe output power of 10.5 W is obtained for lasers with tapered gratings only. Small variations in central lobe output power with RW injection current density also indicate the robustness of that layout. For lasers with tapered waveguides, high RW injection current densities up to 150 A/mm2 have to be applied in order to obtain high central lobe output powers. Lasers with straight waveguide and grating operate best at low RW injection current densities, 50 A/mm2 applied in this study. Using the layout optimizations discussed in this study may help to increase the application potential of DBR tapered diode lasers.

Highly efficient continuous-wave Nd:YAG ceramic lasers at 946 nm

NASA Astrophysics Data System (ADS)

Zhu, H. Y.; Xu, C. W.; Zhang, J.; Tang, D. Y.; Luo, D. W.; Duan, Y. M.

2013-07-01

Highly efficient CW operation of diode-end-pumped Nd:YAG ceramic lasers at 946 nm is experimentally demonstrated. When a 5 mm long in-house fabricated Nd:YAG ceramic was used as the gain medium, a maximum output power of 10.5 W was obtained under an incident pump power of 35 W, corresponding to an optical conversion efficiency of 30%, while, when a 3 mm long ceramic sample was used, a maximum output power of 8.7 W was generated with a slope efficiency of 65% with respect to the absorbed pump power. Both the optical conversion efficiency and slope efficiency are the highest results reported so far for the diode-pumped 946 nm lasers.

Mode-locked Yb:YAG thin-disk oscillator with 41 µJ pulse energy at 145 W average infrared power and high power frequency conversion.

PubMed

Bauer, Dominik; Zawischa, Ivo; Sutter, Dirk H; Killi, Alexander; Dekorsy, Thomas

2012-04-23

We demonstrate the generation of 1.1 ps pulses containing more than 41 µJ of energy directly out of an Yb:YAG thin-disk without any additional amplification stages. The laser oscillator operates in ambient atmosphere with a 3.5 MHz repetition rate and 145 W of average output power at a fundamental wavelength of 1030 nm. An average output power of 91.5 W at 515 nm was obtained by frequency doubling with a conversion efficiency exceeding 65%. Third harmonic generation resulted in 34 W at 343 nm at 34% efficiency. © 2012 Optical Society of America

High-efficiency diode-pumped actively Q-switched ceramic Nd:YAG/BaWO₄ Raman laser operating at 1666 nm.

PubMed

Zhang, H N; Chen, X H; Wang, Q P; Zhang, X Y; Chang, J; Gao, L; Shen, H B; Cong, Z H; Liu, Z J; Tao, X T; Li, P

2014-05-01

A diode-pumped actively Q-switched Raman laser employing BaWO4 as the Raman active medium and a ceramic Nd:YAG laser operating at 1444 nm as the pump source is demonstrated. The first-Stokes-Raman generation at 1666 nm is achieved. With a pump power of 20.3 W and pulse repetition frequency rate of 5 kHz, a maximum output power of 1.21 W is obtained, which is the highest output power for a 1.6 μm Raman laser. The corresponding optical-to-optical conversion efficiency is 6%; the pulse energy and peak power are 242 μJ and 8.96 kW, respectively.

980-nm, 15-W cw laser diodes on F-mount-type heat sinks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bezotosnyi, V V; Krokhin, O N; Oleshchenko, V A

2015-12-31

We have studied the key optical emission parameters of laser diodes (emission wavelength, 980 nm; stripe contact width, 95 μm) mounted directly on F- and C-mount-type copper heat sinks, without intermediate elements (submounts). When effectively cooled by a thermoelectric microcooler, the lasers on the F-mount operated stably at output powers up to 20 W. The lasers were tested for reliable operation at an output power of 15 W for 100 h, and no decrease in output power was detected to within measurement accuracy. The experimentally determined maximum total efficiency is 71.7% and the efficiency at a nominal output power ofmore » 15 W is 61%. We compare parameters of the laser diodes mounted on C- and F-mounts and discuss the advantages of the F-mounts. (lasers)« less

Experimental investigation of a diode-pumped powerful continuous-wave dual-wavelength Nd:YAG laser at 946 and 938.6 nm

NASA Astrophysics Data System (ADS)

Chen, F.; Yu, X.; Yan, R. P.; Li, X. D.; Li, D. J.; Yang, G. L.; Xie, J. J.; Guo, J.

2013-05-01

In this paper, a diode-pumped high-power continuous-wave (cw) dual-wavelength Nd:YAG laser at 946 and 938.6 nm is reported. By using an end-pumped structure, comparative experiments indicate that a 5 mm-length Nd:YAG crystal with a Nd3+-doping concentration of 0.3 at.% is favorable for high-power laser operation, and the optimal transmissivity of the output coupler is 9%. As a result, a maximum output power of 17.2 W for a dual-wavelength laser at 946 and 938.6 nm is obtained at an incident pump power of 75.9 W, corresponding to a slope efficiency of 26.5%. To the best of our knowledge, this is the highest output power of a quasi-three-level dual-wavelength laser using a conventional Nd:YAG crystal achieved to date. By using a traveling knife-edge method, the beam quality factor and far-field divergence angle at 17 W power level are estimated to be 4.0 and 6.13 mrad, respectively.

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.

36 W Q-switched Ho:YAG laser at 2097 nm pumped by a Tm fiber laser: evaluation of different Ho3+ doping concentrations

NASA Astrophysics Data System (ADS)

Antipov, O. L.; Eranov, I. D.; Kositsyn, R. I.

2017-01-01

A laser oscillator based on Ho:YAG crystal pumped by a Tm fiber laser with an acousto-optical Q-switch was optimized for maximum output power and pulse-to-pulse stability. Stable operation at 2097 nm in Q-switched mode is demonstrated, with pulse repetition rates from 10 to 30 kHz, and output power of 36 W (at 55 W of pump power at 1908 nm) in the good quality beam. The influence of Ho ion up-conversion and thermal lensing on the oscillation efficiency is discussed.

Continuous-wave laser operation at 743 and 753 nm based on a diode-pumped c-cut Pr:YAlO3 crystal

NASA Astrophysics Data System (ADS)

Lin, Xiuji; Huang, Xiaoxu; Liu, Bin; Xu, Bin; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Li, Dongzhen; Liu, Jian; Xu, Jun

2018-02-01

We report on blue-diode-pumped continuous-wave Pr:YAlO3 (YAP) crystal lasers. Using a b-cut sample, a maximum output power of 181 mW is achieved at ∼747 nm with slope efficiency of 12.7% with respect to the absorbed power. Using a c-cut sample, a dual-wavelength laser at ∼743 and ∼753 nm is obtained with a total maximum output power of 72 mW by using the blue diode pumping, for the first time to our knowledge. These laser emissions are all linearly polarized and M2 factors of these output laser beams are also measured. YAP is experimentally verified to be one of effective oxide hosts for Pr-doped visible laser operation besides its fluoride counterparts.

Orange and red upconversion laser pumped by an avalanche mechanism in Pr3+, Yb3+:BaY2F8

NASA Astrophysics Data System (ADS)

Osiac, E.; Heumann, E.; Huber, G.; Kück, S.; Sani, E.; Toncelli, A.; Tonelli, M.

2003-06-01

The letter reports on upconverted orange (607.5 nm, 3P0→3H6) and red (638.7 nm, 3P0→3F2) laser oscillation at room temperature observed in Pr3+, Yb3+:BaY2F8 under excitation at 822 or 841 nm at 300 K. The upconversion mechanism that populates the emitting level is an avalanche excitation mechanism. Output powers up to 55 mW and slope efficiencies up to 27% were demonstrated at 607.5 nm. At 638.7 nm, the maximum output power was 26 mW with a slope efficiency of about 13.5%.

Disordered Nd:LuYSiO5 crystal lasers operating on the 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 transitions

NASA Astrophysics Data System (ADS)

Guan, Xiaofeng; Zhou, Zhiyong; Huang, Xiaoxu; Xu, Bin; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Xu, Jun

2017-11-01

We report on diode-pumped disordered Nd:LuYSiO5 (Nd:LYSO) crystal lasers operating on the 4F3/2 → 4I11/2 and 4F3/2 → 4I 13/2 transitions. Simultaneous laser operation at 1074 and 1078 nm is achieved with maximum output power of 4.46 W and slope efficiency of 39.6%. Single wavelength laser at 1358 nm with maximum output power of 1.15 W and slope efficiency of 11.8% is also obtained. Moreover, four single-wavelength lasers at 1058, 1107, 1330 and 1386 nm with relatively low gains are achieved with maximum output powers of 2.72, 1.22, 0.52 and 0.42 W, respectively, for the first time to our knowledge. Lasing at non-traditional emission lines was obtained by using output couplers with dielectric coatings for specific wavelength ranges.

Switchable dual-wavelength SOA-based fiber laser with continuous tunability over the C-band at room-temperature.

PubMed

Ummy, M A; Madamopoulos, N; Razani, M; Hossain, A; Dorsinville, R

2012-10-08

We propose and demonstrate a simple compact, inexpensive, SOA-based, dual-wavelength tunable fiber laser, that can potentially be used for photoconductive mixing and generation of waves in the microwave and THz regions. A C-band semiconductor optical amplifier (SOA) is placed inside a linear cavity with two Sagnac loop mirrors at its either ends, which act as both reflectors and output ports. The selectivity of dual wavelengths and the tunability of the wavelength difference (Δλ) between them is accomplished by placing a narrow bandwidth (e.g., 0.3 nm) tunable thin film-based filter and a fiber Bragg grating (with bandwidth 0.28 nm) inside the loop mirror that operates as the output port. A total output power of + 6.9 dBm for the two wavelengths is measured and the potential for higher output powers is discussed. Optical power and wavelength stability are measured at 0.33 dB and 0.014 nm, respectively.

Mode-locked Ti:sapphire laser oscillators pumped by wavelength-multiplexed laser diodes

NASA Astrophysics Data System (ADS)

Sugiyama, Naoto; Tanaka, Hiroki; Kannari, Fumihiko

2018-05-01

We directly pumped a Ti:sapphire laser by combining 478 and 520 nm laser diodes to prevent the effect of absorption loss induced by the pump laser of shorter wavelengths (∼450 nm). We obtain a continuous-wave output power of 660 mW at a total incident pump power of 3.15 W. We demonstrate mode locking using a semiconductor saturable absorber mirror, and 126 fs pulses were obtained at a repetition rate of 192 MHz. At the maximum pump power, the average output power is 315 mW. Shorter mode-locked pulses of 42 and 48 fs were respectively achieved by Kerr-lens mode locking with average output powers of 280 and 360 mW at a repetition rate of 117 MHz.

Power scaling of laser diode pumped Pr3+:LiYF4 cw lasers: efficient laser operation at 522.6 nm, 545.9 nm, 607.2 nm, and 639.5 nm.

PubMed

Gün, Teoman; Metz, Philip; Huber, Günter

2011-03-15

We report efficient cw laser operation of laser diode pumped Pr(3+)-doped LiYF4 crystals in the visible spectral region. Using two InGaN laser diodes emitting at λ(P)=443.9 nm with maximum output power of 1 W each and a 2.9-mm-long crystal with a doping concentration of 0.5%, output powers of 938 mW, 418 mW, 384 mW, and 773 mW were achieved for the laser wavelengths 639.5 nm, 607.2 nm, 545.9 nm, and 522.6 nm, respectively. The maximum absorbed pump powers were approximately 1.5 W, resulting in slope efficiencies of 63.6%, 32.0%, 52.1%, and 61.5%, as well as electro-optical efficiencies of 9.4%, 4.2%, 3.8%, and 7.7%, respectively. Within these experiments, laser diode-pumped laser action at 545.9 nm was demonstrated for what is believed to be the first time.

3.1 W narrowband blue external cavity diode laser

NASA Astrophysics Data System (ADS)

Peng, Jue; Ren, Huaijin; Zhou, Kun; Li, Yi; Du, Weichuan; Gao, Songxin; Li, Ruijun; Liu, Jianping; Li, Deyao; Yang, Hui

2018-03-01

We reported a high-power narrowband blue diode laser which is suitable for subsequent nonlinear frequency conversion into the deep ultraviolet (DUV) spectral range. The laser is based on an external cavity diode laser (ECDL) system using a commercially available GaN-based high-power blue laser diode emitting at 448 nm. Longitudinal mode selection is realized by using a surface diffraction grating in Littrow configuration. The diffraction efficiency of the grating was optimized by controlling the polarization state of the laser beam incident on the grating. A maximum optical output power of 3.1 W in continuous-wave operation with a spectral width of 60 pm and a side-mode suppression ratio (SMSR) larger than 10 dB at 448.4 nm is achieved. Based on the experimental spectra and output powers, the theoretical efficiency and output power of the subsequent nonlinear frequency conversion were calculated according to the Boyd- Kleinman theory. The single-pass conversion efficiency and output power is expected to be 1.9×10-4 and 0.57 mW, respectively, at the 3.1 W output power of the ECDL. The high-power narrowband blue diode laser is very promising as pump source in the subsequent nonlinear frequency conversion.

Diode-pumped quasi-three-level CW Nd:CLNGG and Nd:CNGG lasers.

PubMed

He, Kunna; Wei, Zhiyi; Li, Dehua; Zhang, Zhiguo; Zhang, Huaijin; Wang, Jiyang; Gao, Chunqing

2009-10-12

We have demonstrated what is to our knowledge the first quasi-three-level CW Nd:CLNGG laser with simple linear resonator. When the pump power was 18.2 W, a maximum output power of 1.63 W was obtained at the dual-wavelength of 935 nm and 928 nm. The optical-to-optical conversion efficiency was 9.0% and the slope efficiency was 11.5%. Lasing characteristics of a quasi-three-level CW Nd:CNGG laser were also investigated. A maximum output power of 1.87 W was obtained at the single-wavelength of 935 nm with 15.2 W pump power, corresponding to an optical-to-optical conversion efficiency of 12.3% and a slope efficiency of 15.6%.

Double-pump-pass singly resonant optical parametric oscillator for efficient generation of infrared light at 2300 nm based on PPMgSLT

NASA Astrophysics Data System (ADS)

Lee, Seungmin; Rhee, Bum Ku

2015-02-01

The pump laser was a cw-diode-pumped, acousto-optically Q-switched Nd:YAG laser. The laser had a pulse width of ~85 ns when operating at 10 kHz repetition rates. For infrared output of 2300 nm, we used 35-mm-long PPMgSLT which has a grating period of 32.7 μm for the first-order quasi-phase matching, resulting in the signal wavelength of 1980 nm at the crystal temperature of 76.5oC. Our optical parametric oscillator (OPO) was of a simple linear extra-cavity structure, formed by two flat dichroic mirrors with a separation of ~45 mm. The input coupling mirror had a high transmission of 98% for the pump, high reflectance of 98% at the signal and idler wavelengths, whereas the output coupler had a high reflectance of 98% at the pump wavelength. Hence, the OPO can be considered as singly resonant with double-pass pumping. In order to find an optimum reflectance for the efficient generation of infrared radiation of 2300 nm, we used the three different output mirrors whose reflectivity are ranging from 90% to 38% at the signal wavelength. We measured the signal and idler power as a function of the pumping power of Nd:YAG laser for three different output couplers. A maximum extraction efficiency with an optimum reflectance of output mirror was 27% for the idler, corresponding to 5.6 W of average output power. The fluctuations in the idler root-mean-square output power were measured to be below 1.5%. Our result is comparable with the recent one based on PPLN even with a simple cavity.

Sum frequency mixing of copper vapor laser output in KDP and beta-BBO

NASA Astrophysics Data System (ADS)

Coutts, D. W.; Ainsworth, M. D.; Piper, J. A.

1989-09-01

Generation at 271 nm by frequency summing the two copper vapor laser (CVL) output wavelengths (at 511 and 578 nm) in beta-BBO and KDP is reported. A maximum sum frequency output of 100 mW was obtained for 6.8 W total pump power from a CVL operating with a fully unstable (M = 16) confocal cavity.

40nm tunable multi-wavelength fiber laser

NASA Astrophysics Data System (ADS)

Jia, Qingsong; Wang, Tianshu; Zhang, Peng; Dong, Keyan; Jiang, Huilin

2014-12-01

A Brillouin-Erbium multi-wavelength tunable fiber laser at C-band is demostrated. A 10 km long singlemode fiber(SMF), a 6 m long Erbium-doped fiber, two couplers, a wavelength division multiplexer, a isolator, an optical circulator, a 980nm pump laser and a narrow linewidth tunable laser are included in the structure. A segment of 10 km-long single-mode fiber (SMF) between the two ports of a 1×2 coupler is used as Brillouin gain. Ebiumdoped fiber amplifier (EDFA) consists of a segment of 6m er-doped fiber pumped by 980nm laser dioder . A narrow linewidth tunable laser from 1527 to 1607 nm as Brillouin bump, At the Brillouin pump power of 8mW and the 980 nm pump power of 400 mw, 16 output channels with 0.08 nm spacing and tuning range of 40 nm from 1527 nm to 1567 nm are achieved. We realize the tunable output of wavelength by adjusting the 980 nm pump power and the Brillouin pump wavelength. Stability of the multiwavelength fiber laser is also observed.

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.

Cascaded a-cut Nd:YVO4 self-Raman with second-Stokes laser at 1313 nm

NASA Astrophysics Data System (ADS)

Xie, Zhi; Duan, Yanmin; Guo, Junhong; Huang, Xiaohong; Yan, Lifen; Zhu, Haiyong

2017-11-01

A diode-end-pumped, acousto-optic Q-switched second-Stokes self-Raman laser at 1313 nm was demonstrated in a common a-cut Nd:YVO4 crystal, with the primary Raman shift of 890 cm-1. At the incident pump power of 17.1 W, the maximum average output power up to 2.51 W and pulse width of 5 ns for second-Stokes were obtained with the pulse repetition frequency of 50 kHz. The slope efficiency and conversion efficiency with respect to the incident pump power are about 23.7% and 14.7%. The efficient output should be attributed to suitable transmittance of the output coupler used.

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.

Dual-wavelength mid-infrared CW and Q-switched laser in diode end-pumped Tm,Ho:GdYTaO4 crystal

NASA Astrophysics Data System (ADS)

Wang, Beibei; Gao, Congcong; Dou, Renqin; Nie, Hongkun; Sun, Guihua; Liu, Wenpeng; Yu, Haijuan; Wang, Guoju; Zhang, Qingli; Lin, Xuechun; He, Jingliang; Wang, Wenjun; Zhang, Bingyuan

2018-02-01

Dual-wavelength continuous-wave and Q-switched lasers are demonstrated in a Tm,Ho:GdYTaO4 crystal under 790 nm laser diode end pumping for the first time to the best of our knowledge. The laser operates with a dual wavelength at 1949.677 nm and 2070 nm for continuous-wave with a spacing of about 120 nm. The maximum output power is 0.332 W with a pump power of 3 W. By using graphene as the saturable absorber, a passively Q-switched operation is performed with a dual-wavelength at 1950.323 nm and 2068.064 nm with a wavelength interval of about 118 nm. The maximum average output power of the Q-switched laser goes up to 200 mW with a minimum pulse duration of 1.2 µs and a maximum repetition rate of 34.72 kHz.

High-brightness 800nm fiber-coupled laser diodes

NASA Astrophysics Data System (ADS)

Berk, Yuri; Levy, Moshe; Rappaport, Noam; Tessler, Renana; Peleg, Ophir; Shamay, Moshe; Yanson, Dan; Klumel, Genadi; Dahan, Nir; Baskin, Ilya; Shkedi, Lior

2014-03-01

Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. Single emitters offer reliable multi-watt output power from a 100 m lateral emission aperture. By their combination and fiber coupling, pump powers up to 100 W can be achieved from a low-NA fiber pigtail. Whilst in the 9xx nm spectral range the single emitter technology is very mature with <10W output per chip, at 800nm the reliable output power from a single emitter is limited to 4 W - 5 W. Consequently, commercially available fiber coupled modules only deliver 5W - 15W at around 800nm, almost an order of magnitude down from the 9xx range pumps. To bridge this gap, we report our advancement in the brightness and reliability of 800nm single emitters. By optimizing the wafer structure, laser cavity and facet passivation process we have demonstrated QCW device operation up to 19W limited by catastrophic optical damage to the 100 μm aperture. In CW operation, the devices reach 14 W output followed by a reversible thermal rollover and a complete device shutdown at high currents, with the performance fully rebounded after cooling. We also report the beam properties of our 800nm single emitters and provide a comparative analysis with the 9xx nm single emitter family. Pump modules integrating several of these emitters with a 105 μm / 0.15 NA delivery fiber reach 35W in CW at 808 nm. We discuss the key opto-mechanical parameters that will enable further brightness scaling of multi-emitter pump modules.

Diffraction limited 1064nm monolithic DBR-master oscillator power amplifier with more than 7W output power

NASA Astrophysics Data System (ADS)

Zink, Christof; Maaβdorf, André; Fricke, Jörg; Ressel, Peter; Maiwald, Martin; Sumpf, Bernd; Erbert, Götz; Tränkle, Günther

2018-02-01

High brightness diode lasers with a spectrally narrowband emission, several watts of output power with an almost diffraction limited beam quality are requested light sources for several applications. In this work, a monolithic master oscillator power amplifier will be presented. The resonator of the master oscillator is formed by a high-reflection DBR grating on the rear side and an internal DBR mirror. Its power is amplified in a ridge waveguide followed by a tapered section. The monolithic MOPA provides over 7 W at 1064 nm with a narrow spectral emission width below 20 pm and an almost diffraction limited beam.

Future directions in 980-nm pump lasers: submarine deployment to low-cost watt-class terrestrial pumps

NASA Astrophysics Data System (ADS)

Gulgazov, Vadim N.; Jackson, Gordon S.; Lascola, Kevin M.; Major, Jo S.; Parke, Ross; Richard, Tim; Rossin, Victor V.; Zhang, Kai

1999-09-01

The demands of global bandwidth and distribution are rising rapidly as Internet usage grows. This fundamentally means that more photons are flowing within optical cables. While transmitting sources launches some optical power, the majority of the optical power that is present within modern telecommunication systems originates from optical amplifiers. In addition, modern optical amplifiers offer flat optical gain over broad wavelength bands, thus making possible dense wavelength de-multiplexing (DWDM) systems. Optical amplifier performance, and by extension the performance of the laser pumps that drive them, is central to the future growth of both optical transmission and distribution systems. Erbium-doped amplifiers currently dominate optical amplifier usage. These amplifiers absorb pump light at 980 nm and/or 1480 nm, and achieve gain at wavelengths around 1550 nm. 980 nm pumps achieve better noise figures and are therefore used for the amplification of small signals. Due to the quantum defect, 1480 nm lasers deliver more signal photon per incident photon. In addition, 1480 nm lasers are less expensive than 980 nm lasers. Thus, 1480 nm pump lasers are used for amplification in situations where noise is not critical. The combination of these traits leads to the situation where many amplifiers contain 980 nm lasers to pump the input section of the Er- doped fiber with 1480 nm lasers being used to pump the latter section of Er fiber. This can be thought of as using 980 nm lasers to power an optical pre-amplifier with the power amplification function being pump with 1480 nm radiation. This paper will focus on 980 nm pump lasers and the impact that advances in 980 nm pump technology will have on optical amplification systems. Currently, 980 nm technology is rapidly advancing in two areas, power and reliability. Improving reliability is becoming increasingly important as amplifiers move towards employing more pump lasers and using these pump lasers without redundancy. Since the failure rate allowable for an amplifier is not a function of the number of pumps employed in the amplifier, the allowable failure rate of an individual pump laser is decreasing for next-generation amplifiers. This will lead to specifications for terrestrial pumps well below 1000 FIT, and may lead to the case where high power amplifiers need laser pump reliability to approach 100 FIT. In addition, 980 nm laser diodes are now being deployed in submarine systems where failure rates lower than 100 FIT are commonly specified. It is obvious that both terrestrial and submarine markets are pushing allowable failure rates for pumps for optical amplifiers to continually decrease. A second push for improvement is in the output power of 980 nm pump modules. There exist a number of motivations for increasing the output power of pump lasers. First, each additional channel in a DWDM system requires additional power. To first order, a doubling in channel count implies a doubling in pump power. Second, larger amplifiers require multiple pumps. Higher output power from pump modules allows for fewer pumps, less complicated control systems and smaller size amplifiers. The discussion of this paper will focus on how current development progress of 980 nm laser diodes addresses these issues: better reliability and higher output powers.

High efficiency laser-pumped emerald lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lai, S.T.

1987-09-25

Highly efficient laser operation has been achieved in emerald. In a quasi-cw laser-pumped emerald laser, 64% output slope efficiency has been measured at 768 nm, corresponding to a laser quantum yield of 76%. An output power of 1.6 W was reached at 3.6 W of pump power at 647.1 nm from a krypton laser, and was pump power limited. The emerald laser has a tuning range of 720 to 842 nm. The round trip loss excluding the excited state absorption (ESA) is 0.4%/cm. These results indicate the high laser efficiency and the high optical quality of the emerald attainable inmore » the present laser.« less

Synchronization of 1064 and 1319 nm Pulses Emitted from Actively Mode-Locked Nd:YAG Lasers and Its Application to 589 nm Sum-Frequency Generation

NASA Astrophysics Data System (ADS)

Saito, Norihito; Akagawa, Kazuyuki; Hayano, Yutaka; Saito, Yoshihiko; Takami, Hideki; Iye, Masanori; Wada, Satoshi

2005-11-01

Sum-frequency generation was carried out by mixing 1064 and 1319 nm pulses emitted from actively mode-locked neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers for efficient 589 nm light generation. A radio frequency of approximately 75 MHz was split into two and fed to acousto-optic mode lockers of two lasers for mode-locked operation. The synchronization of the pulses was achieved by controlling the phase difference between the radio frequencies. The maximum output power at 589 nm reached 260 mW, which corresponded to an energy conversion efficiency of more than 13%. The output power was 3.8-fold that in continuous-wave operation.

Continuous 1052, 1064 nm dual-wavelength Nd:YAG laser

NASA Astrophysics Data System (ADS)

Wang, Xiaozhong; Yuan, Haiyang; Wang, Mingshan; Huang, Wencai

2016-10-01

Dual-wavelength lasers are usually obtained through balancing the net gain of the two oscillating lines. Competition between transitions 1052 nm, 1061 nm and 1064 nm is utilized to realize a continuous wave 1052 and 1064 nm dual-wavelength Nd:YAG laser firstly in this paper. A specially designed Fabry-Perot band-pass filter is exploited as output coupler to control the thresholds of the oscillating wavelengths. The maximum power of the dual-wavelength laser is 1.6 W and the slope efficiency is about 10%. The power instability of the output dual-wavelength laser is smaller than ±4% in half an hour. The mechanism presented in this paper may provide a new way to obtain dual-wavelength lasers.

> 6 MW peak power at 532 nm from passively Q-switched Nd:YAG/Cr4+:YAG microchip laser.

PubMed

Bhandari, Rakesh; Taira, Takunori

2011-09-26

Megawatt peak power, giant pulse microchip lasers are attractive for wavelength conversion, provided their output is linearly polarized. We use a [110] cut Cr(4+):YAG for passively Q-switched Nd:YAG microchip laser to obtain a stable, linearly polarized output. Further, we optimize the conditions for second harmonic generation at 532 nm wavelength to achieve > 6 MW peak power, 1.7 mJ, 265 ps, 100 Hz pulses with a conversion efficiency of 85%. © 2011 Optical Society of America

303 nm continuous wave ultraviolet laser generated by intracavity frequency-doubling of diode-pumped Pr3+:LiYF4 laser

NASA Astrophysics Data System (ADS)

Zhu, Pengfei; Zhang, Chaomin; Zhu, Kun; Ping, Yunxia; Song, Pei; Sun, Xiaohui; Wang, Fuxin; Yao, Yi

2018-03-01

We demonstrate an efficient and compact ultraviolet laser at 303 nm generated by intracavity frequency doubling of a continuous wave (CW) laser diode-pumped Pr3+:YLiF4 laser at 607 nm. A cesium lithium borate (CLBO) crystal, cut for critical type I phase matching at room temperature, is used for second-harmonic generation (SHG) of the fundamental laser. By using an InGaN laser diode array emitting at 444.3 nm with a maximum incident power of 10 W, as high as 68 mW of CW output power at 303 nm is achieved. The output power stability in 4 h is better than 2.85%. To the best of our knowledge, this is high efficient UV laser generated by frequency doubling of an InGaN laser diode array pumped Pr3+:YLiF4 laser.

High-power operation of highly reliable narrow stripe pseudomorphic single quantum well lasers emitting at 980 nm

NASA Technical Reports Server (NTRS)

Larsson, A.; Forouhar, S.; Cody, J.; Lang, R. J.

1990-01-01

Ridge waveguide pseudomorphic InGaAs/GaAs/AlGaAs single-quantum-well lasers exhibiting record high quantum efficiencies and high output power densities (105 mW per facet from a 6 micron wide stripe) at a lasing wavelength of 980 nm are discussed that were fabricated from a graded index separate confinement heterostructure grown by molecular beam epitaxy. Life testing at an output power of 30 mW per uncoated facet reveals a slow gradual degradation during the initial 500 h of operation after which the operating characteristics of the lasers become stable. The emission wavelength, the high output power, and the fundamental lateral mode operation render these lasers suitable for pumping Er3+-doped fiber amplifiers.

Red and orange laser operation of Pr:KYF4 pumped by a Nd:YAG/LBO laser at 469.1 nm and a InGaN laser diode at 444 nm.

PubMed

Xu, B; Starecki, F; Pabœuf, D; Camy, P; Doualan, J L; Cai, Z P; Braud, A; Moncorgé, R; Goldner, Ph; Bretenaker, F

2013-03-11

We report the basic luminescence properties and the continuous-wave (CW) laser operation of a Pr(3+)-doped KYF(4) single crystal in the Red and Orange spectral regions by using a new pumping scheme. The pump source is an especially developed, compact, slightly tunable and intra-cavity frequency-doubled diode-pumped Nd:YAG laser delivering a CW output power up to about 1.4 W around 469.1 nm. At this pump wavelength, red and orange laser emissions are obtained at about 642.3 and 605.5 nm, with maximum output powers of 11.3 and 1 mW and associated slope efficiencies of 9.3% and 3.4%, with respect to absorbed pump powers, respectively. For comparison, the Pr:KYF(4) crystal is also pumped by a InGaN blue laser diode operating around 444 nm. In this case, the same red and orange lasers are obtained, but with maximum output powers of 7.8 and 2 mW and the associated slope efficiencies of 7 and 5.8%, respectively. Wavelength tuning for the two lasers is demonstrated by slightly tilting the crystal. Orange laser operation and laser wavelength tuning are reported for the first time.

Efficient upconversion-pumped continuous wave Er3+:LiLuF4 lasers

NASA Astrophysics Data System (ADS)

Moglia, Francesca; Müller, Sebastian; Reichert, Fabian; Metz, Philip W.; Calmano, Thomas; Kränkel, Christian; Heumann, Ernst; Huber, Günter

2015-04-01

We report on detailed spectroscopic investigations and efficient visible upconversion laser operation of Er3+:LiLuF4. This material allows for efficient resonant excited-state-absorption (ESA) pumping at 974 nm. Under spectroscopic conditions without external feedback, ESA at the laser wavelength of 552 nm prevails stimulated emission. Under lasing conditions in a resonant cavity, the high intracavity photon density bleaches the ESA at 552 nm, allowing for efficient cw laser operation. We obtained the highest output power of any room-temperature crystalline upconversion laser. The laser achieves a cw output power of 774 mW at a slope efficiency of 19% with respect to the incident pump power delivered by an optically-pumped semiconductor laser. The absorption efficiency of the pump radiation is estimated to be below 50%. To exploit the high confinement in waveguides for this laser, we employed femtosecond-laser pulses to inscribe a cladding of parallel tracks of modified material into Er3+:LiLuF4 crystals. The core material allows for low-loss waveguiding at pump and laser wavelengths. Under Ti:sapphire pumping at 974 nm, the first crystalline upconversion waveguide laser has been realized. We obtained waveguide-laser operation with up to 10 mW of output power at 553 nm.

Fiber-Based 589 nm Laser for Sodium Guide Star

DTIC Science & Technology

2006-02-01

are combined in a 980/1060 nm WDM coupler and free-space launched through an isolator designed for 1060 nm into a 23 m long Yb doped fiber. This fiber...lenses. The final-stage amplifier comprised a 23 m long YDF with a core diameter of 8 lam and a D-shaped inner cladding of 400 jtm diameter. It was...resolution). (b) High resolution spectrum of the 1178 nm output beam at 534 m W output power, linewidth (FWHM) - 0. 6 nm (0.05 nm resolution). The

5.5nm wavelength-tunable high-power MOPA diode laser system at 971 nm

NASA Astrophysics Data System (ADS)

Tawfieq, Mahmoud; Müller, André; Fricke, Jörg; Della Casa, Pietro; Ressel, Peter; Ginolas, Arnim; Feise, David; Sumpf, Bernd; Tränkle, Günther

2018-02-01

In this work, a widely tunable hybrid master oscillator power amplifier (MOPA) diode laser with 6.2 W of output power at 971.8 nm will be presented. The MO is a DBR laser, with a micro heater embedded on top of the DBR grating for wavelength tunability. The emitted light of the MO is collimated and coupled into a tapered amplifier using micro cylindrical lenses, all constructed on a compact 25 mm × 25 mm conduction cooled laser package. The MOPA system emits light with a measured spectral width smaller than 17 pm, limited by the spectrometer, and with a beam propagation factor of M2 1/e2 = 1.3 in the slow axis. The emission is thus nearly diffraction limited with 79% of the total power within the central lobe (4.9 W diffraction limited). The electrically controlled micro-heater provides up to 5.5 nm of wavelength tunability, up to a wavelength of 977.3 nm, while maintaining an output power variation of only +/- 0.16 % for the entire tuning range.

Diode-pumped continuous-wave and femtosecond Cr:LiCAF lasers with high average power in the near infrared, visible and near ultraviolet.

PubMed

Demirbas, Umit; Baali, Ilyes; Acar, Durmus Alp Emre; Leitenstorfer, Alfred

2015-04-06

We demonstrate continuous-wave (cw), cw frequency-doubled, cw mode-locked and Q-switched mode-locked operation of multimode diode-pumped Cr:LiCAF lasers with record average powers. Up to 2.54 W of cw output is obtained around 805 nm at an absorbed pump power of 5.5 W. Using intracavity frequency doubling with a BBO crystal, 0.9 W are generated around 402 nm, corresponding to an optical-to-optical conversion efficiency of 12%. With an intracavity birefringent tuning plate, the fundamental and frequency-doubled laser output is tuned continuously in a broad wavelength range from 745 nm to 885 nm and from 375 to 440 nm, respectively. A saturable Bragg reflector is used to initiate and sustain mode locking. In the cw mode-locked regime, the Cr:LiCAF laser produces 105-fs long pulses near 810 nm with an average power of 0.75 W. The repetition rate is 96.4 MHz, resulting in pulse energies of 7.7 nJ and peak powers of 65 kW. In Q-switched mode-locked operation, pulses with energies above 150 nJ are generated.

High-power, continuous-wave, mid-infrared optical parametric oscillator based on MgO:sPPLT.

PubMed

Chaitanya Kumar, S; Ebrahim-Zadeh, M

2011-07-01

We report a stable, high-power, cw, mid-IR optical parametric oscillator using MgO-doped stoichiometric periodically poled LiTaO₃ (MgO:sPPLT) pumped by a Yb fiber laser at 1064 nm. The singly resonant oscillator (SRO), based on a 30 mm long crystal, is tunable over 430 nm from 3032 to 3462 nm and can generate as much as 5.5 W of mid-IR output power, with >4 W of over 60% of the tuning range and under reduced thermal effects, enabling room temperature operation. Idler power scaling measurements at ~3.3 μm are compared with an MgO-doped periodically poled LiNbO₃ cw SRO, confirming that MgO:sPPLT is an attractive material for multiwatt mid-IR generation. The idler output at 3299 nm exhibits a peak-to-peak power stability better than 12.8% over 5 h and frequency stability of ~1 GHz, while operating close to room temperature, and has a linewidth of ~0.2 nm, limited by the resolution of the wavemeter. The corresponding signal linewidth at 1570 nm is ~21 MHz.

Compact dual-wavelength Nd:GdVO4 laser working at 1063 and 1065 nm.

PubMed

Wu, Bo; Jiang, Peipei; Yang, Dingzhong; Chen, Tao; Kong, Jian; Shen, Yonghang

2009-04-13

We report a compact diode-laser pumped Nd:GdVO(4) laser with stable dual-wavelength output at 1063 nm and 1065 nm simultaneously. Two types of resonant cavity configurations were presented to support the stable dual-wavelength operation of the laser. Using a polarization beam splitter(PBS) included T-shaped cavity, we obtained a total power output over 5 W in two orthogonal polarized beam directions with 4 W in sigma polarization (1065.5 nm) and 1 W in pi polarization (1063.1 nm). By combining a half-wave-plate with the PBS in the laser cavity, a new configuration favoring one beam direction dual-wavelength output with same polarization direction was realized. A phenomenon of further line splitting was observed in both 1065 nm and 1063 nm.

Diode-pumped Cr-doped ZnMnSe and ZnMgSe lasers

NASA Astrophysics Data System (ADS)

Říha, A.; Němec, M.; Jelínková, H.; Čech, M.; Vyhlídal, D.; Doroshenko, M. E.; Komar, V. K.; Gerasimenko, A. S.

2017-12-01

Chromium ions Cr2+ are known to have good fluorescence properties in the mid-infrared spectral region around the wavelength of 2.5 μm. The aim of this study was the investigation of new laser crystal materials - Zn0.95Mn0.05Se, Zn0.70Mn 0.30Se, and Zn0.75Mg0.25Se doped by Cr2+ ions and comparison of their spectral and laser characteristics. The spectroscopic parameters as absorption and fluorescence spectra as well as lifetimes were measured. As optical pumping the laser diode generating radiation at the wavelength of 1.69 μm (pulse repetition rate 10 Hz, pulse width 2 ms) was used. The longitudinal-pumped resonator was hemispherical with an output coupler radius of curvature 150 mm. The laser emission spectra were investigated and the highest intensity of emitted radiation was achieved at wavelengths 2451 nm, 2469 nm, and 2470 nm from the Cr:Zn0.95Mn0.05Se, Cr:Zn0.70Mn0.30Se, and Cr:Zn0.75Mg0.25Se laser systems, respectively. The input-output characteristics of laser systems were measured; the maximum output peak power 177 mW was obtained for Cr:Zn0.95Mn0.05Se laser system with slope efficiency of 6.3 % with respect to absorbed peak power. The output peak power as well as output beam spatial structure were stable during measurements. For the selection of the lasing wavelength, the single 1.5 mm thick quartz plate was placed at the Brewster angle inside the optical resonator between the output coupler and laser active medium. This element provided the tuning in the wavelength range 2290-2578 nm, 2353-2543 nm, and 2420-2551 nm for Cr:Zn0.95Mn0.05Se, Cr:Zn0.70Mn0.30Se, and Cr:Zn0.75Mg0.25Se, respectively. The obtained spectral FWHM linewidth of the individual output radiation was 10 nm. A comparison with previously measured Cr:ZnSe laser system was added in the end

Generation of efficient 33 GHz optical combs using cascaded stimulated Brillouin scattering effects in optical fiber

NASA Astrophysics Data System (ADS)

Al-Mansoori, M. H.; Al-Sheriyani, A.; Al-Nassri, S.; Hasoon, F. N.

2017-06-01

In this paper, we demonstrate a multi-wavelength Brillouin-erbium fiber laser (BEFL) with ~33 GHz frequency spacing using cascaded stimulated Brillouin scattering effects in optical fiber. The proposed laser structure exhibits a stable output channel with a tuning range of 19 nm, from 1549 nm to 1568 nm. The number of stable output channels produced is six channels with a triple-Brillouin frequency spacing. The output channels exhibit high output power and high optical signal-to-noise ratios (OSNRs). The laser structure has the potential to be used as a multi-wavelength source for optical communication systems.

Diode pumped passively Q-switched Nd:LuAG laser at 1442.6 nm

NASA Astrophysics Data System (ADS)

Guan, Chen; Liu, Zhaojun; Cong, Zhenhua; Liu, Yang; Xu, Xiaodong; Xu, Jun; Huang, Qingjie; Rao, Han; Chen, Xia; Zhang, Yanmin; Wu, Qianwen; Bai, Fen; Zhang, Sasa

2017-02-01

A diode-end-pumped passively Q-switched Nd:LuAG laser at 1442.6 nm was demonstrated with a V3+:YAG crystal as the saturable absorber. Under continuous-wave (CW) operation, the maximum output power of 1.83 W was obtained with an absorbed pumping power of 11.1 W. The corresponding optical-to-optical conversion efficiency was 16.5%. Under Q-switched operation, the maximum average output power of 424 mW was obtained at the same pumping power. The pulse duration and pulse repetition rate were 72 ns and 17.4 kHz, respectively.

Cascaded c-cut Nd:YVO4 self-Raman laser operation with a single 259 cm-1 shift

NASA Astrophysics Data System (ADS)

Guo, Junhong; Zhu, Haiyong; Duan, Yanmin; Xu, Changwen; Ruan, Xiukai; Cui, Guihua; Yan, Lifen

2017-03-01

A cascaded c-cut Nd:YVO4 crystal self-Raman operation was demonstrated with a Raman shift of 259 cm-1. The Stokes oscillation with a primary Raman shift of 890 cm-1 was suppressed and a cascaded self-Raman with a single Raman shift of 259 cm-1 was realized based on suitable coating design. At an incident pump power of 13.3 W, the second Stokes at 1129 nm was obtained as the main output laser and the output power was about 0.81 W. As the incident pump power increased, dual Stokes at 1129 and 1163 nm were obtained. A maximum output power of up to 1.0 W with a conversion efficiency of 6.7% was achieved at an incident pump power of 14.9 W and a pulse repetition frequency of 15 kHz.

Advances in 7xx-nm fiber-coupled modules with application to Tm fiber laser pumping and DPAL (Conference Presentation)

NASA Astrophysics Data System (ADS)

Patterson, Steven G.; Guiney, Tina; Stapleton, Dean; Braker, Joseph; Alegria, Kim; Irwin, David A.; Ebert, Christopher

2017-02-01

DILAS has leveraged its industry-leading work in manufacturing low SWaP fiber-coupled modules extending the wavelength range to 793nm for Tm fiber laser pumping. Ideal for medical, industrial and military applications, modules spanning from single emitter-based 9W to TBar-based 200W of 793nm pump power will be discussed. The highlight is a lightweight module capable of <200W of 793nm pump power out of a package weighing < 400 grams. In addition, other modules spanning from single emitter-based 9W to TBar-based 200W of 793nm pump power will be presented. In addition, advances in DPAL modules, emitting at the technologically important wavelengths near 766nm and 780nm, will be detailed. Highlights include a fully microprocessor controlled fiber-coupled module that produces greater than 400W from a 600 micron core fiber and a line width of only 56.3pm. The micro-processor permits the automated center wavelength and line width tuning of the output over a range of output powers while retaining excellent line center and line width stability over time.

A CW green laser emission by self-sum-frequency-mixing in Nd:GdCOB crystal

NASA Astrophysics Data System (ADS)

Shao, Y.; Jin, H. J.; Lin, J.; Zhang, D.; Tao, Z. H.; Zhang, T. Y.; Li, Y. L.; Ruan, Q. R.

2011-10-01

A compact and efficient green laser light at 538 nm produced by self-sum-frequency-mixing of both fundamental infrared laser waves (1061 and 1091 nm) in Nd:GdCa4O(BO3)3 (Nd:GdCOB) crystal is demonstrated. With 18.2 W of diode pump power, a maximum output power of 1.73 W in the green spectral range at 538 nm has been achieved, corresponding to an optical-to-optical conversion efficiency of 9.5%; the output power stability over 30 min is better than 3%. To the best of our knowledge, this is first work on self-sum-frequency-mixing of a diode pumped Nd:GdCOB laser.

High power continuous operation of a widely tunable quantum cascade laser with an integrated amplifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slivken, S.; Sengupta, S.; Razeghi, M., E-mail: razeghi@eecs.northwestern.edu

2015-12-21

Wide electrical tuning and high continuous output power is demonstrated from a single mode quantum cascade laser emitting at a wavelength near 4.8 μm. This is achieved in a space efficient manner by integrating an asymmetric sampled grating distributed feedback tunable laser with an optical amplifier. An initial demonstration of high peak power operation in pulsed mode is demonstrated first, with >5 W output over a 270 nm (113 cm{sup −1}) spectral range. Refinement of the geometry leads to continuous operation with a single mode spectral coverage of 300 nm (120 cm{sup −1}) and a maximum continuous power of 1.25 W. The output beam is shown tomore » be nearly diffraction-limited, even at high amplifier current.« less

All-fibre ytterbium laser tunable within 45 nm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdullina, S R; Babin, S A; Vlasov, A A

2007-12-31

A tunable ytterbium-doped fibre laser is fabricated. The laser is tuned by using a tunable fibre Bragg grating (FBG) as a selecting intracavity element. The laser is tunable within 45 nm (from 1063 to 1108 nm) and emits {approx}6 W in the line of width {approx}0.15 nm, the output power and linewidth being virtually invariable within the tuning range. The method is proposed for synchronous tuning the highly reflecting and output FBGs, and a tunable ytterbium all-fibre laser is built. (lasers)

High power fiber coupled diode lasers for display and lighting applications

NASA Astrophysics Data System (ADS)

Drovs, Simon; Unger, Andreas; Dürsch, Sascha; Köhler, Bernd; Biesenbach, Jens

2017-02-01

The performance of diode lasers in the visible spectral range has been continuously improved within the last few years, which was mainly driven by the goal to replace arc lamps in cinema or home projectors. In addition, the availability of such high power visible diode lasers also enables new applications in the medical field, but also the usage as pump sources for other solid state lasers. This paper summarizes the latest developments of fiber coupled sources with output power from 1.4 W to 120 W coupled into 100 μm to 400 μm fibers in the spectral range around 405 nm and 640 nm. New developments also include the use of fiber coupled multi single emitter arrays at 450 nm, as well as very compact modules with multi-W output power.

Discrete multi-wavelength tuning of a continuous wave diode-pumped Nd:GdVO4 laser

NASA Astrophysics Data System (ADS)

Nadimi, Mohammad; Waritanant, Tanant; Major, Arkady

2018-05-01

Discrete multi-wavelength operation of a diode-pumped Nd:GdVO4 laser at four different wavelengths was demonstrated using a single birefringent filter plate. The laser achieved maximum output powers of 5.92 W, 5.66 W, 5.56 W and 3.98 W at 1063.2 nm, 1070.8 nm, 1082.5 nm and 1086.2 nm wavelengths, respectively. To the best of our knowledge, apart from achieving the maximum output powers at ~1071 nm and ~1086 nm and best efficiencies at ~1071 nm, ~1083 nm and ~1086 nm wavelengths for a Nd:GdVO4 laser, this is also the largest number of wavelengths from the 4F3/2  →  4I11/2 transition that was ever obtained in a controlled manner from a single laser setup based on any of the Nd-doped laser crystals.

Microchip laser based on Yb:YAG/V:YAG monolith crystal

NASA Astrophysics Data System (ADS)

Nejezchleb, Karel; Šulc, Jan; Jelínková, Helena; Škoda, Václav

2016-03-01

V:YAG crystal was investigated as a passive Q-switch of longitudinally diode-pumped microchip laser, emitting radiation at wavelength 1030.5 nm. This laser was based on diffusion bonded monolith crystal (diameter 3 mm) which combines in one piece an active laser part (Yb:YAG crystal, 10 at.% Yb/Y, 3 mm long) and saturable absorber (V:YAG crystal, 2 mm long, initial transmission 86 % @ 1031 nm). The microchip resonator consisted of dielectric mirrors directly deposited on the monolith surfaces (pump mirror HT @ 968 nm and HR @ 1031 nm on Yb:YAG part, output coupler with reflection 55 % @ 1031 nm on the V:YAG part). For longitudinal CW pumping of Yb:YAG part, a fibre coupled (core diameter 100 μm, NA = 0.22, emission @ 968 nm) laser diode was used. The laser threshold was 3.8W. The laser slope efficiency for output mean in respect to incident pumping was 16 %. The linearly polarized generated transversal intensity beam profile was close to the fundamental Gaussian mode. The generated pulse length, stable and mostly independent on pumping power, was equal to 1.3 ns (FWHM). The single pulse energy was increasing with the pumping power and for the maximum pumping 9.7W it was 78 μJ which corresponds to the pulse peak-power 56 kW. The maximum Yb:YAG/V:YAG microchip laser mean output power of 1W was reached without observable thermal roll-over. The corresponding Q-switched pulses repetition rate was 13.1 kHz.

FDSOI 28nm performances study for RF energy scavenging

NASA Astrophysics Data System (ADS)

Rochefeuille, E.; Alicalapa, F.; Douyère, A.; Vuong, T. P.

2018-03-01

This paper presents a study on an integrated technology: Fully-Depleted-Silicon-On-Insulator (FDSOI) at a 28nm node. FDSOI results are compared to another technology: Complementary-Metal-Oxide-Semiconductor (CMOS) 350nm. The aim of this work was to demonstrate the advantages of using FDSOI technology in RF energy scavenging applications. Characteristics of transistors are pointed out and results showed an improved 22%-output voltage gain for a series rectifier and a 13%-output voltage gain for a Dickson charge pump in FDSOI technology compared to CMOS, for an input voltage and power of 0.5 V and 0 dBm respectively. Those results allowed to prove that FDSOI 28nm is a better technology choice for energy scavenging and low-power applications.

DPSSL and FL pumps based on 980-nm telecom pump laser technology: changing the industry

NASA Astrophysics Data System (ADS)

Lichtenstein, Norbert; Schmidt, Berthold E.; Fily, Arnaud; Weiss, Stefan; Arlt, Sebastian; Pawlik, Susanne; Sverdlov, Boris; Muller, Jurgen; Harder, Christoph S.

2004-06-01

Diode-pumped solid state laser (DPSSL) and fiber laser (FL) are believed to become the dominant systems of very high power lasers in the industrial environment. Today, ranging from 100 W to 5 - 10 kW in light output power, their field of applications spread from biomedical and sensoring to material processing. Key driver for the wide spread of such systems is a competitive ratio of cost, performance and reliability. Enabling high power, highly reliable broad-area laser diodes and laser diode bars with excellent performance at the relevant wavelengths can further optimize this ratio. In this communication we present, that this can be achieved by leveraging the tremendous improvements in reliability and performance together with the high volume, low cost manufacturing areas established during the "telecom-bubble." From today's generations of 980-nm narrow-stripe laser diodes 1.8 W of maximum CW output power can be obtained fulfilling the stringent telecom reliability at operating conditions. Single-emitter broad-area lasers deliver in excess of 11 W CW while from similar 940-nm laser bars more than 160 W output power (CW) can be obtained at 200 A. In addition, introducing telecom-grade AuSn-solder mounting technology on expansion matched subassemblies enables excellent reliability performance. Degradation rates of less than 1% over 1000 h at 60 A are observed for both 808-nm and 940-nm laser bars even under harsh intermittent operation conditions.

A diode-pumped Tm:CaYAlO4 laser at 1851 nm

NASA Astrophysics Data System (ADS)

Lan, Jinglong; Guan, Xiaofeng; Xu, Bin; Moncorgé, Richard; Xu, Huiying; Cai, Zhiping

2017-07-01

Laser emission at ~1850 nm is of great interest for neural stimulation applications. In this letter, we report on the diode-pumped continuous-wave (CW) and Q-switched (QS) laser operation of Tm:CaYAlO4 at 1851 nm, for the first time to our knowledge. In the CW regime, a maximum output power up to 0.62 W is obtained with a laser slope efficiency of about 18.0%. Using a Cr:ZnSe saturable absorber, QS laser operation is achieved with a maximum average output power of 0.25 W, the narrowest pulse width of 107 ns and the highest repetition rate of 5.85 kHz. The corresponding pulse peak power and pulse energy are about 388 W and 42.8 µJ, respectively. In this Q-switched mode, wavelength tuning is also realized over about 3 nm by slightly tilting the saturable absorber.

Efficient laser-diode end-pumped Nd:GGG lasers at 1054 and 1067 nm.

PubMed

Xu, Bin; Xu, Huiying; Cai, Zhiping; Camy, P; Doualan, J L; Moncorgé, R

2014-10-10

Efficient and compact laser-diode end-pumped Nd:GGG simultaneous multiwavelength continuous-wave lasers at ∼1059, ∼1060 and ∼1062  nm were first demonstrated in a free-running 30 mm plano-concave laser cavity. The maximum output power was up to 3.92 W with a slope efficiency of about 53.6% with respect to the absorbed pump power. By inserting a 0.1 mm optical glass plate acting as a Fabry-Pérot etalon, a single-wavelength laser at ∼1067  nm with a maximum output power of 1.95 W and a slope efficiency of 28.5% can be obtained. Multiwavelength lasers, including those at ∼1054 or ∼1067  nm, were also achievable by suitably tilting the glass etalon. These simultaneous multiwavelength lasers provide a potential source for terahertz wave generation.

Cr:ZnSe laser pumped with Tm:YAP microchip laser

NASA Astrophysics Data System (ADS)

Koranda, Petr; Sulc, Jan; Doroshenko, Maxim; Jelinková, Helena; Basiev, Tasoltan T.; Osiko, Vjatcheslav; Badikov, V. V.; Badikov, D.

2010-02-01

Cr:ZnSe laser coherently longitudinally pumped with Tm:YAP microchip laser was realised. The pumping laser consisted of Tm:YAP crystal (3x3 mm) with resonator mirrors deposited directly on its faces (on rear face the dielectric layer with high reflectance for 1998 nm wavelength and high transmittance for 790 nm pumping radiation wavelength; on output face the dielectric layer with reflectance 97% at 1998 nm wavelength). The maximal output power was 5.5 W and the generated radiation wavelength was 1998 nm. The main advantage of this pumping was stable and still output without relaxation spikes (non-spiking). The Tm:YAP laser radiation was collimated and focused by the set of two CaF2 lenses. The pumping beam spot diameter inside the Cr:ZnSe crystal was 300 μm. The Cr:ZnSe laser resonator consisted of flat rear mirror (HT at 1998 nm and HR at 2100 - 2900 nm) and curved output coupler (r = -150 mm, R = 95% at 2100 - 2700 nm). The maximal output energy of stable radiation was 4 mJ (pulse duration 10 ms, repetition rate 10 Hz). For wavelength tuning the Lyott filter (quartz plate under Brewster angle) was placed between the Cr:ZnSe crystal and output coupler. The generated radiation wavelength was continuously tunable from 2246 - 2650 nm.

Development of multiwavelength excitation light source for autofluorescence and photodynamic diagnosis systems

NASA Astrophysics Data System (ADS)

Kenar, Necla; Lim, H. S.; Mirzaaghasi, Amin

2014-02-01

New design of the excitation light source that can stably generate light with center wavelengths of 450nm, 530nm, 632.8nm and white light for auto-fluorescence(AF) and photodynamic diagnosis(PDD) of cancer in clinics in a single system is presented in this study. The light source consists of Xenon Lamp (300W), light guide module including motorize filter wheel equipped with optical filters with corresponding to wavelength bands, servo motor, motorize iris, a cooling system, power supply and optical transmission part for the output light. The transmission part of the light source was developed to collimate the light with desired wavelength into input of fiber optic. Output powers are obtained average 99.91 mW for 450+/-40 nm, 111.01 mW for 530+/-10nm, and 78.50 mW for 632.8+/-10nm.

Microsecond gain-switched master oscillator power amplifier (1958 nm) with high pulse energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ke Yin; Weiqiang Yang; Bin Zhang

2014-02-28

An all-fibre master oscillator power amplifier (MOPA) emitting high-energy pulses at 1958 nm is presented. The seed laser is a microsecond gain-switched thulium-doped fibre laser (TDFL) pumped with a commercial 1550-nm pulsed fibre laser. The TDFL operates at a repetition rate f in the range of 10 to 100 kHz. The two-stage thulium-doped fibre amplifier is built to scale the energy of the pulses generated by the seed laser. The maximum output pulse energy higher than 0.5 mJ at 10 kHz is achieved which is comparable with the theoretical maximum extractable pulse energy. The slope efficiency of the second stagemore » amplifier with respect to the pump power is 30.4% at f = 10 kHz. The wavelength of the output pulse laser is centred near 1958 nm at a spectral width of 0.25 nm after amplification. Neither nonlinear effects nor significant amplified spontaneous emission (ASE) is observed in the amplification experiments. (lasers)« less

Graphene-PVA saturable absorber for generation of a wavelength-tunable passively Q-switched thulium-doped fiber laser in 2.0 µm

NASA Astrophysics Data System (ADS)

Ahmad, H.; Samion, M. Z.; Sharbirin, A. S.; Norizan, S. F.; Aidit, S. N.; Ismail, M. F.

2018-05-01

Graphene, a 2D material, has been used for generation of pulse lasers due to the presence of its various fascinating optical properties compared to other materials. Hence in this paper, we report the first demonstration of a thulium doped fiber laser with a wavelength-tunable, passive Q-switched output using a graphene-polyvinyl-alcohol composite film for operation in the 2.0 µm region. The proposed laser has a wavelength-tunable output spanning from 1932.0 nm to 1946.0 nm, giving a total tuning range of 14.0 nm. The generated pulse has a maximum repetition rate and average output power of 36.29 kHz and 0.394 mW at the maximum pump power of 130.87 mW, as well as a pulse width of 6.8 µs at this pump power. The generated pulses have a stable output, having a signal-to-noise ratio of 31.75 dB, and the laser output is stable when tested over a period of 60 min. The proposed laser would have multiple applications for operation near the 2.0 micron region, especially for bio-medical applications and range-finding.

Development of all-solid-state coherent 589 nm light source: toward the realization of sodium lidar and laser guide star adaptive optics

NASA Astrophysics Data System (ADS)

Saito, Norihito; Akagawa, Kazuyuki; Kato, Mayumi; Takazawa, Akira; Hayano, Yutaka; Saito, Yoshihiko; Ito, Meguru; Takami, Hideki; Iye, Masanori; Wada, Satoshi

2006-12-01

We report an all-solid-state coherent 589 nm light source in single-pass sum-frequency generation (SFG) with actively mode-locked Nd:YAG lasers for the realization of sodium lidar and laser guide star adaptive optics. The Nd:YAG lasers are constructed as a LD-side-pumped configuration and are operated at 1064 and 1319 nm for 589 nm light generation in SFG. Output powers of 16.5 and 5.3 W at 1064 and 1319 nm are obtained with two pumping chambers. Each chamber consisted of three 80-W-LD arrays. Single transverse mode TEM 00; M2 ~1.1 is achieved with adjustment of cavity length considering thermal lens effect with increase of input LD power. The cavity length is set to approximately 1 m. Accordingly the mode-locked lasers are operated at a repetition rate of approximately 150 MHz. Synchronization of two pulse trains at 1064 and 1319 nm is accomplished by control of phase difference between two radio frequencies input in acousto-optic mode-lockers. Then temporal delay is controlled with a resolution of 37 ps/degree. Pump beams are mixed in periodically poled stoichiometric lithium tantalate (PPSLT) without an antireflection coating. The effective aperture and length of the crystal are 0.5 × 2 mm2 and 15 mm. When input intensity is set at 5.6 MW/cm , an average output power of 4.6 W is obtained at 589.159 nm. Precise tuning to the sodium D II line is accomplished by thermal control of etalons set in the Nd:YAG lasers. The output power at 589.159 nm is stably maintained within +/-1.2% for 8 hours.

Increasing power and amplified spontaneous emission suppression for weak signal amplification in pulsed fiber amplifier

NASA Astrophysics Data System (ADS)

Luo, Yi; Zhang, Hanwei; Wang, Xiaolin; Su, Rongtao; Ma, Pengfei; Zhou, Pu; Jiang, Zongfu

2017-10-01

In the pulsed fiber amplifiers with repetition frequency of several tens kHz, amplified spontaneous emission (ASE) is easy to build up because of the low repetition frequency and weak pulse signal. The ASE rises the difficulty to amplify the weak pulse signal effectively. We have demonstrated an all-fiber preamplifier stage structure to amplify a 40 kHz, 10 ns bandwidth (FWHM) weak pulse signal (299 μW) with center wavelength of 1062 nm. Compared synchronous pulse pump with continuous wave(CW) pump, the results indicate that synchronous pulse pump shows the better capability of increasing the output power than CW pump. In the condition of the same pump power, the output power of synchronous pulse pump is twice as high as CW pump. In order to suppress ASE, a longer gain fiber is utilized to reabsorb the ASE in which the wavelength is shorter than 1062nm. We amplified weak pulse signal via 0.8 m and 2.1 m gain fiber in synchronous pulse pump experiments respectively, and more ASE in the output spectra are observed in the 0.8 m gain fiber system. Due to the weaker ASE and consequent capability of higher pump power, the 2.1 m gain fiber is capable to achieve higher output power than shorter fiber. The output power of 2.1 m gain fiber case is limited by pump power.

Ultra-wideband all-fiber tunable Tm/Ho-co-doped laser at 2 μm.

PubMed

Xue, Guanghui; Zhang, Bin; Yin, Ke; Yang, Weiqiang; Hou, Jing

2014-10-20

We demonstrate an all-fiber tunable Tm/Ho-codoped laser operating in the 2 μm wavelength region. The wavelength tuning range of the Tm/Ho-codoped fiber laser (THFL) with 1-m length of Tm/Ho-codoped fiber (THDF) was from 1727 nm to 2030 nm. Efficient short wavelength operation and ultra-wide wavelength tuning range of 303 nm were both achieved. To the best of our knowledge, this is the broadest tuning range that has been reported for an all-fiber rare-earth-doped laser to date. By increasing the THDF length to 2 m, the obtainable wavelength of the THFL was further red-shifted to the range from 1768 nm to 2071 nm. The output power of the THFL was scaled up from 1810 nm to 2010 nm by using a stage of Tm/Ho-codoped fiber amplifier (THFA), which exhibited the maximum slope efficiency of 42.6% with output power of 408 mW at 1910 nm.

Area-Efficient 60 GHz +18.9 dBm Power Amplifier with On-Chip Four-Way Parallel Power Combiner in 65-nm CMOS

NASA Astrophysics Data System (ADS)

Farahabadi, Payam Masoumi; Basaligheh, Ali; Saffari, Parvaneh; Moez, Kambiz

2017-06-01

This paper presents a compact 60-GHz power amplifier utilizing a four-way on-chip parallel power combiner and splitter. The proposed topology provides the capability of combining the output power of four individual power amplifier cores in a compact die area. Each power amplifier core consists of a three-stage common-source amplifier with transformer-coupled impedance matching networks. Fabricated in 65-nm CMOS process, the measured gain of the 0.19-mm2 power amplifier at 60 GHz is 18.8 and 15 dB utilizing 1.4 and 1.0 V supply. Three-decibel band width of 4 GHz and P1dB of 16.9 dBm is measured while consuming 424 mW from a 1.4-V supply. A maximum saturated output power of 18.3 dBm is measured with the 15.9% peak power added efficiency at 60 GHz. The measured insertion loss is 1.9 dB at 60 GHz. The proposed power amplifier achieves the highest power density (power/area) compared to the reported 60-GHz CMOS power amplifiers in 65 nm or older CMOS technologies.

Continuous-wave laser at 440 nm based on frequency-doubled diode-pumped Nd:GdVO(4) crystal.

PubMed

Castaing, Marc; Balembois, François; Georges, Patrick

2008-09-01

We present for the first time, to the best of our knowledge, a frequency-doubled Nd:GdVO(4) laser operating in a cw on the pure three-level laser line at 880 nm. We obtained 300 mW at 440 nm for 23 W of incident pump power at 808 nm. Moreover, with a 25% output coupler we obtained a cw power of 1.9 W at the fundamental wavelength at 880 nm.

High power Yb:CALGO ultrafast regenerative amplifier for industrial application

NASA Astrophysics Data System (ADS)

Caracciolo, E.; Guandalini, A.; Pirzio, F.; Kemnitzer, M.; Kienle, F.; Agnesi, A.; Aus der Au, J.

2017-02-01

We present a high-power, single-crystal based, Yb:CALGO regenerative amplifier. The system delivers more than 50 W output power in continuous-wave regime, with diffraction limited beam quality. In Q-switching regime the spectrum is centered at 1043 nm and is 11 nm wide. In regenerative amplification experiments we achieved 34 W at 500 kHz with 12.7 nm FWHM wide spectra centered at 1044 nm seeding with a broadly tunable, single-prism SESAM mode-locked Yb:CALGO laser providing 9 nm wide spectra at 1049 nm. Pulse duration after compression was 140 fs, with excellent beam quality (M2 < 1.25).

Dual-comb self-mode-locked monolithic Yb:KGW laser with orthogonal polarizations.

PubMed

Chang, M T; Liang, H C; Su, K W; Chen, Y F

2015-04-20

The dependence of lasing threshold on the output transmission is numerically analyzed to find the condition for the gain-to-loss balance for the orthogonal Np and Nm polarizations with a Ng-cut Yb:KGW laser crystal. With the numerical analysis, an orthogonally polarized dual-comb self-mode-locked operation is experimentally achieved with a coated Yb:KGW crystal to form a monolithic cavity. At a pump power of 5.2 W, the average output power, the pulse repetition rate, and the pulse duration are measured to be 0.24 (0.6) W, 25.8 (25.3) GHz, and 1.06 (1.12) ps for the output along the Np (Nm) polarization.

Studies on 405nm blue-violet diode laser with external grating cavity

NASA Astrophysics Data System (ADS)

Li, Bin; Gao, Jun; Zhao, Jun; Yu, Anlan; Luo, Shiwen; Xiong, Dongsheng; Wang, Xinbing; Zuo, Duluo

2016-03-01

Spectroscopy applications of free-running laser diodes (LD) are greatly restricted as its broad band spectral emission. And the power of a single blue-violet LD is around several hundred milliwatts by far, it is of great importance to obtain stable and narrow line-width laser diodes with high efficiency. In this paper, a high efficiency external cavity diode laser (ECDL) with high output power and narrow band emission at 405 nm is presented. The ECDL is based on a commercially available LD with nominal output power of 110 mW at an injection current of 100 mA. The spectral width of the free-running LD is about 1 nm (FWHM). A reflective holographic grating which is installed on a home-made compact adjustable stage is utilized for optical feedback in Littrow configuration. In this configuration, narrow line-width operation is realized and the effects of grating groove density as well as the groove direction related to the beam polarization on the performances of the ECDL are experimentally investigated. In the case of grating with groove density of 3600 g/mm, the threshold is reduced from 21 mA to 18.3 mA or 15.6 mA and the tuning range is 3.95 nm or 6.01 nm respectively when the grating is orientated in TE or TM polarization. In addition, an output beam with a line-width of 30 pm and output power of 92.7 mW is achieved in TE polarization. With these narrow line-width and high efficiency, the ECDL is capable to serve as a light source for spectroscopy application such as Raman scattering and laser induced fluorescence.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schearer, L.D.; Leduc, M.

Over 250 mW of CW laser emission at 1084 nm is obtained from Nd:LiNbO{sub 3} when the rod is end-pumped along the crystalline {open quote}{ital y}{close quote} axis by 1 W from a Kr{sup +} laser at 752 nm. The laser can be tuned over 3 nm at the 1084 nm peak with a thin, uncoated etalon in the cavity. Thresholds of 30 mW of absorbed pump power were obtained with a weak output coupler, rising to 220 mW with a 35% transmitting output mirror. No pump-induced photorefractive effects were observed.

Passively Q-switched microchip Er, Yb:YAl3(BO3)4 diode-pumped laser.

PubMed

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

2012-07-01

We report, for the first time to our knowledge, a diode-pumped cw and passively Q-switched microchip Er, Yb:YAl(3)(BO(3))(4) laser. A maximal output power of 800 mW at 1602 nm in the cw regime was obtained at an absorbed pump power of 7.7 W. By using Co(2+):MgAl(2)O(4) as a saturable absorber, a TEM(00)-mode Q-switched average output power of 315 mW was demonstrated at 1522 nm, with pulse duration of 5 ns and pulse energy of 5.25 μJ at a repetition rate of 60 kHz.

Average power scaling of UV excimer lasers drives flat panel display and lidar applications

NASA Astrophysics Data System (ADS)

Herbst, Ludolf; Delmdahl, Ralph F.; Paetzel, Rainer

2012-03-01

Average power scaling of 308nm excimer lasers has followed an evolutionary path over the last two decades driven by diverse industrial UV laser microprocessing markets. Recently, a new dual-oscillator and beam management concept for high-average power upscaling of excimer lasers has been realized, for the first time enabling as much as 1.2kW of stabilized UV-laser average output power at a UV wavelength of 308nm. The new dual-oscillator concept enables low temperature polysilicon (LTPS) fabrication to be extended to generation six glass substrates. This is essential in terms of a more economic high-volume manufacturing of flat panel displays for the soaring smartphone and tablet PC markets. Similarly, the cost-effective production of flexible displays is driven by 308nm excimer laser power scaling. Flexible displays have enormous commercial potential and can largely use the same production equipment as is used for rigid display manufacturing. Moreover, higher average output power of 308nm excimer lasers aids reducing measurement time and improving the signal-to-noise ratio in the worldwide network of high altitude Raman lidar stations. The availability of kW-class 308nm excimer lasers has the potential to take LIDAR backscattering signal strength and achievable altitude to new levels.

A tunable erbium-doped fiber ring laser with power-equalized output

NASA Astrophysics Data System (ADS)

Yeh, Chien-Hung; Lin, Ming-Ching; Chi, Sien

2006-12-01

We propose and demonstrate a tunable erbium-based fiber ring laser with power-equalized output. When a mode-restricting intracavity fiber Fabry-Perot tunable filter (FFP-TF) is combined, the proposed resonator can guarantee a tunable laser oscillation. This proposed laser can obtain the flatter lasing wavelength in an effectively operating range of 1533.3 to 1574.6 nm without any other operating mechanism. Moreover, the performances of the output power, wavelength tuning range, and side-mode suppression ratio (SMSR) were studied.

The characteristics of Kerr-lens mode-locked self-Raman Nd:YVO4 1176 nm laser

NASA Astrophysics Data System (ADS)

Li, Zuohan; Peng, Jiying; Yao, Jianquan; Han, Ming

2017-03-01

In this paper we report on a compact and feasible dual-concave cavity CW Kerr-lens mode-locked self-Raman Nd:YVO4 laser. A self-starting diode-pumped picosecond Nd:YVO4 1176 nm laser is demonstrated without any additional components, where the stimulated Stokes Raman scattering and Kerr-lens-induced mode locking are operated in the same crystal. With an incident pump power of 12 W, the average output power at 1176 nm is up to 643 mW. Meanwhile, the repetition rate and the pulse width of the fundamental laser are measured to be 1.53 GHz and 8.6 ps, respectively. In addition, the yellow laser output at 588 nm is realized by frequency doubling with a LiB3O5 crystal.

The effect of low-level laser irradiation on dog spermatozoa motility is dependent on laser output power.

PubMed

Corral-Baqués, M I; Rivera, M M; Rigau, T; Rodríguez-Gil, J E; Rigau, J

2009-09-01

Biological tissues respond to low-level laser irradiation and so do dog spermatozoa. Among the main parameters to be considered when a biological tissue is irradiated is the output power. We have studied the effects on sperm motility of 655 nm continuous wave diode laser irradiation at different output powers with 3.34 J (5.97 J/cm(2)). The second fraction of fresh dog sperm was divided into five groups: control, and four to be irradiated with an average output power of 6.8 mW, 15.4 mW, 33.1 mW and 49.7 mW, respectively. At 0 min and 45 min after irradiation, pictures were taken and a computer aided sperm analysis (CASA) performed to analyse different motility parameters. The results showed that different output powers affected dog semen motility parameters differently. The highest output power showed the most intense effects. Significant changes in the structure of the motile sperm subpopulation were linked to the different output powers used.

High energy 523 nm ND:YLF pulsed slab laser with novel pump beam waveguide design

NASA Astrophysics Data System (ADS)

Yang, Qi; Zhu, Xiaolei; Ma, Jian; Lu, Tingting; Ma, Xiuhua; Chen, Weibiao

2015-11-01

A laser diode pumped Nd:YLF master oscillator power amplifier (MOPA) green laser system with high pulse energy and high stable output is demonstrated. At a repetition rate of 50 Hz, 840 mJ pulse energy, 9.1 ns pulse width of 1047 nm infrared laser emitting is obtained from the MOPA system. The corresponding peak power is 93 MW. Extra-cavity frequency doubling with a LiB3O5 crystal, pulse energy of 520 mJ at 523 nm wavelength is achieved. The frequency conversion efficiency reaches up to 62%. The output pulse energy instability of the laser system is less than 0.6% for one hour.

kW-level commercial Yb-doped aluminophosphosilicate ternary laser fiber

NASA Astrophysics Data System (ADS)

Sun, Shihao; Zhan, Huan; Li, Yuwei; Liu, Shuang; Jiang, Jiali; Peng, Kun; Wang, Yuying; Ni, Li; Wang, Xiaolong; Jiang, Lei; Yu, Juan; Liu, Gang; Lu, Pengfei; Wang, Jianjun; Jing, Feng; Lin, Aoxiang

2018-03-01

Based on a master oscillator power amplifier configuration, laser performance of commercial Nufern-20/400-8M Ybdoped aluminophosphosilicate ternary laser fiber was investigated. Pumped by 976 nm laser diodes, 982 W laser output power was obtained with a slope efficiency of 84.9%. Spectrum of output was centered at 1066.56nm with 3dB bandwidth less than 0.32 nm, and the nonlinearity suppression ratio was more than 39dB. Beam quality of Mx2 and M2y were 1.55 and 1.75 at 982 W, respectively. The laser performance indicated that Nufern-20/400-8M Yb-doped aluminophosphosilicate ternary laser fiber is highly competitive for industry fiber laser use.

Backward pumping kilowatt Yb3+-doped double-clad fiber laser

NASA Astrophysics Data System (ADS)

Han, Z. H.; Lin, X. C.; Hou, W.; Yu, H. J.; Zhou, S. Z.; Li, J. M.

2011-09-01

A ytterbium-doped double-clad fiber laser generating up to 1026 W of continuous-wave output power at 1085 nm with a slope efficiency of 74% by single-ended backward pumping configuration is reported. The core diameter was 20 μm with a low numerical aperture of 0.06, and a good beam quality (BPP < 1.8 mm mrad) is achieved without special mode selection methods. No undesirable roll-over was observed in output power with increasing pump power, and the maximum output power was limited by the available pump power. The instability of maximum output power was better than ±0.6%. Different pumping configurations were also compared in experiment, which shows good agreements with theoretical analyses.

Wavelength stabilized multi-kW diode laser systems

NASA Astrophysics Data System (ADS)

Köhler, Bernd; Unger, Andreas; Kindervater, Tobias; Drovs, Simon; Wolf, Paul; Hubrich, Ralf; Beczkowiak, Anna; Auch, Stefan; Müntz, Holger; Biesenbach, Jens

2015-03-01

We report on wavelength stabilized high-power diode laser systems with enhanced spectral brightness by means of Volume Holographic Gratings. High-power diode laser modules typically have a relatively broad spectral width of about 3 to 6 nm. In addition the center wavelength shifts by changing the temperature and the driving current, which is obstructive for pumping applications with small absorption bandwidths. Wavelength stabilization of high-power diode laser systems is an important method to increase the efficiency of diode pumped solid-state lasers. It also enables power scaling by dense wavelength multiplexing. To ensure a wide locking range and efficient wavelength stabilization the parameters of the Volume Holographic Grating and the parameters of the diode laser bar have to be adapted carefully. Important parameters are the reflectivity of the Volume Holographic Grating, the reflectivity of the diode laser bar as well as its angular and spectral emission characteristics. In this paper we present detailed data on wavelength stabilized diode laser systems with and without fiber coupling in the spectral range from 634 nm up to 1533 nm. The maximum output power of 2.7 kW was measured for a fiber coupled system (1000 μm, NA 0.22), which was stabilized at a wavelength of 969 nm with a spectral width of only 0.6 nm (90% value). Another example is a narrow line-width diode laser stack, which was stabilized at a wavelength of 1533 nm with a spectral bandwidth below 1 nm and an output power of 835 W.

Investigation of continuous wave and pulsed laser performance based on Nd3+:Gd0.6Y1.4SiO5 crystal

NASA Astrophysics Data System (ADS)

Feng, Chao; Liu, Zhaojun; Cong, Zhenhua; Shen, Hongbin; Li, Yongfu; Wang, Qingpu; Fang, Jiaxiong; Xu, Xiaodong; Xu, Jun; Zhang, Xingyu

2015-12-01

We systematically investigated a laser diode (LD) pumped Nd:GYSO (Nd3+:Gd0.6Y1.4SiO5) laser. The output power of the continuous wave laser was as high as 3.5 W with a slope efficiency of 31.8%. In the Q-switched operation; the laser exhibited dual-wavelengths output (1073.6 nm and 1074.7 nm) synchronously with a Cr4+:YAG as the saturable absorber (SA). Additionally, a passively mode-locked laser was demonstrated using a semiconductor SA mirror with a maximum average output power of 510 mW at a central wavelength of 1074 nm, while the pulse width of the laser was as short as 5 ps. Our experiment proved that the Nd:GYSO mixed crystal was a promising material for a solid-state laser.

Demonstration of multi-wavelength tunable fiber lasers based on a digital micromirror device processor.

PubMed

Ai, Qi; Chen, Xiao; Tian, Miao; Yan, Bin-bin; Zhang, Ying; Song, Fei-jun; Chen, Gen-xiang; Sang, Xin-zhu; Wang, Yi-quan; Xiao, Feng; Alameh, Kamal

2015-02-01

Based on a digital micromirror device (DMD) processor as the multi-wavelength narrow-band tunable filter, we demonstrate a multi-port tunable fiber laser through experiments. The key property of this laser is that any lasing wavelength channel from any arbitrary output port can be switched independently over the whole C-band, which is only driven by single DMD chip flexibly. All outputs display an excellent tuning capacity and high consistency in the whole C-band with a 0.02 nm linewidth, 0.055 nm wavelength tuning step, and side-mode suppression ratio greater than 60 dB. Due to the automatic power control and polarization design, the power uniformity of output lasers is less than 0.008 dB and the wavelength fluctuation is below 0.02 nm within 2 h at room temperature.

High-power and highly reliable 638-nm band BA-LD for CW operation

NASA Astrophysics Data System (ADS)

Nishida, Takehiro; Kuramoto, Kyosuke; Abe, Shinji; Kusunoki, Masatsugu; Miyashita, Motoharu; Yagi, Tetsuya

2018-02-01

High-power laser diodes (LDs) are strongly demanded as light sources of display applications. In multiple spatial light modulator-type projectors or liquid crystal displays, the light source LDs are operated under CW condition. The high-power 638-nm band broad-area LD for CW operation was newly developed. The LD consisted of two stripes with each width of 75 μm to reduce both an optical power density at a front facet and a threshold current. The newly improved epitaxial technology was also applied to the LD to suppress an electron overflow from an active layer. The LD showed superior output characteristics, such as output of 1.77 W at case temperature of 55 °C with wall plug efficiency (WPE) of 23%, which was improved by 40% compared with the current product. The peak WPE at 25 °C reached 40.6% under the output power of 2.37 W, CW, world highest.

Simultaneous triple 914 nm, 1084 nm, and 1086 nm operation of a diode-pumped Nd:YVO4 laser

NASA Astrophysics Data System (ADS)

Lü, Yanfei; Xia, Jing; Liu, Huilong; Pu, Xiaoyun

2014-10-01

We report a diode-pumped continuous-wave (cw) triple-wavelength Nd:YVO4 laser operating at 914, 1084, and 1086 nm. A theoretical analysis has been introduced to determine the threshold conditions for simultaneous triple-wavelength laser. Using a T-shaped cavity, we realized an efficient triple-wavelength operation at 4F3/2→4I9/2 and 4F3/2→4I11/2 transitions for Nd:YVO4 crystal, simultaneously. At an absorbed pump power of 16 W (or 25 W of incident pump power), the maximum output power was 2.3 W, which included 914 nm, 1084 nm, and 1086 nm three wavelengths, and the optical conversion efficiency with respect to the absorbed pump power was 14.4%.

Single- and dual-wavelength laser operation of a diode-pumped Nd:LaF3 single crystal around 1.05 μm and 1.32 μm

NASA Astrophysics Data System (ADS)

Xu, Bin; Huang, Xiaoxu; Lan, Jinglong; Lin, Zhi; Wang, Yi; Xu, Huiying; Cai, Zhiping; Moncorgé, Richard

2016-07-01

Calibrated room temperature polarized emission spectra recorded between 850 and 1400 nm and nearly free from any reabsorption effect are presented for the first time. A laser output power of 2.35 W is obtained at 1063.45 nm with a laser slope efficiency of about 56% by pumping an uncoated Nd:LaF3 single crystal with a fiber-coupled laser diode at 790 nm inside a standard two-mirror linear laser cavity. True dual-wavelength laser operation on two orthogonally polarized laser lines around 1040 and 1065 nm as well as continuous laser wavelength tuning around 1040 nm, 1048 nm and 1064 nm are also achieved for the first time by using either an intracavity etalon or a birefringent filter. Laser operation is finally obtained around 1330.73 nm with a maximum output power of 0.18 W and a laser slope efficiency of about 4% and simultaneous dual-wavelength laser operation at 1329.04 and 1359.67 nm is demonstrated by using a glass etalon.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shlapakovski, A.; Gorev, S.; Krasik, Ya. E.

The influence of laser beam parameters on the output pulses of a resonant microwave compressor with a laser-triggered plasma switch was investigated. The S-band compressor, consisting of a rectangular waveguide-based cavity and H-plane waveguide tee with a shorted side arm, was filled with pressurized dry air and pumped by 1.8-μs-long microwave pulses of up to 450 kW power. A Nd:YAG laser was used to ignite the gas discharge in the tee side arm for output pulse extraction. The laser beam (at 213 nm or 532 nm) was directed along the RF electric field lines. It was found that the compressor operated most effectivelymore » when the laser beam was focused at the center of the switch waveguide cross-section. In this case, the power extraction efficiency reached ∼47% at an output power of ∼14 MW, while when the laser beam was not focused the maximal extraction efficiency was only ∼20% at ∼6 MW output power. Focusing the laser beam resulted also in a dramatic decrease (down to <1 ns) in the delay of the output pulses' appearance with respect to the time of the beam's entrance into the switch, and the jitter of the output pulses' appearance was minimized. In addition, the quality of the output pulses' waveform was significantly improved.« less

Investigative study of a diode-pumped continuous-wave Tm:YAP laser as an efficient 1.94 μm pump source

NASA Astrophysics Data System (ADS)

Kwiatkowski, Jacek; Zendzian, Waldemar; Jabczynski, Jan K.

2016-12-01

A detailed study of a Tm:YAP laser in continuous-wave (CW), single-pass end-pumped by a 793 nm diode laser is presented. The laser based on c-cut 3 at. % Tm:YAP crystal was experimentally examined and presented in the dependence on transmittance and radius of curvature of output coupling mirrors. A detailed spectral analysis was presented. The influence of a heat-sink cooling water temperature on the laser performance was studied. At room temperature, for an output coupling transmission of 19.5%, the maximum CW output power of 4.53 W was achieved, corresponding to a slope efficiency of 41.5% and an optical-to-optical conversion efficiency of 25.7% with respect to the incident pump power, respectively. We have shown that the output spectrum at a certain wavelength (e.g. 1940 nm) for a given pump power can be realized via the change of resonator parameters (OC transmittance, mode size).

High-power diode-pumped solid-state lasers for optical space communications

NASA Technical Reports Server (NTRS)

Koechner, Walter; Burnham, Ralph; Kasinski, Jeff; Bournes, Pat; Dibiase, Don; Le, Khoa; Marshall, Larry; Hays, Alan

1991-01-01

The design and performance of a large diode-pumped multi-stage Nd:YAG laser system for space and airborne applications will be described. The laser operates at a repetition rate of 40 Hz and produces an output either at 1.064 micron or 532 nm with an average power in the Q-switched mode of 30 W at the fundamental and 20 W at the second harmonic wavelength. The output beam is diffraction limited (TEM 00 mode) and can optionally also be operated in a single longitudinal mode. The output energy ranges from 1.25 Joule/pulse in the free lasing mode, 0.75 Joule in a 17 nsec Q-switched pulse, to 0.5 Joules/pulse at 532 nm. The overall electrical efficiency for the Q-switched second harmonic output is 4.

The simulation of thermal characteristics of 980 nm vertical cavity surface emitting lasers

NASA Astrophysics Data System (ADS)

Fang, Tianxiao; Cui, Bifeng; Hao, Shuai; Wang, Yang

2018-02-01

In order to design a single mode 980 nm vertical cavity surface emitting laser (VCSEL), a 2 μm output aperture is designed to guarantee the single mode output. The effects of different mesa sizes on the lattice temperature, the output power and the voltage are simulated under the condition of continuous working at room temperature, to obtain the optimum process parameters of mesa. It is obtained by results of the crosslight simulation software that the sizes of mesa radius are between 9.5 to 12.5 μm, which cannot only obtain the maximum output power, but also improve the heat dissipation of the device. Project supported by the Beijing Municipal Eduaction Commission (No. PXM2016_014204_500018) and the Construction of Scientific and Technological Innovation Service Ability in 2017 (No. PXM2017_014204_500034).

A global design of high power Nd 3+-Yb 3+ co-doped fiber lasers

NASA Astrophysics Data System (ADS)

Fan, Zhang; Chuncan, Wang; Tigang, Ning

2008-09-01

A global optimization method - niche hybrid genetic algorithm (NHGA) based on fitness sharing and elite replacement is applied to optimize Nd3+-Yb3+ co-doped fiber lasers (NYDFLs) for obtaining maximum signal output power. With a objective function and different pumping powers, five critical parameters (the fiber length, L; the proportion of pump power for pumping Nd3+, η; Nd3+ and Yb3+ concentrations, NNd and NYb and output mirror reflectivity, Rout) of the given NYDFLs are optimized by solving the rate and power propagation equations. Results show that dividing equally the input pump power among 808 nm (Nd3+) and 940 nm (Yb3+) is not an optimal choice and the pump power of Nd3+ ions should be kept around 10-13.78% of the total pump power. Three optimal schemes are obtained by NHGA and the highest slope efficiency of the laser is able to reach 80.1%.

Tunable high-power blue external cavity semiconductor laser

NASA Astrophysics Data System (ADS)

Ding, Ding; Lv, Xueqin; Chen, Xinyi; Wang, Fei; Zhang, Jiangyong; Che, Kaijun

2017-09-01

A commercially available high-power GaN-based blue laser diode has been operated in a simple Littrow-type external cavity (EC). Two kinds of EC configurations with the grating lines perpendicular (A configuration) and parallel (B configuration) to the p-n junction are evaluated. Good performance has been demonstrated for the EC laser with B configuration due to the better mode selection effect induced by the narrow feedback wavelength range from the grating. Under an injection current of 1100 mA, the spectral linewidth is narrowed significantly down to ∼0.1 nm from ∼1 nm (the free-running width), with a good wavelength-locking behavior and a higher than 35 dB-amplified spontaneous emission suppression ratio. Moreover, a tuning bandwidth of 3.6 nm from 443.9 nm to 447.5 nm is realized with output power of 1.24 W and EC coupling efficiency of 80% at the central wavelength. The grating-coupled blue EC laser with narrow spectral linewidth, flexible wavelength tunability, and high output power shows potential applications in atom cooling and trapping, high-resolution spectroscopy, second harmonic generation, and high-capacity holographic data storage.

Scalable waveguide design for three-level operation in Neodymium doped fiber laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pax, Paul H.; Khitrov, Victor V.; Drachenberg, Derrek R.

We have constructed a double clad neodymium doped fiber laser operating on the three-level 4F 3/2 → 4I 9/2 transition. The laser has produced 11.5 W at 925 nm with 55% slope efficiency when pumped at 808 nm, comparable to the best previous results for a double-clad fiber configuration on this transition. Higher power pumping with both 808 nm and 880 nm sources resulted in an output of 27 W, albeit at lower slope efficiency. In both cases, output power was limited by available pump, indicating the potential for further power scaling. To suppress the stronger four-level 4F 3/2 →more » 4I 11/2 transition we developed a waveguide that provides spectral filtering distributed along the length of the fiber, based on an all-solid micro-structured optical fiber design, with resonant inclusions creating a leakage path to the cladding. Furthermore, the waveguide supports large mode areas and provides strong suppression at selectable wavelength bands, thus easing the restrictions on core and cladding sizes that limited power scaling of previous approaches.« less

Scalable waveguide design for three-level operation in Neodymium doped fiber laser

DOE PAGES

Pax, Paul H.; Khitrov, Victor V.; Drachenberg, Derrek R.; ...

2016-12-12

We have constructed a double clad neodymium doped fiber laser operating on the three-level 4F 3/2 → 4I 9/2 transition. The laser has produced 11.5 W at 925 nm with 55% slope efficiency when pumped at 808 nm, comparable to the best previous results for a double-clad fiber configuration on this transition. Higher power pumping with both 808 nm and 880 nm sources resulted in an output of 27 W, albeit at lower slope efficiency. In both cases, output power was limited by available pump, indicating the potential for further power scaling. To suppress the stronger four-level 4F 3/2 →more » 4I 11/2 transition we developed a waveguide that provides spectral filtering distributed along the length of the fiber, based on an all-solid micro-structured optical fiber design, with resonant inclusions creating a leakage path to the cladding. Furthermore, the waveguide supports large mode areas and provides strong suppression at selectable wavelength bands, thus easing the restrictions on core and cladding sizes that limited power scaling of previous approaches.« less

Compact and efficient CW 473nm blue laser with LBO intracavity frequency doubling

NASA Astrophysics Data System (ADS)

Qi, Yan; Wang, Yu; Wang, Yanwei; Zhang, Jing; Yan, Boxia

2016-10-01

With diode end pumped Nd:YAG directly and LBO intracavity frequency doubling, a compact, high efficient continuous wave blue laser at 473nm is realized. When the incident pump power reach 6.2W, 630mW maximum output power of blue laser at 473nm is achieved with 15mm long LBO, the optical-to-optical conversion efficiency is as high as 10.2%.

All-fiber, ultra-wideband tunable laser at 2 μm.

PubMed

Li, Z; Alam, S U; Jung, Y; Heidt, A M; Richardson, D J

2013-11-15

We report a direct diode-pumped all-fiber tunable laser source at 2 μm with a tuning range of more than 250 nm. A 3 dB power flatness of 200 nm with a maximum output power of 30 mW at 1930 nm was achieved. The laser has a high optical signal-to-noise ratio (OSNR) of more than 40 dB across the whole tuning range.

1.5  kW ytterbium-doped single-transverse-mode, linearly polarized monolithic fiber master oscillator power amplifier.

PubMed

Huang, Long; Ma, Pengfei; Tao, Rumao; Shi, Chen; Wang, Xiaolin; Zhou, Pu

2015-04-01

A linearly polarized monolithic fiber laser based on a master oscillator power amplifier structure with a master oscillator and a one-stage power amplifier is reported. We design a homemade oscillator based on the theory that, in the coiled gain fiber, the higher modes and the polarized mode of the fundamental mode along the fast axis are suppressed effectively because of their obviously higher bend loss than that of the polarized mode of the fundamental mode along the slow axis. The oscillator operates at 1080 nm, launching a 30 W seed laser with a high polarization extinction ratio of 19 dB into the power amplifier via a mode field adapter. The power amplifier utilizes Yb-doped polarization-maintaining fiber of 20/400  μm, which produces nearly diffraction-limited output power of about 1.5 kW with an optical-optical efficiency of 81.5% and a polarization extinction ratio of 13.8 dB. Both the M(x)² factor and the M(y)² factor of the collimated beam are measured to be about 1.2. The spectral width of the output power is broadened approximately linearly, and the full width at half maximum of the spectrum at the maximum output power is about 5.8 nm. It is known as the highest linearly polarized output power to the best of our knowledge.

Design and fabrication of six-volt vertically-stacked GaAs photovoltaic power converter

PubMed Central

Zhao, Yongming; Sun, Yurun; He, Yang; Yu, Shuzhen; Dong, Jianrong

2016-01-01

A six-volt vertically-stacked, high current GaAs photovoltaic power converter (PPC) has been designed and fabricated to produce output power over 1 W under monochromatic illumination. An N++-GaAs/P++-AlGaAs tunnel junctions (TJs) structure has been used for connecting each sub-cell in this vertically-stacked PPC device. The thickness of the each GaAs sub-cell has been derived based on the calculation of absorption depth of photons with a wavelength of 808 nm using absorption coefficient obtained from ellipsometry measurements. The devices were characterized under non-uniform CW laser illumination at 808 nm with incident power up to 4.1 W. A maximum conversion efficiency of 50.2% was achieved at 0.3 W under non-uniform (coupled in optical fiber) monochromatic illumination, dropping to 42.5% at 4.1 W. The operating voltage at the maximum power point is 5.5–6.0 V, depending on the incident laser power, and an output electrical power output of 1.3 W can be extracted at a laser power of 2.9 W and the maximum electrical power output amounts to 1.72 W. The external quantum efficiency (EQE) measurement indicates that the performance of PPC can be further improved by refining the design of the thickness of sub-cells and improving TJs. PMID:27901079

Continuous-wave dual-wavelength operation of a distributed feedback laser diode with an external cavity using a volume Bragg grating

NASA Astrophysics Data System (ADS)

Zheng, Yujin; Sekine, Takashi; Kurita, Takashi; Kato, Yoshinori; Kawashima, Toshiyuki

2018-03-01

We demonstrate continuous-wave dual-wavelength operation of a broad-area distributed feedback (DFB) laser diode with a single external-cavity configuration. This high-power DFB laser has a narrow bandwidth (<0.29 nm) and was used as a single-wavelength source. A volume Bragg grating was used as an output coupler for the external-cavity DFB laser to output another stable wavelength beam with a narrow bandwidth of 0.27 nm. A frequency difference for dual-wavelength operation of 0.88 THz was achieved and an output power of up to 415 mW was obtained. The external-cavity DFB laser showed a stable dual-wavelength operation over the practical current and temperature ranges.

Advances in generation of high-repetition-rate burst mode laser output.

PubMed

Jiang, Naibo; Webster, Matthew C; Lempert, Walter R

2009-02-01

It is demonstrated that the incorporation of variable pulse duration flashlamp power supplies into an Nd:YAG burst mode laser system results in very substantial increases in the realizable energy per pulse, the total pulse train length, and uniformity of the intensity envelope. As an example, trains of 20 pulses at burst frequencies of 50 and 20 kHz are demonstrated with individual pulse energy at 1064 nm of 220 and 400 mJ, respectively. Conversion efficiency to the second- (532 nm) and third- (355 nm) harmonic wavelengths of approximately 50% and 35-40%, respectively, is also achieved. Use of the third-harmonic output of the burst mode laser as a pump source for a simple, home built optical parametric oscillator (OPO) produces pulse trains of broadly wavelength tunable output. Sum-frequency mixing of OPO signal output at 622 nm with residual output from the 355 nm pump beam is shown to produce uniform bursts of tunable output at approximately 226 nm, with individual pulse energy of approximately 0.5 mJ. Time-correlated NO planar laser induced fluorescence (PLIF) image sequences are obtained in a Mach 3 wind tunnel at 500 kHz, representing, to our knowledge, the first demonstration of NO PLIF imaging at repetition rates exceeding tens of hertz.

Investigation of the Low Power Stage of an 1178 nm Raman System

DTIC Science & Technology

2013-12-23

LEANNE HENRY, DR-III, DAF KENTON T. WOOD, DR-IV, DAF Work Unit Manager Chief, Laser Division This report is published in the...and 1069 nm pumped Raman laser system where the second Stokes is amplified in a 1121 nm resonator defined by high reflector fiber Bragg gratings (FBGs...the gratings was found to impact the performance of the laser and needs to be dealt with in order to obtain high 1178 nm output power levels. In order

Vertical cavity surface-emitting semiconductor lasers with injection laser pumping

NASA Astrophysics Data System (ADS)

McDaniel, D. L., Jr.; McInerney, J. G.; Raja, M. Y. A.; Schaus, C. F.; Brueck, S. R. J.

1990-05-01

Continuous-wave GaAs/GaAlAs edge-emitting diode lasers were used to pump GaAs/AlGaAs and InGaAs/AlGaAs vertical cavity surface-emitting lasers (VCSELs) with resonant periodic gain (RPG) at room temperature. Pump threshold as low as 11 mW, output powers as high as 27 mW at 850 nm, and external differential quantum efficiencies of about 70 percent were observed in GaAs/AlGaAs surface -emitters; spectral brightness 22 times that of the pump laser was also observed. Output powers as high as 85 mW at 950 nm and differential quantum efficiencies of up to 58 percent were recorded for the InGaAs surface-emitting laser. This is the highest quasi-CW output power ever reported for any RPG VCSEL, and the first time such a device has been pumped using an injection laser diode.

Fabrication of the polarization independent spectral beam combining grating

NASA Astrophysics Data System (ADS)

Liu, Quan; Jin, Yunxia; Wu, Jianhong; Guo, Peiliang

2016-03-01

Owing to damage, thermal issues, and nonlinear optical effects, the output power of fiber laser has been proven to be limited. Beam combining techniques are the attractive solutions to achieve high-power high-brightness fiber laser output. The spectral beam combining (SBC) is a promising method to achieve high average power output without influencing the beam quality. A polarization independent spectral beam combining grating is one of the key elements in the SBC. In this paper the diffraction efficiency of the grating is investigated by rigorous coupled-wave analysis (RCWA). The theoretical -1st order diffraction efficiency of the grating is more than 95% from 1010nm to 1080nm for both TE and TM polarizations. The fabrication tolerance is analyzed. The polarization independent spectral beam combining grating with the period of 1.04μm has been fabricated by holographic lithography - ion beam etching, which are within the fabrication tolerance.

Diode-pumped continuous-wave and passively Q-switched Nd:GdLuAG laser at 1443.9 nm

NASA Astrophysics Data System (ADS)

Wu, Qianwen; Liu, Zhaojun; Zhang, Sasa; Cong, Zhenghua; Guan, Chen; Xue, Feng; Chen, Hui; Huang, Qingjie; Xu, Xiaodong; Xu, Jun; Qin, Zengguang

2017-12-01

We investigated the 1443.9 nm laser characteristics of Nd:GdLuAG crystal. Diode-end-pumping configuration was employed under both continuous-wave (CW) and passively Q-switched operations. For CW operation, the maximum average output power was 1.36 W with a slope efficiency of 15%. By using a V3+:YAG crystal as the saturable absorber, we obtained the maximum average output power of 164 mW under Q-switched operation. The corresponding pulse energy was 29.3 μJ and pulse duration was 59 ns.

Femtosecond (191 fs) NaY(WO4)2 Tm,Ho-codoped laser at 2060 nm.

PubMed

Lagatsky, A A; Han, X; Serrano, M D; Cascales, C; Zaldo, C; Calvez, S; Dawson, M D; Gupta, J A; Brown, C T A; Sibbett, W

2010-09-15

We report, for the first time to our knowledge, femtosecond-pulse operation of a Tm,Ho:NaY(WO(4))(2) laser at around 2060 nm. Transform-limited 191 fs pulses are produced with an average output power of 82 mW at a 144 MHz pulse repetition frequency. Maximum output power of up to 155 mW is generated with a corresponding pulse duration of 258 fs. An ion-implanted InGaAsSb quantum-well-based semiconductor saturable absorber mirror is used for passive mode-locking maintenance.

A high power diode-side-pumped Nd:YAG/BaWO4 Raman laser at 1103 nm

NASA Astrophysics Data System (ADS)

Li, Lei; Zhang, Xingyu; Liu, Zhaojun; Wang, Qingpu; Cong, Zhenhua; Zhang, Yuangeng; Wang, Weitao; Wu, Zhenguo; Zhang, Huaijin

2013-04-01

Pulsed operation at 1103 nm of a diode-side-pumped Nd:YAG laser with intracavity Raman shifting in BaWO4 is reported. The first Stokes wavelength at 1103 nm was generated by a Raman shift of 332 cm-1 from the fundamental wave (1064 nm). A maximum power at 1103 nm of 9.4 W was obtained for a diode pump power of 115 W at a pulse repetition rate of 15 kHz. The pump-to-Stokes conversion efficiency was up to 8.2%. When the output power at 1103 nm was over 7 W, a second Stokes line at 1145 nm was also observed in the experiment. Our research indicates that efficient Raman conversion can be realized by a Raman frequency shift at 332 cm-1 in BaWO4 Raman lasers.

A high power, continuous-wave, single-frequency fiber amplifier at 1091 nm and frequency doubling to 545.5 nm

NASA Astrophysics Data System (ADS)

Stappel, M.; Steinborn, R.; Kolbe, D.; Walz, J.

2013-07-01

We present a high power single-frequency ytterbium fiber amplifier system with an output power of 30 W at 1091 nm. The amplifier system consists of two stages, a preamplifier stage in which amplified spontaneous emission is efficiently suppressed (>40 dB) and a high power amplifier with an efficiency of 52%. Two different approaches to frequency doubling are compared. We achieve 8.6 W at 545.5 nm by single-pass frequency doubling in a MgO-doped periodically poled stoichiometric LiTaO3 crystal and up to 19.3 W at 545.5 nm by frequency doubling with a lithium-triborate crystal in an external enhancement cavity.

An efficient continuous-wave 591 nm light source based on sum-frequency mixing of a diode pumped Nd:GdVO4-Nd:CNGG laser

NASA Astrophysics Data System (ADS)

Zhao, Y. D.; Liu, J. H.

2013-08-01

We report a laser architecture to obtain continuous-wave (CW) yellow-orange light sources at the 591 nm wavelength. An 808 nm diode pumped a Nd:GdVO4 crystal emitting at 1063 nm. A part of the pump power was then absorbed by the Nd:CNGG crystal. The remaining pump power was used to pump a Nd:CNGG crystal emitting at 1329 nm. Intracavity sum-frequency mixing at 1063 and 1329 nm was then realized in a LiB3O5 (LBO) crystal to reach the yellow-orange radiation. We obtained a CW output power of 494 mW at 591 nm with a pump laser diode emitting 17.8 W at 808 nm.

Concentric Parallel Combining Balun for Millimeter-Wave Power Amplifier in Low-Power CMOS with High-Power Density

NASA Astrophysics Data System (ADS)

Han, Jiang-An; Kong, Zhi-Hui; Ma, Kaixue; Yeo, Kiat Seng; Lim, Wei Meng

2016-11-01

This paper presents a novel balun for a millimeter-wave power amplifier (PA) design to achieve high-power density in a 65-nm low-power (LP) CMOS process. By using a concentric winding technique, the proposed parallel combining balun with compact size accomplishes power combining and unbalance-balance conversion concurrently. For calculating its power combination efficiency in the condition of various amplitude and phase wave components, a method basing on S-parameters is derived. Based on the proposed parallel combining balun, a fabricated 60-GHz industrial, scientific, and medical (ISM) band PA with single-ended I/O achieves an 18.9-dB gain and an 8.8-dBm output power at 1-dB compression and 14.3-dBm saturated output power ( P sat) at 62 GHz. This PA occupying only a 0.10-mm2 core area has demonstrated a high-power density of 269.15 mW/mm2 in 65 nm LP CMOS.

Surgical effects on soft tissue produced by a 405-nm violet diode laser in vivo

NASA Astrophysics Data System (ADS)

Miyazaki, H.; Kato, J.; Kawai, S.; Hatayama, H.; Uchida, K.; Otsuki, M.; Tagami, J.; Yokoo, S.

2011-12-01

This study evaluated the surgical performance of a 405-nm diode laser in vivo, using living rat liver tissue. Tissue was incised by irradiation with the laser at low output power ranging from 1 W (722 W/cm2) to 3 W (2165 W/cm2) on a manual control at a rate of 1 mm/s. As a control, incisions using a stainless scalpel were compared. Immediately after operation, the surface of the incisions was macroscopically observed and histopathologically evaluated by microscopy. Laser-ablated liver tissue was smooth with observable signs of remnant carbonization and easily acquired hemostasis. The thickness of the denatured layer increased in proportion to the output power; the coagulation layer did not thicken accordingly. Bleeding could not be stopped for tissues incised with the stainless scalpel. The 405-nm diode laser thus proved to be effective for ablating soft tissue with high hemostatic ability at low power.

Cladding-pumped ytterbium-doped fiber laser with radially polarized output.

PubMed

Lin, Di; Daniel, J M O; Gecevičius, M; Beresna, M; Kazansky, P G; Clarkson, W A

2014-09-15

A simple technique for directly generating a radially polarized output beam from a cladding-pumped ytterbium-doped fiber laser is reported. Our approach is based on the use of a nanograting spatially variant waveplate as an intracavity polarization-controlling element. The laser yielded ~32 W of output power (limited by available pump power) with a radially polarized TM (01)-mode output beam at 1040 nm with a corresponding slope efficiency of 66% and a polarization purity of 95%. The beam-propagation factor (M(2)) was measured to be ~1.9-2.1.

Efficient single-mode (TEM{sub 00}) Nd : YVO{sub 4} laser with longitudinal 808-nm diode pumping

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2013-10-31

A single-mode Nd : YVO{sub 4} laser with unidirectional longitudinal pumping by laser diodes with λ = 808 nm and a power of 40 W is studied. In the TEM{sub 00} mode, the output laser power is 24 W with the optical efficiency η{sub opt} = 57.1 % (slope efficiency 63.3 %), which, as far as we know, is the best result for Nd{sup 3+} : YVO{sub 4} lasers with longitudinal pumping at λ = 808 nm from one face of the active crystal. Estimates of thermal effects show that, using a Nd : YVO{sub 4} crystal (length 20 mm,more » diameter 3 mm, dopant concentration 0.27 at%) with two undoped ends and bidirectional diode pumping with a total power of 170 W, one can obtain an output power of ∼100 W in the TEM{sub 00} mode from one active element. (lasers)« less

Theoretical and experimental study on the Nd:YAG/BaWO4/KTP yellow laser generating 8.3 W output power.

PubMed

Cong, Zhenhua; Zhang, Xingyu; Wang, Qingpu; Liu, Zhaojun; Chen, Xiaohan; Fan, Shuzhen; Zhang, Xiaolei; Zhang, Huaijin; Tao, Xutang; Li, Shutao

2010-06-07

A diode-side-pumped actively Q-switched intracavity frequency-doubled Nd:YAG/BaWO(4)/KTP Raman laser is studied experimentally and theoretically. Rate equations are used to analyze the Q-switched yellow laser by considering the transversal distributions of the intracavity photon density and the inversion population density. An 8.3 W 590 nm laser is obtained with a 125.8 W 808 nm pump power and a 15 kHz pulse repetition frequency. The corresponding optical conversion efficiency from diode laser to yellow laser is 6.57%, much higher than that of the former reported side-pumped yellow laser. The output powers with respect to the incident pump power are in agreement with the theoretical results on the whole.

Self-mode-locking operation of a diode-end-pumped Tm:YAP laser with watt-level output power

NASA Astrophysics Data System (ADS)

Zhang, Su; Zhang, Xinlu; Huang, Jinjer; Wang, Tianhan; Dai, Junfeng; Dong, Guangzong

2018-03-01

We report on a high power continuous wave (CW) self-mode-locked Tm:YAP laser pumped by a 792 nm laser diode. Without any additional mode-locking elements in the cavity, stable and self-starting mode-locking operation has been realized. The threshold pump power of the CW self-mode-locked Tm:YAP laser is only 5.4 W. The maximum average output power is as high as 1.65 W at the pump power of 12 W, with the repetition frequency of 468 MHz and the center wavelength of 1943 nm. To the best of our knowledge, this is the first CW self-mode-locked Tm:YAP laser. The experiment results show that the Tm:YAP crystal is a promising gain medium for realizing the high power self-mode-locking operation at 2 µm.

Multi-Watt femtosecond optical parametric master oscillator power amplifier at 43 MHz.

PubMed

Mörz, Florian; Steinle, Tobias; Steinmann, Andy; Giessen, Harald

2015-09-07

We present a high repetition rate mid-infrared optical parametric master oscillator power amplifier (MOPA) scheme, which is tunable from 1370 to 4120nm. Up to 4.3W average output power are generated at 1370nm, corresponding to a photon conversion efficiency of 78%. Bandwidths of 6 to 12nm with pulse durations between 250 and 400fs have been measured. Strong conversion saturation over the whole signal range is observed, resulting in excellent power stability. The system consists of a fiber-feedback optical parametric oscillator that seeds an optical parametric power amplifier. Both systems are pumped by the same Yb:KGW femtosecond oscillator.

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.

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.

Broadband light generation by femtosecond pulse amplification with stimulated Raman scattering in a high-power erbium-doped fiber amplifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamura, K.; Yoshida, E.; Sugawa, T.

1995-08-01

It is shown for the first time to our knowledge that short-pulse amplification in high-power erbium-doped fiber amplifiers, simultaneously accompanied by stimulated Raman scattering, generates a broadband optical spectrum at high output power (270 mW). At 20 dB down from the peak the continuum extended over 329 nm, from 1427 to 1756 nm. The FWHM bandwidth was 125 nm, centered at 1650 nm. The coherence was measured to be 15 fringes, which corresponds to a 25-{mu}m coherence length. {copyright} {ital 1995} {ital Optical} {ital Society} {ital of} {ital America}.

High power resonant pumping of Tm-doped fiber amplifiers in core- and cladding-pumped configurations.

PubMed

Creeden, Daniel; Johnson, Benjamin R; Rines, Glen A; Setzler, Scott D

2014-11-17

We have demonstrated ultra-high efficiency amplification in Tm-doped fiber with both core- and cladding-pumped configurations using a resonant tandem-pumping approach. These Tm-doped fiber amplifiers are pumped in-band with a 1908 nm Tm-doped fiber laser and operate at 1993 nm with >90% slope efficiency. In a core-pumped configuration, we have achieved 92.1% slope efficiency and 88.4% optical efficiency at 41 W output power. In a cladding-pumped configuration, we have achieved 123.1 W of output power with 90.4% optical efficiency and a 91.6% slope efficiency. We believe these are the highest optical efficiencies achieved in a Tm-doped fiber amplifier operating in the 2-micron spectral region.

Beam shaping by using small-aperture SLM and DM in a high power laser

NASA Astrophysics Data System (ADS)

Li, Sensen; Lu, Zhiwei; Du, Pengyuan; Wang, Yulei; Ding, Lei; Yan, Xiusheng

2018-03-01

High-power laser plays an important role in many fields, such as directed energy weapon, optoelectronic contermeasures, inertial confinement fusion, industrial processing and scientific research. The uniform nearfield and wavefront are the important part of the beam quality for high power lasers, which is conducive to maintaining the high spatial beam quality in propagation. We demonstrate experimentally that the spatial intensity and wavefront distribution at the output is well compensated in the complex high-power solid-state laser system by using the small-aperture spatial light modulator (SLM) and deformable mirror (DM) in the front stage. The experimental setup is a hundred-Joule-level Nd:glass laser system operating at three wavelengths at 1053 nm (1ω), 527 nm (2ω) and 351 nm (3ω) with 3 ns pulse duration with the final output beam aperture of 60 mm. While the clear arperture of the electrically addressable SLM is less than 20 mm and the effective diameter of the 52-actuators DM is about 15 mm. In the beam shaping system, the key point is that the two front-stage beam shaping devices needs to precompensate the gain nonuniform and wavefront distortion of the laser system. The details of the iterative algorithm for improving the beam quality are presented. Experimental results show that output nearfield and wavefont are both nearly flat-topped with the nearfield modulation of 1.26:1 and wavefront peak-to-valley value of 0.29 λ at 1053nm after beam shaping.

Highly stable, efficient Tm-doped fiber laser—a potential scalpel for low invasive surgery

NASA Astrophysics Data System (ADS)

Michalska, M.; Brojek, W.; Rybak, Z.; Sznelewski, P.; Mamajek, M.; Swiderski, J.

2016-11-01

We report an all-fiber, diode-pumped, continuous-wave Tm3+-doped fiber laser emitting 37.4 W of output power with a slope efficiency as high as 57% with respect to absorbed pump power at 790 nm. The laser operated at ~1.94 µm and the output beam quality factor M 2 was measured to be ~1.2. The output beam was very stable with power fluctuations  <1% measured over 1 h. The laser system is to be implemented as a scalpel for low-invasive soft-tissue surgery.

Thulium fiber laser for the use in low-invasive endoscopic and robotic surgery of soft biological tissues

NASA Astrophysics Data System (ADS)

Michalska, M.; Brojek, W.; Rybak, Z.; Sznelewski, P.; Mamajek, M.; Gogler, S.; Swiderski, J.

2016-12-01

An all-fiber, diode-pumped, continuous-wave Tm3+-doped fiber laser operated at a wavelength of 1.94 μm was developed. 37.4 W of output power with a slope efficiency as high as 57% with respect to absorbed pump power at 790 nm was demonstrated. The laser output beam quality factor M2 was measured to be 1.2. The output beam was very stable with power fluctuations <1% measured over 1 hour. The laser system is to be implemented as a scalpel for surgery of soft biological tissues.

Spectral narrowing of a 980 nm tapered diode laser bar

NASA Astrophysics Data System (ADS)

Vijayakumar, Deepak; Jensen, Ole Bjarlin; Lucas Leclin, Ga"lle; Petersen, Paul Michael; Thestrup, Birgitte

2011-03-01

High power diode laser bars are interesting in many applications such as solid state laser pumping, material processing, laser trapping, laser cooling and second harmonic generation. Often, the free running laser bars emit a broad spectrum of the order of several nanometres which limit their scope in wavelength specific applications and hence, it is vital to stabilize the emission spectrum of these devices. In our experiment, we describe the wavelength narrowing of a 12 element 980 nm tapered diode laser bar using a simple Littman configuration. The tapered laser bar which suffered from a big smile has been "smile corrected" using individual phase masks for each emitter. The external cavity consists of the laser bar, both fast and slow axis micro collimators, smile correcting phase mask, 6.5x beam expanding lens combination, a 1200 lines/mm reflecting grating with 85% efficiency in the first order, a slow axis focusing cylindrical lens of 40 mm focal length and an output coupler which is 10% reflective. In the free running mode, the laser emission spectrum was 5.5 nm wide at an operating current of 30A. The output power was measured to be in excess of 12W. Under the external cavity operation, the wavelength spread of the laser could be limited to 0.04 nm with an output power in excess of 8 W at an operating current of 30A. The spectrum was found to be tuneable in a range of 16 nm.

High repetition-rate Q-switched and intracavity doubled diode-pumped Nd:YAG laser

NASA Technical Reports Server (NTRS)

Hemmati, Hamid; Lesh, James R.

1992-01-01

A Nd:YAG laser was end pumped with 2.2 W of continuous-wave (CW) diode laser output. Efficient operation of the laser at high repetition rates was emphasized. This laser provides 890 mW of TEM00 CW output at 1064 nm, and 340 mW of 532 nm average power at a Q-switched repetition rate of 25 kHz. Experimental data are compared with analysis.

Laser at 532 nm by intracavity frequency-doubling in BBO

NASA Astrophysics Data System (ADS)

Yuan, Xiandan; Wang, Jinsong; Chen, Yongqi; Wu, Yulong; Qi, Yunfei; Sun, Meijiao; Wang, Qi

2017-06-01

A simple and compact linear resonator green laser at 532 nm is generated by intracavity frequency-doubling of a diode-side-pumped acousto-optically (AO) Q-switched Nd:YAG laser at 1064 nm. Two acousto-optic Q-switches were placed orthogonally with each other to improve the hold-off capacity. As high as 214 W of continuous-wave (CW) and 154 W of quasi-continuous-wave (QCW) output power at 1064 nm were obtained when the pumping power was 1598 W. The type I phase-matched BBO crystal was used as the nonlinear medium in the second harmonic generation. A green laser with an average output power of 37 W was obtained at a repetition rate of 20 kHz and a pulse width of 54 ns, which corresponds to pulse energy of 1.85 mJ per pulse and a peak power 34.26 kW, respectively. Project supported by the Beijing Engineering Technology Research Center of All-Solid-State Lasers Advanced Manufacturing, the National High Technology Research and Development Program of China (No. 2014AA032607), and the National Natural Science Foundation of China (Nos. 61404135, 61405186, 61308032, 61308033).

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.

Highly stable self-pulsed operation of an Er:Lu2O3 ceramic laser at 2.7 µm

NASA Astrophysics Data System (ADS)

Wang, Li; Huang, Haitao; Shen, Deyuan; Zhang, Jian; Chen, Hao; Tang, Dingyuan

2017-04-01

We report on the highly stable self-pulsed operation of a 2.74 µm Er:Lu2O3 ceramic laser pumped by a wavelength locked narrow bandwidth 976 nm laser diode. The operating pulse repetition rate is continuously tunable from 126 kHz to 270 kHz depending on the pump power level. For 12.3 W of absorbed diode pump power, the Er:Lu2O3 ceramic laser generates 820 mW of average output power at a 270 kHz repetition rate and with a pulse duration of 183 ns. The corresponding pulse-to-pulse amplitude fluctuation is estimated to be less than 0.7%. In the continues-wave (CW) mode of operation, the laser yields over 1.3 W of output power with a slope efficiency of 11.9% with respect to the 976 nm pump power.

10 W single-mode Er/Yb co-doped all-fiber amplifier with suppressed Yb-ASE

NASA Astrophysics Data System (ADS)

Sobon, G.; Sliwinska, D.; Abramski, K. M.; Kaczmarek, P.

2014-02-01

In this work we demonstrate a single-frequency, single-mode all-fiber master oscillator power amplifier (MOPA) source, based on erbium-ytterbium co-doped double-clad fiber emitting 10 W of continuous wave power at 1565 nm. In the power amplifier stage, the amplified spontaneous emission from Yb3+ ions (Yb-ASE) is forced to recirculate in a loop resonator in order to provide stable lasing at 1060 nm. The generated signal acts as an additional pump source for the amplifier and is reabsorbed by the Yb3+ ions in the active fiber, allowing an increase in the efficiency and boosting the output power. The feedback loop also protects the amplifier from parasitic lasing or self-pulsing at a wavelength of 1 μm. This allows one to significantly scale the output power in comparison to a conventional setup without any Yb-ASE control.

Efficient visible and UV generation by frequency conversion of a mode-filtered fiber amplifier

NASA Astrophysics Data System (ADS)

Kliner, Dahv A. V.; Di Teodoro, Fabio; Koplow, Jeffrey P.; Moore, Sean W.; Smith, Arlee V.

2003-07-01

We have generated the second, third, fourth, and fifth harmonics of the output of a Yb-doped fiber amplifier seeded by a passively Q-switched Nd:YAG microchip laser. The fiber amplifier employed multimode fiber (25 μm core diameter, V ~ 7.4) to provide high-peak-power pulses, but diffraction-limited beam quality was obtained by use of bend-loss-induced mode filtering. The amplifier output had a pulse duration of 0.97 ns and smooth, transform-limited temporal and spectral profiles (~500 MHz linewidth). We obtained high nonlinear conversion efficiencies using a simple optical arrangement and critically phase-matched crystals. Starting with 320 mW of average power at 1064 nm (86 ´J per pulse at a 3.7 kHz repetition rate), we generated 160 mW at 532 nm, 38 mW at 355 nm, 69 mW at 266 nm, and 18 mW at 213 nm. The experimental results are in excellent agreement with calculations. Significantly higher visible and UV powers will be possible by operating the fiber amplifier at higher repetition rates and pulse energies and by further optimizing the nonlinear conversion scheme.

Theoretical and experimental investigations on high peak power Q-switched Nd:YAG laser at 1112 nm

NASA Astrophysics Data System (ADS)

He, Miao; Yang, Feng; Wang, Zhi-Chao; Gao, Hong-Wei; Yuan, Lei; Li, Chen-Long; Zong, Nan; Shen, Yu; Bo, Yong; Peng, Qin-Jun; Cui, Da-Fu; Xu, Zu-Yan

2018-07-01

We report on the experimental measurement and theoretical analysis on a Q-switched high peak power laser diode (LD) side-pumped 1112 nm Nd:YAG laser by means of special mirrors coating design in cavity. In theory, a numerical model, based on four-wavelength rate equations, is performed to analyze the competition process of different gain lines and the output characteristics of the Q-switched Nd:YAG laser. In the experiment, a maximum output power of 25.2 W with beam quality factor M2 of 1.46 is obtained at the pulse repetition rate of 2 kHz and 210 ns of pulse width, corresponding to a pulse energy and peak power of 12.6 mJ and 60 kW, respectively. The experimental data agree well with the theoretical simulation results.

Coherence and linewidth studies of a 4-nm high power FEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fawley, W.M.; Sessler, A.M.; Scharlemann, E.T.

Recently the SSRL/SLAC and its collaborators elsewhere have considered the merits of a 2 to 4-nm high power FEL utilizing the SLAC linac electron beam. The FEL would be a single pass amplifier excited by spontaneous emission rather than an oscillator, in order to eliminate the need for a soft X-ray resonant cavity. We have used GINGER, a multifrequency 2D FEL simulation code, to study the expected linewidth and coherence properties of the FEL, in both the exponential and saturated gain regimes. We present results concerning the effective shot noise input power and mode shape, the expected subpercent output linemore » widths, photon flux, and the field temporal and spatial correlation functions. We also discuss the effects of tapering the wiggler upon the output power and line width.« less

1030 nm high power polarization maintained fiber laser with narrow linewidth and near-diffraction-limited beam quality

NASA Astrophysics Data System (ADS)

Chu, Qiuhui; Zhao, Pengfei; Li, Chengyu; Wang, Bopeng; Lin, Honghuan; Guo, Chao; Liu, Yu; Jing, Feng; Tang, Chuanxiang

2018-03-01

A high power 1030 nm ytterbium-doped polarization maintained fiber laser with optimized parameters is presented in this paper. The master oscillator power amplifier system with counter-pumped amplifier is established. The output power is 900 W, along with a light-to-light efficiency of 64.2%. The amplified spontaneous emission suppression ratio of spectrum reaches to 40 dB with 3 dB linewidth of 0.14 nm. The polarization extinction ratio is 12 dB, and the beam quality factor is M2x=1.07, M2y=1.12. To the best of our knowledge, this is the first demonstration of 1030 nm high power fiber laser with narrow linewidth, near linear polarization, and neardiffraction-limited beam quality

High power high repetition rate VCSEL array side-pumped pulsed blue laser

NASA Astrophysics Data System (ADS)

van Leeuwen, Robert; Zhao, Pu; Chen, Tong; Xu, Bing; Watkins, Laurence; Seurin, Jean-Francois; Xu, Guoyang; Miglo, Alexander; Wang, Qing; Ghosh, Chuni

2013-03-01

High power, kW-class, 808 nm pump modules based on the vertical-cavity surface-emitting laser (VCSEL) technology were developed for side-pumping of solid-state lasers. Two 1.2 kW VCSEL pump modules were implemented in a dual side-pumped Q-switched Nd:YAG laser operating at 946 nm. The laser output was frequency doubled in a BBO crystal to produce pulsed blue light. With 125 μs pump pulses at a 300 Hz repetition rate 6.1 W QCW 946 nm laser power was produced. The laser power was limited by thermal lensing in the Nd:YAG rod.

Single frequency 1083nm ytterbium doped fiber master oscillator power amplifier laser.

PubMed

Huang, Shenghong; Qin, Guanshi; Shirakawa, Akira; Musha, Mitsuru; Ueda, Ken-Ichi

2005-09-05

Single frequency 1083nm ytterbium fiber master oscillator power amplifier system was demonstrated. The oscillator was a linear fiber cavity with loop mirror filter and polarization controller. The loop mirror with unpumped ytterbium fiber as a narrow bandwidth filter discriminated and selected laser longitudinal modes efficiently. Spatial hole burning effect was restrained by adjusting polarization controller appropriately in the linear cavity. The amplifier was 5 m ytterbium doped fiber pumped by 976nm pigtail coupled laser diode. The linewidth of the single frequency laser was about 2 KHz. Output power up to 177 mW was produced under the launched pump power of 332 mW.

A simple sub-nanosecond ultraviolet light pulse generator with high repetition rate and peak power.

PubMed

Binh, P H; Trong, V D; Renucci, P; Marie, X

2013-08-01

We present a simple ultraviolet sub-nanosecond pulse generator using commercial ultraviolet light-emitting diodes with peak emission wavelengths of 290 nm, 318 nm, 338 nm, and 405 nm. The generator is based on step recovery diode, short-circuited transmission line, and current-shaping circuit. The narrowest pulses achieved have 630 ps full width at half maximum at repetition rate of 80 MHz. Optical pulse power in the range of several hundreds of microwatts depends on the applied bias voltage. The bias voltage dependences of the output optical pulse width and peak power are analysed and discussed. Compared to commercial UV sub-nanosecond generators, the proposed generator can produce much higher pulse repetition rate and peak power.

Diode-pumped cw Nd:YAG three-level laser at 869 nm.

PubMed

Lü, Yanfei; Xia, Jing; Cheng, Weibo; Chen, Jifeng; Ning, Guobin; Liang, Zuoliang

2010-11-01

We report for the first time (to our knowledge) a diode-pumped Nd:YAG laser emitting at 869 nm based on the (4)F(3/2)-(4)I(9/2) transition, generally used for a 946 nm emission. Power of 453 mW at 869 nm has been achieved in cw operation with a fiber-coupled laser diode emitting 35.4 W at 809 nm. Intracavity second-harmonic generation in the cw mode has also been demonstrated with power of 118 mW at 435 nm by using a BiB(3)O(6) nonlinear crystal. In our experiment, we used a LiNbO(3) crystal lens to complement the thermal lens of the laser rod, and we obtained good beam quality and high output power stability.

Volume Bragg grating narrowed high-power and highly efficient cladding-pumped Raman fiber laser.

PubMed

Liu, Jun; Yao, Weichao; Zhao, Chujun; Shen, Deyuan; Fan, Dianyuan

2014-12-10

High-power and highly efficient operation of a single-mode cladding-pumped Raman fiber laser with narrow lasing bandwidth is demonstrated. The spectral narrowing was realized by an external cavity containing a volume Bragg grating with a center wavelength of 1658 nm. A maximum output power of 10.4 W at 1658.3 nm with a spectral linewidth (FWHM) of ∼0.1  nm was obtained for the launched pump power of 18.4 W, corresponding to a slope efficiency of 109% with respect to the launched pump power. Lasing characteristics of free-running operation are also evaluated and discussed.

Influence of load by high power on the optical coupler

NASA Astrophysics Data System (ADS)

Bednarek, Lukas; Poboril, Radek; Vanderka, Ales; Hajek, Lukas; Nedoma, Jan; Vasinek, Vladimir

2016-12-01

Nowadays, aging of the optical components is a very current topic. Therefore, some investigations are focused on this area, so that the aging of the optical components is accelerated by thermal, high power and gamma load. This paper deals by findings of the influence of the load by laser with high optical power on the transmission parameters of the optical coupler. The investigated coupler has one input and eight outputs (1x8). Load by laser with high optical power is realized using a fiber laser with a cascade configuration EDFA amplifiers. The output power of the amplifier is approximately 250 mW. Duration of the load is moving from 104 hours to 139 hours. After each load, input power and output powers of all branches are measured. Following parameters of the optical coupler are calculated using formulas: the insertion losses of the individual branches, split ratio, total losses, homogeneity of the losses and cross-talk between different branches. All measurements are performed at wavelengths 1310 nm and 1550 nm. Individual optical powers are measured 20 times, due to the exclusion of statistical error of the measurement. After measuring, the coupler is connected to the amplifier for next cycle of the load. The paper contains an evaluation of the results of the coupler before and after four cycles of the burden.

Evaluation of Energy Dose and Output Power Optimum of Diode’s Laser of 450 nm and 650 nm in Photoantimicrobial Mechanisms Against Inhibition of C. Albicans Biofilm Cells

NASA Astrophysics Data System (ADS)

Dewi-Astuty, S.; Suhariningsih; Dyah-Astuti, S.; Baktir, A.

2018-03-01

Photoantimicrobial as a pathogenic microbial inhibitory therapy system such as C. albicans in biofilms forms has been studied in vitro. Mechanisms of inhibiting called inactivating used the absorb principles of a dye agents such as chlorophyll against the photon energy of diode laser which any number of ROS product depend on energy doses of a laser, time of irradiation, concentration and time of incubation the dyes agent. The inactivation profile of C. albicans biofilm cells was observed based on cell viability reduction after photoantimicrobial treatment with or without oxygenation by XTT assay test. Results show that the inhibiting significantly with the time incubation of the dye agents and the oxygen degree inside the sample. The inhibition for oxygenation biofilm’s group 10% lower than without oxygenation biofilm’s group at the maximum of reduction of cell viability occurred in the 3hour incubation group. Optimum of inactivation are 89.6% (without oxygenation) and 94.8% (with oxygenation) after irradiation with 450 nm laser (power output 128.73 at energy dose 86.09 J/cm2), While, by 650 nm laser (power output 164.53 mW at energy dose 92.52 J/cm2) irradiation treatment obtained optimum of inactivation are 89.5% (without oxygenation) and 92.3% (with oxygenation).

Watt-level single-frequency tunable neodymium MOPA fiber laser operating at 915-937 nm

NASA Astrophysics Data System (ADS)

Rota-Rodrigo, S.; Gouhier, B.; Laroche, M.; Zhao, J.; Canuel, B.; Bertoldi, A.; Bouyer, P.; Traynor, N.; Cadier, B.; Robin, T.; Santarelli, G.

2018-02-01

We have developed a Watt-level single-frequency tunable fiber laser in the 915-937 nm spectral window. The laser is based on a neodymium-doped fiber master oscillator power amplifier architecture, with two amplification stages using a 20 mW extended cavity diode laser as seed. The system output power is higher than 2 W from 921 to 933 nm, with a stability better than 1.4% and a low relative intensity noise.

Generation of spectrally-stable continuous-wave emission and ns pulses at 800 nm and 975 nm with a peak power of 4 W using a distributed Bragg reflector laser and a ridge-waveguide power amplifier

NASA Astrophysics Data System (ADS)

Klehr, A.; Wenzel, H.; Fricke, J.; Bugge, F.; Liero, A.; Hoffmann, Th.; Erbert, G.; Tränkle, G.

2015-03-01

Semiconductor based sources which emit high-power spectrally stable nearly diffraction-limited optical pulses in the nanosecond range are ideally suited for a lot of applications, such as free-space communications, metrology, material processing, seed lasers for fiber or solid state lasers, spectroscopy, LIDAR and frequency doubling. Detailed experimental investigations of 975 nm and 800 nm diode lasers based on master oscillator power amplifier (MOPA) light sources are presented. The MOPA systems consist of distributed Bragg reflector lasers (DBR) as master oscillators driven by a constant current and ridge waveguide power amplifiers which can be driven DC and by current pulses. In pulse regime the amplifiers modulated with rectangular current pulses of about 5 ns width and a repetition frequency of 200 kHz act as optical gates, converting the continuous wave (CW) input beam emitted by the DBR lasers into a train of short optical pulses which are amplified. With these experimental MOPA arrangements no relaxation oscillations in the pulse power occur. With a seed power of about 5 mW at a wavelength of 973 nm output powers behind the amplifier of about 1 W under DC injection and 4 W under pulsed operation, corresponding to amplification factors of 200 (amplifier gain 23 dB) and 800 (gain 29 dB) respectively, are reached. At 800 nm a CW power of 1 W is obtained for a seed power of 40 mW. The optical spectra of the emission of the amplifiers exhibit a single peak at a constant wavelength with a line width < 10 pm in the whole investigated current ranges. The ratios between laser and ASE levels were > 50 dB. The output beams are nearly diffraction limited with beam propagation ratios M2lat ~ 1.1 and M2ver ~ 1.2 up to 4 W pulse power.

Multichannel extremely broadband near-IR radiation sources for optical coherence tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wojtkowski, M; Fujimoto, J G; Lapin, P I

The construction and output parameters of two experimental samples of near-IR radiation sources based on the superposition of radiation from several superluminescent diodes are described. The first, three-channel sample emitting 18 mW of cw output power in a spectral band of width 105 nm through a single-mode fibre, is optimised for ophthalmology coherence tomography. The second, four-channel sample emits the 870-nm band of width more than 200 nm, which corresponds to the record coherence length smaller than 4 {mu}m. (laser applications and other topics in quantum electronics)

Laser-diode pumped 40-W Yb:YAG ceramic laser.

PubMed

Hao, Qiang; Li, Wenxue; Pan, Haifeng; Zhang, Xiaoyi; Jiang, Benxue; Pan, Yubai; Zeng, Heping

2009-09-28

We demonstrated a high-power continuous-wave (CW) polycrystalline Yb:YAG ceramic laser pumped by fiber-pigtailed laser diode at 968 nm with 400 mum fiber core. The Yb:YAG ceramic laser performance was compared for different Yb(3+) ion concentrations in the ceramics by using a conventional end-pump laser cavity consisting of two flat mirrors with output couplers of different transmissions. A CW laser output of 40 W average power with M(2) factor of 5.8 was obtained with 5 mol% Yb concentration under 120 W incident pump power. This is to the best of our knowledge the highest output power in end-pumped bulk Yb:YAG ceramic laser.

High power single mode 980 nm AlGaInAs/AlGaAs quantum well lasers with a very low threshold current

NASA Astrophysics Data System (ADS)

Zhen, Dong; Cuiluan, Wang; Hongqi, Jing; Suping, Liu; Xiaoyu, Ma

2013-11-01

To achieve low threshold current as well as high single mode output power, a graded index separate confinement heterostructure (GRIN-SCH) AlGaInAs/AlGaAs quantum well laser with an optimized ridge waveguide was fabricated. The threshold current was reduced to 8 mA. An output power of 76 mW was achieved at 100 mA current at room temperature, with a slope efficiency of 0.83 W/A and a horizon divergent angle of 6.3°. The maximum single mode output power of the device reached as high as 450 mW.

Diode-pumped quasi-three-level Nd:GdV O4-Nd:YAG sum-frequency laser at 464 nm

NASA Astrophysics Data System (ADS)

Lu, Jie

2014-04-01

We report a laser architecture to obtain continuous-wave (cw) blue radiation at 464 nm. A 808 nm diode pumped a Nd:GdV O4 crystal emitting at 912 nm. A part of the pump power was then absorbed by the Nd:GdV O4 crystal. The remainder was used to pump a Nd:YAG crystal emitting at 946 nm. Intracavity sum-frequency mixing at 912 and 946 nm was then realized in a LiB3O5 (LBO) crystal to produce blue radiation. We obtained a cw output power of 1.52 W at 464 nm with a pump laser diode emitting 18.4 W at 808 nm.

2.4 μm diode-pumped Dy2+:CaF2 laser

NASA Astrophysics Data System (ADS)

Švejkar, Richard; Papashvili, Alexander G.; Šulc, Jan; Němec, Michal; Jelínková, Helena; Doroshenko, Maxim E.; Batygov, Sergei H.; Osiko, Vyacheslav V.

2018-01-01

In this work, a cryogenic cooled, longitudinal diode-pumped Dy2+ :CaF2 laser was investigated for the first time. The temperature dependence of the spectroscopy and the laser properties of Dy2+ :CaF2 are presented. The tested Dy2+ :CaF2 crystal was a longitudinal pump in a near-IR region (926 nm) by laser diode radiation. The maximal mean output power and slope efficiency at 78 K during the pulse regime of the laser were 57.5 mW and 7%, respectively. Furthermore, the CW regime was successfully tested and a maximum output power of 0.37 W was obtained for the absorbed pumping power 5.7 W. The emission laser wavelength was 2367 nm.

Growth, spectroscopic properties and laser output of Er : Ca 4YO(BO 3) 3 and Er : Yb : Ca 4YO(BO 3) 3 crystals

NASA Astrophysics Data System (ADS)

Zhang, Huaijin; Meng, Xianlin; Wang, Changqing; Wang, Pu; Zhu, Li; Liu, Xuesong; Dong, Chunming; Yang, Yuyong; Cheng, Ruiping; Dawes, Judith; Piper, Jim; Zhang, Shaojun; Sun, Lianke

2000-09-01

In this paper, Er : Ca 4YO(BO 3) 3 (Er : YCOB) and Er : Yb : Ca 4YO(BO 3) 3 (Er : Yb : YCOB) crystals with large size and excellent quality have been grown by the Czochralski method. The absorption and emission spectra of Er : YCOB and Er : Yb : YCOB crystals have been measured; the emission spectrum of Er : Yb : YCOB crystal shows that the strongest emission peak is located at 1537 nm. An output power of about 2 mW at the wavelength of 1553 nm has been obtained under the pumping power of a fiber-coupled laser diode (LD) of 1600 mW at 976 nm, using a Y direction cut 2.5 mm thick Er : Yb : YCOB crystal sample.

Widely wavelength tunable gain-switched Er³⁺-doped ZBLAN fiber laser around 2.8 μm.

PubMed

Wei, Chen; Luo, Hongyu; Shi, Hongxia; Lyu, YanJia; Zhang, Han; Liu, Yong

2017-04-17

In this paper, we demonstrate a wavelength widely tunable gain-switched Er³⁺-doped ZBLAN fiber laser around 2.8 μm. The laser can be tuned over 170 nm (2699 nm~2869.9 nm) for various pump power levels, while maintaining stable μs-level single-pulse gain-switched operation with controllable output pulse duration at a selectable repetition rate. To the best of our knowledge, this is the first wavelength tunable gain-switched fiber laser in the 3 μm spectral region with the broadest tuning range (doubling the record tuning range) of the pulsed fiber lasers around 3 μm. Influences of pump energy and power on the output gain-switched laser performances are investigated in detail. This robust, simple, and versatile mid-infrared pulsed fiber laser source is highly suitable for many applications including laser surgery, material processing, sensing, spectroscopy, as well as serving as a practical seed source in master oscillator power amplifiers.

Efficient continuous-wave, broadly tunable and passive Q-switching lasers based on a Tm3+:CaF2 crystal

NASA Astrophysics Data System (ADS)

Liu, Jingjing; Zhang, Cheng; Zu, Yuqian; Fan, Xiuwei; Liu, Jie; Guo, Xinsheng; Qian, Xiaobo; Su, Liangbi

2018-04-01

Laser operations in the continuous-wave as well as in the pulsed regime of a 4 at.% Tm3+:CaF2 crystal are reported. For the continuous-wave operation, a maximum average output power of 1.15 W was achieved, and the corresponding slope efficiency was more than 64%. A continuous tuning range of about 160 nm from 1877-2036 nm was achieved using a birefringent filter. Using Argentum nanorods as a saturable absorber, the significant pulsed operation of a passively Q-switched Tm3+:CaF2 laser was observed at 1935.4 nm for the first time, to the best of our knowledge. A maximum output power of 385 mW with 41.4 µJ pulse energy was obtained under an absorbed pump power of 2.04 W. The present results indicate that the Tm3+:CaF2 lasers could be promising laser sources to operate in the eye-safe spectral region.

Dual-wavelength waveguide lasers at 1064 and 1079 nm in Nd:YAP crystal by direct femtosecond laser writing.

PubMed

Nie, Weijie; Cheng, Chen; Jia, Yuechen; Romero, Carolina; Vázquez de Aldana, Javier R; Chen, Feng

2015-05-15

Low-loss depressed cladding waveguides have been produced in Nd:YAP laser crystal by using direct femtosecond laser writing. Under optical pump at 812 nm at room temperature, continuous-wave simultaneous dual-wavelength laser oscillations at 1064 and 1079 nm, both along TM polarization, have been realized in the waveguiding structures. It has been found that, with the variation of pump polarization, the intensity ratio of 1064 and 1079 nm emissions varies periodically, while the polarization of output dual-wavelength laser remains unchanged. The maximum output power achieved for the Nd:YAP waveguide lasers is ∼200  mW with a slope efficiency of 33.4%.

High-power linearly polarized diode-side-pumped a-cut Nd:GdVO4 rod laser

NASA Astrophysics Data System (ADS)

Li, Xiaowen; Qian, Jianqiang; Zhang, Baitao

2017-03-01

An efficiently high-power diode-side-pumped Nd:GdVO4 rod laser system was successfully demonstrated, operating in continuous wave (CW) and acousto-optically (AO) Q-switched regime. With a 65 mm-long a-cut Nd:GdVO4 crystal, a maximum linearly polarized CW output power of 60 W at 1063.2 nm was obtained under an absorbed pump power of 180 W, corresponding to a slope efficiency of 50.6%. The output laser beam was linearly polarized with a degree of polarization of 98%. In AO Q-switched operation, the highest output power, minimum pulse width, and highest peak power were achieved to be 42 W, 36 ns, and 58 kW at the pulse repetition frequency of 20 kHz.

High power ultraviolet light emitting diodes based on GaN /AlGaN quantum wells produced by molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Cabalu, J. S.; Bhattacharyya, A.; Thomidis, C.; Friel, I.; Moustakas, T. D.; Collins, C. J.; Komninou, Ph.

2006-11-01

In this paper, we report on the growth by molecular beam epitaxy and fabrication of high power nitride-based ultraviolet light emitting diodes emitting in the spectral range between 340 and 350nm. The devices were grown on (0001) sapphire substrates via plasma-assisted molecular beam epitaxy. The growth of the light emitting diode (LED) structures was preceded by detailed materials studies of the bottom n-AlGaN contact layer, as well as the GaN /AlGaN multiple quantum well (MQW) active region. Specifically, kinetic conditions were identified for the growth of the thick n-AlGaN films to be both smooth and to have fewer defects at the surface. Transmission-electron microscopy studies on identical GaN /AlGaN MQWs showed good quality and well-defined interfaces between wells and barriers. Large area mesa devices (800×800μm2) were fabricated and were designed for backside light extraction. The LEDs were flip-chip bonded onto a Si submount for better heat sinking. For devices emitting at 340nm, the measured differential on-series resistance is 3Ω with electroluminescence spectrum full width at half maximum of 18nm. The output power under dc bias saturates at 0.5mW, while under pulsed operation it saturates at approximately 700mA to a value of 3mW, suggesting that thermal heating limits the efficiency of these devices. The output power of the investigated devices was found to be equivalent with those produced by the metal-organic chemical vapor deposition and hydride vapor-phase epitaxy methods. The devices emitting at 350nm were investigated under dc operation and the output power saturates at 4.5mW under 200mA drive current.

A diode-pumped Nd:YAlO3 dual-wavelength yellow light source

NASA Astrophysics Data System (ADS)

Zhang, Jing; Fu, Xihong; Zhai, Pei; Xia, Jing; Li, Shutao

2013-11-01

We present what is, to the best of our knowledge, the first diode-pumped Nd:YAlO3 (Nd:YAP) continuous-wave (cw) dual-wavelength yellow laser at 593 nm and 598 nm, based on sum-frequency generation between 1064 and 1339 nm in a-axis polarization using LBO crystal and between 1079 and 1341 nm in c-axis polarization using PPKTP crystal, respectively. At an incident pump power of 17.3 W, the maximum output power obtained at 593 nm and 598 nm is 0.18 W and 1.86 W, respectively. The laser experiment shows that Nd:YAP crystal can be used for an efficient diode-pumped dual-wavelength yellow laser system.

Trace heavy metal ions promoted extracellular electron transfer and power generation by Shewanella in microbial fuel cells.

PubMed

Xu, Yu-Shang; Zheng, Tao; Yong, Xiao-Yu; Zhai, Dan-Dan; Si, Rong-Wei; Li, Bing; Yu, Yang-Yang; Yong, Yang-Chun

2016-07-01

Although microbial fuel cells (MFCs) is considered as one of the most promising technology for renewable energy harvesting, low power output still accounts one of the bottlenecks and limits its further development. In this work, it is found that Cu(2+) (0.1μgL(-1)-0.1mgL(-1)) or Cd(2+) (0.1μgL(-1)-1mgL(-1)) significantly improve the electricity generation in MFCs. The maximum power output achieved with trace level of Cu(2+) (∼6nM) or Cd(2+) (∼5nM) is 1.3 times and 1.6 times higher than that of the control, respectively. Further analysis verifies that addition of Cu(2+) or Cd(2+) effectively improves riboflavin production and bacteria attachment on the electrode, which enhances bacterial extracellular electron transfer (EET) in MFCs. These results unveil the mechanism for power output enhancement by Cu(2+) or Cd(2+) addition, and suggest that metal ion addition should be a promising strategy to enhance EET as well as power generation of MFCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-gain (43 dB), high-power (40 W), highly efficient multipass amplifier at 995 nm in Yb:LiYF4

NASA Astrophysics Data System (ADS)

Manni, Jeffrey; Harris, Dennis; Fan, Tso Yee

2018-06-01

A simple implementation of a multipass amplifier along with the use of a cryogenic Yb:LiYF4 (YLF) gain medium has enabled the demonstration of a bulk amplifier with an unprecedented combination of large-signal gain (43 dB), efficiency (>50% optical), average output power (40 W) and a near-diffraction-limited output beam.

Broadband supercontinuum generation in a telecommunication fibre pumped by a nanosecond Tm, Ho:YVO{sub 4} laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou Ren-Lai; Ren Jian-Cun; Lou Shu-Li

2015-07-31

Broadband supercontinuum (SC) generation in a telecommunication fibre [8/125-μm single mode fibre (SMF) and 50/125-μm multimode fibre (MMF)] directly pumped by a nanosecond Q-switched Tm, Ho:YVO{sub 4} laser is demonstrated. At a 7-kHz pulse repetition frequency (PRF), an output average power of 0.53 W in the 1.95 – 2.5-μm spectral band and 3.51 W in the 1.9 – 2.6-μm spectral band are achieved in SMF and MMF, respectively (the corresponding optic-to-optic conversion efficiencies are 34.6% and 73.7%). The output spectra have extremely high flat segments in the range 2070 – 2390 nm and 2070 – 2475 nm with negligible intensitymore » variation (less than 2%). The SC average power is scalable from 2.1 to 4.2 W by increasing the PRF from 5 to 15 kHz, while maintaining pump power. Compared with the input pump pulse, the output SC pulse width is broadened, and no split is found. The stability of the output SC power has been monitored for a week and the fluctuations being less than 6%. (control of radiation parameters)« less

Large-mode-area single-mode-output Neodymium-doped silicate glass all-solid photonic crystal fiber

PubMed Central

Li, Wentao; Chen, Danping; Qinling, Zhou; Hu, Lili

2015-01-01

We have demonstrated a 45 μm core diameter Neodymium-doped all-solid silicate glass photonic crystal fiber laser with a single mode laser output. The structure parameters and modes information of the fiber are both demonstrated by theoretical calculations using Finite Difference Time Domain (FDTD) method and experimental measurements. Maximum 0.8 W output power limited by launched pump power has been generated in 1064 nm with laser beam quality factor M2 1.18. PMID:26205850

Compact 151 W green laser with U-type resonator for prostate surgery

NASA Astrophysics Data System (ADS)

Bazyar, Hossein; Aghaie, Mohammad; Daemi, Mohammad Hossein; Bagherzadeh, Seyed Morteza

2013-04-01

We analyzed, designed and fabricated a U-type resonator for intra-cavity frequency doubling of a diode-side-pumped Q-switched Nd:YAG rod laser with high power and high stability for surgery of prostatic tissue. The resonator stability conditions were analyzed graphically in the various configurations for a U-type resonator. We obtained green light at 532 nm using a single KTP crystal, with average output power of 151 W at 10 kHz repetition rate, and with 113 ns pulse duration at 810 W input pump power. We achieved 1064-532 nm conversion efficiency of 75.8%, and pump-to-green optical-optical efficiency of 18.6%. The green power fluctuation was ±1.0% and pointing stability was better than 4 μrad. The green laser output was coupled to a side-firing medical fiber to transfer the laser beam to the prostatic tissue.

Performance of continuous wave and acousto-optically Q-switched Tm, Ho: YAP laser pumped by diode laser

NASA Astrophysics Data System (ADS)

Li, Guoxing; Xie, Wenqiang; Yang, Xining; Zhang, Ziqiu; Zhang, Hongda; Zhang, Liang

2018-02-01

A two-end-pumped a-cut Tm(0.5%), Ho(0.5%):YAP laser output at 2119nm is reported under cryogenic temperature. The maximum output power reached to 7.76W with the incident pump power of 24.2W in CW mode. With the acousto-optically Q-switch, an average power of 7.3W can be obtained, when the pulse repetition frequency was 7.5 kHz. The corresponding optical-to-optical conversion efficiency was 30.2% and the slope efficiency was 31.4%. Then, the laser output characteristics in the repetition frequency of 7.5 kHz and 10kHz were researched. The output power, the optical-to-optical conversion efficiency and slope efficiency were increased with the increase of the repetition frequency. In the same repetition frequency, the pulse duration was decreasing with the growth of the incident pump power.

Incoherent beam combining of fiber lasers by an all-fiber 7 × 1 signal combiner at a power level of 14 kW.

PubMed

Lei, Chengmin; Gu, Yanran; Chen, Zilun; Wang, Zengfeng; Zhou, Pu; Ma, Yanxing; Xiao, Hu; Leng, Jinyong; Wang, Xiaolin; Hou, Jing; Xu, Xiaojun; Chen, Jinbao; Liu, Zejin

2018-04-16

We demonstrate an all-fiber 7 × 1 signal combiner with an output core diameter of 50 μm for high power incoherent beam combining of seven self-made Yb-doped single-mode fiber lasers around a wavelength of 1080 nm and output power of 2 kW. 14.1 kW combined output power is achieved with a total transmission efficiency of higher than 98.5% and a beam quality of M 2 = 5.37, which is close to the theoretical results based on finite-difference beam propagation technique. To the best of our knowledge, this is the highest output power ever reported for all-fiber structure beam combining generation, which indicates the feasibility and potential of >10 kW high brightness incoherent beam combining based on an all-fiber signal combiner.

High power passive mode-locked L-band fiber laser based on microfiber topological insulator saturable absorber

NASA Astrophysics Data System (ADS)

Semaan, Georges; Meng, Yichang; Salhi, Mohamed; Niang, Alioune; Guesmi, Khmaies; Luo, Zhi-Chao; Sanchez, Francois

2016-04-01

In this communication, we demonstrate a passive mode-locked Er:Yb co-doped double-clad fiber laser using a tapered microfiber topological insulator (Bi2Se3) saturable absorber (TISA). The topological insulator is drop-casted onto the tapered fiber and optically deposited by optical tweezer effect. We use a ring laser setup including the fabricated TISA. By carefully optimizing the cavity losses and output coupling ratio, the mode-locked laser can operate in L-band with a high average output power. At a maximum pump power of 5 W, we obtain the 91st harmonic mode-locking of soliton bunches with a 3dB spectral bandwidth of 1.06nm, a repetition rate of 640.9 MHz and an average output power of 308mW. As far as we know, this is the highest output power yet reported of a mode-locked fiber laser operating with a TISA.

High-power 1.25 µm InAs QD VECSEL based on resonant periodic gain structure

NASA Astrophysics Data System (ADS)

Albrecht, Alexander R.; Rotter, Thomas J.; Hains, Christopher P.; Stintz, Andreas; Xin, Guofeng; Wang, Tsuei-Lian; Kaneda, Yushi; Moloney, Jerome V.; Malloy, Kevin J.; Balakrishnan, Ganesh

2011-03-01

We compare an InAs quantum dot (QD) vertical external-cavity surface-emitting laser (VECSEL) design consisting of 4 groups of 3 closely spaced QD layers with a resonant periodic gain (RPG) structure, where each of the 12 QD layers is placed at a separate field antinode. This increased the spacing between the QDs, reducing strain and greatly improving device performance. For thermal management, the GaAs substrate was thinned and indium bonded to CVD diamond. A fiber-coupled 808 nm diode laser was used as pump source, a 1% transmission output coupler completed the cavity. CW output powers over 4.5 W at 1250 nm were achieved.

Improvement and formation of UV-induced damage on LBO crystal surface during long-term high-power third-harmonic generation.

PubMed

Hong, Hailong; Liu, Qiang; Huang, Lei; Gong, Mali

2013-03-25

We demonstrate the improvement and formation of UV-induced damage on LBO crystal output surface during long-term (130 h) high-power (20 W) high-repetition-rate (80 kHz) third-harmonic generation. The output surface was super-polished (RMS surface roughness <0.6 nm) to sub-nanometer scale super smooth roughness. The surface lifetime has been improved more than 20-fold compared with the as-polished ones (RMS surface roughness 4.0~8.0 nm). The damage could be attributed to the consequence of thermal effects resulted from impurity absorptions. Simultaneously, it was verified that the impurities originated in part from the UV-induced deposition.

Stable continuous-wave single-frequency Nd:YAG blue laser at 473 nm considering the influence of the energy-transfer upconversion.

PubMed

Wang, Yaoting; Liu, Jianli; Liu, Qin; Li, Yuanji; Zhang, Kuanshou

2010-06-07

We report a continuous-wave (cw) single frequency Nd:YAG blue laser at 473 nm end-pumped by a laser diode. A ring laser resonator was designed, the frequency doubling efficiency and the length of nonlinear crystal were optimized based on the investigation of the influence of the frequency doubling efficiency on the thermal lensing effect induced by energy-transfer upconversion. By intracavity frequency doubling with PPKTP crystal, an output power of 1 W all-solid-state cw blue laser of single-frequency operation was achieved. The stability of the blue output power was better than +/- 1.8% in the given four hours.

Tunable femtosecond near-infrared source based on a Yb:LYSO-laser-pumped optical parametric oscillator

NASA Astrophysics Data System (ADS)

Wen-Long, Tian; Zhao-Hua, Wang; Jiang-Feng, Zhu; Zhi-Yi, Wei

2016-01-01

We demonstrate a widely tunable near-infrared source from 767 nm to 874 nm generated by the intracavity second harmonic generation (SHG) in an optical parametric oscillator pumped by a Yb:LYSO solid-state laser. The home-made Yb:LYSO oscillator centered at 1035 nm delivers an average power of 2 W and a pulse duration as short as 351 fs. Two MgO doped periodically poled lithium niobates (MgO:PPLN) with grating periods of 28.5-31.5 μm in steps of 0.5 μm and 19.5-21.3 μm in steps of 0.2 μm are used for the OPO and intracavity SHG, respectively. The maximum average output power of 180 mW at 798 nm was obtained and the output pulses have pulse duration of 313 fs at 792 nm if a sech2-pulse shape was assumed. In addition, tunable signal femtosecond pulses from 1428 nm to 1763 nm are also realized with the maximum average power of 355 mW at 1628 nm. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB922402), the National Key Scientific Instruments Development Program of China (Grant No. 2012YQ120047), the National Natural Science Foundation of China (Grant Nos. 61205130 and 11174361), and the Key Deployment Project of Chinese Academy of Sciences (Grant No. KJZD-EW-L11-03).

Ultra-narrow-linewidth erbium-doped lasers on a silicon photonics platform

NASA Astrophysics Data System (ADS)

Li, Nanxi; Purnawirman, Purnawirman; Magden, E. Salih; Singh, Gurpreet; Singh, Neetesh; Baldycheva, Anna; Hosseini, Ehsan S.; Sun, Jie; Moresco, Michele; Adam, Thomas N.; Leake, Gerald; Coolbaugh, Douglas; Bradley, Jonathan D. B.; Watts, Michael R.

2018-02-01

We report ultra-narrow-linewidth erbium-doped aluminum oxide (Al2O3:Er3+) distributed feedback (DFB) lasers with a wavelength-insensitive silicon-compatible waveguide design. The waveguide consists of five silicon nitride (SiNx) segments buried under silicon dioxide (SiO2) with a layer Al2O3:Er3+ deposited on top. This design has a high confinement factor (> 85%) and a near perfect (> 98%) intensity overlap for an octave-spanning range across near infrared wavelengths (950-2000 nm). We compare the performance of DFB lasers in discrete quarter phase shifted (QPS) cavity and distributed phase shifted (DPS) cavity. Using QPS-DFB configuration, we obtain maximum output powers of 0.41 mW, 0.76 mW, and 0.47 mW at widely spaced wavelengths within both the C and L bands of the erbium gain spectrum (1536 nm, 1566 nm, and 1596 nm). In a DPS cavity, we achieve an order of magnitude improvement in maximum output power (5.43 mW) and a side mode suppression ratio (SMSR) of > 59.4 dB at an emission wavelength of 1565 nm. We observe an ultra-narrow linewidth of ΔνDPS = 5.3 +/- 0.3 kHz for the DPS-DFB laser, as compared to ΔγQPS = 30.4 +/- 1.1 kHz for the QPS-DFB laser, measured by a recirculating self-heterodyne delayed interferometer (RSHDI). Even narrower linewidth can be achieved by mechanical stabilization of the setup, increasing the pump absorption efficiency, increasing the output power, or enhancing the cavity Q.

Wavelength tunability of laser based on Yb-doped YGAG ceramics

NASA Astrophysics Data System (ADS)

Šulc, Jan; Jelínková, Helena; Jambunathan, Venkatesan; Miura, Taisuke; Endo, Akira; Lucianetti, Antonio; Mocek, TomáÅ.¡

2015-02-01

The wavelength tunability of diode pumped laser based on Yb-doped mixed garnet Y3Ga2Al3O12 (Yb:YGAG) ceramics was investigated. The tested Yb:YGAG sample (10% Yb/Y) was in the form of 2mm thick plane-parallel face-polished plate (without AR coatings). A fiber (core diameter 100 μm, NA= 0.22) coupled laser diode (LIMO, LIMO35-F100-DL980-FG-E) with emission at wavelength 969 nm, was used for longitudinal Yb:YGAG pumping. The laser diode was operating in the pulsed regime (2 ms pulse length, 10 Hz repetition rate). The duty-cycle 2% ensured a low thermal load even under the maximum diode pumping power amplitude 20W (ceramics sample was only air-cooled). The 145mm long semi-hemispherical laser resonator consisted of a flat pumping mirror (HR @ 1.01 - 1.09 μm, HT @ 0.97 μm) and curved (r = 150mm) output coupler with a reflectivity of ˜ 97% @ 1.01 - 1.09 μm. Wavelength tuning of the ytterbium laser was accomplished by using a birefringent filter (single 1.5mm thick quartz plate) placed inside the optical resonator at the Brewster angle between the output coupler and the laser active medium. The laser was continuously tunable over ˜ 58nm (from 1022nm to 1080 nm) and the tuning band was mostly limited by the free spectral range of used birefringent filter. The maximum output power amplitude 3W was obtained at wavelength 1046nm for absorbed pump power amplitude 10.6W. The laser slope efficiency was 34%.

100-mW high-power three-section tunable distributed Bragg reflector laser diodes with a real refractive-index-guided self-aligned structure

NASA Astrophysics Data System (ADS)

Takayama, Toru; Mochida, Atsunori; Orita, Kenji; Tamura, Satoshi; Ohnishi, Toshikazu; Yuri, Masaaki; Shimizu, Hirokazu

2002-05-01

High-power (>100mW) 820 nm-band distributed Bragg reflector (DBR) laser diodes (LDs) with stable fundamental transverse mode operation and continuous wavelength tuning characteristics have been developed. To obtain high-power LDs with a stable fundamental transverse mode in 820 nm wavelength range, an AlGaAs narrow stripe (2.0 micrometers ) real refractive-index-guided self-aligned (RISA) structure is utilized. In the RISA structure, the index step between inside and outside the stripe region ((Delta) n) can be precisely controlled in the order of 10-3). To maintain a stable fundamental transverse mode up to an output power over 100 mW, (Delta) n is designed to be 4x10-3. Higher-order transverse modes are effectively suppressed by a narrow stripe geometry. Further, to achieve continuous wavelength tuning capability, the three-section LD structure, which consists of the active (700micrometers ), phase control (300micrometers ), and DBR(500micrometers ) sections, is incorporated. Our DBR LDs show a maximum output power over 200mW with a stable fundamental transverse mode, and wavelength tuning characteristics ((Delta) (lambda) ~2nm) under 100 mW CW operation.

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.

Multiwavelength L-band fiber laser with bismuth-oxide EDF and photonic crystal fiber

NASA Astrophysics Data System (ADS)

Ramzia Salem, A. M.; Al-Mansoori, M. H.; Hizam, H.; Mohd Noor, S. B.; Abu Bakar, M. H.; Mahdi, M. A.

2011-05-01

A multiwavelength laser comb using a bismuth-based erbium-doped fiber and 50 m photonic crystal fiber is demonstrated in a ring cavity configuration. The fiber laser is solely pumped by a single 1455 nm Raman pump laser to exploit its higher power delivery compared to that of a single-mode laser diode pump. At 264 mW Raman pump power and 1 mW Brillouin pump power, 38 output channels in the L-band have been realized with an optical signal-to-noise ratio above 15 dB and a Stokes line spacing of 0.08 nm. The laser exhibits a tuning range of 12 nm and produces stable Stokes lines across the tuning range between Brillouin pump wavelengths of 1603 nm and 1615 nm.

Quasi-CW diode-pumped self-starting adaptive laser with self-Q-switched output.

PubMed

Smith, G; Damzen, M J

2007-05-14

An investigation is made into a quasi-CW (QCW) diode-pumped holographic adaptive laser utilising an ultra high gain (approximately 10(4)) Nd:YVO(4) bounce amplifier. The laser produces pulses at 1064 nm with energy approximately 0.6 mJ, duration <3 ns and peak power approximately 200 kW, with high stability, via self-Q-switching effects due to the transient dynamics of the writing and replay of the gain hologram for each pump pulse. The system produces a near-diffraction-limited output with M(2)<1.3 and operates with a single longitudinal mode. In a further adaptive laser configuration, the output was amplified to obtain pulses of approximately 5.6 mJ energy, approximately 7 ns duration and approximately 1 MW peak power. The output spatial quality is also M(2)<1.3 with SLM operation. Up to 2.9 mJ pulse energy of frequency doubled green (532 nm) radiation is obtained, using an LBO crystal, representing approximately 61% conversion efficiency. This work shows that QCW diode-pumped self-adaptive holographic lasers can provide a useful source of high peak power, short duration pulses with excellent spatial quality and narrow linewidth spectrum.

Diode-pumped simultaneous multi-wavelength linearly polarized Nd:YVO4 laser at 1062, 1064 and 1066 nm

NASA Astrophysics Data System (ADS)

Lin, Zhi; Wang, Yi; Xu, Bin; Xu, Huiying; Cai, Zhiping

2016-01-01

We report on a diode-end-pumped simultaneous multiple wavelength Nd:YVO4 laser. Dual-wavelength laser is achieved at a π-polarized 1064 nm emission line and a σ-polarized 1066 nm emission line with total maximum output power of 1.38 W. Moreover, tri-wavelength laser emission at the π-polarized 1064 nm emission line and σ-polarized 1062 and 1066 nm emission lines can also be obtained with total maximum output power of about 1.23 W, for the first time to our knowledge. The operation of such simultaneous dual- and tri-wavelength lasers is only realized by employing a simple glass etalon to modulate the intracavity losses for these potential lasing wavelengths inside of an intracavity polarizer, which therefore makes a very compact two-mirror linear cavity and simultaneous orthogonal lasing possible. Such orthogonal linearly polarized multi-wavelength laser sources could be especially promising in THz wave generation and in efficient nonlinear frequency conversion to visible lasers.

Efficient second-harmonic conversion of CW single-frequency Nd:YAG laser light by frequency locking to a monolithic ring frequency doubler

NASA Technical Reports Server (NTRS)

Gerstenberger, D. C.; Tye, G. E.; Wallace, R. W.

1991-01-01

Efficient second-harmonic conversion of the 1064-nm output of a diode-pumped CW single-frequency Nd:YAG laser to 532 nm was obtained by frequency locking the laser to a monolithic ring resonator constructed of magnesium-oxide-doped lithium niobate. The conversion efficiency from the fundamental to the second harmonic was 65 percent. Two hundred milliwatts of CW single-frequency 532-nm light were produced from 310 mW of power of 1064-nm light. This represents a conversion efficiency of 20 percent from the 1-W diode laser used to pump the Nd:YAG laser to single-frequency 532-nm output. No signs of degradation were observed for over 500 h of operation.

Exploring the self-mode-locked dynamics of cryogenic diode-pumped Nd:YLF lasers: switching of orthogonal polarizations

NASA Astrophysics Data System (ADS)

Huang, T. L.; Y Cho, C.; Liang, H. C.; Huang, K. F.; Chen, Y. F.

2017-08-01

The self-mode-locked output for cryogenic Nd:YLF laser at the temperature range of 90 K to 290 K is thoroughly investigated. Linearly polarized self-mode-locked lasing at 1047 nm (1053 nm) with a repetition rate up to 1.59 GHz and a pulse width as short as 52 ps can be realized at temperatures above 155 K (below 135 K). Orthogonally polarized self-mode-locked operation can be observed at temperatures near 145 K. During dual-polarization operation, it is found that the polarized component with higher output power is the fundamental transverse mode, whereas the other component with lower output power becomes the high-order transverse mode. The dominant polarized component can be either π- or σ-polarization, depending on the fine adjustment of the cavity.

High power eye-safe Er3+:YVO4 laser diode-pumped at 976 nm and emitting at 1603 nm

NASA Astrophysics Data System (ADS)

Newburgh, G. A.; Dubinskii, M.

2016-02-01

We report on the performance of an eye-safe laser based on a Er:YVO4 single crystal, diode-pumped at 976 nm (4I15/2-->4I11/2 transition) and operating at 1603 nm (4I13/2-->4I15/2 transition) with good beam quality. A 10 mm long Er3+:YVO4 slab, cut with its c-axis perpendicular to the laser cavity axis, was pumped in σ-polarization and lased in π-polarization. The laser operated in a quasi-continuous wave (Q-CW) regime with nearly 9 W output power, and with a slope efficiency of about 39% with respect to absorbed power. This is believed to be the highest efficiency and highest power achieved from an Er3+:YVO4 laser pumped in the 970-980 nm absorption band.

Formation of an indium tin oxide nanodot/Ag nanowire electrode as a current spreader for near ultraviolet AlGaN-based light-emitting diodes

NASA Astrophysics Data System (ADS)

Park, Jae-Seong; Kim, Jae-Ho; Kim, Jun-Yong; Kim, Dae-Hyun; Na, Jin-Young; Kim, Sun-Kyung; Kang, Daesung; Seong, Tae-Yeon

2017-01-01

Indium tin oxide (ITO) nanodots (NDs) were combined with Ag nanowires (Ag NWs) as a p-type electrode in near ultraviolet AlGaN-based light-emitting diodes (LEDs) to increase light output power. The Ag NWs were 30 ± 5 nm in diameter and 25 ± 5 μm in length. The transmittance of 10 nm-thick ITO-only was 98% at 385 nm, while the values for ITO ND/Ag NW were 83%-88%. ITO ND/Ag NW films showed lower sheet resistances (32-51 Ω sq-1) than the ITO-only film (950 Ω sq-1). LEDs (chip size: 300 × 800 μm2) fabricated using the ITO NDs/Ag NW electrodes exhibited higher forward-bias voltages (3.52-3.75 V at 20 mA) than the LEDs with the 10 nm-thick ITO-only electrode (3.5 V). The LEDs with ITO ND/Ag NW electrodes yielded a 24%-62% higher light output power (at 20 mA) than those with the 10 nm-thick ITO-only electrode. Furthermore, finite-difference time-domain (FDTD) simulations were performed to investigate the extraction efficiency. Based on the emission images and FDTD simulations, the enhanced light output with the ITO ND/Ag NW electrodes is attributed to improved current spreading and better extraction efficiency.

Characterization of an optimized light source and comparison to pulsed dye laser for superficial and deep vessel clearance.

PubMed

Weiss, Robert A; Ross, E Victor; Tanghetti, Emil A; Vasily, David B; Childs, James J; Smirnov, Mikhail Z; Altshuler, Gregory B

2011-02-01

An arc lamp-based device providing optimized spectrum and pulse shape was characterized and compared with two pulsed dye laser (PDL) systems using a vascular phantom. Safety and effectiveness for facial telangiectasia are presented in clinical case studies. An optimized pulsed light source's (OPL) spectral and power output were characterized and compared with two 595 nm PDL devices. Purpuric threshold fluences were determined for the OPL and PDLs on Fitzpatrick type II normal skin. A vascular phantom comprising blood-filled quartz capillaries beneath porcine skin was treated by the devices at their respective purpuric threshold fluences for 3 ms pulse widths, while vessel temperatures were monitored with an infrared (IR) camera. Patients with Fitzpatrick skin types II-III received a split-face treatment with the OPL and a 595 nm PDL. The OPL provided a dual-band output spectrum from 500 to 670 nm and 850-1,200 nm, pulse widths from 3 to 100 ms, and fluences to 80 J/cm(2). The smooth output power measured during all pulse widths provides unambiguous vessel size selectivity. Percent energy in the near infra-red increased with decreasing output power from 45% to 60% and contributed 15-26% to heating of deep vessels, respectively. At purpuric threshold fluences the ratio of OPL to PDL vessel temperature rise was 1.7-2.8. OPL treatments of facial telangiectasia were well-tolerated by patients demonstrating significant improvements comparable to PDL with no downtime. Intense pulsed light (IPL) and PDL output pulse and spectral profiles are important for selective treatment of vessels in vascular lesions. The OPL's margin between purpuric threshold fluence and treatment fluence for deeper, larger vessels was greater than the corresponding margin with PDLs. The results warrant further comparison studies with IPLs and other PDLs. Copyright © 2011 Wiley-Liss, Inc.

Simultaneous dual-wavelength laser operation at 937 and 1062 nm in Nd3+:Gd3Ga5O12

NASA Astrophysics Data System (ADS)

Gao, F.; Sun, G. C.; Li, Y. D.; Dong, Y.; Li, S. T.

2013-08-01

Diode-end-pumped continuous-wave (cw) simultaneous dual-wavelength laser operation at 937 and 1062 nm in a single Nd3+:Gd3Ga5O12 (Nd:GGG) crystal was demonstrated. A total output power of 1.12 W at the two fundamental wavelengths was achieved at incident pump power of 17.6 W. The optical-to-optical conversion was up to 6.4% with respect to the incident pump power. To the best of our knowledge, this is first work on cw simultaneous dual-wavelength operation at 937 and 1062 nm in Nd:GGG crystal.

Red laser-diode pumped 806 nm Tm3+: ZBLAN fibre laser

NASA Astrophysics Data System (ADS)

Juárez-Hernández, M.; Mejía, E. B.

2017-06-01

A Tm3+-doped fluorozirconate (ZBLAN) fibre laser operating CW at 806 nm when diode-pumped at 687 nm is described for the first time. This device is based on the 3F4  →  3H6 transition, and is suitable for first telecom window and sensing applications. A slope efficiency of 50.3% and low threshold pump-power of 11.6 mW were obtained. Maximum output power of 15 mW for 40 mW coupled pump was achieved.

Performance of a 967 nm CW diode end-pumped Er:GSGG laser at 2.79 μm

NASA Astrophysics Data System (ADS)

Wu, Z. H.; Sun, D. L.; Wang, S. Z.; Luo, J. Q.; Li, X. L.; Huang, L.; Hu, A. L.; Tang, Y. Q.; Guo, Q.

2013-05-01

We demonstrated a 967 nm diode end-pumped Er:GSGG laser operated at 2.794 μm with spectral width 3.6 nm in the continuous wave (CW) mode. A maximum output power of 440 mW is obtained at an incident pumping power of 3.4 W, which corresponds to an optical-to-optical efficiency of 13% and slope efficiency of 13.2%. The results suggest that a short cavity and efficient cooling setup for the crystal help to improve laser performance.

Wavelength-tunable thulium-doped fiber laser by employing a self-made Fabry-Perot filter

NASA Astrophysics Data System (ADS)

Wang, Y. P.; Ju, Y. L.; Wu, C. T.; Liu, W.; Yang, C.

2017-06-01

In this demonstration, we proposed a novel wavelength-tunable thulium-doped fiber laser (TDFL) with a self-made Fabry-Perot (F-P) filter. When the F-P filter was not inserted, the maximum output power of 11.1 W was achieved when the pump power was 70.2 W. The corresponding optical-to-optical conversion efficiency was 15.8% and the slope efficiency was 22.1%. When the F-P filter was inserted, the output wavelength could be tuned from 1952.9 to 1934.9 nm with the change of cavity length of F-P filter which was fixed on a piezoelectric ceramic transducer (PZT) controlled by the voltage applied to it. The full width at half maximum (FWHM) was no more than 0.19 nm. Furthermore, the wavelength fluctuations of the tunable fiber laser were kept within  ±0.2 nm.

High-power thulium-doped fiber laser in an all-fiber configuration

NASA Astrophysics Data System (ADS)

Baravets, Yauhen; Todorov, Filip; Honzatko, Pavel

2016-12-01

High-power Tm-doped fiber lasers are greatly suitable for various applications, such as material processing, medicine, environmental monitoring and topography. In this work we present an all-fiber narrowband CW laser in near fundamental mode operation based on a Tm-doped double-clad active fiber pumped by 793 nm laser diodes with a central wavelength stabilized at 2039 nm by a fiber Bragg grating. The achieved output power is 60 W with a slope efficiency of 46%. The measured beam quality factor is less than 1.4. Further increasing of the output power is possible using various power scaling techniques, for example, coherent combination of several Tm-doped fiber lasers. The developed fiber laser could be employed for welding, cutting and marking of thermoplastics in industry, minimally invasive surgery in medicine or sensors in lidar systems. Future improvements of thulium fiber lasers are possible due to the extremely wide gain-bandwidth of the active medium and the rapid growth of 2-μm fiber components production.

A Co2+-doped alumina-rich Mg0.4Al2.4O4 spinel crystal as saturable absorber for a LD pumped Er: glass microchip laser at 1535 nm

NASA Astrophysics Data System (ADS)

Jiang, D. P.; Zou, Y. Q.; Su, L. B.; Tang, H. L.; Wu, F.; Zheng, L. H.; Li, H. J.; Xu, J.

2011-05-01

Co2+-doped Mg0.4Al2.4O4 single crystal up to varnothing28×40 mm3 was successfully grown by the Czochralski method. By using this crystal as saturable absorber, we have demonstrated a diode-end-pumped passively Q-switched Er:glass microchip laser operating at 1535 nm for the first time to the best of our knowledge. The dependences of average output power, repetition rate and pulse energy on the incident pump power were investigated. In the passive Q-switching regime, a maximum average output power of 22.12 mW was obtained at the incident pump power of 410 mW. The narrowest pulse width, the largest pulse energy and the highest peak power were obtained to be about 3.5 ns, 4.8 μJ, and 1.37 kW, respectively.

Experimental study of a VBG-based Tm : YLF slab laser at different output coupler parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, X M; Ding, Y; Dai, T Y

2015-04-30

The performance of a Tm : YLF slab laser is studied at different output coupler parameters. Use is made of a 20-mm-long a-cut slab crystal doped with 2.5 at. % thulium ions. With a volume Bragg grating and a Fabry – Perot etalon, the selected output wavelength of this Tm : YLF slab laser is 1908 nm. For the optimised output coupler with a transmission of 20% and a radius of curvature of 300 mm, the output power exceeds 74.1 W and the slope efficiency with respect to the absorbed pump power reaches 48.4%. In addition, the beam quality ofmore » the Tm : YLF slab laser is improved. (lasers)« less

Properties and Frequency Conversion of High-Brightness Diode-Laser Systems

NASA Astrophysics Data System (ADS)

Boller, Klaus-Jochen; Beier, Bernard; Wallenstein, Richard

An overview of recent developments in the field of high-power, high-brightness diode-lasers, and the optically nonlinear conversion of their output into other wavelength ranges, is given. We describe the generation of continuous-wave (CW) laser beams at power levels of several hundreds of milliwatts to several watts with near-perfect spatial and spectral properties using Master-Oscillator Power-Amplifier (MOPA) systems. With single- or double-stage systems, using amplifiers of tapered or rectangular geometry, up to 2.85 W high-brightness radiation is generated at wavelengths around 810nm with AlGaAs diodes. Even higher powers, up to 5.2W of single-frequency and high spatial quality beams at 925nm, are obtained with InGaAs diodes. We describe the basic properties of the oscillators and amplifiers used. A strict proof-of-quality for the diode radiation is provided by direct and efficient nonlinear optical conversion of the diode MOPA output into other wavelength ranges. We review recent experiments with the highest power levels obtained so far by direct frequency doubling of diode radiation. In these experiments, 100mW single-frequency ultraviolet light at 403nm was generated, as well as 1W of single-frequency blue radiation at 465nm. Nonlinear conversion of diode radiation into widely tunable infrared radiation has recently yielded record values. We review the efficient generation of widely tunable single-frequency radiation in the infrared with diode-pumped Optical Parametric Oscillators (OPOs). With this system, single-frequency output radiation with powers of more than 0.5W was generated, widely tunable around wavelengths of 2.1,m and 1.65,m and with excellent spectral and spatial quality. These developments are clear indicators of recent advances in the field of high-brightness diode-MOPA systems, and may emphasize their future central importance for applications within a vast range of optical wavelengths.

16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers.

PubMed

Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E; Petersen, Paul Michael

2011-01-17

Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and 3.3 (slow axis) match the M2-values of the laser with lowest spatial coherence. The principle of spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future.

High-power single-pass pumped diamond Raman oscillator

NASA Astrophysics Data System (ADS)

Heinzig, Matthias; Walbaum, Till; Williams, Robert J.; Kitzler, Ondrej; Mildren, Richard P.; Schreiber, Thomas; Eberhardt, Ramona; Tünnermann, Andreas

2018-02-01

We present our recent advances on power scaling of a high-power single-pass pumped CVD-diamond Raman oscillator at 1.2 μm. The single pass scheme reduced feedback to the high gain fiber amplifier, which pumps the oscillator. The Yb-doped multi-stage fiber amplifier itself enables up to 1 kW output power at a narrow linewidth of 0.16 nm. We operate this laser in quasi-cw mode at 10% duty cycle and on-time (pulse) duration of 10 ms. With a maximum conversion efficiency of 39%, a maximum steady-state output power of 380 W and diffraction limited beam quality was achieved.

Neon-hydrogen penning plasma laser in a helical hallow-cathode discharge

NASA Astrophysics Data System (ADS)

Pramatarov, P. M.; Stefanova, M. S.; Ganciu, M.; Karelin, A. V.; Yancharina, A. M.; Ivanova, J. P.; Yakovlenko, S. I.

1991-07-01

A Penning plasma laser (PPL) operating at the NeI 585.3 nm and NeI 1.15 μm lines in Ne-H2 mixture has been realized. Helical configuration of the electrodes was used. The dependence of the laser-pulse shape and output power on current pulse duration and amplitude values were investigated. Peak output powers of 1.5 W for the yellow line and 1.2 W for the IR line have been measured. The population inversion mechanism for the 585.3 nm line is discussed in the frames of a model for PPL. The main factor maintaining the population inversion on both lines is depopulation of the Ne(1 s 2) level by Penning reactions with H2.

Neon-hydrogen Penning plasma laser in a helical hallow-cathode discharge

NASA Astrophysics Data System (ADS)

Pramatarov, P. M.; Stefanova, M. S.; Ivanova, J. P.; Ganciu, M.; Karelin, A. V.; Iakovlenko, S. I.; Iancharina, A. M.

1991-07-01

A Penning plasma laser (PPL) operating at the NeI 585.3 nm and NeI 1.15-micron lines in Ne-H2 mixture has been realized. Helical configuration of the electrodes was used. The dependence of the laser-pulse shape and output power on current pulse duration and amplitude values were investigated. Peak output powers of 1.5 W for the yellow line and 1.2 W for the IR line have been measured. The population inversion mechanism for the 585.3 nm line is discussed in the frames of a model for PPL. The main factor maintaining the population inversion on both lines is depopulation of the Ne(1S2) level by Penning reactions with H2.

Inhibited-coupling HC-PCF based beam-delivery-system for high power green industrial lasers

NASA Astrophysics Data System (ADS)

Chafer, M.; Gorse, A.; Beaudou, B.; Lekiefs, Q.; Maurel, M.; Debord, B.; Gérôme, F.; Benabid, F.

2018-02-01

We report on an ultra-low loss Hollow-Core Photonic Crystal Fiber (HC-PCF) beam delivery system (GLO-GreenBDS) for high power ultra-short pulse lasers operating in the green spectral range (including 515 nm and 532 nm). The GLOBDS- Green combines ease-of-use, high laser-coupling efficiency, robustness and industrial compatible cabling. It comprises a pre-aligned laser-injection head, a sheath-cable protected HC-PCF and a modular fiber-output head. It enables fiber-core gas loading and evacuation in a hermetic fashion. A 5 m long GLO-BDS were demonstrated for a green short pulse laser with a transmission coefficient larger than 80%, and a laser output profile close to single-mode (M2 <1.3).

760 nm high-performance VCSEL growth and characterization

NASA Astrophysics Data System (ADS)

Rinaldi, Fernando; Ostermann, Johannes M.; Kroner, Andrea; Riedl, Michael C.; Michalzik, Rainer

2006-04-01

High-performance vertical-cavity surface-emitting lasers (VCSELs) with an emission wavelength of approximately 764 nm are demonstrated. This wavelength is very attractive for oxygen sensing. Low threshold currents, high optical output power, single-mode operation, and stable polarization are obtained. Using the surface relief technique and in particular the grating relief technique, we have increased the single-mode output power to more than 2.5mW averaged over a large device quantity. The laser structure was grown by molecular beam epitaxy (MBE) on GaAs (100)-oriented substrates. The devices are entirely based on the AlGaAs mixed compound semiconductor material system. The growth process, the investigations of the epitaxial material together with the device fabrication and characterization are discussed in detail.

Shot noise startup of the 6 NM SASE FEL at the Tesla Test Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierini, P.; Fawley, W.M.

We present here an analysis of the shot noise startup of the 6 nm SASE FEI proposal at the TESLA Test Facility in DESY The statistical of the saturation length and output power due to the intrinsic randomness of the noise startup are investigated with the use of the 2D time dependent code GINGER, that takes into account propagation effects and models shot noise. We then provide estimates for the spectral contents and linewidth of the emitted radiation and describe its spiking characteristics. The output radiation will develop superradiant spikes seeded by the shot noise in the electron beam, whichmore » can entrance the average emitted power at the expense of some spectral broadening.« less

Design and characterization of a novel power over fiber system integrating a high power diode laser

NASA Astrophysics Data System (ADS)

Perales, Mico; Yang, Mei-huan; Wu, Cheng-liang; Hsu, Chin-wei; Chao, Wei-sheng; Chen, Kun-hsein; Zahuranec, Terry

2017-02-01

High power 9xx nm diode lasers along with MH GoPower's (MHGP's) flexible line of Photovoltaic Power Converters (PPCs) are spurring high power applications for power over fiber (PoF), including applications for powering remote sensors and sensors monitoring high voltage equipment, powering high voltage IGBT gate drivers, converters used in RF over Fiber (RFoF) systems, and system power applications, including powering UAVs. In PoF, laser power is transmitted over fiber, and is converted to electricity by photovoltaic cells (packaged into Photovoltaic Power Converters, or PPCs) which efficiently convert the laser light. In this research, we design a high power multi-channel PoF system, incorporating a high power 976 nm diode laser, a cabling system with fiber break detection, and a multichannel PPC-module. We then characterizes system features such as its response time to system commands, the PPC module's electrical output stability, the PPC-module's thermal response, the fiber break detection system response, and the diode laser optical output stability. The high power PoF system and this research will serve as a scalable model for those interested in researching, developing, or deploying a high power, voltage isolated, and optically driven power source for high reliability utility, communications, defense, and scientific applications.

Optimisation of frequency-modulated characteristics of output radiation in a lidar with Raman amplification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grigorievsky, V I; Tezadov, Ya A

2016-03-31

The reported study is aimed at increasing the power in the transmission path of a lidar with Raman amplification for longpath sensing of methane by optimising the frequency-modulated characteristics of the output radiation. The pump current of the used distributed-feedback master laser was modulated by a linearfrequency signal with simultaneous application of a non-synchronous high-frequency signal. For such a modulation regime, the Raman amplifier provided the mean output power of 2.5 W at a wavelength of 1650 nm. The spectral broadening did not significantly decrease the lidar sensitivity at long paths. (lidars)

Switchable and tunable dual-wavelength Er-doped fiber ring laser with single-frequency lasing wavelengths

NASA Astrophysics Data System (ADS)

Zhang, Haiwei; Shi, Wei; Bai, Xiaolei; Sheng, Quan; Xue, Lifang; Yao, Jianquan

2018-02-01

We obtain a switchable and tunable dual-wavelength single-frequency Er-doped ring fiber laser. In order to realize single-longitudinal output, two saturable-absorber-based tracking narrow-band filters are formed in 3- meter-long unpumped Er-doped fiber to narrow the linewidth via using the PM-FBG as a reflection filter. The maximum output power is 2.11 mW centered at 1550.16 nm and 1550.54 nm when the fiber laser operates in dual-wavelength mode. The corresponding linewidths of those two wavelengths are measured to be 769 Hz and 673 Hz, respectively. When the temperature around the PM-FBG is changed from 15 °C to 55 °C, the dual-wavelength single-frequency fiber laser can be tuned from 1550.12 nm to 1550.52 nm and from 1550.49 nm to 1550.82 nm, respectively.

High-efficency stable 213-nm generation for LASIK application

NASA Astrophysics Data System (ADS)

Wang, Zhenglin; Alameh, Kamal; Zheng, Rong

2005-01-01

213nm Solid-state laser technology provides an alternative method to replace toxic excimer laser in LASIK system. In this paper, we report a compact fifth harmonic generation system to generate high pulse energy 213nm laser from Q-switched Nd:YAG laser for LASIK application based on three stages harmonic generation procedures. A novel crystal housing was specifically designed to hold the three crystals with each crystal has independent, precise angular adjustment structure and automatic tuning control. The crystal temperature is well maintained at ~130°C to improve harmonic generation stability and crystal operation lifetime. An output pulse energy 35mJ is obtained at 213nm, corresponding to total conversion efficiency ~10% from 1064nm pump laser. In system verification tests, the 213nm output power drops less than 5% after 5 millions pulse shots and no significant damage appears in the crystals.

Packaging of wavelength stabilized 976nm 100W 105µm 0.15 NA fiber coupled diode lasers

NASA Astrophysics Data System (ADS)

Jiang, Xiaochen; Liu, Rui; Gao, Yanyan; Zhang, Tujia; He, Xiaoguang; Zhu, Jing; Zhang, Qiang; Yang, Thomas; Zhang, Cuipeng

2016-03-01

Fiber coupled diode lasers are widely used in many fields now especially as pumps in fiber laser systems. In many fiber laser applications, high brightness pumps are essential to achieve high brightness fiber lasers. Furthermore, 976nm wavelength absorption band is narrow with Yb3+ doped fiber lasers which is more challenging for controlling wavelength stabilized in diode laser modules. This study designed and implemented commercial available high brightness and narrow wavelength width lasers to be able to use in previous mentioned applications. Base on multiple single emitters using spatial and polarization beam combining as well as fiber coupling techniques, we report a wavelength stabilized, 105μm NA 0.15 fiber coupled diode laser package with 100W of optical output power at 976 nm, which are 14 emitters inside each multiple single emitter module. The emitting aperture of the combined lasers output are designed and optimized for coupling light into a 105μm core NA 0.15 fiber. Volume Bragg grating technology has been used to improve spectral characteristics of high-power diode lasers. Mechanical modular design and thermal simulation are carried out to optimize the package. The spectral width is roughly 0.5 nm (FWHM) and the wavelength shift per °C < 0.02nm. The output spectrum is narrowed and wavelength is stabilized using Volume Bragg gratings (VBGs). The high brightness package has an electrical to optical efficiency better than 45% and power enclosure more than 90% within NA 0.12. Qualification tests have been included on this kind of package. Mechanical shock, vibration and accelerated aging tests show that the package is reliability and the MTTF is calculated to be more than 100k hours at 25°C.

75 W 40% efficiency single-mode all-fiber erbium-doped laser cladding pumped at 976 nm.

PubMed

Kotov, L V; Likhachev, M E; Bubnov, M M; Medvedkov, O I; Yashkov, M V; Guryanov, A N; Lhermite, J; Février, S; Cormier, E

2013-07-01

Optimization of Yb-free Er-doped fiber for lasers and amplifiers cladding pumped at 976 nm was performed in this Letter. The single-mode fiber design includes an increased core diameter of 34 μm and properly chosen erbium and co-dopant concentrations. We demonstrate an all-fiber high power laser and power amplifier based on this fiber with the record slope efficiency of 40%. To the best of our knowledge, the achieved output power of 75 W is the highest power reported for such lasers.

Effect of 655 nm laser different powers on dog sperm motility parameters

NASA Astrophysics Data System (ADS)

Corral-Baqués, M. I.; Rigau, T.; Rivera, M. M.; Rodríguez-Gil, J. E.; Rigau, J.

2006-04-01

Introduction: One of the most appreciated features of the sperm is its motility, which depends on a big energy consumption despite differences among species. Laser acts direct or indirectly on mitochondria increasing ATP production. Material and method: By means of a Computer Aided Sperm Analysis (CASA) we have studied the effects of a 655 nm continuous wave diode laser irradiation at different power outputs with a dose of 3.3418 J on sperm motility. After an eosine-nigrosine stain to establish its quality, the second fraction of fresh beagle dog sperm was divided into 5 groups, 1 control and four to be irradiated respectively with an average output power of 6.84 mW, 15.43 mW, 33.05 mW and 49.66 mW. At times 0 and 45 minutes from irradiation pictures were taken and analysed with the Sperm class Analyzer SCA2002 programme. The motility parameters of 4987 spermatozoa studied were: curvilinear velocity (VCL), progressive velocity (VSL), straightness (STR), wobble (WOB), average path velocity (VAP), linearity (LIN), mean amplitude of lateral head displacement (ALHmed), beat cross frequency (BCF) and the total motility (MT). At time 15 minutes after irradiation a hypoosmotic swelling test (HOST) was done. Results: Several motility parameters that affect the overall motile sperm subpopulation structure have been changed by different output powers of a 655 nm diode laser irradiation, and prevents the decrease of the sperm motility properties along time.

High-efficiency and high-reliability 9xx-nm bars and fiber-coupled devices at Coherent

NASA Astrophysics Data System (ADS)

Zhou, Hailong; Kennedy, Keith; Weiss, Eli; Li, Jun; Anikitchev, Serguei; Reichert, Patrick; Du, Jihua; Schleuning, David; Nabors, David; Reed, Murray; Toivonen, Mika; Lehkonen, Sami; Haapamaa, Jouko

2006-02-01

Ongoing optimization of epitaxial design within Coherent device engineering has led to a family of high power-conversion-efficiency (PCE) products on conductively cooled packages (CCP) and fiber array packages (FAP). At a 25°C heat sink temperature, the PCE was measured at 71.5% with 75W CW output power on 30% fill-factor (FF) bars with passive cooling. At heat sink temperatures as high as 60°C the PCE of these bars is still maintained above 60%. Powered by such high efficiency 9xx nm diodes, Coherent FAP products have consistently exceeded 55% PCE up to 50W power levels, with 62% PCE demonstrated out of the fiber. High linear-power-density (LPD) operation of 100μm x 7-emitter bars at LPD = 80 mW/μm was also demonstrated. Bars with 7-emitter were measured up to 140W QCW power before catastrophic optical mirror damage (COMD) occurred, which corresponds to a COMD value of 200mW/μm or 2D facet power density of 29.4 MW/cm2. Leveraging these improvements has enabled high power FAPs with >90W CW from an 800μm-diameter fiber bundle. Extensive reliability testing has already accumulated 400,000 total real-time device hours at a variety of accelerated and non-accelerated operating conditions. A random failure rate <0.5% per kilo-hours and gradual degradation rate <0.4% per kilo-hours have been observed. For a 30% FF 50W CW 9xx nm bar, this equates to >30,000 hours of median lifetime at a 90% confidence level. More optimized 30% FF 9xx nm bars are under development for power outputs up to 80W CW with extrapolated median lifetimes greater than 20,000 hours.

In vivo monitoring laser tissue interaction using high resolution Fourier-domain optical coherence tomography

NASA Astrophysics Data System (ADS)

Jo, Hang Chan; Shin, Dong Jun; Ahn, Jin-Chul; Chung, Phil-Sang; Kim, DaeYu

2017-02-01

Laser-induced therapies include laser ablation to remove or cut target tissue by irradiating high-power focused laser beam. These laser treatments are widely used tools for minimally invasive surgery and retinal surgical procedures in clinical settings. In this study, we demonstrate laser tissue interaction images of various sample tissues using high resolution Fourier-domain optical coherence tomography (Fd-OCT). We use a Q-switch diode-pumped Nd:YVO4 nanosecond laser (532nm central wavelength) with a 4W maximum output power at a 20 kHz repetition rate to ablate in vitro and in vivo samples including chicken breast and mouse ear tissues. The Fd-OCT system acquires time-series Bscan images at the same location during the tissue ablation experiments with 532nm laser irradiation. The real-time series of OCT cross-sectional (B-scan) images compare structural changes of 532nm laser ablation using same and different laser output powers. Laser tissue ablation is demonstrated by the width and the depth of the tissue ablation from the B-scan images.

High-power pulsed and CW diode-pumped mode-locked Nd:YAG lasers

NASA Technical Reports Server (NTRS)

Marshall, Larry R.; Hays, A. D.; Kaz, Alex; Kasinski, Jeff; Burnham, R. L.

1991-01-01

The operation of both pulsed and CW diode-pumped mode-locked Nd:YAG lasers are presented. The pulsed laser produced 1.0 mJ with pulsewidths of 90 psec at 20 Hz. The CW pumped laser produced 6 W output at 1.064 microns and 3 W output at 532 nm.

Compact diode laser module at 1116 nm with an integrated optical isolation and a PM-SMF output

NASA Astrophysics Data System (ADS)

Jedrzejczyk, Daniel; Hofmann, Julian; Werner, Nils; Sahm, Alexander; Paschke, Katrin

2017-02-01

In this work, a fiber-coupled diode laser module emitting around 1116 nm with an output power P < 60 mW is realized. As a laser light source a distributed Bragg reflector (DBR) ridge waveguide diode laser is applied. The module comprises temperature stabilizing components, a micro-lens system as well as an optical micro-isolator. At the output, a polarization-maintaining single-mode fiber (PM-SMF) with a core diameter of 5.5 μm and a standard FC/APC connector are utilized. The generated diffraction limited beam is characterized by a narrow linewidth ( δν < 10 MHz) and a high polarization extinction ratio (PER > 25 dB).

LD-cladding-pumped 50 pm linewidth Tm 3+ -doped silica fiber laser.

PubMed

Yunjun, Zhang; Baoquan, Yao; Youlun, Ju; Hui, Zhou; Yuezhu, Wang

2008-05-26

We report on a Tm(3+)-doped fiber laser source operating at 1936.4 nm with a very narrow linewidth (50 pm) laser output. Up to 2.4 W cw laser power was obtained from an 82 cm long Tm(3+)-doped multimode-core fiber cladding pumped by a 792 nm laser diode (LD). The fiber laser cavity included a high-reflective dichroic and a low-reflective FBG output coupler. The multimode fiber Bragg grating (FBG) transmission spectrum and output laser spectrum were measured. By adjusting the distance between the dichroic and the Tm(3+)-doped fiber end, the multipeak laser spectrum changed to a single-peak laser spectrum.

Record power, ultra-broadband supercontinuum source based on highly GeO₂ doped silica fiber.

PubMed

Jain, D; Sidharthan, R; Moselund, P M; Yoo, S; Ho, D; Bang, O

2016-11-14

We demonstrate highly germania doped fibers for mid-infrared supercontinuum generation. Experiments ensure a highest output power of 1.44 W for a broadest spectrum from 700 nm to 3200 nm and 6.4 W for 800 nm to 2700 nm from these fibers, while being pumped by a broadband Erbium-Ytterbium doped fiber based master oscillator power amplifier. The effect of repetition frequency of pump source and length of germania-doped fiber has also been investigated. Further, germania doped fiber has been pumped by conventional supercontinuum source based on silica photonic crystal fiber supercontinuum source. At low power, a considerable broadening of 200-300 nm was observed. Further broadening of spectrum was limited due to limited power of pump source. Our investigations reveal the unexploited potential of germania doped fiber for mid-infrared supercontinuum generation. These measurements ensure the potential of germania based photonic crystal fiber or a step-index fiber supercontinuum source for high power ultra-broad band emission being by pumped a 1060 nm or a 1550 nm laser source. To the best of our knowledge, this is the record power, ultra-broadband, and all-fiberized supercontinuum light source based on silica and germania fiber ever demonstrated to the date.

Short-wavelength InAlGaAs/AlGaAs quantum dot superluminescent diodes

NASA Astrophysics Data System (ADS)

Liang, De-Chun; An, Qi; Jin, Peng; Li, Xin-Kun; Wei, Heng; Wu, Ju; Wang, Zhan-Guo

2011-10-01

This paper reports the fabrication of J-shaped bent-waveguide superluminescent diodes utilizing an InAlGaAs/AlGaAs quantum dot active region. The emission spectrum of the device is centred at 884 nm with a full width at half maximum of 37 nm and an output power of 18 mW. By incorporating an Al composition into the quantum dot active region, short-wavelength superluminescent diode devices can be obtained. An intersection was found for the light power-injection current curves measured from the straight-waveguide facet and the bent-waveguide facet, respectively. The result is attributed to the conjunct effects of the gain and the additional loss of the bent waveguide. A numerical simulation is performed to verify the qualitative explanation. It is shown that bent waveguide loss is an important factor that affects the output power of J-shaped superluminescent diode devices.

408-fs SESAM mode locked Cr:ZnSe laser

NASA Astrophysics Data System (ADS)

Bu, Xiangbao; Shi, Yuhang; Xu, Jia; Li, Huijuan; Wang, Pu

2018-01-01

We report self-starting femtosecond operation of a 127-MHz SESAM mode locked Cr:ZnSe laser around 2420 nm. A thulium doped double clad fiber laser at 1908 nm was used as the pumping source. In the normal dispersion regime, stable pulse pairs with constant phase differences in the multipulse regime were observed. The maximum output power was 342 mW with respect to incident pump power of 4.8 W and the corresponding slope efficiency was 10.4%. By inserting a piece of sapphire plate, dispersion compensation was achieved and the intra-cavity dispersion was moved to the anomalous regime. A maximum output power of 403 mW was obtained and the corresponding slope efficiency was 12.2%. Pulse width was measured to be 408 fs by a collinear autocorrelator using two-photon absorption in an InGaAs photodiode. The laser spectrum in multipulse operation showed a clear periodic modulation.

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.

Multi-watt passively Q-switched Yb:YAB/Cr:YAG microchip lasers

NASA Astrophysics Data System (ADS)

Serres, Josep Maria; Loiko, Pavel; Mateos, Xavier; Liu, Junhai; Zhang, Huaijing; Yumashev, Konstantin; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc

2017-02-01

A trigonal 5.6 at.% Yb:YAl3(BO3)4 (Yb:YAB) crystal is employed in continuous-wave (CW) and passively Q-switched microchip lasers pumped by a diode at 978 nm. Using a 3 mm-thick, c-cut Yb:YAB crystal, which has a higher pump absorption efficiency, efficient CW microchip laser operation is demonstrated. This laser generated a maximum output power of 7.18 W at 1041-1044 nm with a slope efficiency η of 67% (with respect to the absorbed pump power) and an almost diffraction-limited beam, M2 x,y < 1.1. Inserting a Cr:YAG saturable absorber, stable passive Q-switching of the Yb:YAB microchip laser was obtained. The maximum average output power from the Yb:YAB/Cr:YAG laser reached 2.82 W at 1042 nm with η = 53% and a conversion efficiency with respect to the CW mode of 65% (when using a 0.7 mm-thick Cr:YAG). The latter corresponded to a pulse duration and energy of 7.1 ns / 47 μJ at a pulse repetition rate (PRR) of 60 kHz. Using a 1.3 mm-thick Cr:YAG, 2.02 W were achieved at 1041 nm corresponding to η = 38%. The pulse characteristics were 4.9 ns / 83 μJ at PRR = 24.3 kHz and the maximum peak power reached 17 kW. Yb:YAB crystals are very promising for compact sub-ns power-scalable microchip lasers.

Broadly tunable femtosecond mode-locking in a Tm:KYW laser near 2 μm.

PubMed

Lagatsky, A A; Calvez, S; Gupta, J A; Kisel, V E; Kuleshov, N V; Brown, C T A; Dawson, M D; Sibbett, W

2011-05-09

Efficient mode-locking in a Tm:KY(WO(4))(2) laser is demonstrated by using InGaAsSb quantum-well SESAMs. Self-starting ultrashort pulse generation was realized in the 1979-2074 nm spectral region. Maximum average output power up to 411 mW was produced around 1986 nm with the corresponding pulse duration and repetition rate of 549 fs and 105 MHz respectively. Optimised pulse durations of 386 fs were produced with an average power of 235 mW at 2029 nm. © 2011 Optical Society of America

High power multiple wavelength diode laser stack for DPSSL application without temperature control

NASA Astrophysics Data System (ADS)

Hou, Dong; Yin, Xia; Wang, Jingwei; Chen, Shi; Zhan, Yun; Li, Xiaoning; Fan, Yingmin; Liu, Xingsheng

2018-02-01

High power diode laser stack is widely used in pumping solid-state laser for years. Normally an integrated temperature control module is required for stabilizing the output power of solid-state laser, as the output power of the solid-state laser highly depends on the emission wavelength and the wavelength shift of diode lasers according to the temperature changes. However the temperature control module is inconvenient for this application, due to its large dimension, high electric power consumption and extra adding a complicated controlling system. Furthermore, it takes dozens of seconds to stabilize the output power when the laser system is turned on. In this work, a compact hard soldered high power conduction cooled diode laser stack with multiple wavelengths is developed for stabilizing the output power of solid-state laser in a certain temperature range. The stack consists of 5 laser bars with the pitch of 0.43mm. The peak output power of each bar in the diode laser stack reaches as much as 557W and the combined lasing wavelength spectrum profile spans 15nm. The solidstate laser, structured with multiple wavelength diode laser stacks, allows the ambient temperature change of 65°C without suddenly degrading the optical performance.

High power diode lasers emitting from 639 nm to 690 nm

NASA Astrophysics Data System (ADS)

Bao, L.; Grimshaw, M.; DeVito, M.; Kanskar, M.; Dong, W.; Guan, X.; Zhang, S.; Patterson, J.; Dickerson, P.; Kennedy, K.; Li, S.; Haden, J.; Martinsen, R.

2014-03-01

There is increasing market demand for high power reliable red lasers for display and cinema applications. Due to the fundamental material system limit at this wavelength range, red diode lasers have lower efficiency and are more temperature sensitive, compared to 790-980 nm diode lasers. In terms of reliability, red lasers are also more sensitive to catastrophic optical mirror damage (COMD) due to the higher photon energy. Thus developing higher power-reliable red lasers is very challenging. This paper will present nLIGHT's released red products from 639 nm to 690nm, with established high performance and long-term reliability. These single emitter diode lasers can work as stand-alone singleemitter units or efficiently integrate into our compact, passively-cooled Pearl™ fiber-coupled module architectures for higher output power and improved reliability. In order to further improve power and reliability, new chip optimizations have been focused on improving epitaxial design/growth, chip configuration/processing and optical facet passivation. Initial optimization has demonstrated promising results for 639 nm diode lasers to be reliably rated at 1.5 W and 690nm diode lasers to be reliably rated at 4.0 W. Accelerated life-test has started and further design optimization are underway.

Diode-pumped continuous-wave and passively Q-switched 1066 nm Nd:GYNbO4 laser

NASA Astrophysics Data System (ADS)

Ma, Yufei; Peng, Zhenfang; He, Ying; Li, Xudong; Yan, Renpeng; Yu, Xin; Zhang, Qingli; Ding, Shoujun; Sun, Dunlu

2017-08-01

A diode-pumped passively Q-switched 1066 nm laser with a novel Nd:Gd0.69Y0.3NbO4 mixed crystal was demonstrated for the first time to the best of our knowledge. In the continuous-wave (CW) operation, optimization selection of output couplers was carried out, and a maximum output power of 2.13 W was obtained when the plane mirror with transmission of 25% was chosen and the absorbed pump power was 10.5 W. The Cr4+:YAG passively Q-switched Nd:Gd0.69Y0.3NbO4 laser performance was investigated. At an absorbed pump power of 10.5 W, using Cr4+:YAG with initial transmission of 80%, the obtained minimum pulse width was 7.2 ns with the pulse repetition rate of 19 kHz. The single pulse energy and peak power were estimated to be 26.7 µJ and 3.7 kW, respectively.

Narrow linewidth picosecond UV pulsed laser with mega-watt peak power.

PubMed

Huang, Chunning; Deibele, Craig; Liu, Yun

2013-04-08

We demonstrate a master oscillator power amplifier (MOPA) burst mode laser system that generates 66 ps/402.5 MHz pulses with mega-watt peak power at 355 nm. The seed laser consists of a single frequency fiber laser (linewidth < 5 KHz), a high bandwidth electro-optic modulator (EOM), a picosecond pulse generator, and a fiber based preamplifier. A very high extinction ratio (45 dB) has been achieved by using an adaptive bias control of the EOM. The multi-stage Nd:YAG amplifier system allows a uniformly temporal shaping of the macropulse with a tunable pulse duration. The light output from the amplifier is converted to 355 nm, and over 1 MW peak power is obtained when the laser is operating in a 5-μs/10-Hz macropulse mode. The laser output has a transform-limited spectrum with a very narrow linewidth of individual longitudinal modes. The immediate application of the laser system is the laser-assisted hydrogen ion beam stripping for the Spallation Neutron Source (SNS).

A fundamental mode Nd:GdVO4 laser pumped by a large aperture 808 nm VCSEL

NASA Astrophysics Data System (ADS)

Hao, Y. Q.; Ma, J. L.; Yan, C. L.; Liu, G. J.; Ma, X. H.; Gong, J. F.; Feng, Y.; Wei, Z. P.; Wang, Y. X.; Zhao, Y. J.

2013-05-01

A fundamental mode Nd:GdVO4 laser pumped by a vertical cavity surface emitting laser (VCSEL) is experimentally demonstrated. The VCSEL has a circular output-beam which makes it easier for it to be directly coupled to a Nd:GdVO4 microcrystal. In our research, a large aperture 808 nm VCSEL, with a multi-ring-shaped aperture (MRSA) and an almost Gaussian-shaped far-field profile, is used as the pumping source. Experimental results for the Nd:GdVO4 laser pumped by the VCSEL are presented. The maximum output peak power of 0.754 W is obtained under a pump peak power of 1.3 W, and the corresponding opto-optic conversion efficiency is 58.1%. The average slope efficiency is 65.8% from the threshold pump power of 0.2 W to the pump power of 1.3 W. The laser beam quality factors are measured to be {M}x2=1.2 0 and {M}y2=1.1 5.

High-efficiency ytterbium-free erbium-doped all-glass double cladding silicate glass fiber for resonantly-pumped fiber lasers.

PubMed

Qiang, Zexuan; Geng, Jihong; Luo, Tao; Zhang, Jun; Jiang, Shibin

2014-02-01

A highly efficient ytterbium-free erbium-doped silicate glass fiber has been developed for high-power fiber laser applications at an eye-safe wavelength near 1.55 μm. Our preliminary experiments show that high laser efficiency can be obtained from a relatively short length of the gain fiber when resonantly pumped at 1535 nm in both core- and cladding-pumping configurations. With a core-pumping configuration as high as 75%, optical-to-optical efficiency and 4 W output power were obtained at 1560 nm from a 1 m long gain fiber. When using a cladding-pumping configuration, approximately 13 W output power with 67.7% slope efficiency was demonstrated from a piece of 2 m long fiber. The lengths of silicate-based gain fiber are much shorter than their silica-based counterparts used in other experiments, which is significantly important for high-power narrow-band and/or pulsed laser applications.

Demonstration of enhanced continuous-wave operation of blue laser diodes on a semipolar 202¯1¯ GaN substrate using indium-tin-oxide/thin-p-GaN cladding layers.

PubMed

Mehari, Shlomo; Cohen, Daniel A; Becerra, Daniel L; Nakamura, Shuji; DenBaars, Steven P

2018-01-22

The benefits of utilizing transparent conductive oxide on top of a thin p-GaN layer for continuous-wave (CW) operation of blue laser diodes (LDs) were investigated. A very low operating voltage of 5.35 V at 10 kA/cm 2 was obtained for LDs with 250 nm thick p-GaN compared to 7.3 V for LDs with conventional 650 nm thick p-GaN. An improved thermal performance was also observed for the thin p-GaN samples resulting in a 40% increase in peak light output power and a 32% decrease in surface temperature. Finally, a tradeoff was demonstrated between low operating voltage and increased optical modal loss in the indium tin oxide (ITO) with thinner p-GaN. LDs lasing at 445 nm with 150 nm thick p-GaN had an excess modal loss while LDs with an optimal 250 nm thick p-GaN resulted in optical output power of 1.1 W per facet without facet coatings and a wall-plug efficiency of 15%.

Power and efficiency scaling of diode pumped Cr:LiSAF lasers: 770-1110 nm tuning range and frequency doubling to 387-463 nm.

PubMed

Demirbas, Umit; Baali, Ilyes

2015-10-15

We report significant average power and efficiency scaling of diode-pumped Cr:LiSAF lasers in continuous-wave (cw), cw frequency-doubled, and mode-locked regimes. Four single-emitter broad-area laser diodes around 660 nm were used as the pump source, which provided a total pump power of 7.2 W. To minimize thermal effects, a 20 mm long Cr:LiSAF sample with a relatively low Cr-concentration (0.8%) was used as the gain medium. In cw laser experiments, 2.4 W of output power, a slope efficiency of 50%, and a tuning range covering the 770-1110 nm region were achieved. Intracavity frequency doubling with beta-barium borate (BBO) crystals generated up to 1160 mW of blue power and a record tuning range in the 387-463 nm region. When mode locked with a saturable absorber mirror, the laser produced 195 fs pulses with 580 mW of average power around 820 nm at a 100.3 MHz repetition rate. The optical-to-optical conversion efficiency of the system was 33% in cw, 16% in cw frequency-doubled, and 8% in cw mode-locked regimes.

Femtosecond OPO based on MgO:PPLN synchronously pumped by a 532 nm fiber laser

NASA Astrophysics Data System (ADS)

Cao, Jianjun; Shen, Dongyi; Zheng, Yuanlin; Feng, Yaming; Kong, Yan; Wan, Wenjie

2017-05-01

With the rapid progress in fiber technologies, femtosecond fiber lasers, which are compact, cost-effective and stable, have been developed and are commercially available. Studies of optical parametric oscillators (OPOs) pumped by this type of laser are demanding. Here we report a femtosecond optical parametric oscillator (OPO) at 79.6 MHz repetition rate based on MgO-doped periodically poled LiNbO3 (MgO:PPLN), synchronously pumped by the integrated second harmonic radiation of a femtosecond fiber laser at 532 nm. The signal delivered by the single resonant OPO is continuously tunable from 757 to 797 nm by tuning the crystal temperature in a poling period of 7.7 μ \\text{m} . The output signal shows good beam quality in TEM00 mode profile with pulse duration of 206 fs at 771 nm. Maximum output signal power of 71 mW is obtained for a pump power of 763 mW and a low pumping threshold of 210 mW is measured. Moreover, grating tuning and cavity length tuning of the signal wavelength are also investigated.

Femtosecond deep-infrared optical parametric oscillator pumped directly by a Ti:sapphire laser

NASA Astrophysics Data System (ADS)

O'Donnell, Callum; Chaitanya Kumar, S.; Zawilski, Kevin T.; Schunemann, Peter G.; Ebrahim-Zadeh, Majid

2018-02-01

We report a high-repetition-rate femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) based on the nonlinear optical crystal, CdSiP2 (CSP), pumped directly by a Ti:sapphire laser, for the first time. By pumping CSP at <1 μm, we have achieved practical output powers at the longest wavelengths generated by any Ti:sapphire-pumped OPO. Using a combination of pump wavelength tuning, type-I critical phase-matching, and cavity delay tuning, we have generated continuously tunable radiation across 6654-8373 nm (1194-1503 cm-1) at 80.5 MHz repetition rate, providing up to 20 mW of average power at 7314 nm and <7 mW beyond 8000 nm, with idler spectra exhibiting bandwidths of 140-180 nm across the tuning range. Moreover, the near-IR signal is tunable across 1127-1192 nm, providing up to 37 mW of average power at 1150 nm. Signal pulses, characterised using intensity autocorrelation, have durations of 260-320 fs, with corresponding time-bandwidth product of ΔυΔτ 1. The idler and signal output exhibit a TEM00 spatial profile with single-peak Gaussian distribution. With an equivalent spectral brightness of 6.68×1020 photons s-1 mm-2 sr-1 0.1% BW-1, this OPO represents a viable table-top alternative to synchrotron and supercontinuum sources for deep-IR applications in spectroscopy, metrology and medical diagnostics.

Megawatt level UV output from [110] Cr⁴⁺:YAG passively Q-switched microchip laser.

PubMed

Bhandari, Rakesh; Taira, Takunori

2011-11-07

Recent development of megawatt peak power, giant pulse microchip lasers has opened new opportunities for efficient wavelength conversion, provided the output of the microchip laser is linearly polarized. We obtain > 2 MW peak power, 260 ps, 100 Hz pulses at 266 nm by fourth harmonic conversion of a linearly polarized Nd:YAG microchip laser that is passively Q-switched with [110] cut Cr⁴⁺:YAG. The SHG and FHG conversion efficiencies are 85% and 51%, respectively.

Improved output power of GaN-based light-emitting diodes grown on a nanopatterned sapphire substrate

NASA Astrophysics Data System (ADS)

Chan, Chia-Hua; Hou, Chia-Hung; Tseng, Shao-Ze; Chen, Tsing-Jen; Chien, Hung-Ta; Hsiao, Fu-Li; Lee, Chien-Chieh; Tsai, Yen-Ling; Chen, Chii-Chang

2009-07-01

This letter describes the improved output power of GaN-based light-emitting diodes (LEDs) formed on a nanopatterned sapphire substrate (NPSS) prepared through etching with a self-assembled monolayer of 750-nm-diameter SiO2 nanospheres used as the mask. The output power of NPSS LEDs was 76% greater than that of LEDs on a flat sapphire substrate. Three-dimensional finite-difference time-domain calculation predicted a 40% enhancement in light extraction efficiency of NPSS LEDs. In addition, the reduction of full widths at half maximum in the ω-scan rocking curves for the (0 0 2) and (1 0 2) planes of GaN on NPSS suggested improved crystal quality.

Wavelength tunable CW red laser generated based on an intracavity-SFG composite cavity

NASA Astrophysics Data System (ADS)

Zhang, Z. N.; Bai, Y.; Lei, G. Z.; Bai, B.; Sun, Y. X.; Hu, M. X.; Wang, C.; Bai, J. T.

2016-12-01

We report a wavelength-tunable watt-level continuous wave (CW) red laser that uses a composite cavity based on an intracavity sum-frequency generation (SFG). The composite cavity is composed of a LD side-pumped Nd: GdVO4 p-polarized 1062.9 nm resonant cavity and a resonant optical parametric oscillator (SRO) of s-polarized signal light using a periodically poled crystal MgO: PPLN. Based on the temperature tuning from 30 °C to 200 °C, the CW red laser beams are obtained in a tunable waveband from 634.4 nm to 649.1 nm, corresponding to a tunable output waveband from 3278.0 nm to 2940.2 nm of the mid-infrared idler lights. The maximum CW output power of the red laser at 634.4 nm and the idler light at 3278.0 nm reach 3.03 W and 4.13 W under 30 °C, respectively.

High power, widely tunable dual-wavelength 2 μm laser based on intracavity KTP optical parametric oscillator

NASA Astrophysics Data System (ADS)

Yan, Dexian; Wang, Yuye; Xu, Degang; Shi, Wei; Zhong, Kai; Liu, Pengxiang; Yan, Chao; Mei, Jialin; Shi, Jia; Yao, Jianquan

2017-01-01

We presented a high power, widely tunable narrowband 2 μm dual-wavelength source employing intracavity optical parametric oscillator with potassium titanium oxide phosphate (KTP) crystal. Two identical KTP crystals were oriented oppositely in the OPO cavity to compensate the walk-off effect. The output average power of dual-wavelength 2 μm laser was up to 18.18 W at 10 kHz with the peak power of 165 kW. The two wavelengths can be tuned in the range of 2070.7 nm to 2191.1 nm for ordinary light while in the range of 2190.7 nm to 2065.9 nm for extraordinary light with the full width at half maximum (FWHM) about 0.8 nm. The pulse width of the tunable laser was as narrow as 11 ns. The beam quality factor M 2 was less than 4 during wavelength tuning.

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.

Solid-state Yb : YAG amplifier pumped by a single-mode laser at 920 nm

NASA Astrophysics Data System (ADS)

Obronov, I. V.; Demkin, A. S.; Myasnikov, D. V.

2018-03-01

An optical amplifier scheme for ultrashort 1030-nm pulses is proposed based on an Yb : YAG crystal with axial pumping by a transverse single-mode laser at a wavelength of 920 nm. A small-signal gain up to 40 dB per pass with a high output beam quality is demonstrated. The maximum average power is 14 W with a slope efficiency exceeding 50%.

Diode-side-pumped continuous wave Nd³⁺ : YVO₄ self-Raman laser at 1176 nm.

PubMed

Kores, Cristine Calil; Jakutis-Neto, Jonas; Geskus, Dimitri; Pask, Helen M; Wetter, Niklaus U

2015-08-01

Here we report, to the best of our knowledge, the first diode-side-pumped continuous wave (cw) Nd3+:YVO4 self-Raman laser operating at 1176 nm. The compact cavity design is based on the total internal reflection of the laser beam at the pumped side of the Nd3+:YVO4 crystal. Configurations with a single bounce and a double bounce of the laser beam at the pumped faced have been characterized, providing a quasi-cw peak output power of more than 8 W (multimode) with an optical conversion efficiency of 11.5% and 3.7 W (TEM00) having an optical conversion efficiency of 5.4%, respectively. Cw output power of 1.8 W has been demonstrated.

Optimized Biasing of Pump Laser Diodes in a Highly Reliable Metrology Source for Long-Duration Space Missions

NASA Technical Reports Server (NTRS)

Poberezhskiy, Ilya; Chang, Daniel; Erlig, Hernan

2011-01-01

Non Planar Ring Oscillator (NPRO) lasers are highly attractive for metrology applications. NPRO reliability for prolonged space missions is limited by reliability of 808 nm pump diodes. Combined laser farm aging parameter allows comparing different bias approaches. Monte-Carlo software developed to calculate the reliability of laser pump architecture, perform parameter sensitivity studies To meet stringent Space Interferometry Mission (SIM) Lite lifetime reliability / output power requirements, we developed a single-mode Laser Pump Module architecture that: (1) provides 2 W of power at 808 nm with >99.7% reliability for 5.5 years (2) consists of 37 de-rated diode lasers operating at -5C, with outputs combined in a very low loss 37x1 all-fiber coupler

High-power Femtosecond Optical Parametric Amplification at 1 kHz in BiB(3)O(6) pumped at 800 nm.

PubMed

Petrov, Valentin; Noack, Frank; Tzankov, Pancho; Ghotbi, Masood; Ebrahim-Zadeh, Majid; Nikolov, Ivailo; Buchvarov, Ivan

2007-01-22

Substantial power scaling of a travelling-wave femtosecond optical parametric amplifier, pumped near 800 nm by a 1 kHz Ti:sapphire laser amplifier, is demonstrated using monoclinic BiB(3)O(6) in a two stage scheme with continuum seeding. Total energy output (signal plus idler) exceeding 1 mJ is achieved, corresponding to an intrinsic conversion efficiency of approximately 32% for the second stage. The tunability extends from 1.1 to 2.9 microm. The high parametric gain and broad amplification bandwidth of this crystal allowed the maintenance of the pump pulse duration, leading to pulse lengths less than 140 fs, both for the signal and idler pulses, even at such high output levels.

High-power dual-wavelength Ho-doped fiber laser at >2 μm tandem pumped by a 1.15 μm fiber laser

PubMed Central

Jin, Xiaoxi; Lou, Zhaokai; Chen, Yizhu; Zhou, Pu; Zhang, Hanwei; Xiao, Hu; Liu, Zejin

2017-01-01

We demonstrated a high-power continuous-wave (CW) dual-wavelength Ho-doped fiber laser (HDFL) at 2049 nm and 2153 nm with a simple coupled-cavity configuration. A ~100 W laser diode-pumped fiber laser at 1150 nm served as the pump source. The maximum output power reached ~22.3 W and the slope efficiency was 23%. By altering the incident pump power, the power ratio of two signal wavelengths could be tuned in a large range due to gain competition. As far as we know, this is the first CW dual-wavelength HDFL with the power exceeding ten-watt-level, and the first dual-wavelength HDFL with the central wavelengths exceeding 2.0 μm and 2.15 μm respectively. PMID:28181571

High-power dual-wavelength Ho-doped fiber laser at >2 μm tandem pumped by a 1.15 μm fiber laser

NASA Astrophysics Data System (ADS)

Jin, Xiaoxi; Lou, Zhaokai; Chen, Yizhu; Zhou, Pu; Zhang, Hanwei; Xiao, Hu; Liu, Zejin

2017-02-01

We demonstrated a high-power continuous-wave (CW) dual-wavelength Ho-doped fiber laser (HDFL) at 2049 nm and 2153 nm with a simple coupled-cavity configuration. A ~100 W laser diode-pumped fiber laser at 1150 nm served as the pump source. The maximum output power reached ~22.3 W and the slope efficiency was 23%. By altering the incident pump power, the power ratio of two signal wavelengths could be tuned in a large range due to gain competition. As far as we know, this is the first CW dual-wavelength HDFL with the power exceeding ten-watt-level, and the first dual-wavelength HDFL with the central wavelengths exceeding 2.0 μm and 2.15 μm respectively.

High-power, continuous-wave, second-harmonic generation at 532 nm in periodically poled KTiOPO(4).

PubMed

Samanta, G K; Kumar, S Chaitanya; Mathew, M; Canalias, C; Pasiskevicius, V; Laurell, F; Ebrahim-Zadeh, M

2008-12-15

We report efficient generation of high-power, cw, single-frequency radiation in the green in a simple, compact configuration based on single-pass, second-harmonic generation of a cw ytterbium fiber laser at 1064 nm in periodically poled KTiOPO(4). Using a crystal containing a 17 mm single grating with period of 9.01 microm, we generate 6.2 W of cw radiation at 532 nm for a fundamental power of 29.75 W at a single-pass conversion efficiency of 20.8%. Over the entire range of pump powers, the generated green output is single frequency with a linewidth of 8.5 MHz and has a TEM(00) spatial profile with M(2)<1.34. The demonstrated green power can be further improved by proper thermal management of crystal heating effects at higher pump powers and also by optimized design of the grating period to include thermal issues.

Radially polarized passively mode-locked thin-disk laser oscillator emitting sub-picosecond pulses with an average output power exceeding the 100 W level.

PubMed

Beirow, Frieder; Eckerle, Michael; Dannecker, Benjamin; Dietrich, Tom; Ahmed, Marwan Abdou; Graf, Thomas

2018-02-19

We report on a high-power passively mode-locked radially polarized Yb:YAG thin-disk oscillator providing 125 W of average output power. To the best of our knowledge, this is the highest average power ever reported from a mode-locked radially polarized oscillator without subsequent amplification stages. Mode-locking was achieved by implementing a SESAM as the cavity end mirror and the radial polarization of the LG* 01 mode was obtained by means of a circular Grating Waveguide Output Coupler. The repetition rate was 78 MHz. A pulse duration of 0.97 ps and a spectral bandwidth of 1.4 nm (FWHM) were measured at the maximum output power. This corresponds to a pulse energy of 1.6 µJ and a pulse peak power of 1.45 MW. A high degree of radial polarization of 97.3 ± 1% and an M 2 -value of 2.16 which is close to the theoretical value for the LG* 01 doughnut mode were measured.

Semiconductor lasers with a continuous tuning range above 100 nm in the nearest IR spectral region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostin, Yu O; Lobintsov, A A; Shramenko, M V

2015-08-31

We have developed two new types of lasers based on quantum-confined semiconductor optical amplifiers with an acousto-optic tunable filter in an external fibre ring cavity. The lasers offer continuous wavelength tuning ranges from 780 to 885 and from 880 to 1010 nm, 20 mW of cw output power, and a tuning rate up to 10{sup 4} nm s{sup -1} at an instantaneous spectral linewidth less than 0.1 nm. (lasers)

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.

Design and characterization of a powered elbow prosthesis.

PubMed

Bennett, Daniel A; Mitchell, Jason; Goldfarb, Michael

2015-01-01

This paper describes the design of a powered elbow prosthesis, which incorporates a belt and cable drive transmission with a brushless DC motor to achieve an output torque of approximately 18.4 Nm, a backdrive torque of 1.5 Nm, and a speed of up to 360 deg/s while remaining within the anthropomorphic envelope with regard to mass and size. The measured torque and speed of the prosthesis is commensurate with nominal capability of the natural limb (for purposes of performing activities of daily living).

Pr:YAlO(3) microchip laser.

PubMed

Fibrich, Martin; Jelínková, Helena; Sulc, Jan; Nejezchleb, Karel; Skoda, Václav

2010-08-01

A cw Pr:YAlO(3) microchip-laser operation in the near-IR spectral region is reported. A microchip resonator was formed by dielectric mirrors directly deposited on the Pr:YAlO(3) crystal surfaces. For active medium pumping, a GaN laser diode providing up to 1W of output power at approximately 448 nm was used. 139mW of laser radiation at 747nm wavelength has been extracted from the microchip-laser system. Slope efficiency related to the incident pumping power was approximately 25%.

Diode-pumped passively mode-locked and passively stabilized Nd3+:BaY2F8 laser

NASA Astrophysics Data System (ADS)

Agnesi, Antonio; Guandalini, Annalisa; Tomaselli, Alessandra; Sani, Elisa; Toncelli, Alessandra; Tonelli, Mauro

2004-07-01

Continuous-wave mode locking (CW-ML) of a diode-pumped Nd3+:BaY2F8 laser is reported for the first time to our knowledge. Pulses as short as 4.8 ps were measured with a total output power of almost equal to 1 W at 1049 nm, corresponding to 3.4 W of absorbed power from the pump diode at 806 nm. A novel technique for passive stabilization of CW-ML has been demonstrated.

Experimental investigation on a diode-pumped cesium-vapor laser stably operated at continuous-wave and pulse regime.

PubMed

Chen, Fei; Xu, Dongdong; Gao, Fei; Zheng, Changbin; Zhang, Kuo; He, Yang; Wang, Chunrui; Guo, Jin

2015-05-04

Employing a fiber-coupled diode-laser with a center wavelength of 852.25 nm and a line width of 0.17 nm, experimental investigation on diode-end-pumped cesium (Cs) vapor laser stably operated at continuous-wave (CW) and pulse regime is carried out. A 5 mm long cesium vapor cell filled with 60 kPa helium and 20 kPa ethane is used as laser medium. Using an output coupler with reflectivity of 48.79%, 1.26 W 894.57 nm CW laser is obtained at an incident pump power of 4.76 W, corresponding an optical-optical efficiency of 26.8% and a slope-efficiency of 28.8%, respectively. The threshold temperature is 67.5 °C. Stable pulsed cesium laser with a maximum average output power of 2.6 W is obtained at a repetition rate of 76 Hz, and the pulse repetition rate can be extend to 1 kHz with a pulse width of 18 μs.

All-optical gain-clamped wideband serial EDFA with ring-shaped laser

NASA Astrophysics Data System (ADS)

Lu, Yung-Hsin; Chi, Sien

2004-01-01

We experimentally investigate the static and dynamic properties of all-optical gain-clamped wideband (1530-1600 nm) serial erbium-doped fiber amplifier with a single ring-shaped laser, which consists of a circulator and a fiber Bragg grating at the output end. The lasing light passing through the second stage is intentionally blocked at the output end by a C/L-band wavelength division multiplexer owning the huge insertion loss, and thus, the copropagating ring-laser light is formed by the first stage. This design can simultaneously clamp the gains of 1547 and 1584 nm probes near 14 dB and shows the same dynamic range of input power up to -4 dBm for conventional band and long-wavelength band. Furthermore, the transient responses of 1551 and 1596 nm surviving channels exhibit small power excursions (<0.54 dB) as the total saturating tone with -2 dBm is modulated on and off at 270 Hz.

300-mW narrow-linewidth deep-ultraviolet light generation at 193 nm by frequency mixing between Yb-hybrid and Er-fiber lasers.

PubMed

Xuan, Hongwen; Zhao, Zhigang; Igarashi, Hironori; Ito, Shinji; Kakizaki, Kouji; Kobayashi, Yohei

2015-04-20

A narrow-linewidth, high average power deep-ultraviolet (DUV) coherent laser emitting at 193 nm is demonstrated by frequency mixing a Yb-hybrid laser with an Er-fiber laser. The Yb-hybrid laser consists of Yb-fiber lasers and an Yb:YAG amplifier. The average output power of the 193 nm laser is 310 mW at 6 kHz, which corresponds to a pulse energy of 51 μJ. To the best of our knowledge, this is the highest average power and pulse energy ever reported for a narrow-linewidth 193 nm light generated by a combination of solid-state and fiber lasers with frequency mixing. We believe this laser will be beneficial for the application of interference lithography by seeding an injection-locking ArF eximer laser.

Analysis and design of high-power and efficient, millimeter-wave power amplifier systems using zero degree combiners

NASA Astrophysics Data System (ADS)

Tai, Wei; Abbasi, Mortez; Ricketts, David S.

2018-01-01

We present the analysis and design of high-power millimetre-wave power amplifier (PA) systems using zero-degree combiners (ZDCs). The methodology presented optimises the PA device sizing and the number of combined unit PAs based on device load pull simulations, driver power consumption analysis and loss analysis of the ZDC. Our analysis shows that an optimal number of N-way combined unit PAs leads to the highest power-added efficiency (PAE) for a given output power. To illustrate our design methodology, we designed a 1-W PA system at 45 GHz using a 45 nm silicon-on-insulator process and showed that an 8-way combined PA has the highest PAE that yields simulated output power of 30.6 dBm and 31% peak PAE.

Cr/ITO semi-transparent n-type electrode for high-efficiency AlGaN/InGaN-based near ultraviolet light-emitting diodes

NASA Astrophysics Data System (ADS)

Kim, Hwankyo; Kim, Dae-Hyun; Seong, Tae-Yeon

2017-11-01

We investigated the electrical performance of near ultraviolet (NUV) (390 nm) light-emitting diodes (LEDs) fabricated with various semi-transparent Cr/ITO n-type contacts. It was shown that after annealing at 400 °C, Cr/ITO (10 nm/40 nm) contact was ohmic with a specific contact resistance of 9.8 × 10-4 Ωcm2. NUV AlGaN-based LEDs fabricated with different Cr/ITO (6-12 nm/40 nm) electrodes exhibited forward-bias voltages of 3.27-3.30 V at an injection current of 20 mA, which are similar to that of reference LED with Cr/Ni/Au (20 nm/25 nm/200 nm) electrode (3.29 V). The LEDs with the Cr/ITO electrodes gave series resistances of 10.69-11.98 Ω, while the series resistance is 10.84 Ohm for the reference LED. The transmittance of the Cr/ITO samples significantly improved when annealed at 400 °C. The transmittance (25.8-45.2% at 390 nm) of the annealed samples decreased with increasing Cr layer thickness. The LEDs with the Cr/ITO electrodes exhibited higher light output power than reference LED (with Cr/Ni/Au electrode). In particular, the LED with the Cr/ITO (12 nm/40 nm) electrode showed 9.3% higher light output power at 100 mA than reference LED. Based on the X-ray photoemission spectroscopy (XPS) and electrical results, the ohmic formation mechanism is described and discussed.

Guide star lasers for adaptive optics

NASA Astrophysics Data System (ADS)

Roberts, William Thomas, Jr.

Exploitation of the imaging capabilities of the new generation of ground-based astronomical telescopes relies heavily on Adaptive Optics (AO). Current AO system designs call for sodium guide star lasers capable of producing at least eight Watts of power tuned to the peak of the sodium D2 line, with a high duty cycle to avoid saturation, and with 0.5-1.0 GHz spectral broadening. This work comprises development and testing of six candidate laser systems and materials which may afford a path to achieving these goals. An end-pumped CW dye laser producing 4.0 Watts of tuned output power was developed and used to obtain the first accurate measurement of sodium layer scattering efficiency. Methods of optimizing the laser output through improving pump overlap efficiency and reducing the number of intracavity scattering surfaces are covered. The 1181 nm fluorescence peak of Mn5+ ion in Ba5 (PO4)3Cl could be tuned and doubled to reach 589 nm. While efforts to grow this crystal were under way, the Mn5+ ion in natural apatite (Ca5(PO4)3F) was studied as a potential laser material. Fluorescence saturation measurements and transmission saturation are presented, as well as efforts to obtain CW lasing in natural apatite. A Q-switched laser color-center laser in LiF : F-2 was developed and successfully tuned and doubled to the sodium D 2 line. Broad-band lasing of 80 mW and tuned narrow-band lasing of 35 mW at 1178 nm were obtained with 275 mW of input pump power at 1064 nm. The measured thermal properties of this material indicate its potential for scaling to much higher power. A Q-switched intracavity Raman laser was developed in which CaWO 4 was used to shift a Nd:YAG laser, the frequency-doubled output of which was centered at 589.3 nm. To obtain light at 589.0 nm, a compositionally tuned pump laser of Nd : Y3Ga1.1Al3.9O 12 was produced which generated the desired shift, but was inhomogeneous broadened, limiting the tunable power of the material. Finally, temperature tuning of a Nd:YAG laser was demonstrated in which the laser emitted up to 8.6 Watts at a temperature of -21.5 C, bringing the wavelength into a regime favorable for efficient Raman shifting by CaWO4.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dontsova, E I; Kablukov, S I; Babin, Sergei A

A cladding-pumped ytterbium-doped fibre laser has been tuned to shorter emission wavelengths (from 1040 to 1017 nm). The laser output power obtained has been compared to calculation results. We have studied frequency doubling of the laser in a KTiOPO{sub 4} (KTP) crystal with type II phase matching in the XY plane and demonstrated wavelength tuning in the range 510 - 520 nm. (lasers)

An All-Digital Fast Tracking Switching Converter with a Programmable Order Loop Controller for Envelope Tracking RF Power Amplifiers

PubMed Central

Anabtawi, Nijad; Ferzli, Rony; Harmanani, Haidar M.

2017-01-01

This paper presents a step down, switched mode power converter for use in multi-standard envelope tracking radio frequency power amplifiers (RFPA). The converter is based on a programmable order sigma delta modulator that can be configured to operate with either 1st, 2nd, 3rd or 4th order loop filters, eliminating the need for a bulky passive output filter. Output ripple, sideband noise and spectral emission requirements of different wireless standards can be met by configuring the modulator’s filter order and converter’s sampling frequency. The proposed converter is entirely digital and is implemented in 14nm bulk CMOS process for post layout verification. For an input voltage of 3.3V, the converter’s output can be regulated to any voltage level from 0.5V to 2.5V, at a nominal switching frequency of 150MHz. It achieves a maximum efficiency of 94% at 1.5 W output power. PMID:28919657

Investigation of 100 mJ all solid state end-pumped 1064 nm Q-switched laser

NASA Astrophysics Data System (ADS)

Xie, Shiyong; Wang, Caili; Liu, Hui; Bo, Yong; Xu, Zuyan

2017-11-01

High energy 1064 nm Q-switched laser output is obtained by LD vertical array end pumping Nd:YAG. Cylindrical lens are used for beam shaping of LD array for different divergence angle of fast and slow axis. Based on the theoretical simulation of fundamental mode radius using ABCD transfer matrix, the resonant cavity is optimized and curvature radius of cavity mirrors is determined. The intracavity power density is calculated according to the output laser pulse energy and transmittance of output coupling mirror is optimized under the condition that optical device is not damaged. 1064 nm laser with a maximum output of 110 mJ is generated under LD pump energy of 600 mJ, corresponding to optical conversion efficiency of 18.3%. The laser pulse width is 11 ns and divergence angle is 1.2 mrad. For saturation phenomenon of Q-switched laser output, LD temperature is adjusted to make wavelength deviate from absorption peak of Nd:YAG crystal. The parasitic oscillation, which affects the enhancement of Q-switched laser energy, can be effectively suppressed by reducing gain of pump end of laser medium, which provides an effective technical means for obtaining high energy end-pumped Q-switched laser.

Temperature changes on the root surfaces of mandibular incisors after an 810-nm high-intensity intracanal diode laser irradiation

NASA Astrophysics Data System (ADS)

da Fonseca Alvarez, Andrea; Moura-Netto, Cacio; Daliberto Frugoli, Alexandre; Fernando, Casemiro; Correa Aranha, Ana Cecilia; Davidowicz, Harry

2012-01-01

Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 °C was considered acceptable as a safe threshold when applying the diode laser. Results: The results showed that only 3.5-W output power increased the outer surface temperature above the critical value. Conclusion: The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls.

Simulation of medical Q-switch flash-pumped Er:YAG laser

NASA Astrophysics Data System (ADS)

-Yan-lin, Wang; Huang-Chuyun; Yao-Yucheng; Xiaolin, Zou

2011-01-01

Er: YAG laser, the wavelength is 2940nm, can be absorbed strongly by water. The absorption coefficient is as high as 13000 cm-1. As the water strong absorption, Erbium laser can bring shallow penetration depth and smaller surrounding tissue injury in most soft tissue and hard tissue. At the same time, the interaction between 2940nm radiation and biological tissue saturated with water is equivalent to instantaneous heating within limited volume, thus resulting in the phenomenon of micro-explosion to removal organization. Different parameters can be set up to cut enamel, dentin, caries and soft tissue. For the development and optimization of laser system, it is a practical choice to use laser modeling to predict the influence of various parameters for laser performance. Aim at the status of low Erbium laser output power, flash-pumped Er: YAG laser performance was simulated to obtain optical output in theory. the rate equation model was obtained and used to predict the change of population densities in various manifolds and use the technology of Q-switch the simulate laser output for different design parameters and results showed that Er: YAG laser output energy can achieve the maximum average output power of 9.8W under the given parameters. The model can be used to find the potential laser systems that meet application requirements.

Laser performance and modeling of RE3+:YAG double-clad crystalline fiber waveguides

NASA Astrophysics Data System (ADS)

Li, Da; Lee, Huai-Chuan; Meissner, Stephanie K.; Meissner, Helmuth E.

2018-02-01

We report on laser performance of ceramic Yb:YAG and single crystal Tm:YAG double-clad crystalline fiber waveguide (CFW) lasers towards the goal of demonstrating the design and manufacturing strategy of scaling to high output power. The laser component is a double-clad CFW, with RE3+:YAG (RE = Yb, Tm respectively) core, un-doped YAG inner cladding, and ceramic spinel or sapphire outer cladding. Laser performance of the CFW has been demonstrated with 53.6% slope efficiency and 27.5-W stable output power at 1030-nm for Yb:YAG CFW, and 31.6% slope efficiency and 46.7-W stable output power at 2019-nm for Tm:YAG CFW, respectively. Adhesive-Free Bond (AFB®) technology enables a designable refractive index difference between core and inner cladding, and designable core and inner cladding sizes, which are essential for single transverse mode CFW propagation. To guide further development of CFW designs, we present thermal modeling, power scaling and design of single transverse mode operation of double-clad CFWs and redefine the single-mode operation criterion for the double-clad structure design. The power scaling modeling of double-clad CFW shows that in order to achieve the maximum possible output power limited by the physical properties, including diode brightness, thermal lens effect, and simulated Brillion scattering, the length of waveguide is in the range of 0.5 2 meters. The length of an individual CFW is limited by single crystal growth and doping uniformity to about 100 to 200 mm lengths, and also by availability of starting crystals and manufacturing complexity. To overcome the limitation of CFW lengths, end-to-end proximity-coupling of CFWs is introduced.

Spectral Changes in Metal Halide and High-pressure Sodium Lamps Equipped with Electronic Dimming

NASA Technical Reports Server (NTRS)

Bubenheim, David L.; Sargis, Raman; Wilson, David

1995-01-01

Electronic dimming of high-intensity discharge lamps offers control of photosynthetic photon flux (PPF) but is often characterized as causing significant spectral changes. Growth chambers with 400-W metal halide (MH) and high-pressure sodium (HPS) lamps were equipped with a dimmer system using silicon-controlled rectifiers (SCR) as high-speed switches. Phase control operation turned the line power off for some period of the alternating current cycle. At full power, the electrical input to HPS and MH lamps was 480 W (root mean squared) and could be decreased to 267 W and 428 W, respectively, before the arc was extinguished. Concomitant with this decrease in input power, PPF decreased by 60% in HPS and 50% in MH. The HPS lamp has characteristic spectral peaks at 589 and 595 nm. As power to the HPS lamps was decreased, the 589-nm peak remained constant while the 595-nm peak decreased, equaling the 589-nm peak at 345-W input, and the 589-nm peak was almost absent at 270-W input. The MH lamp has a broader spectral output but also has a peak at 589 nm and another smaller peak at 545 nm. As input power to the MH lamps decreased, the peak at 589 diminished to equal the 545-nm peak. As input power approached 428 W, the 589-nm peak shifted to 570 nm. While the spectrum changed as input power was decreased in the MH and HPS lamps, the phytochrome equilibrium ratio (P(sub fr):P(sub tot)) remains unchanged for both lamp types.

Experimental demonstration of fiber optical parametric chirped-pulse amplification

NASA Astrophysics Data System (ADS)

Zhou, Yue; Cheung, Kim K. Y.; Chui, P. C.; Wong, Kenneth K. Y.

2010-02-01

A fiber optical parametric chirped-pulse amplifier (FOPCPA) is experimentally demonstrated. A 1.76 ps signal at 1542 nm with a peak power of 20 mW is broadened to 40 ps, and then amplified by a 100-ps pulsed pump at 1560 nm. The corresponding idler at 1578 nm is generated as the FOPCPA output. The same medium used to stretch the signal is deployed to compress the idler to 3.8 ps, and another spool of fiber is deployed to further compress the idler to 1.87 ps. The peak power of the compressed idler is 2 W, which corresponds to a gain of 20 dB.

Passive mode locking of a Tm,Ho:KY(WO4)2 laser around 2 microm.

PubMed

Lagatsky, A A; Fusari, F; Calvez, S; Gupta, J A; Kisel, V E; Kuleshov, N V; Brown, C T A; Dawson, M D; Sibbett, W

2009-09-01

We report the first demonstration, to our knowledge, of passive mode locking in a Tm(3+), Ho(3+)-codoped KY(WO(4))(2) laser operating in the 2000-2060 nm spectral region. An InGaAsSb-based quantum well semiconductor saturable absorber mirror is used for the initiation and stabilization of the ultrashort pulse generation. Pulses as short as 3.3 ps were generated at 2057 nm with average output powers up to 315 mW at a pulse repetition frequency of 132 MHz for 1.15 W of absorbed pump power at 802 nm from a Ti:sapphire laser.

Efficient Q-switched operation in 1.64 μm Er:YAG tapered rod laser

NASA Astrophysics Data System (ADS)

Polyakov, Vadim M.; Vitkin, Vladimir V.; Krylov, Alexandr A.; Uskov, Alexander V.; Mak, Andrey A.

2017-02-01

We model output characteristics of the 1645 nm 8 mJ 10 ns 100 Hz Q-switched Er:YAG DPSSL. The laser is end pumped at a wavelength of 1532 nm. Fiber-coupled diode laser module was 10 nm FWHM, 12 W CW, 200 μm, NA 0.22. Various tapering of the active rod has been considered for 1 mm diameter, 20 mm long and 0.5% Er doping. We discuss the heat deposition process, the energy storage efficiency and the average power limitations for Q-switched regime of generation and amplification, and find the system scalable for the high power operation.

High power, 1060-nm diode laser with an asymmetric hetero-waveguide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, T; Zhang, Yu; Hao, E

2015-07-31

By introducing an asymmetric hetero-waveguide into the epitaxial structure of a diode laser, a 6.21-W output is achieved at a wavelength of 1060 nm. A different design in p- and n-confinement, based on optimisation of energy bands, is used to reduce voltage loss and meet the requirement of high power and high wall-plug efficiency. A 1060-nm diode laser with a single quantum well and asymmetric hetero-structure waveguide is fabricated and analysed. Measurement results show that the asymmetric hetero-structure waveguide can be efficiently used for reducing voltage loss and improving the confinement of injection carriers and wall-plug efficiency. (lasers)

Blue laser diode (450 nm) systems for welding copper

NASA Astrophysics Data System (ADS)

Silva Sa, M.; Finuf, M.; Fritz, R.; Tucker, J.; Pelaprat, J.-M.; Zediker, M. S.

2018-02-01

This paper will discuss the development of high power blue laser systems for industrial applications. The key development enabling high power blue laser systems is the emergence of high power, high brightness laser diodes at 450 nm. These devices have a high individual brightness rivaling their IR counterparts and they have the potential to exceed their performance and price barriers. They also have a very high To resulting in a 0.04 nm/°C wavelength shift. They have a very stable lateral far-field profile which can be combined with other diodes to achieve a superior brightness. This paper will report on the characteristics of the blue laser diodes, their integration into a modular laser system suitable for scaling the output power to the 1 kW level and beyond. Test results will be presented for welding of copper with power levels ranging from 150 Watts to 600 Watts

'Squeezing' near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion.

PubMed

Karalis, Aristeidis; Joannopoulos, J D

2016-07-01

We numerically demonstrate near-field planar ThermoPhotoVoltaic systems with very high efficiency and output power, at large vacuum gaps. Example performances include: at 1200 °K emitter temperature, output power density 2 W/cm(2) with ~47% efficiency at 300 nm vacuum gap; at 2100 °K, 24 W/cm(2) with ~57% efficiency at 200 nm gap; and, at 3000 °K, 115 W/cm(2) with ~61% efficiency at 140 nm gap. Key to this striking performance is a novel photonic design forcing the emitter and cell single modes to cros resonantly couple and impedance-match just above the semiconductor bandgap, creating there a 'squeezed' narrowband near-field emission spectrum. Specifically, we employ surface-plasmon-polariton thermal emitters and silver-backed semiconductor-thin-film photovoltaic cells. The emitter planar plasmonic nature allows for high-power and stable high-temperature operation. Our simulations include modeling of free-carrier absorption in both cell electrodes and temperature dependence of the emitter properties. At high temperatures, the efficiency enhancement via resonant mode cross-coupling and matching can be extended to even higher power, by appropriately patterning the silver back electrode to enforce also an absorber effective surface-plasmon-polariton mode. Our proposed designs can therefore lead the way for mass-producible and low-cost ThermoPhotoVoltaic micro-generators and solar cells.

‘Squeezing’ near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion

PubMed Central

Karalis, Aristeidis; Joannopoulos, J. D.

2016-01-01

We numerically demonstrate near-field planar ThermoPhotoVoltaic systems with very high efficiency and output power, at large vacuum gaps. Example performances include: at 1200 °K emitter temperature, output power density 2 W/cm2 with ~47% efficiency at 300 nm vacuum gap; at 2100 °K, 24 W/cm2 with ~57% efficiency at 200 nm gap; and, at 3000 °K, 115 W/cm2 with ~61% efficiency at 140 nm gap. Key to this striking performance is a novel photonic design forcing the emitter and cell single modes to cros resonantly couple and impedance-match just above the semiconductor bandgap, creating there a ‘squeezed’ narrowband near-field emission spectrum. Specifically, we employ surface-plasmon-polariton thermal emitters and silver-backed semiconductor-thin-film photovoltaic cells. The emitter planar plasmonic nature allows for high-power and stable high-temperature operation. Our simulations include modeling of free-carrier absorption in both cell electrodes and temperature dependence of the emitter properties. At high temperatures, the efficiency enhancement via resonant mode cross-coupling and matching can be extended to even higher power, by appropriately patterning the silver back electrode to enforce also an absorber effective surface-plasmon-polariton mode. Our proposed designs can therefore lead the way for mass-producible and low-cost ThermoPhotoVoltaic micro-generators and solar cells. PMID:27363522

Development of a red diode laser system for photodynamic therapy

NASA Astrophysics Data System (ADS)

Halkiotis, Konstantinos N.; Yova, Dido M.; Uzunoglou, Nikolaos K.; Papastergiou, Georgios; Matakias, Sotiris; Koukouvinos, Ilias

1998-07-01

The effectiveness of photodynamic treatment modality has been proven experimentally for a large variety of tumors, during the last years. This therapy utilizes the combined action of light and photosensitizing drug. Until now, a disadvantage of PDT has be the low tissue penetration of light, at the wavelengths of most commonly available lasers, for clinical studies. The red wavelength offers the advantage of increased penetration depth in tissue, in addition several new wavelength offers the advantage of increased penetration depth in tissue, in addition several new photosensitizers present absorption band at the region 630nm to 690nm. The development of high power red diode laser system for photodynamic therapy, has provided a cost effective alternative to existing lasers for use in PDT. This paper will describe the system design, development and performance of a diode laser system, connected with a fiber optic facility, to be used for PDT. The system was based on a high power semiconductor diode laser emitting at 655nm. The laser output power was approximately 60mW at the output of a 62.5/125/900 micron fiber optic probe. FUll technical details and optical performance characteristics of the system will be discussed in this paper.

UV lifetime demonstrator for space-based applications

NASA Astrophysics Data System (ADS)

Albert, Michael; Puffenburger, Kent; Schum, Tom; Fitzpatrick, Fran; Litvinovitch, Slava; Jones, Darrell; Rudd, Joseph; Hovis, Floyd

2016-05-01

A long-lived UV laser is an enabling technology for a number of high-priority, space-based lidar instruments. These include next generation cloud and aerosol lidars that incorporates a UV channel, direct detection 3-D wind lidars, and ozone DIAL (differential absorption lidar) systems. In previous SBIR funded work we developed techniques for increasing the survivability of components in high power UV lasers and demonstrated improved operational lifetimes. In this Phase III ESTO funded effort we are designing and building a TRL (Technology Readiness Level) 6 demonstrator that will have increased output power and a space-qualifiable package that is mechanically robust and thermally-stable. For full space compatibility, thermal control will be through pure conductive cooling. Contamination control processes and optical coatings will be chosen that are compatible with lifetimes in excess of 1 billion shots. The 1064nm output will be frequency tripled to provide greater than 100 mJ pulses of 355 nm light at 150 Hz. The laser module build was completed in the third quarter of 2015 at which time a series of life tests were initiated. The first phase of the lifetime testing is a 532 nm only test that is expected to complete in April 2016. The 532 nm lifetest will be followed by a 4 month half power UV life test and then a four month full power UV life test. The lifetime tests will be followed by thermal/vacuum (TVAC) and vibration testing to demonstrate that the laser optics module design is at TRL 6.

Yb-fiber-pumped mid-infrared picosecond optical parametric oscillator tunable across 6.2-6.7 µm

NASA Astrophysics Data System (ADS)

Kumar, S. Chaitanya; Casals, J. Canals; Parsa, S.; Zawilski, K. T.; Schunemann, P. G.; Ebrahim-Zadeh, M.

2018-06-01

We report a high-average-power picosecond optical parametric oscillator (OPO) tunable in the mid-infrared (mid-IR) based on CdSiP2 synchronously pumped by an Yb-fiber laser at 80 MHz repetition rate. Successful operation of this high-repetition-rate singly-resonant picosecond OPO has been enabled by the improved CSP crystal quality over a long interaction length. The OPO can be tuned across 1264-1284 nm in the near-IR signal and 6205-6724 nm in the mid-IR idler by temperature tuning the CSP crystal over 39-134 °C. By deploying a 5% output coupler for the resonant signal, we have extracted up to 44 mW of average power in the near-IR and up to 95 mW of non-resonant idler power at 6205 nm at 6.3% total conversion efficiency, with > 50 mW over > 55% of the mid-IR tuning range. We have investigated temperature-tuning characteristics of the OPO and compared the data with the theoretical calculations using the recent Sellmeier and thermo-optic coefficients for CdSiP2. The signal pulses from the OPO exhibit a Gaussian pulse duration of 19 ps centered at 1284 nm. We have also studied the output power stability of the OPO, resulting in a passive stability better than 1.9% rms for the near-IR signal and 2.4% rms for the mid-IR idler, measured over > 17 h, with both beams in high spatial quality.

Directly q-switched high power resonator based on XLMA-fibers

NASA Astrophysics Data System (ADS)

Giesberts, M.; Fitzau, O.; Hoffmann, H.-D.; Lange, R.; Bachert, C.; Krause, V.

2018-02-01

In this paper we present a simple approach to achieving nanosecond pulses from a directly q-switched high-power resonator based on extra-large mode area (XLMA) fibers with a beam quality factor M2 < 15. An average output power of > 500 W has been demonstrated for repetition frequencies between 50-100 kHz. The resonator consists of a single fiber q-switched with soldered Pockels-cells which exhibit a very high contrast ratio leading to output pulses down to about 10 ns and peak powers up to > 250 kW at 1064 nm wavelength. By using this design instead of a fiber MOPA setup, a cost-effective and less complex system could be implemented.

Integrated photonic power divider with arbitrary power ratios.

PubMed

Xu, Ke; Liu, Lu; Wen, Xiang; Sun, Wenzhao; Zhang, Nan; Yi, Ningbo; Sun, Shang; Xiao, Shumin; Song, Qinghai

2017-02-15

Integrated optical power splitters are one of the fundamental building blocks in photonic integrated circuits. Conventional multimode interferometer-based power splitters are widely used as they have reasonable footprints and are easy to fabricate. However, it is challenging to realize arbitrary split ratios, especially for multi-outputs. In this Letter, an ultra-compact power splitter with a QR code-like nanostructure is designed by a nonlinear fast search method. The highly functional structure is composed of a number of freely designed square pixels with the size of 120×120  nm which could be either dielectric or air. The light waves are scattered by a number of etched squares with optimized locations, and the scattered waves superimpose at the outputs with the desired power ratio. We demonstrate 1×2 splitters with 1:1, 1:2, and 1:3 split ratios, and a 1×3 splitter with the ratio of 1:2:1. The footprint for all the devices is only 3.6×3.6  μm. Well-controlled split ratios are measured for all the cases. The measured transmission efficiencies of all the splitters are close to 80% over 30 nm wavelength range.

Spectral Changes in Metal Halide and High-Pressure Sodium Lamps Equipped with Electronic Dimming

NASA Technical Reports Server (NTRS)

Bubenheim, David L.; Sargis, Raman; Wilson, David

1995-01-01

Electronic dimming of high-intensity discharge lamps offers control of Photosynthetic Photon Flux (PPF) but is often characterized as causing significant spectral changes. Growth chambers with 400-W Metal Halide (MH) and High-Pressure Sodium (HPS) lamps were equipped with a dimmer system using Silicon-Controlled Rectifiers (SCR) as high-speed switches. Phase control operation turned the line power off for some period of the alternating current cycle. At full power, the electrical input to HPS and MH lamps was 480 W (root mean squared) and could be decreased to 267 W and 428 W, respectively, before the arc was extinguished. Concomitant with this decrease in input power, PPF decreased by 60% in HPS and 50% in MH. The HPS lamp has characteristic spectral peaks at 589 and 595 nm. As power to the HPS lamps was decreased, the 589-nm peak remained constant while the 595-nm peak decreased, equaling the 589-nm peak at 345-W input, and 589-nm peak was almost absent at 270-W input. The MH lamp has a broader spectral output but also has a peak at 589 nm and another smaller peak at 545 nm. As input power approached 428 W, the 589-nm peak shifted to 570 nm. While the spectrum changed as input power was decreased in the MH and HPS lamps, the phytochrome equilibrium ratio (P(sub ft):P(sub tot)) remains unchanged for both lamp types.

Phase-stable, multi-µJ femtosecond pulses from a repetition-rate tunable Ti:Sa-oscillator-seeded Yb-fiber amplifier

NASA Astrophysics Data System (ADS)

Saule, T.; Holzberger, S.; De Vries, O.; Plötner, M.; Limpert, J.; Tünnermann, A.; Pupeza, I.

2017-01-01

We present a high-power, MHz-repetition-rate, phase-stable femtosecond laser system based on a phase-stabilized Ti:Sa oscillator and a multi-stage Yb-fiber chirped-pulse power amplifier. A 10-nm band around 1030 nm is split from the 7-fs oscillator output and serves as the seed for subsequent amplification by 54 dB to 80 W of average power. The µJ-level output is spectrally broadened in a solid-core fiber and compressed to 30 fs with chirped mirrors. A pulse picker prior to power amplification allows for decreasing the repetition rate from 74 MHz by a factor of up to 4 without affecting the pulse parameters. To compensate for phase jitter added by the amplifier to the feed-forward phase-stabilized seeding pulses, a self-referencing feed-back loop is implemented at the system output. An integrated out-of-loop phase noise of less than 100 mrad was measured in the band from 0.4 Hz to 400 kHz, which to the best of our knowledge corresponds to the highest phase stability ever demonstrated for high-power, multi-MHz-repetition-rate ultrafast lasers. This system will enable experiments in attosecond physics at unprecedented repetition rates, it offers ideal prerequisites for the generation and field-resolved electro-optical sampling of high-power, broadband infrared pulses, and it is suitable for phase-stable white light generation.

Theoretical study and design of third-order random fiber laser

NASA Astrophysics Data System (ADS)

Xie, Zhaoxin; Shi, Wei; Fu, Shijie; Sheng, Quan; Yao, Jianquan

2018-02-01

We present result of achieving a random fiber laser at a working wavelength of 1178nm while pumping at 1018nm. The laser power is realized by 200m long cavity which includes three high reflectivity fiber Bragg gratings. This simple and efficient random fiber laser could provide a novel approach to realize low-threshold and high-efficiency 1178nm long wavelength laser. We theoretically analyzed the laser power in random fiber lasers at different pump power by changing three high reflectivity fiber Bragg gratings. We also calculated the forward and backward power of 1st-order stokes, 2nd-order stokes, 3rd-order stokes. With the theoretical analysis, we optimize the cavity's reflectivity to get higher laser power output. The forward random laser exhibits larger gain, the backward random laser has lower gain. By controlling the value of angle-cleaved end fiber's reflectivity to 3×10-7, when the high reflectivity increases from 0.01 to 0.99, the laser power increases, using this proposed configuration, the 1178nm random laser can be generated easily and stably.

Polarization-maintaining fiber pulse compressor by birefringent hollow-core photonic bandgap fiber

NASA Astrophysics Data System (ADS)

Shirakawa, Akira; Tanisho, Motoyuki; Ueda, Ken-Ichi

2006-12-01

Structural birefringent properties of a hollow-core photonic-bandgap fiber were carefully investigated and applied to all-fiber chirped-pulse amplification as a compressor. The group birefringence of as high as 6.9×10-4 and the dispersion splitting by as large as 149 ps/nm/km between the two principal polarization modes were observed at 1557 nm. By launching the amplifier output to one of the polarization modes a 17-dB polarization extinction ratio was obtained without any pulse degradation originating from polarization-mode dispersion. A hybrid fiber stretcher effectively compensates the peculiar dispersion of the photonic-bandgap fiber and pedestal-free 440-fs pulses with a 1-W average power and 21-nJ pulse energy were obtained. Polarization-maintaining fiber-pigtail output of high-power femtosecond pulses is useful for various applications.

Enhanced Output Power of PZT Nanogenerator by Controlling Surface Morphology of Electrode.

PubMed

Jung, Woo-Suk; Lee, Won-Hee; Ju, Byeong-Kwon; Yoon, Seok-Jin; Kang, Chong-Yun

2015-11-01

Piezoelectric power generation using Pb(Zr,Ti)O3(PZT) nanowires grown on Nb-doped SrTiO3(nb:STO) substrate has been demonstrated. The epitaxial PZT nanowires prepared by a hydrothermal method, with a diameter and length of approximately 300 nm and 7 μm, respecively, were vertically aligned on the substrate. An embossed Au top electrode was applied to maximize the effective power generation area for non-uniform PZT nanowires. The PZT nanogenerator produced output power density of 0.56 μW/cm2 with a voltage of 0.9 V and current of 75 nA. This research suggests that the morphology control of top electrode can be useful to improve the efficiency of piezoelectric power generation.

High power single-longitudinal-mode Ho:YLF unidirectional ring laser based on a composite structure of acousto-optic device and wave plate

NASA Astrophysics Data System (ADS)

Dai, T. Y.; Fan, Z. G.; Wu, J.; Ju, Y. L.; Yao, B. Q.; Zhang, Z. G.; Teng, K.; Xu, X. G.; Duan, X. M.

2017-05-01

We report a unidirectional single-longitudinal-mode Ho:YLF ring laser. An acousto-optic modulator and two half-wave plates were used to enforce the Ho:YLF ring laser in a unidirectional operation. The single-longitudinal-mode output power could reach 3.73 W successfully when the incident pump power was 16.4 W. The corresponding slope efficiency was 27.1%. The wavelength of the single-longitudinal-mode Ho:YLF ring laser was 2063.8 nm. The M2 factor was 1.12. The results illustrated that the single-longitudinal-mode output power could be further enhanced by increasing the radio frequency power of the acousto-optic modulator.

A 160 W single-frequency laser based on an active tapered double-clad fiber amplifier

NASA Astrophysics Data System (ADS)

Trikshev, A. I.; Kurkov, A. S.; Tsvetkov, V. B.; Filatova, S. A.; Kertulla, J.; Filippov, V.; Chamorovskiy, Yu K.; Okhotnikov, O. G.

2013-06-01

We present a CW single-frequency laser at 1062 nm (linewidth <3 MHz) with 160 W of total output power based on a two stage fiber amplifier. A GTWave fiber is used for the first stage of the amplifier. A tapered double-clad fiber (T-DCF) is used for the second stage of the amplifier. The high output power is achieved due to the amplified spontaneous emission (ASE) filtering and increased stimulated Brillouin scattering (SBS) threshold inherent to the axially non-uniform geometry.

Actively mode-locked Tm-Ho:LiYF4 and Tm-Ho:BaY2F8 lasers

NASA Astrophysics Data System (ADS)

Gatti, D.; Galzerano, G.; Toncelli, A.; Tonelli, M.; Laporta, P.

2007-01-01

We report on the generation of mode-locking pulse trains with high average output powers from diode-pumped Tm-Ho:LiYF4 and Tm-Ho:BaY2F8 lasers emitting at around 2 μm. The highest output power of 365 mW was obtained with the Tm-Ho:YLF4 laser, whereas the shortest pulse duration of 120 ps and the widest tunability range of 59 nm was achieved with the Tm-Ho:BaY2F8 laser.

Photothermal effect of infrared lasers on ex vivo lamb brain tissues

NASA Astrophysics Data System (ADS)

Özgürün, Baturay; Gülsoy, Murat

2018-02-01

Here, the most suitable infrared laser for a neurosurgery operation is suggested, among 1940-nm thulium fiber, 1470-nm diode, 1070-nm ytterbium fiber and 980-nm diode lasers. Cortical and subcortical ex-vivo lamb brain tissues are exposed to the laser light with the combinations of some laser parameters such as output power, energy density, operation mode (continuous and pulsed-modulated) and operation time. In this way, the greatest ablation efficiency associated with the best neurosurgical laser type can be defined. The research can be divided into two parts; pre-dosimetry and dosimetry studies. The former is used to determine safe operation zones for the dosimetry study by defining coagulation and carbonization onset times for each of the brain tissues. The latter is the main part of this research, and both tissues are exposed to laser irradiation with various energy density levels associated with the output power and operation time. In addition, photo-thermal effects are compared for two laser operation modes, and then coagulation and ablation diameters to calculate the ablation efficiency are measured under a light microscope. Consequently, results are compared graphically and statistically, and it is found that thulium and 1470-nm diode lasers can be utilized as subcortical and cortical tissue ablator devices, respectively.

Evaluation of miniature vacuum ultraviolet lamps for stability and operating characteristics, Lyman-Alpha task

NASA Technical Reports Server (NTRS)

Hurd, W. A.

1985-01-01

Modifications required to change the near ultraviolet source in the Optical Contamination Monitor to a source with output at or near the Lyman-Alpha hydrogen line are discussed. The effort consisted of selecting, acquiring and testing candidate miniature ultraviolet lamps with significant output in or near 121.6 nm. The effort also included selection of a miniature dc high-voltage power supply capable of operating the lamp. The power supply was required to operate from available primary power supplied by the Optical Effect Module (DEM) and it should be flight qualified or have the ability to be qualified by the user.

Polarization-maintaining, high-energy, wavelength-tunable, Er-doped ultrashort pulse fiber laser using carbon-nanotube polyimide film.

PubMed

Senoo, Y; Nishizawa, N; Sakakibara, Y; Sumimura, K; Itoga, E; Kataura, H; Itoh, K

2009-10-26

A high-energy, wavelength-tunable, all-polarization-maintaining Er-doped ultrashort fiber laser was demonstrated using a polyimide film dispersed with single-wall carbon nanotubes. A variable output coupler and wavelength filter were used in the cavity configuration, and high-power operation was demonstrated. The maximum average power was 12.6 mW and pulse energy was 585 pJ for stable single-pulse operation with an output coupling ratio as high as 98.3%. Wide wavelength-tunable operation at 1532-1562 nm was also demonstrated by controlling the wavelength filter. The RF amplitude noise characteristics were examined in terms of their dependence on output coupling ratio and oscillation wavelength.

High-power 0.87-micron channel substrate planar lasers for spaceborne communications

NASA Technical Reports Server (NTRS)

Connolly, J. C.; Stewart, T. R.; Gilbert, D. B.; Slavin, S. E.; Carlin, D. B.

1988-01-01

High-power single-mode channeled-substrate planar AlGaAs diode lasers are being developed for reliable high-power operation for use as sources in spaceborne optical communication systems. The CSP laser structure has been optimized for operation at an emission wavelength of 870 nm. Such devices have exhibited output powers in excess of 80 mW CW at an operating temperature of 80 C.

5-nJ Femtosecond Ti3+:sapphire laser pumped with a single 1 W green diode

NASA Astrophysics Data System (ADS)

Muti, Abdullah; Kocabas, Askin; Sennaroglu, Alphan

2018-05-01

We report a Kerr-lens mode-locked, extended-cavity femtosecond Ti3+:sapphire laser directly pumped at 520 nm with a 1 W AlInGaN green diode. To obtain energy scaling, the short x-cavity was extended with a q-preserving multi-pass cavity to reduce the pulse repetition rate to 5.78 MHz. With 880 mW of incident pump power, we obtained as high as 90 mW of continuous-wave output power from the short cavity by using a 3% output coupler. In the Kerr-lens mode-locked regime, the extended cavity produced nearly transform-limited 95 fs pulses at 776 nm. The resulting energy and peak power of the pulses were 5.1 nJ and 53 kW, respectively. To our knowledge, this represents the highest pulse energy directly obtained to date from a mode-locked, single-diode-pumped Ti3+:sapphire laser.

Tunable, high-repetition-rate, dual-signal-wavelength femtosecond optical parametric oscillator based on BiB3O6

NASA Astrophysics Data System (ADS)

Meng, Xianghao; Wang, Zhaohua; Tian, Wenlong; Fang, Shaobo; Wei, Zhiyi

2018-01-01

We have demonstrated a high-repetition-rate tunable femtosecond dual-signal-wavelength optical parametric oscillator (OPO) based on BiB3O6 (BiBO) crystal, synchronously pumped by a frequency-doubled mode-locked Yb:KGW laser. The cavity is simple since no dispersion compensators are used in the cavity. The wavelength range of dual-signal is widely tunable from 710 to 1000 nm. Tuning is accomplished by rotating phase-matching angle of BiBO, and optimizing cavity length and output coupler. Using a 3.75 W pump laser, the maximum average dual-signal output power is 760 mW at 707 and 750 nm, leading to a conversion efficiency of 20.3% not taking into account the idler power. Our experimental results show a non-critical phase-matching configuration pumped by a high peak power laser source. The operation of the dual-signal benefits from the balance of phase matching and group velocity mismatching between the two signals.

Order of magnitude improvement of nano-contact spin torque nano-oscillator performance.

PubMed

Banuazizi, Seyed Amir Hossein; Sani, Sohrab R; Eklund, Anders; Naiini, Maziar M; Mohseni, Seyed Majid; Chung, Sunjae; Dürrenfeld, Philipp; Malm, B Gunnar; Åkerman, Johan

2017-02-02

Spin torque nano-oscillators (STNO) represent a unique class of nano-scale microwave signal generators and offer a combination of intriguing properties, such as nano sized footprint, ultrafast modulation rates, and highly tunable microwave frequencies from 100 MHz to close to 100 GHz. However, their low output power and relatively high threshold current still limit their applicability and must be improved. In this study, we investigate the influence of the bottom Cu electrode thickness (t Cu ) in nano-contact STNOs based on Co/Cu/NiFe GMR stacks and with nano-contact diameters ranging from 60 to 500 nm. Increasing t Cu from 10 to 70 nm results in a 40% reduction of the threshold current, an order of magnitude higher microwave output power, and close to two orders of magnitude better power conversion efficiency. Numerical simulations of the current distribution suggest that these dramatic improvements originate from a strongly reduced lateral current spread in the magneto-dynamically active region.

Tm:CaGdAlO4: spectroscopy, microchip laser and passive Q-switching by carbon nanostructures

NASA Astrophysics Data System (ADS)

Loiko, Pavel; Mateos, Xavier; Choi, Sun Young; Rotermund, Fabian; Liebald, Christoph; Peltz, Mark; Vernay, Sophie; Rytz, Daniel; Wang, Yicheng; Kemnitzer, Matthias; Agnesi, Antonio; Vilejshikova, Elena; Yumashev, Konstantin; Griebner, Uwe; Petrov, Valentin

2017-02-01

Absorption, stimulated-emission and gain cross-sections are determined for 3 at.% Tm:CaGdAlO4. This crystal is employed in a microchip laser diode-pumped at 802 nm. In the continuous-wave (CW) regime, this laser generates 1.16 W at 1883-1893 nm with a slope efficiency of 32% with respect to the absorbed pump power. Using a special "bandpass" output coupler, vibronic CW laser operation up to 2043 nm is achieved. For passive Q-switching of the Tm:CaGdAlO4 laser-saturable absorbers (SAs) based on CVD-grown graphene and randomly-oriented arc-discharge single-walled carbon nanotubes (SWCNTs) in a PMMA film. The SWCNT-SA demonstrates superior performance. The laser produced a maximum average output power of 245 mW at 1844 nm with a slope efficiency of 8%. The latter corresponds to a pulse energy and duration of 6 μJ and 138 ns, respectively, at a repetition rate of 41 kHz. Using the graphene-SA, 2.8 μJ, 490 ns pulses are obtained at a repetition rate of 86 kHz.

Hundred-watt-level high power random distributed feedback Raman fiber laser at 1150 nm and its application in mid-infrared laser generation.

PubMed

Zhang, Hanwei; Zhou, Pu; Wang, Xiong; Du, Xueyuan; Xiao, Hu; Xu, Xiaojun

2015-06-29

Two kinds of hundred-watt-level random distributed feedback Raman fiber have been demonstrated. The optical efficiency can reach to as high as 84.8%. The reported power and efficiency of the random laser is the highest one as we know. We have also demonstrated that the developed random laser can be further used to pump a Ho-doped fiber laser for mid-infrared laser generation. Finally, 23 W 2050 nm laser is achieved. The presented laser can obtain high power output efficiently and conveniently and opens a new direction for high power laser sources at designed wavelength.

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.

High power 808 nm vertical cavity surface emitting laser with multi-ring-shaped-aperture structure

NASA Astrophysics Data System (ADS)

Hao, Y. Q.; Shang, C. Y.; Feng, Y.; Yan, C. L.; Zhao, Y. J.; Wang, Y. X.; Wang, X. H.; Liu, G. J.

2011-02-01

The carrier conglomeration effect has been one of the main problems in developing electrically pumped high power vertical cavity surface emitting laser (VCSEL) with large aperture. We demonstrate a high power 808 nm VCSEL with multi-ring-shaped-aperture (MRSA) to weaken the carrier conglomeration effect. Compared with typical VCSEL with single large aperture (SLA), the 300-μm-diameter VCSEL with MRSA has more uniform near field and far field patterns. Moreover, MRSA laser exhibits maximal CW light output power 0.3 W which is about 3 times that of SLA laser. And the maximal wall-plug efficiency of 17.4% is achieved, higher than that of SLA laser by 10%.

A dual-end-pumped Ho:YAG laser with a high energy output

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, X M; Cui, Zh; Dai, T Y

2015-08-31

We report a high energy output from a Ho:YAG oscillator resonantly double-end pumped by Tm:YLF lasers at room temperature. The maximum pulse energy of 52.5 mJ was achieved at a pulse repetition rate of 100Hz and a pulse duration of 35.2 ns, corresponding to a peak power of approximately 1.5 MW. The output wavelength was 2090.7 nm with beam quality factor M{sup 2} ∼ 1.2. (lasers)

Laser-diode-pumped 1319-nm monolithic non-planar ring single-frequency laser

NASA Astrophysics Data System (ADS)

Wang, Qing; Gao, Chunqing; Zhao, Yan; Yang, Suhui; Wei, Guanghui; 2, Dongmei Hong

2003-10-01

Single-frequency 1319-nm laser was obtained by using a laser-diode-pumped monolithic Nd:YAG crystal with a non-planar ring oscillator (NPRO). When the NPRO laser was pumped by an 800-?m fiber coupled laser diode, the output power of the single-frequency 1319-nm laser was 220 mW, and the slope efficiency was 16%. With a 100-1m fiber coupled diode laser pumped, 99-mW single-frequency 1319-nm laser was obtained with a slope efficiency of 29%.

High-power supercontinuum generation using high-repetition-rate ultrashort-pulse fiber laser for ultrahigh-resolution optical coherence tomography in 1600 nm spectral band

NASA Astrophysics Data System (ADS)

Yamanaka, Masahito; Kawagoe, Hiroyuki; Nishizawa, Norihiko

2016-02-01

We describe the generation of a high-power, spectrally smooth supercontinuum (SC) in the 1600 nm spectral band for ultrahigh-resolution optical coherence tomography (UHR-OCT). A clean SC was achieved by using a highly nonlinear fiber with normal dispersion properties and a high-quality pedestal-free pulse obtained from a passively mode-locked erbium-doped fiber laser operating at 182 MHz. The center wavelength and spectral width were 1578 and 172 nm, respectively. The output power of the SC was 51 mW. Using the developed SC source, we demonstrated UHR-OCT imaging of biological samples with a sensitivity of 109 dB and an axial resolution of 4.9 µm in tissue.

11 W narrow linewidth laser source at 780nm for laser cooling and manipulation of Rubidium

NASA Astrophysics Data System (ADS)

Sané, S. S.; Bennetts, S.; Debs, J. E.; Kuhn, C. C. N.; McDonald, G. D.; Altin, P. A.; Close, J. D.; Robins, N. P.

2012-04-01

We present a narrow linewidth continuous laser source with over 11 Watts of output power at 780nm, based on single-pass frequency doubling of an amplified 1560nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10kHz. The fibre seed is tunable over 60GHz, which allows access to the D2 transitions in 87Rb and 85Rb, providing a viable high-power source for laser cooling as well as for large-momentum-transfer beamsplitters in atom interferometry. Sources of this type will pave the way for a new generation of high flux, high duty-cycle degenerate quantum gas experiments.

InP/InGaP quantum-dot SESAM mode-locked Alexandrite laser

NASA Astrophysics Data System (ADS)

Ghanbari, Shirin; Fedorova, Ksenia A.; Krysa, Andrey B.; Rafailov, Edik U.; Major, Arkady

2018-02-01

A semiconductor saturable absorber mirror (SESAM) passively mode-locked Alexandrite laser was demonstrated. Using an InP/InGaP quantum-dot saturable absorber mirror, pulse duration of 420 fs at 774 nm was obtained. The laser was pumped at 532 nm and generated 325 mW of average output power in mode-locked regime with a pump power of 7.12 W. To the best of our knowledge, this is the first report of a passively mode-locked Alexandrite laser using SESAM in general and quantum-dot SESAM in particular.

1.44-μm giant pulse generation

NASA Astrophysics Data System (ADS)

Šulc, Jan; Arátor, Pavel; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

2007-02-01

We have compared two solid-state saturable absorbers for Q-switching of longitudinally diode-pumped Nd:YAG laser operating at wavelength 1444 nm: vanadium doped garnet (V 3+:Y 3Al IIO 5, V:YAG), and cobalt doped spinel (Co 2+:MgAl IIO 4, Co:MALO). V:YAG crystal with initial transmission 91% was 2.2mm thick. Co:MALO crystal with initial transmission 91% was 2.0mm thick. Q-switched laser consisted of the Nd:YAG composite rod (8mm long Nd-doped part, 4mm long undoped YAG part) and the saturable absorber placed in 80mm long hemispheric cavity. As an output coupler was used concave mirror (r = 150mm) with reflectivity 98% on lasing wavelength. Giant pulses were obtained with both passive Q-switches. When V:YAG saturable absorber was used, 55 ns long (FWHM) pulses were generated with peak power 0.47kW (pulse energy 26 μJ). Using Co:MALO, more powerful pulses were obtained (40 ns long, 1.0kW peak power, 45 μJ energy). Advantage of less efficient V:YAG consist in possibility of diffusion bonding between Q-switch and laser active medium which allows to prepare miniature compact laser device. This concept was demonstrated by using of Nd:YAG/V:YAG monolith crystal (4mm long undoped YAG part, 8mm long Nd:YAG part, 0.5mm long V:YAG part - initial transmission 97% @ 1444 nm). This monolithic crystal, originally designed for 1338nm lasing, was placed into 23mm long cavity resonating at wavelength 1444 nm. For output coupler reflectivity 96% pulses 39 ns long with peak power 0.64kW were generated at wavelength 1444 nm.

Tm:GGAG crystal for 2μm tunable diode-pumped laser

NASA Astrophysics Data System (ADS)

Šulc, Jan; Boháček, Pavel; Němec, Michal; Fibrich, Martin; Jelínková, Helena; Trunda, Bohumil; Havlák, Lubomír.; Jurek, Karel; Nikl, Martin

2016-04-01

The spectroscopy properties and wavelength tunability of diode pumped laser based on Tm-doped mixed gadolinium-gallium-aluminium garnet Gd3(GaxAl1-x)5O12 (Tm:GGAG) single crystal were investigated for the first time. The crystal was grown by Czochralski method in a slightly oxidative atmosphere using an iridium crucible. The tested Tm:GGAG sample was cut from the grown crystal boule perpendicularly to growth direction (c-axis). The composition of sample was determined using electron microprobe X-ray elemental analysis. For spectroscopy and laser experiments 3.5mm thick plane-parallel face-polished plate (without AR coatings) with composition Gd2.76Tm0.0736Ga2.67Al2.50O12 (2.67 at.% Tm/Gd) was used. A fiber (core diameter 400 μm, NA= 0.22) coupled laser diode (emission wavelength 786 nm) was used for longitudinal Tm:GGAG pumping. The laser diode was operating in the pulsed regime (10 ms pulse length, 10 Hz repetition rate, maximum power amplitude 18 W). The 145mm long semi-hemispherical laser resonator consisted of a flat pumping mirror (HR @ 1.8- 2.10 μm, HT @ 0.78 μm) and curved (r = 150mm) output coupler with a reflectivity of » 97% @ 1.8- 2.10 µm. The maximum laser output power amplitude 1.14W was obtained at wavelength 2003nm for absorbed pump power amplitude 4.12W. The laser slope efficiency was 37% in respect to absorbed pumping power. Wavelength tuning was accomplished by using 2mm thick MgF2 birefringent filter placed inside the laser resonator at the Brewster angle. The laser was continuously tunable over 180nm in a spectral region from 1856nm to 2036 nm.

Stable C-band fiber laser with switchable multi-wavelength output using coupled microfiber Mach-Zehnder interferometer

NASA Astrophysics Data System (ADS)

Ahmad, H.; Jasim, A. A.

2017-07-01

A compact coupled microfiber Mach-Zehnder interferometer (CM-MZI) is proposed and experimentally demonstrated for C-band region multi-wavelength tuning and switching in a fiber laser. The CM-MZI is fabricated using a 9 μm single tapered silica optical microfiber fabricated by flame-drawing technique and exploits multi-mode interference to produce spatial mode beating and suppress mode competition of the homogeneous gain medium. The output wavelength spacing is immune to changes in the external environment, but can be changed from 1.5 nm to 1.4 nm by slightly modifying the path-length difference of the CM-MZI. The proposed laser is capable of generating single, dual, triple, quintuple, and sextuple stabilize wavelengths outputs over a range of more than 32 nm using polarization rotation (PR) and macro-bending. The lasers having a 3 dB line-width of less than ∼30 pm and peak-to-floor of about 55 dB at a pump power of 38 mW.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreeva, E V; Il'ichenko, S N; Kostin, Yu O

Quantum-well superluminescent diodes (SLD) with extremely thin active (AlGa)As and (InGa)As layers and centre wavelengths about 810, 840, 860 and 880 nm are experimentally studied. Their emission spectrum possesses the shape close to Gaussian, its FWHM being 30 – 60 nm depending on the length of the active channel and the level of pumping. Under cw injection, the output power of light-emitting modules based on such SLDs can amount to 1.0 – 25 mW at the output of a single-mode fibre. It is demonstrated that the operation lifetime of these devices exceeds 30000 hours. Based on the light-emitting modules themore » prototypes of combined BroadLighter series light sources are implemented having a bell-shaped spectrum with the width up to 100 nm. (optical radiation sources)« less

A highly integrated single-mode 1064 nm laser with 8.5 kHz linewidth for dual-wavelength active optical clock

NASA Astrophysics Data System (ADS)

Shi, Tiantian; Pan, Duo; Chang, Pengyuan; Shang, Haosen; Chen, Jingbiao

2018-04-01

Without exploiting any frequency selective elements, we have realized a highly integrated, single-mode, narrow-linewidth Nd:YAG 1064 nm laser, which is end-pumped by the 808.6 nm diode laser in an integrated invar cavity. It turns out that each 1064 nm laser achieves a most probable linewidth of 8.5 kHz by beating between two identical laser systems. The output power of the 1064 nm laser increases steadily as the 808.6 nm pump power is raised, which can be up to 350 mW. Moreover, the resonant wavelength of cavity grows continuously in a certain crystal temperature range. Such a 1064 nm laser will be frequency stabilized to an ultrastable cavity by using the Pound-Drever-Hall technique and used as the good cavity laser to lock the main cavity length of 1064/1470 nm good-bad cavity dual-wavelength active optical clock.

The Shock and Vibration Bulletin. Part 2. Measurement Techniques and Data Analysis, Dynamic Measurements, Vibration and Acoustics

DTIC Science & Technology

1980-09-01

angular dis- meters ( 3.3 inches). The user supplies t 15 volt regulated turbance when multiplied by a long line-of-sight distance power , and the...chosing these numbers o the vibration power will mostly f+l be allocated to the main resonan - > = f . f ces of the test item in a correct 1 (fV+l-f ) .. I...Generators Data Noraircoustic Mark V Lng EPT 1094B Output Acoustic Power 50 kW 10 KW Air Supply Pressure 827.36 N/m 2 X 103 (120 psig) 275.78 N/m 2 X 103

Continuous-wave and actively Q-switched resonantly dual-end-pumped Er : YAG ceramic laser emitting at 1.6 μm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dai, T Y; Deng, Yu; Ju, Y-L

2015-12-31

We demonstrate a continuous-wave (cw) and actively Q-switched Er : YAG ceramic laser resonantly dual-end-pumped by a 1532 nm fibre-coupled laser diode. A maximum cw output power of 1.48 W at 1645.3 nm is obtained at an absorbed pump power of 12.72 W, corresponding to a slope efficiency of 19.2%. In the Q-switched regime the maximum pulse energy of 0.84 mJ is reached at a pulse repetition rate of 100 Hz, pulse duration of 48.03 ns and absorbed pump power of 10.51 W. (lasers)

Nonradiative relaxation and laser action in tunable solid state laser crystals

NASA Technical Reports Server (NTRS)

Petricevic, V.; Gayen, S. K.; Alfano, R. R.

1989-01-01

Room-temperature pulsed laser action was obtained in chromium-activated forsterite (Cr:Mg2SiO4) for both 532 and 1064 nm pumping. Free running laser emission in both cases is centered at 1235 nm and has a bandwidth of approximately 30 nm. Slope efficiency as high as 22 percent was measured. Using different sets of output mirrors and a single birefrigent plate as the intracavity wavelength selecting element tunability over the 1167 to 1268 nm spectral range was demonstrated. Continuous wave laser operation at room temperature was obtained for 1064 nm pumping from a CW Nd:YAG laser. The output power slope efficiency is 6.8 percent. The gain cross section is estimated to be 1.1 x 10 to the 19th sq cm. Spectroscopic studies suggest that the laser action is due to a center other than the trivalent chromium (Cr 3+), presumably the tetravalent chromium (Cr 4+) in a tetrahedrally coordinated site.

Testing a high-power LED based light source for hyperspectral imaging microscopy

NASA Astrophysics Data System (ADS)

Klomkaew, Phiwat; Mayes, Sam A.; Rich, Thomas C.; Leavesley, Silas J.

2017-02-01

Our lab has worked to develop high-speed hyperspectral imaging systems that scan the fluorescence excitation spectrum for biomedical imaging applications. Hyperspectral imaging can be used in remote sensing, medical imaging, reaction analysis, and other applications. Here, we describe the development of a hyperspectral imaging system that comprised an inverted Nikon Eclipse microscope, sCMOS camera, and a custom light source that utilized a series of high-power LEDs. LED selection was performed to achieve wavelengths of 350-590 nm. To reduce scattering, LEDs with low viewing angles were selected. LEDs were surface-mount soldered and powered by an RCD. We utilized 3D printed mounting brackets to assemble all circuit components. Spectraradiometric calibration was performed using a spectrometer (QE65000, Ocean Optics) and integrating sphere (FOIS-1, Ocean Optics). Optical output and LED driving current were measured over a range of illumination intensities. A normalization algorithm was used to calibrate and optimize the intensity of the light source. The highest illumination power was at 375 nm (3300 mW/cm2), while the lowest illumination power was at 515, 525, and 590 nm (5200 mW/cm2). Comparing the intensities supplied by each LED to the intensities measured at the microscope stage, we found there was a great loss in power output. Future work will focus on using two of the same LEDs to double the power and finding more LED and/or laser diodes and chips around the range. This custom hyperspectral imaging system could be used for the detection of cancer and the identification of biomolecules.

Laser performance of in-band pumped Er : LiYF4 and Er : LiLuF4 crystals

NASA Astrophysics Data System (ADS)

Gorbachenya, K. N.; Kurilchik, S. V.; Kisel, V. E.; Yasukevich, A. S.; Kuleshov, N. V.; Nizamutdinov, A. S.; Korableva, S. L.; Semashko, V. V.

2016-02-01

Spectroscopic properties of Er : LiLuF4 and Er : LiYF4 crystals in the spectral region near 1.5 μm and the lasing characteristics of these crystals under in-band pumping at a wavelength of 1522 nm are studied. With the Er : LiLuF4 crystal, the maximum slope efficiency with respect to the absorbed pump power was 44% at a wavelength of 1609 nm. Continuous-wave operation of an inband pumped Er : LiYF4 laser is obtained for the first time. The output power at a wavelength of 1606 nm was 58 mW with a slope efficiency of 21%.

Single Frequency Monolithic Solid State Green Laser as a Potential Source for Vibrometry Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sotor, Jaroslaw Z.; Antonczak, Arkadiusz J.; Abramski, Krzysztof M.

2010-05-28

In this paper miniature, monolithic single frequency solid state laser operating at 532 nm is presented. Developed Nd:GdVO{sub 4}/YVO{sub 4}/KTP consist of three crystal bonded together with a UV adhesive. The single frequency operation was obtained in wide temperature range from 17 deg. C to 27 deg. C. The laser operated with output power up to 90 mW at 532 nm. The total optical efficiency (808 nm to 532 nm) was 9.5%. Power stability was at the level of +-0.8% and the long term frequency stability was approximately 3centre dot10{sup -8}. The beam has a Gaussian profile and the M2more » parameter was below 1.1.« less

Ultra-large core birefringent Yb-doped tapered double clad fiber for high power amplifiers.

PubMed

Fedotov, Andrey; Noronen, Teppo; Gumenyuk, Regina; Ustimchik, Vasiliy; Chamorovskii, Yuri; Golant, Konstantin; Odnoblyudov, Maxim; Rissanen, Joona; Niemi, Tapio; Filippov, Valery

2018-03-19

We present a birefringent Yb-doped tapered double-clad fiber with a record core diameter of 96 µm. An impressive gain of over 38 dB was demonstrated for linearly polarized CW and pulsed sources at a wavelength of 1040 nm. For the CW regime the output power was70 W. For a mode-locked fiber laser a pulse energy of 28 µJ with 292 kW peak power was reached at an average output power of 28 W for a 1 MHz repetition rate. The tapered double-clad fiber has a high value of polarization extinction ratio at 30 dB and is capable of delivering the linearly polarized diffraction-limited beam (M 2 = 1.09).

Growth and laser properties of Nd:Ca 4YO(BO 3) 3 crystal

NASA Astrophysics Data System (ADS)

Zhang, H. J.; Meng, X. L.; Zhu, L.; Wang, C. Q.; Cheng, R. P.; Yu, W. T.; Zhang, S. J.; Sun, L. K.; Chow, Y. T.; Zhang, W. L.; Wang, H.; Wong, K. S.

1999-02-01

Nd:Ca 4YO(BO 3) 3 (Nd:YCOB) crystal was grown by the Czochralski method, and its structure was measured by using a four circle X-ray diffractometer. The transparent spectrum from 200 to 2600 nm was measured at room temperature. The fluorescence spectrum near 1.06 μm showed that the main emission wavelength of Nd:YCOB crystal was centered at 1060.8 nm. Laser output at 1.06 μm has been demonstrated when it was pumped by a Ti:sapphire laser at the wavelength of 794 nm, the highest output power was 68 mW under pumping power of 311 mW, the pumping threshold was 163 mW and slope efficiency was 46.9%. The self-frequency doubled green light has been observed when it was pumped by a Ti:sapphire or a laser diode (LD). A 14.5 mm Nd:YCOB crystal sample cut at ( θ, φ)=(90°, 33°) was used for type I second-frequency generation (SHG) of the 1.06 μm laser pulse. The SHG conversion efficiency was 22%.

Dependence of Laminar Flow Fluctuation on Indium Composition in In0.07GaAs/GaAs Quantum Wells for 940-nm Infrared Light-Emitting Diodes

NASA Astrophysics Data System (ADS)

Kim, Dae-Kwang; Lee, Hyung-Joo; An, Won-Chan; Kim, Hong-Gun; Kwac, Lee-Ku

2018-05-01

The effect of laminar flow fluctuation on the indium composition of In0.07GaAs quantum wells was investigated in order to obtain a higher output power from infrared lighting-emitting diodes (IR-LEDs) having a 940-nm wavelength. By controlling the injection pressure, we obtained various laminar flow conditions. Through subsequent photoluminescence (PL) and X-ray diffraction (XRD) measurements, a noticeable improvement in the optical and the crystalline characteristics of the In0.07GaAs quantum wells was observed at an optimum laminar flow. This result could be attributed to a reduction of non-crystallization in InGaAs quantum wells that had their indium composition improved via the optimized laminar flow. Overall, a significantly improved output power (11.2 mW) was obtained from a 940-nm IR-LED chip fabricated at an optimum laminar flow of 500 sccm, and a remarkable increase of approximately 250% was displayed compared to a conventional chip (3.9 mW) fabricated at a laminar flow of 100 sccm.

Optically pumped quantum-dot Cd(Zn)Se/ZnSe laser and microchip converter for yellow-green spectral region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lutsenko, E V; Voinilovich, A G; Rzheutskii, N V

2013-05-31

The room temperature laser generation in the yellow-green ({lambda} = 558.5-566.7 nm) spectral range has been demonstrated under optical pumping by a pulsed nitrogen laser of Cd(Zn)Se/ZnSe quantum dot heterostructures. The maximum achieved laser wavelength was as high as {lambda} = 566.7 nm at a laser cavity length of 945 {mu}m. High values of both the output pulsed power (up to 50 W) and the external differential quantum efficiency ({approx}60%) were obtained at a cavity length of 435 {mu}m. Both a high quality of the laser heterostructure and a low lasing threshold ({approx}2 kW cm{sup -2}) make it possible tomore » use a pulsed InGaN laser diode as a pump source. A laser microchip converter based on this heterostructure has demonstrated a maximum output pulse power of {approx}90 mW at {lambda} = 560 nm. The microchip converter was placed in a standard TO-18 (5.6 mm in diameter) laser diode package. (semiconductor lasers. physics and technology)« less

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Planar excilamp on rare gas chlorides pumped by a transverse self-sustained discharge

NASA Astrophysics Data System (ADS)

Panchenko, Aleksei N.; Tarasenko, Viktor F.

2006-02-01

The design and parameters of a UV—VUV spontaneous radiation source — an excilamp operating on chlorides of rare gases ArCl*, KrCl* and XeCl* in the wavelength range 175—308 nm are presented. The Ne—Xe(Kr, Ar)—HCl mixtures were excited by a high-pressure self-sustained discharge with spark preionisation. It is shown that upon pumping mixtures of rare gases and halogens by a transverse discharge, the intensities of the B—X emission band of molecules ArCl*, KrCl* and XeCl* are comparable and up to 90% of the emission energy of excilamps can be concentrated in the UV region. The peak UV power density at 222 and 308 nm on the output window of the excilamp was ~2 kW cm-2 for the pulse energy up to ~ 3 mJ. The output emission energy of the excilamp at 175 nm achieved ~0.6 mJ and the peak power density was ~0.4 kW cm-2.

FIBER AND INTEGRATED OPTICS: Directional pattern and other output properties of a quantum-well injection laser for the 780-nm spectral region

NASA Astrophysics Data System (ADS)

Davydova, Evgeniya I.; Drakin, A. E.; Eliseev, P. G.; Pak, G. T.; Popovichev, V. V.; Uspenskiĭ, M. B.; Khlopotin, S. E.; Shishkin, Viktor A.

1992-10-01

An optical model is constructed for a GaAlAs/GaAs stripe-geometry laser heterostructure with a ridge-waveguide configuration in the p-type emitter layer. This waveguide configuration provides lateral optical confinement. The directional characteristics of the output are found as a function of the parameters of the structure. The quantum-well active layer is in a three-layer waveguide (in a separate-confinement structure). Laser structures were fabricated experimentally by MOCVD epitaxy followed by ion-chemical etching and vacuum deposition of zinc selenide on the mesa stripes. Low-threshold lasers with a cw, single-frequency power up to 40 μW were obtained. In single-spatial-mode operation, a power up to 80 μW was achieved at a wavelength of 780 nm. Windows of ZnSe were grown on the laser facets to improve the optical strength.

Efficient laser emission from cladding waveguide inscribed in Nd:GdVO(4) crystal by direct femtosecond laser writing.

PubMed

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

2014-08-01

We report on the fabrication of depressed cladding waveguides in Nd:GdVO(4) laser crystal by using femtosecond laser inscription. The cross section of the structure is a circular shape with a diameter of 150 μm. Under the optical pump at 808 nm, the continuous wave (cw) as well as pulsed (Q-switched by graphene saturable absorber) waveguide lasing at 1064 nm has been realized, supporting guidance of both TE and TM polarizations. The maximum output power of 0.57 W was obtained in the cw regime, while the maximum pulse energy of the pulsed laser emissions was up to 19 nJ (corresponding to a maximum average output power of 0.33 W, at a resonant frequency of 18 MHz). The slope efficiencies achieved for the cw and pulsed Nd:GdVO(4) waveguide lasers were as high as 68% and 52%, respectively.

Spiking suppression of high power QCW pulse 1319 nm Nd:YAG laser with different intracavity doublers

NASA Astrophysics Data System (ADS)

Bian, Qi; Zuo, Jun-Wei; Guo, Chuan; Xu, Chang; Shen, Yu; Zong, Nan; Bo, Yong; Peng, Qin-Jun; Chen, Hong-Bin; Cui, Da-Fu; Xu, Zu-Yan

2016-09-01

We describe the results of our efforts in suppressing spiking of a high power, high beam quality 1319 nm Nd:YAG microsecond-pulse laser with three different intracavity frequency doublers. The 1319 nm laser is generated by a quasi-continuous-wave diode-pumped Nd:YAG ring laser system. One potassium titanyl phosphate (KTP), two KTPs and one lithium triborate (LBO) as frequency doublers are installed in the ring resonator and tested, respectively. At 800 Hz repetition rate, with a pulse width of 100 µs, performances of spiking suppression for each case are observed. The average output power are 23.6 W, 22.7 W and 23.4 W with beam quality factors of M 2  =  2.21, 1.28 and 1.25 for one KTP, two KTPs and one LBO, respectively. The corresponding brightness are 270 MW/(cm2·sr), 780 MW/(cm2·sr) and 860 MW/(cm2·sr). With better beam quality, higher brightness, and easier maintainability, the LBO is the best option of the three. A laser rate equation model including the insertion loss of the doubler is applied for theoretical analysis of the output temporal pulse shape and power, and the simulated results agree well with the experimental data.

940nm QCW diode laser bars with 70% efficiency at 1 kW output power at 203K: analysis of remaining limits and path to higher efficiency and power at 200K and 300K

NASA Astrophysics Data System (ADS)

Frevert, C.; Bugge, F.; Knigge, S.; Ginolas, A.; Erbert, G.; Crump, P.

2016-03-01

Both high-energy-class laser facilities and commercial high-energy pulsed laser sources require reliable optical pumps with the highest pulse power and electro-optical efficiency. Although commercial quasi-continuous wave (QCW) diode laser bars reach output powers of 300…500 W further improvements are urgently sought to lower the cost per Watt, improve system performance and reduce overall system complexity. Diode laser bars operating at temperatures of around 200 K show significant advances in performance, and are particularly attractive in systems that use cryogenically cooled solid state lasers. We present the latest results on 940 nm, passively cooled, 4 mm long QCW diode bars which operate under pulse conditions of 1.2 ms, 10 Hz at an output power of 1 kW with efficiency of 70% at 203 K: a two-fold increase in power compared to 300 K, without compromising efficiency. We discuss how custom low-temperature design of the vertical layers can mitigate the limiting factors such as series resistance while sustaining high power levels. We then focus on the remaining obstacles to higher efficiency and power, and use a detailed study of multiple vertical structures to demonstrate that the properties of the active region are a major performance limit. Specifically, one key limit to series resistance is transport in the layers around the active region and the differential internal efficiency is closely correlated to the threshold current. Tailoring the barriers around the active region and reducing transparency current density thus promise bars with increased performance at temperatures of 200 K as well as 300 K.

Performance characterization of mid-infrared difference frequency generation in orientation-patterned gallium phosphide

NASA Astrophysics Data System (ADS)

Wei, Junxiong; Chaitanya Kumar, S.; Ye, Hanyu; Schunemann, Peter G.; Ebrahim-Zadeh, M.

2018-02-01

Orientation-patterned gallium phosphide (OP-GaP) is a recently developed nonlinear material with wide transparency across 0.8-12 μm and high nonlinearity (d14 70 pm/V), which is a promising candidate material for mid-infrared generation. Here we report the full performance characterization of a tunable single-pass nanosecond difference frequency generation (DFG) source based on OP-GaP by mixing the output of a Q-switched Nd:YAG laser at 1.064 μm with the signal from a pulsed MgO:PPLN OPO pumped by the same laser. Using the longest OP-GaP crystal (40 mm) deployed to date, the DFG source provides up to 14 mW of average output power at 2719 nm at 80 kHz repetition rate, with >6 mW across 2492-2782 nm, in TEM00 spatial profile. By performing relevant measurements, detrimental issues such as residual absorption and thermal effects have been studied and confirmed. The temperature and spectral acceptance bandwidths for DFG in the 40-mm-log OP-GaP are measured to be 18 °C and 17 nm, respectively, at 1766 nm. The DFG beam exhibits passive power stability better than 1.7% rms over 1.4 hours at 2774 nm, compared to 1.6% and 0.1% rms for the signal and pump, respectively. The polarization dependence of the input beams on the DFG power has also been systematically investigated, for the first time to our knowledge. Further, we have measured the damage threshold of the OP-GaP crystal to be 0.8 J/cm2 at 1064 nm.

Realization and optimization of a 1 ns pulsewidth multi-stage 250 kW peak power monolithic Yb doped fiber amplifier at 1064 nm

NASA Astrophysics Data System (ADS)

Morasse, Bertrand; Plourde, Estéban

2017-02-01

We present a simple way to achieve and optimize hundreds of kW peak power pulsed output using a monolithic amplifier chain based on solid core double cladding fiber tightly packaged. A fiber pigtailed current driven diode is used to produce nanosecond pulses at 1064 nm. We present how to optimize the use of Fabry-Perot versus DFB type diode along with the proper wavelength locking using a fiber Bragg grating. The optimization of the two pre-amplifiers with respect to the pump wavelength and Yb inversions is presented. We explain how to manage ASE using core and cladding pumping and by using single pass and double pass amplifier. ASE rejection within the Yb fiber itself and with the use of bandpass filter is discussed. Maximizing the amplifier conversion efficiency with regards to the fiber parameters, glass matrix and signal wavelength is described in details. We present how to achieve high peak power at the power amplifier stage using large core/cladding diameter ratio highly doped Yb fibers pumped at 975 nm. The effect of pump bleaching on the effective Yb fiber length is analyzed carefully. We demonstrate that counter-pumping brings little advantage in very short length amplifier. Dealing with the self-pulsation limit of stimulated Brillouin scattering is presented with the adjustment of the seed pulsewidth and linewidth. Future prospects for doubling the output peak power are discussed.

High-power, continuous-wave, single-frequency, all-periodically-poled, near-infrared source.

PubMed

Devi, Kavita; Chaitanya Kumar, S; Ebrahim-Zadeh, M

2012-12-15

We report a high-power, single-frequency, continuous-wave (cw) source tunable across 775-807 nm in the near-infrared, based on internal second harmonic generation (SHG) of a cw singly-resonant optical parametric oscillator (OPO) pumped by a Yb-fiber laser. The compact, all-periodically-poled source employs a 48-mm-long, multigrating MgO doped periodically poled lithium niobate (MgO:PPLN) crystal for the OPO and a 30-mm-long, fan-out grating MgO-doped stoichiometric periodically poled lithium tantalate (MgO:sPPLT) crystal for intracavity SHG, providing as much as 3.7 W of near-infrared power at 793 nm, together with 4 W of idler power at 3232 nm, at an overall extraction efficiency of 28%. Further, the cw OPO is tunable across 3125-3396 nm in the idler, providing as much as 4.3 W at 3133 nm with >3.8  W over 77% of the tuning range together with >3  W of near-infrared power across 56% of SHG tuning range, in high-spatial beam-quality with M2<1.4. The SHG output has an instantaneous linewidth of 8.5 MHz and exhibits a passive power stability better than 3.5% rms over more than 1 min.

Sub-nanosecond periodically poled lithium niobate optical parametric generator and amplifier pumped by an actively Q-switched diode-pumped Nd:YAG microlaser

NASA Astrophysics Data System (ADS)

Liu, L.; Wang, H. Y.; Ning, Y.; Shen, C.; Si, L.; Yang, Y.; Bao, Q. L.; Ren, G.

2017-05-01

A sub-nanosecond seeded optical parametric generator (OPG) based on magnesium oxide-doped periodically poled lithium niobate (MgO:PPLN) crystal is presented. Pumped by an actively Q-switched diode-pumped 1 kHz, 1064 nm, Nd:YAG microlaser and seeded with a low power distributed feedback (DFB) diode continuous-wave (CW) laser, the OPG generated an output energy of 41.4 µJ and 681 ps pulse duration for the signal at 1652.4 nm, achieving a quantum conversion efficiency of 61.2% and a slope efficiency of 41.8%. Signal tuning was achieved from 1651.0 to 1652.4 nm by tuning the seed-laser current. The FWHM of the signal spectrum was approximately from 35 nm to 0.5 nm by injection seed laser. The SHG doubled the frequency of OPG signal to produce a output energy of 12 µJ with the energy conversion efficiency of 29.0% and tunanble wavelength near 826 nm.

High power broadband all fiber super-fluorescent source with linear polarization and near diffraction-limited beam quality.

PubMed

Ma, Pengfei; Huang, Long; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

2016-01-25

In this manuscript, a high power broadband superfluorescent source (SFS) with linear polarization and near-diffraction-limited beam quality is achieved based on an ytterbium-doped (Yb-doped), all fiberized and polarization-maintained master oscillator power amplifier (MOPA) configuration. The MOPA structure generates a linearly polarized output power of 1427 W with a slope efficiency of 80% and a full width at half maximum (FWHM) of 11 nm, which is power scaled by an order of magnitude compared with the previously reported SFSs with linear polarization. In the experiment, both the polarization extinction ratio (PER) and beam quality (M(2) factor) are degraded little during the power scaling process. At maximal output power, the PER and M(2) factor are measured to be 19.1dB and 1.14, respectively. The root-mean-square (RMS) and peak-vale (PV) values of the power fluctuation at maximal output power are just 0.48% and within 3%, respectively. Further power scaling of the whole system is limited by the available pump sources. To the best of our knowledge, this is the first demonstration of kilowatt level broadband SFS with linear polarization and near-diffraction-limited beam quality.

LD-pumped erbium and neodymium lasers with high energy and output beam quality

NASA Astrophysics Data System (ADS)

Kabanov, Vladimir V.; Bezyazychnaya, Tatiana V.; Bogdanovich, Maxim V.; Grigor'ev, Alexandr V.; Lebiadok, Yahor V.; Lepchenkov, Kirill V.; Ryabtsev, Andrew G.; Ryabtsev, Gennadii I.; Shchemelev, Maxim A.

2013-05-01

Physical and fabrication peculiarities which provide the high output energy and beam quality for the diode pumped erbium glass and Nd:YAG lasers are considered. Developed design approach allow to make passively Q-switched erbium glass eye-safe portable laser sources with output energy 8 - 12 mJ (output pulse duration is less than 25 ns, pulse repetition rate up to 5 Hz) and beam quality M2 less than 1.3. To reach these values the erbium laser pump unit parameters were optimized also. Namely, for the powerful laser diode arrays the optimal near-field fill-factor, output mirror reflectivity and heterostructure properties were determined. Construction of advanced diode and solid-state lasers as well as the optical properties of the active element and the pump unit make possible the lasing within a rather wide temperature interval (e.g. from minus forty till plus sixty Celsius degree) without application of water-based chillers. The transversally pumped Nd:YAG laser output beam uniformity was investigated depending on the active element (AE) pump conditions. In particular, to enhance the pump uniformity within AE volume, a special layer which practically doesn't absorb the pump radiation but effectively scatters the pump and lasing beams, was used. Application of such layer results in amplified spontaneous emission suppression and improvement of the laser output beam uniformity. The carried out investigations allow us to fabricate the solid-state Nd:YAG lasers (1064 nm) with the output energy up to 420 mJ at the pulse repetition rate up to 30 Hz and the output energy up to 100 mJ at the pulse repetition rate of of 100 Hz. Also the laser sources with following characteristics: 35 mJ, 30 Hz (266 nm); 60 mJ, 30 Hz (355 nm); 100 mJ, 30 Hz (532 nm) were manufactured on the base of the developed Nd:YAG quantrons.

Double-pass tapered amplifier diode laser with an output power of 1 W for an injection power of only 200 μW.

PubMed

Bolpasi, V; von Klitzing, W

2010-11-01

A 1 W tapered amplifier requiring only 200 μW of injection power at 780 nm is presented in this paper. This is achieved by injecting the seeding light into the amplifier from its tapered side and feeding the amplified light back into the small side. The amplified spontaneous emission of the tapered amplifier is suppressed by 75 dB. The double-passed tapered laser, presented here, is extremely stable and reliable. The output beam remains well coupled to the optical fiber for a timescale of months, whereas the injection of the seed light did not require realignment for over a year of daily operation.

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.

Highly-efficient multi-watt Yb:CaLnAlO4 microchip lasers

NASA Astrophysics Data System (ADS)

Loiko, Pavel; Serres, Josep Maria; Mateos, Xavier; Xu, Xiaodong; Xu, Jun; Yumashev, Konstantin; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc; Major, Arkady

2017-02-01

Tetragonal rare-earth calcium aluminates, CaLnAlO4 where Ln = Gd or Y (CALGO and CALYO, respectively), are attractive laser crystal hosts due to their locally disordered structure and high thermal conductivity. In the present work, we report on highly-efficient power-scalable microchip lasers based on 8 at.% Yb:CALGO and 3 at.% Yb:CALYO crystals grown by the Czochralski method. Pumped by an InGaAs laser diode at 978 nm, the 6 mm-long Yb:CALGO microchip laser generated 7.79 W at 1057-1065 nm with a slope efficiency of η = 84% (with respect to the absorbed pump power) and an optical-to-optical efficiency of ηopt = 49%. The 3 mm-long Yb:CALYO microchip laser generated 5.06 W at 1048-1056 nm corresponding to η = 91% and ηopt = 32%. Both lasers produced linearly polarized output (σ- polarization) with an almost circular beam profile and beam quality factors M2 x,y <1.1. The output performance of the developed lasers was modeled yielding a loss coefficient as low as 0.004-0.007 cm-1. The results indicate that the Yb3+- doped calcium aluminates are very promising candidates for high-peak-power passively Q-switched microchip lasers.

Diamond Shaped Ring Laser Characterization, Package Design and Performance

DTIC Science & Technology

2006-09-01

fabricated by Binoptics, with the end facets formed by chemically assisted ion beam etching . The lasers, designed for operation at 1550 nm, propagated bi...calculated and Corning OptiFocus™ Lensed fiber was chosen to use for the four fiber outputs. Each fiber placement was actively optimized. Output power...aligned using active feedback and placed with submicron precision. The prototype package design was constrained to modification of a prior

Effects of 946-nm thermal shift and broadening on Nd3+:YAG laser performance

NASA Astrophysics Data System (ADS)

Seyed Ebrahim, Pourmand; Ghasem, Rezaei

2015-12-01

Spectroscopic properties of flashlamp pumped Nd3+:YAG laser are studied as a function of temperature in a range from -30 °C to 60 °C. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of 4F3/2 → 4I9/2 are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature. The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is, thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state. Project supported by Estahban Branch, Islamic Azad University.

Improving the Reliability and Modal Stability of High Power 870 nm AlGaAs CSP Laser Diodes for Applications to Free Space Communication Systems

NASA Technical Reports Server (NTRS)

Connolly, J. C.; Alphonse, G. A.; Carlin, D. B.; Ettenberg, M.

1991-01-01

The operating characteristics (power-current, beam divergence, etc.) and reliability assessment of high-power CSP lasers is discussed. The emission wavelength of these lasers was optimized at 860 to 880 nm. The operational characteristics of a new laser, the inverse channel substrate planar (ICSP) laser, grown by metalorganic chemical vapor deposition (MOCVD), is discussed and the reliability assessment of this laser is reported. The highlights of this study include a reduction in the threshold current value for the laser to 15 mA and a degradation rate of less than 2 kW/hr for the lasers operating at 60 mW of peak output power.

A fiber laser pumped dual-wavelength mid-infrared laser based on optical parametric oscillation and intracavity difference frequency generation

NASA Astrophysics Data System (ADS)

Wang, Peng; Shang, Yaping; Li, Xiao; Shen, Meili; Xu, Xiaojun

2017-02-01

We report a dual-wavelength mid-infrared laser based on intracavity difference frequency generation (DFG) in an MgO-doped periodically poled LiNbO3, which was pumped by a dual-wavelength fiber MOPA consisting of two parts: a dual-wavelength seed and a power amplifier. The maximum pump power was 74.1 W and the wavelengths were 1060 nm and 1090 nm. The wavelengths of the mid-infrared output were 3.1 µm and 3.4 µm under maximum pump power with a total idler power of 6.57 W. The corresponding pump-to-idler slope efficiency reached 12%. The contrast for the peak intensity of the emissions for the two idlers was 0.6. A power preamplifier was added in a further experiment to enhance the contrast. The idler output reached 4.45 W under the maximum pump power of 70 W, which was lower than before. However, the contrast for the idler emission peak intensity was increased to 1.18. The signal wave generated in the experiment only had a single wavelength around 1.6 µm, indicating that two kinds of nonlinear processes occurred in the experiment, namely optical parametric oscillation and intracavity DFG.

Improvement in reduced-mode (REM) diodes enable 315 W from 105-μm 0.15-NA fiber-coupled modules

NASA Astrophysics Data System (ADS)

Kanskar, M.; Bao, L.; Chen, Z.; Dawson, D.; DeVito, M.; Dong, W.; Grimshaw, M.; Guan, X.; Hemenway, M.; Martinsen, R.; Urbanek, W.; Zhang, S.

2018-02-01

High-power, high-brightness diode lasers have been pursued for many applications including fiber laser pumping, materials processing, solid-state laser pumping, and consumer electronics manufacturing. In particular, 915 nm - and 976 nm diodes are of interest as diode pumps for the kilowatt CW fiber lasers. As a result, there have been many technical thrusts for driving the diode lasers to have both high power and high brightness to achieve high-performance and reduced manufacturing costs. This paper presents our continued progress in the development of high brightness fiber-coupled product platform, nLIGHT element®. In the past decade, the power coupled into a single 105 μm and 0.15 NA fiber has increased by over a factor of ten through improved diode laser brightness and the development of techniques for efficiently coupling multiple emitters. In this paper, we demonstrate further brightness improvement and power-scaling enabled by both the rise in chip brightness/power and the increase in number of chips coupled into a given numerical aperture. We report a new chip technology using x-REM design with brightness as high as 4.3 W/mm-mrad at a BPP of 3 mm-mrad. We also report record 315 W output from a 2×12 nLIGHT element with 105 μm diameter fiber using x-REM diodes and these diodes will allow next generation of fiber-coupled product capable of 250W output power from 105 μm/0.15 NA beam at 915 nm.

All-fiber linearly polarized high power 2-μm single mode Tm-fiber laser for plastic processing and Ho-laser pumping applications

NASA Astrophysics Data System (ADS)

Scholle, K.; Schäfer, M.; Lamrini, S.; Wysmolek, M.; Steinke, M.; Neumann, J.; Fuhrberg, P.

2018-02-01

In this paper we present a high power, polarized 2 μm Thulium-doped fiber laser with high beam quality. Such laser systems are ideally suited for the processing of plastic materials which are highly transparent in the visible and 1 μm wavelength range and for the pumping of laser sources for the mid-IR wavelength region. For most applications polarized lasers are beneficial, as they can be easily protected from back reflections and combined with other laser sources or power scaled by polarization combining. The Tm-doped fiber laser is pumped in an all-fiber configuration by using a fiber coupled pump diode emitting around 790 nm. This pumping scheme allows the exploitation of the crossrelaxation process to populate the upper laser level. A compact and robust laser configuration was achieved by using an all-fiber configuration with single mode fibers and fiber Bragg gratings (FBG). Different FBG pairs with wavelength around 2 μm were tested. To achieve stable polarized output power the fibers with the FBG were 90° twisted at the splices. Stable linearly polarized output power up to 38 W with an extinction ratio of up to 50:1 was observed. With respect to the diode output power an optical-to-optical efficiency of 51 % was reached with a correspondent slope efficiency of 52 %. The emission linewidth at maximum power was measured to be < 0.3 nm which is well suitable for Ho-laser pumping. First tests of the precise processing of highly transparent plastic materials demonstrate the potentials of these laser systems.

High power laser source for atom cooling based on reliable telecoms technology with all fibre frequency stabilisation

NASA Astrophysics Data System (ADS)

Legg, Thomas; Farries, Mark

2017-02-01

Cold atom interferometers are emerging as important tools for metrology. Designed into gravimeters they can measure extremely small changes in the local gravitational field strength and be used for underground surveying to detect buried utilities, mineshafts and sinkholes prior to civil works. To create a cold atom interferometer narrow linewidth, frequency stabilised lasers are required to cool the atoms and to setup and measure the atom interferometer. These lasers are commonly either GaAs diodes, Ti Sapphire lasers or frequency doubled InGaAsP diodes and fibre lasers. The InGaAsP DFB lasers are attractive because they are very reliable, mass-produced, frequency controlled by injection current and simply amplified to high powers with fibre amplifiers. In this paper a laser system suitable for Rb atom cooling, based on a 1560nm DFB laser and erbium doped fibre amplifier, is described. The laser output is frequency doubled with fibre coupled periodically poled LiNbO3 to a wavelength of 780nm. The output power exceeds 1 W at 780nm. The laser is stabilised at 1560nm against a fibre Bragg resonator that is passively temperature compensated. Frequency tuning over a range of 1 GHz is achieved by locking the laser to sidebands of the resonator that are generated by a phase modulator. This laser design is attractive for field deployable rugged systems because it uses all fibre coupled components with long term proven reliability.

High power tunable mid-infrared optical parametric oscillator enabled by random fiber laser.

PubMed

Wu, Hanshuo; Wang, Peng; Song, Jiaxin; Ye, Jun; Xu, Jiangming; Li, Xiao; Zhou, Pu

2018-03-05

Random fiber laser, as a kind of novel fiber laser that utilizes random distributed feedback as well as Raman gain, has become a research focus owing to its advantages of wavelength flexibility, modeless property and output stability. Herein, a tunable optical parametric oscillator (OPO) enabled by a random fiber laser is reported for the first time. By exploiting a tunable random fiber laser to pump the OPO, the central wavelength of idler light can be continuously tuned from 3977.34 to 4059.65 nm with stable temporal average output power. The maximal output power achieved is 2.07 W. So far as we know, this is the first demonstration of a continuous-wave tunable OPO pumped by a tunable random fiber laser, which could not only provide a new approach for achieving tunable mid-infrared (MIR) emission, but also extend the application scenarios of random fiber lasers.

Compact high-efficiency 100-W-level diode-side-pumped Nd:YAG laser with linearly polarized TEM00 mode output.

PubMed

Xu, Yi-Ting; Xu, Jia-Lin; Guo, Ya-Ding; Yang, Feng-Tu; Chen, Yan-Zhong; Xu, Jian; Xie, Shi-Yong; Bo, Yong; Peng, Qin-Jun; Cui, Dafu; Xu, Zu-Yan

2010-08-20

We present a compact high-efficiency and high-average-power diode-side-pumped Nd:YAG rod laser oscillator operated with a linearly polarized fundamental mode. The oscillator resonator is based on an L-shaped convex-convex cavity with an improved module and a dual-rod configuration for birefringence compensation. Under a pump power of 344 W, a linearly polarized average output power of 101.4 W at 1064 nm is obtained, which corresponds to an optical-to-optical conversion efficiency of 29.4%. The laser is operated at a repetition rate of 400 Hz with a beam quality factor of M(2)=1.14. To the best of our knowledge, this is the highest optical-to-optical efficiency for a side-pumped TEM(00) Nd:YAG rod laser oscillator with a 100-W-level output ever reported.

Very high repetition-rate electro-optical cavity-dumped Nd: YVO4 laser with optics and dynamics stabilities

NASA Astrophysics Data System (ADS)

Liu, Xuesong; Shi, Zhaohui; Huang, Yutao; Fan, Zhongwei; Yu, Jin; Zhang, Jing; Hou, Liqun

2015-02-01

In this paper, a very high repetition-rate, short-pulse, electro-optical cavity-dumped Nd: YVO4 laser is experimentally and theoretically investigated. The laser performance is optimized from two aspects. Firstly, the laser resonator is designed for a good thermal stability under large pump power fluctuation through optics methods. Secondly, dynamics simulation as well as experiments verifies that cavity dumping at very high repetition rate has better stability than medium/high repetition rate. At 30 W, 880 nm pump power, up to 500 kHz, constant 5 ns, stable 1064 nm fundamental-mode laser pulses can be obtained with 10 W average output power.

1-kilowatt CW all-fiber laser oscillator pumped with wavelength-beam-combined diode stacks.

PubMed

Xiao, Y; Brunet, F; Kanskar, M; Faucher, M; Wetter, A; Holehouse, N

2012-01-30

We have demonstrated a monolithic cladding-pumped ytterbium-doped single all-fiber laser oscillator generating 1 kW of CW signal power at 1080 nm with 71% slope efficiency and near diffraction-limited beam quality. Fiber components were highly integrated on "spliceless" passive fibers to promote laser efficiency and alleviate non-linear effects. The laser was pumped through a 7:1 pump combiner with seven 200-W 91x nm fiber-pigtailed wavelength-beam-combined diode-stack modules. The signal power of such a single all-fiber laser oscillator showed no evidence of roll-over, and the highest output was limited only by available pump power.

PCF based high power narrow line width pulsed fiber laser

NASA Astrophysics Data System (ADS)

Chen, H.; Yan, P.; Xiao, Q.; Wang, Y.; Gong, M.

2012-09-01

Based on semiconductor diode seeded multi-stage cascaded fiber amplifiers, we have obtained 88-W average power of a 1063-nm laser with high repetition rate of up to 1.5 MHz and a constant 2-ns pulse duration. No stimulated Brillouin scattering pulse or optical damage occurred although the maximum pulse peak power has exceeded 112 kW. The output laser exhibits excellent beam quality (M2x = 1.24 and M2y = 1.18), associated with a spectral line width as narrow as 0.065 nm (FWHM). Additionally, we demonstrate high polarization extinction ratio of 18.4 dB and good pulse stabilities superior to 1.6 % (RMS).

Subnanosecond Tm:KLuW microchip laser Q-switched by a Cr:ZnS saturable absorber.

PubMed

Loiko, Pavel; Serres, Josep Maria; Mateos, Xavier; Yumashev, Konstantin; Yasukevich, Anatoly; Petrov, Valentin; Griebner, Uwe; Aguiló, Magdalena; Díaz, Francesc

2015-11-15

Passive Q-switching of a compact Tm:KLu(WO(4))(2) microchip laser diode pumped at 805 nm is demonstrated with a polycrystalline Cr(2+):ZnS saturable absorber. This laser generates subnanosecond (780 ps) pulses with a pulse repetition frequency of 5.6 kHz at 1846.6 nm, the shortest pulse duration ever achieved by Q-switching of ~2 μm lasers. The maximum average output power is 146 mW with a slope efficiency of 21% with respect to the absorbed power. This corresponds to a pulse energy of 25.6 μJ and a peak power of 32.8 kW.

Diode pumped Yb:CN laser at 1082 nm and intracavity doubling to the green spectral range

NASA Astrophysics Data System (ADS)

Liu, B.; Li, Y. L.; Jiang, H. L.

2011-08-01

A diode pumped Yb:CaNb2O6 (Yb:CN) laser at 1082 nm with a maximum output of 1.35 W at 13.3 W pump power has been demonstrated. The slope efficiency was 12.4%. Moreover, intracavity second-harmonic generation (SHG) has also been achieved with a maximum green power of 374 mW by using a LiB3O5 (LBO) nonlinear crystal. To the best of our knowledge, this is the first report on continuous wave (CW) green generation by intracavity frequency doubling Yb:CN laser.

Copper-vapor laser in medical practice: gynecology

NASA Astrophysics Data System (ADS)

Chvykov, Vladimir V.; Zazulya, O. I.; Zemskov, Konstantin I.

1993-10-01

About 100 patients were treated for cervical erosion, cervical leukoplakia, and vulval warts in the Gynecology Department of the adult polyclinic of the Zelenograd Center of Medicine. Copper vapor laser (CVL) was used with output average power up to 4 W in two lines (510 nm, 578 nm). Pulse repetition rate was about 10 kHz, pulselength approximately 20 - 40 ns. Four to twelve procedures were sufficient to recover.

Narrowband, tunable, 2 µm optical parametric master-oscillator power amplifier with large-aperture periodically poled Rb:KTP

NASA Astrophysics Data System (ADS)

Coetzee, R. S.; Zheng, X.; Fregnani, L.; Laurell, F.; Pasiskevicius, V.

2018-06-01

A high-energy, ns, narrow-linewidth optical parametric oscillator and amplifier system based on large-aperture periodically poled Rb:KTP is presented. The 2 µm seed source is a singly resonant OPO locked with a transversely chirped volume Bragg grating, allowing a wavelength tuning of 21 nm and output linewidth of 0.56 nm. A maximum output energy of 52 mJ and conversion efficiency of 36% was obtained from the amplifier for a pump energy of 140 mJ. The high-energy and the robust and narrow dual-wavelength spectra obtained make this system an ideal pump source for difference frequency generation-based THz generation schemes.

In-band pumped Q-switched fiber laser based on monolayer graphene

NASA Astrophysics Data System (ADS)

Wu, Hanshuo; Wu, Jian; Xiao, Hu; Leng, Jinyong; Xu, Jiangming; Zhou, Pu

2017-06-01

We propose and demonstrate an in-band pumped all-fiberized passively Q-switched laser emitting at 1080 nm. A single mode 1030 nm fiber laser is used as the pump source, while a 2D material, CVD-grown monolayer graphene, is adopted as a saturable absorber inside the ring cavity. The repetition rate of the output pulses can be varied from 12.74 to 24.6 kHz with the pulse duration around 12 µs. The maximum average output power is 34.25 mW, with the pulse energy of 1.392 µJ. This work proves the practicability of achieving passively Q-switched operation via in-band pump.

Watt-level ~2 μm laser output in Tm3+-doped tungsten tellurite glass double-cladding fiber.

PubMed

Li, Kefeng; Zhang, Guang; Hu, Lili

2010-12-15

We report, for the first time to the best of our knowledge, a watt level cw fiber laser at ~2 μm from a piece of 40-cm-long newly developed highly thulium-doped (3.76 × 10(20) ions/cm(3)) tungsten tellurite glass double cladding fiber pumped by a commercial 800 nm laser diode. The maximum output power of the fiber laser reaches 1.12 W. The slope efficiency and the optical-optical efficiency with respect to the absorbed pump are 20% and 16%, respectively. The lasing threshold is 1.46 W, and the lasing wavelength is centered at 1937 nm.

The Laser Guide Star System for Adaptive Optics at Subaru Telescope

NASA Astrophysics Data System (ADS)

Hayano, Y.; Saito, Y.; Ito, M.; Saito, N.; Akagawa, K.; Takazawa, A.; Ito, M.; Wada, S.; Takami, H.; Iye, M.

We report on the current status of developing the new laser guide star (LGS) system for the Subaru adaptive optics (AO) system. We have three major subsystems: the laser unit, the relay optical fiber and the laser launching telescope. A 4W-class all-solid-state 589nm laser has been developed as a light source for sodium laser guide star. We use two mode-locked Nd:YAG lasers operated at the wavelength of 1064nm and 1319nm to generate sum-frequency conversion into 589nm. The side-LD pumped configuration is used for the mode-locked Nd:YAG lasers. We have carefully considered the thermal lens effect in the cavity to achieve a high beam quality with TEM00; M2 = 1.06. The mode-locked frequency is selected at 143 MHz. We obtained the output powers of 16.5 W and 5.0 W at 1064nm and 1319 nm. Sum frequency generated by mixing two synchronized Nd:YAG mode-locked pulsed beams is precisely tuned to the sodium D2 line by thermal control of the etalon in the 1064nm Nd:YAG laser by observing the maximum fluorescence intensity of heated sodium vapor cell. The maximum output power at 589.159 nm reaches to 4.6 W using a PPMgOSLT crystal as a nonlinear optical crystal. And the output power can be maintained within a stability of +/- 1.2% for more than 3 days without optical damage. We developed a single-mode photonic crystal fiber (PCF) to relay the laser beam from laser clean room, in which the laser unit is located on the Nasmyth platform, to the laser launching telescope mounted behind the secondary mirror of Subaru Telescope. The photonic crystal fiber has solid pure silica core with the mode field diameter of 14 micron, which is relatively larger than that of the conventional step-index type single mode fiber. The length of the PCF is 35m and transmission loss due to the pure silica is 10dB/km at 589nm, which means PCF transmits 92% of the laser beam. We have preliminary achieved 75% throughput in total. Small mode-locked pulse width in time allows us to transmit the high-power laser beam with no suffer from the non-linear scatter effect, i.e. stimulated Brillouin scatter, in the PCF. The laser launching telescope (LLT) has an output clear aperture as 50 cm. It is classical Cassegrain type optical configuration with tertiary mirror to insert the laser beam from the side. The wavefront error is designed to be 60 to 70nm. The LLT is a copy product what European Southern Observatory has been designed for the laser guide star system at Very Large Telescope. We succeeded to launch the laser beam to the sky on October 12, 2006. After several tests on the sky, we succeeded to get an image of the laser guide star with the size of more than 10 arc second. The larger size of the laser guide star is caused by the large optical aberration on the primary mirror of LLT due to the heat stress generated at the trigonal support points. We are making a plan to repair this problem during June and the second laser launching test will start around this summer.

1.6 μm microchip laser

NASA Astrophysics Data System (ADS)

Šulc, J.; Jelínková, H.; Ryba-Romanowski, W.; Lukasiewicz, T.

2009-03-01

Properties of new pulsed-diode-pumped Er:YVO4 and Er:YVO4+CaO microchip lasers working in an ``eye-safe'' spectral region were investigated. As a pumping source, a fiber coupled (core diameter-200 μm) laser diode emitting radiation at wavelength 976 nm was used. The laser diode was operating in pulsed regime with 3 ms pulse width, and 20 Hz repetition rate. The result obtained was 175 mW and 152 mW output peak power for the Er:YVO4 and Er:YVO4+CaO lasers, respectively. The maximal efficiency with respect to the absorbed power was ~ 5%. The laser emission for Er:YVO4 microchip was observed in detail in the range 1593 nm to 1604 nm with respect to pumping. However, for Er:YVO4+CaO crystal only 1604 nm was generated.

Beam quality improvement by population-dynamic-coupled combined guiding effect in end-pumped Nd:YVO4 laser oscillator

NASA Astrophysics Data System (ADS)

Shen, Yijie; Gong, Mali; Fu, Xing

2018-05-01

Beam quality improvement with pump power increasing in an end-pumped laser oscillator is experimentally realized for the first time, to the best of our knowledge. The phenomenon is caused by the population-dynamic-coupled combined guiding effect, a comprehensive theoretical model of which has been well established, in agreement with the experimental results. Based on an 888 nm in-band dual-end-pumped oscillator using four tandem Nd:YVO4 crystals, the output beam quality of M^2= 1.1/1.1 at the pump power of 25 W is degraded to M^2 = 2.5/1.8 at 75 W pumping and then improved to M^2= 1.8/1.3 at 150 W pumping. The near-TEM_{00} mode is obtained with the highest continuous-wave output power of 72.1 W and the optical-to-optical efficiency of 48.1%. This work demonstrates great potential to further scale the output power of end-pumped laser oscillator while keeping good beam quality.

10 kHz ps 1342 nm laser generation by an electro-optically cavity-dumped mode-locked Nd:YVO4 laser

NASA Astrophysics Data System (ADS)

Chen, Ying; Liu, Ke; He, Li-jiao; Yang, Jing; Zong, Nan; Yang, Feng; Gao, Hong-wei; Liu, Zhao; Yuan, Lei; Lan, Ying-jie; Bo, Yong; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

2017-01-01

We have demonstrated an electro-optically cavity-dumped mode-locked (CDML) picosecond Nd:YVO4 laser at 1342 nm with 880 nm diode-laser direct pumping. At a repetition rate of 10 kHz, an average output power of 0.119 W was achieved, corresponding to a pulse energy of 11.9 μJ. Compared with the continuous wave mode-locking pulse energy of 17.5 nJ, the CDML pulse energy was 680 times higher. The pulse width was measured to be 33.4 ps, resulting in the peak power of 356 kW. Meanwhile, the beam quality was nearly diffraction limited with an average beam quality factor M2 of 1.29.

Laser performance of in-band pumped Er : LiYF{sub 4} and Er : LiLuF{sub 4} crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorbachenya, K N; Kisel, V E; Yasukevich, A S

2016-02-28

Spectroscopic properties of Er : LiLuF{sub 4} and Er : LiYF{sub 4} crystals in the spectral region near 1.5 μm and the lasing characteristics of these crystals under in-band pumping at a wavelength of 1522 nm are studied. With the Er : LiLuF{sub 4} crystal, the maximum slope efficiency with respect to the absorbed pump power was 44% at a wavelength of 1609 nm. Continuous-wave operation of an inband pumped Er : LiYF{sub 4} laser is obtained for the first time. The output power at a wavelength of 1606 nm was 58 mW with a slope efficiency of 21%. (lasers)

Au nanocage/SiO2 saturable absorber for passive Q-switching Yb-doped fiber laser

NASA Astrophysics Data System (ADS)

Bai, Jinxi; Li, Ping; Guo, Lei; Zhang, Baitao; Hu, Qiongyu; Wang, Lili; Liu, Binghai; Chen, Xiaohan

2018-05-01

Au nanocages/SiO2 (Au-NCs/SiO2) with the surface plasmon resonance peak at 1060 nm were fabricated and experimentally exploited as the saturable absorber in an all-fiber passively Q-switched ytterbium-doped fiber laser for the first time. Under a pump power of 440 mW, the average output power of 10.6 mW was obtained with the pulse duration 1.4 µs and the repetition rate of 126.9 kHz at 1060.5 nm with the 3 dB spectral width of 0.131 nm. The results indicate that Au-NCs/SiO2 exhibits the potential for applications in the field of pulse lasers.

Watt-level short-length holmium-doped ZBLAN fiber lasers at 1.2  μm.

PubMed

Zhu, Xiushan; Zong, Jie; Wiersma, Kort; Norwood, R A; Prasad, Narasimha S; Obland, Michael D; Chavez-Pirson, Arturo; Peyghambarian, N

2014-03-15

In-band core-pumped Ho3+-doped ZBLAN fiber lasers at the 1.2 μm region were investigated with different gain fiber lengths. A 2.4 W 1190 nm all-fiber laser with a slope efficiency of 42% was achieved by using a 10 cm long gain fiber pumped at a maximum available 1150 nm pump power of 5.9 W. A 1178 nm all-fiber laser was demonstrated with an output power of 350 mW and a slope efficiency of 6.5%. High Ho3+ doping in ZBLAN is shown to be effective in producing single-frequency fiber lasers and short-length fiber amplifiers immune from stimulated Brillouin scattering.

Side-pumping combiner for high-power fiber laser based on tandem pumping

NASA Astrophysics Data System (ADS)

Gu, Yanran; Lei, Chengmin; Liu, Jun; Li, Ruixian; Liu, Le; Xiao, Hu; Chen, Zilun

2017-11-01

We investigate a (2+1)×1 side-pumping combiner numerically and experimentally for high-power fiber laser based on tandem pumping for the first time. The influence of taper ratio and launch mode on the 1018-nm pump coupling efficiency and the leakage power into the coating of the signal fiber (LPC) is analyzed numerically. A side-pumping combiner is developed successfully by tapered-fused splicing technique based on the numerical analysis, consisting of two pump fibers (220/242 μm, NA=0.22) and a signal fiber (40/400 μm, NA=0.06/0.46). The total 1018-nm pump efficiency of the combiner is 98.1%, and the signal light insertion loss is <3%. The results show that, compared with laser diodes pumping, the combiner appears to have a better LPC performance and power handling capability when using 1018-nm fiber as the pump light. Meanwhile, an all-fiber MOPA laser based on tandem pumping with 1080-nm output of 2533 W and the slope efficiency of 82.8% is achieved based on the home-made combiner.

High power and spectral purity continuous-wave photonic THz source tunable from 1 to 4.5 THz for nonlinear molecular spectroscopy

NASA Astrophysics Data System (ADS)

Kiessling, J.; Breunig, I.; Schunemann, P. G.; Buse, K.; Vodopyanov, K. L.

2013-10-01

We report a diffraction-limited photonic terahertz (THz) source with linewidth <10 MHz that can be used for nonlinear THz studies in the continuous wave (CW) regime with uninterrupted tunability in a broad range of THz frequencies. THz output is produced in orientation-patterned (OP) gallium arsenide (GaAs) via intracavity frequency mixing between the two closely spaced resonating signal and idler waves of an optical parametric oscillator (OPO) operating near λ = 2 μm. The doubly resonant type II OPO is based on a periodically poled lithium niobate (PPLN) pumped by a single-frequency Yb:YAG disc laser at 1030 nm. We take advantage of the enhancement of both optical fields inside a high-finesse OPO cavity: with 10 W of 1030 nm pump, 100 W of intracavity power near 2 μm was attained with GaAs inside cavity. This allows dramatic improvement in terms of generated THz power, as compared to the state-of-the art CW methods. We achieved >25 μW of single-frequency tunable CW THz output power scalable to >1 mW with proper choice of pump laser wavelength.

High power single-frequency and frequency-doubled laser with active compensation for the thermal lens effect of terbium gallium garnet crystal.

PubMed

Yin, Qiwei; Lu, Huadong; Su, Jing; Peng, Kunchi

2016-05-01

The thermal lens effect of terbium gallium garnet (TGG) crystal in a high power single-frequency laser severely limits the output power and the beam quality of the laser. By inserting a potassium dideuterium phosphate (DKDP) slice with negative thermo-optical coefficient into the laser resonator, the harmful influence of the thermal lens effect of the TGG crystal can be effectively mitigated. Using this method, the stable range of the laser is broadened, the bistability phenomenon of the laser during the process of changing the pump power is completely eliminated, the highest output power of an all-solid-state continuous-wave intracavity-frequency-doubling single-frequency laser at 532 nm is enhanced to 30.2 W, and the beam quality of the laser is significantly improved.

11-kW direct diode laser system with homogenized 55 × 20 mm2 Top-Hat intensity distribution

NASA Astrophysics Data System (ADS)

Köhler, Bernd; Noeske, Axel; Kindervater, Tobias; Wessollek, Armin; Brand, Thomas; Biesenbach, Jens

2007-02-01

In comparison with other laser systems diode lasers are characterized by a unique overall efficiency, a small footprint and high reliability. However, one major drawback of direct diode laser systems is the inhomogeneous intensity distribution in the far field. Furthermore the output power of current commercially available systems is limited to about 6 kW. We report on a diode laser system with 11 kW output power at a single wavelength of 940 nm aiming for customer specific large area treatment. To the best of our knowledge this is the highest output power reported so far for a direct diode laser system. In addition to the high output power the intensity distribution of the laser beam is homogenized in both axes leading to a 55 x 20 mm2 Top-Hat intensity profile at a working distance of 400 mm. Homogeneity of the intensity distribution is better than 90%. The intensity in the focal plane is 1 kW/cm2. We will present a detailed characterization of the laser system, including measurements of power, power stability and intensity distribution of the homogenized laser beam. In addition we will compare the experimental data with the results of non-sequential raytracing simulations.

A robust low quiescent current power receiver for inductive power transmission in bio implants

NASA Astrophysics Data System (ADS)

Helalian, Hamid; Pasandi, Ghasem; Jafarabadi Ashtiani, Shahin

2017-05-01

In this paper, a robust low quiescent current complementary metal-oxide semiconductor (CMOS) power receiver for wireless power transmission is presented. This power receiver consists of three main parts including rectifier, switch capacitor DC-DC converter and low-dropout regulator (LDO) without output capacitor. The switch capacitor DC-DC converter has variable conversion ratios and synchronous controller that lets the DC-DC converter to switch among five different conversion ratios to prevent output voltage drop and LDO regulator efficiency reduction. For all ranges of output current (0-10 mA), the voltage regulator is compensated and is stable. Voltage regulator stabilisation does not need the off-chip capacitor. In addition, a novel adaptive biasing frequency compensation method for low dropout voltage regulator is proposed in this paper. This method provides essential minimum current for compensation and reduces the quiescent current more effectively. The power receiver was designed in a 180-nm industrial CMOS technology, and the voltage range of the input is from 0.8 to 2 V, while the voltage range of the output is from 1.2 to 1.75 V, with a maximum load current of 10 mA, the unregulated efficiency of 79.2%, and the regulated efficiency of 64.4%.

Development of lasers optimized for pumping Ti:Al2O3 lasers

NASA Technical Reports Server (NTRS)

Rines, Glen A.; Schwarz, Richard A.

1994-01-01

Laboratory demonstrations that were completed included: (1) an all-solid-state, broadly tunable, single-frequency, Ti:Al2O3 master oscillator, and (2) a technique for obtaining 'long' (nominally 100- to 200-ns FWHM) laser pulses from a Q-switched, Nd oscillator at energy levels commensurate with straightforward amplification to the joule level. A diode-laser-pumped, Nd:YLF laser with intracavity SHG was designed, constructed, and evaluated. With this laser greater than 0.9 W of CW, output power at 523.5 nm with 10 W of diode-laser pump power delivered to the Nd:YLF crystal was obtained. With this laser as a pump source, for the first time, to our knowledge, an all solid-state, single frequency, Ti:Al203 laser with sufficient output power to injection seed a high-energy oscillator over a 20-nm bandwidth was demonstrated. The pulsed laser work succeeded in demonstrating pulse-stretching in a Q-switched Nd:YAG oscillator. Pulse energies greater than 50-mJ were obtained in pulses with 100- to 200-ns pulsewidths (FWHM).

All fiber passively mode locked zirconium-based erbium-doped fiber laser

NASA Astrophysics Data System (ADS)

Ahmad, H.; Awang, N. A.; Paul, M. C.; Pal, M.; Latif, A. A.; Harun, S. W.

2012-04-01

All passively mode locked erbium-doped fiber laser with a zirconium host is demonstrated. The fiber laser utilizes the Non-Linear Polarization Rotation (NPR) technique with an inexpensive fiber-based Polarization Beam Splitter (PBS) as the mode-locking element. A 2 m crystalline Zirconia-Yttria-Alumino-silicate fiber doped with erbium ions (Zr-Y-Al-EDF) acts as the gain medium and generates an Amplified Spontaneous Emission (ASE) spectrum from 1500 nm to 1650 nm. The generated mode-locked pulses have a spectrum ranging from 1548 nm to more than 1605 nm, as well as a 3-dB bandwidth of 12 nm. The mode-locked pulse train has an average output power level of 17 mW with a calculated peak power of 1.24 kW and energy per pulse of approximately 730 pJ. The spectrum also exhibits a Signal-to-Noise Ratio (SNR) of 50 dB as well as a repetition rate of 23.2 MHz. The system is very stable and shows little power fluctuation, in addition to being repeatable.

Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

NASA Astrophysics Data System (ADS)

Tawfieq, Mahmoud; Jensen, Ole Bjarlin; Hansen, Anders Kragh; Sumpf, Bernd; Paschke, Katrin; Andersen, Peter E.

2015-03-01

We demonstrate a concept for visible laser sources based on sum-frequency generation of beam combined tapered diode lasers. In this specific case, a 1.7 W sum-frequency generated green laser at 509 nm is obtained, by frequency adding of 6.17 W from a 978 nm tapered diode laser with 8.06 W from a 1063 nm tapered diode laser, inside a periodically poled MgO doped lithium niobate crystal. This corresponds to an optical to optical conversion efficiency of 12.1%. As an example of potential applications, the generated nearly diffraction-limited green light is used for pumping a Ti:sapphire laser, thus demonstrating good beam quality and power stability. The maximum output powers achieved when pumping the Ti:sapphire laser are 226 mW (CW) and 185 mW (mode-locked) at 1.7 W green pump power. The optical spectrum emitted by the mode-locked Ti:sapphire laser shows a spectral width of about 54 nm (FWHM), indicating less than 20 fs pulse width.

Tunable, continuous-wave, ultraviolet source based on intracavity sum-frequency-generation in an optical parametric oscillator using BiB₃O₆.

PubMed

Devi, Kavita; Kumar, S Chaitanya; Ebrahim-Zadeh, M

2013-10-21

We report a continuous-wave (cw) source of tunable radiation across 333-345 nm in the ultraviolet (UV) using bismuth triborate, BiB₃O₆ (BIBO) as the nonlinear gain material. The source is based on internal sum-frequency-generation (SFG) in a cw singly-resonant optical parametric oscillator (OPO) pumped at 532 nm. The compact tunable source employs a 30-mm-long MgO:sPPLT crystal as the OPO gain medium and a 5-mm-long BIBO crystal for intracavity SFG of the signal and pump, providing up to 21.6 mW of UV power at 339.7 nm, with >15 mW over 64% of the SFG tuning range. The cw OPO is also tunable across 1158-1312 nm in the idler, delivering as much as 1.7 W at 1247 nm, with >1W over 65% of the tuning range. The UV output at maximum power exhibits passive power stability better than 3.4% rms and frequency stability of 193 GHz over more than one minute.

Fiber-laser-based, green-pumped, picosecond optical parametric oscillator using fan-out grating PPKTP.

PubMed

Chaitanya Kumar, S; Parsa, S; Ebrahim-Zadeh, M

2016-01-01

We report a stable, Yb-fiber-laser-based, green-pumped, picosecond optical parametric oscillator (OPO) for the near-infrared based on periodically poled potassium titanyl phosphate (PPKTP) nonlinear crystal, using fan-out grating design and operating near room temperature. The OPO is continuously tunable across 726-955 nm in the signal and 1201-1998 nm in the idler, resulting in a total signal plus idler wavelength coverage of 1026 nm by grating tuning at a fixed temperature. The device generates up to 580 mW of average power in the signal at 765 nm and 300 mW in the idler at 1338 nm, with an overall extraction efficiency of up to 52% and a pump depletion >76%. The extracted signal at 765 nm and idler at 1746 nm exhibit excellent passive power stability better than 0.5% and 0.8% rms, respectively, over 1 h with good beam quality in TEM₀₀ mode profile. The output signal pulses have a Gaussian temporal duration of 13.2 ps, with a FWHM spectral bandwidth of 3.4 nm at 79.5 MHz repetition rate. Power scaling limitations of the OPO due to the material properties of PPKTP are studied.

Multipass pumped Nd-based thin-disk lasers: continuous-wave laser operation at 1.06 and 0.9 {mu}m with intracavity frequency doubling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavel, Nicolaie; Luenstedt, Kai; Petermann, Klaus

2007-12-01

The laser performances of the 1.06 {mu}m 4F3/2 --> 4I11/2 four-level transition and of the 0.9 {mu}m 4F3/2 --> I9/24 quasi-three-level transition were investigated using multipass pumped Nd-based media in thin-disk geometry. When pumping at 0.81 {mu}m into the 4F5/2 level, continuous-wave laser operation was obtained with powers in excess of 10 W at 1.06 {mu}m, in the multiwatt region at 0.91 {mu}m in Nd:YVO4 and Nd:GdVO4, and at 0.95 {mu}m in Nd:YAG. Intracavity frequency-doubled Nd:YVO4 thin-disk lasers with output powers of 6.4 W at 532 nm and of 1.6 W at 457 nm were realized at this pumping wavelength.more » The pumping at 0.88 {mu}m, which is directed into the 4F3/2 emitting level, was also employed, and Nd:YVO4 and Nd:GdVO4 thin-disk lasers with {approx}9 W output power at 1.06 {mu}m and visible laser radiation at 0.53 {mu}m with output power in excess of 4 W were realized. Frequency-doubled Nd:vanadate thin-disk lasers with deep blue emission at 0.46 {mu}m were obtained under pumping directly into the 4F3/2 emitting level.« less

Balloonborne lidar experiment

NASA Astrophysics Data System (ADS)

Shepherd, O.; Aurilio, G.; Bucknam, R. D.; Brooke, R. W.; Hurd, A. G.

1980-12-01

The object of this contract was to design a balloonborne lidar experiment capable of performing nightime atmospheric density measurements in the 10 to 40 km altitude domain with a resolution of 100 meters. The payload includes a frequency-tripled Nd:YAG laser with outputs at 353 and 1064 nm, a telescoped receiver with PMT detectors, a command-controlled optical pointing system, and support systems, including thermal control, telemetry, command, and power. Density measurements would be made using the back-scattered 353 nm radiation data with aerosol corrections obtained from 1064 nm radiation scatterings.

Generation of 369.4 nm Radiation by Efficient Doubling of a Diode Laser

NASA Technical Reports Server (NTRS)

Williams, A.; Seidel, D. J.; Maleki, J.

1993-01-01

A resonant cavity second harmonic generation system has been developed to produce 369.4 nm radiation from a 738.8 nm diode laser with 10 mW nominal output power. This system utilizes a polarization technique to lock the cavity to the laser frequency. In this paper we report on an evaluation of the system using a Titanium:Sapphire laser as the input source, and preliminary results with a diode laser source. To our knowledge, this is the deepest uv light ever produced by frequency-doubling a diode laser.

High reliability level on single-mode 980nm-1060 nm diode lasers for telecommunication and industrial applications

NASA Astrophysics Data System (ADS)

Van de Casteele, J.; Bettiati, M.; Laruelle, F.; Cargemel, V.; Pagnod-Rossiaux, P.; Garabedian, P.; Raymond, L.; Laffitte, D.; Fromy, S.; Chambonnet, D.; Hirtz, J. P.

2008-02-01

We demonstrate very high reliability level on 980-1060nm high-power single-mode lasers through multi-cell tests. First, we show how our chip design and technology enables high reliability levels. Then, we aged 758 devices during 9500 hours among 6 cells with high current (0.8A-1.2A) and high submount temperature (65°C-105°C) for the reliability demonstration. Sudden catastrophic failure is the main degradation mechanism observed. A statistical failure rate model gives an Arrhenius thermal activation energy of 0.51eV and a power law forward current acceleration factor of 5.9. For high-power submarine applications (360mW pump module output optical power), this model exhibits a failure rate as low as 9 FIT at 13°C, while ultra-high power terrestrial modules (600mW) lie below 220 FIT at 25°C. Wear-out phenomena is observed only for very high current level without any reliability impact under 1.1A. For the 1060nm chip, step-stress tests were performed and a set of devices were aged during more than 2000 hours in different stress conditions. First results are in accordance with 980nm product with more than 100khours estimated MTTF. These reliability and performance features of 980-1060nm laser diodes will make high-power single-mode emitters the best choice for a number of telecommunication and industrial applications in the next few years.

Characterization of light-control-light system using graphene oxide coated optical waveguide

NASA Astrophysics Data System (ADS)

Ahmad, Harith; Soltani, Soroush; Faizal Ismail, Mohammad; Thambiratnam, Kavintheran; Yi, Chong Wu; Yasin, Moh

2018-07-01

An optical waveguide was coated with graphene oxide (GO) using the drop-casting technique to increase the interaction between the waveguide’s evanescent field and the GO layer. Subsequently, a 1550 nm tunable laser source and 980 nm pump laser is used to study the potential of the GO-film to control the flow of light through the waveguide by altering the state of the waveguide between transparent (ON) and opaque (OFF). The GO layer has a thickness of 0.40 µm and allows a 1550 nm signal with a peak power of  ‑7.0 dBm and average output power of 0 dBm to pass through at a maximum pump power of 60 mW. The waveguide has a responsivity of ~0.1 dB mW‑1, with the time to switch between the ON and OFF states being about 3 ms.

Temperature evolution on human teeth root surface after diode laser assisted endodontic treatment.

PubMed

Gutknecht, Norbert; Franzen, Rene; Meister, Jörg; Vanweersch, Leon; Mir, Maziar

2005-09-01

The thermal rise threshold of an 810-nm semi-conductor diode laser on the root surface when used in root canals in vitro for laser assisted root canal treatment is investigated in this study. A total of 50 human single-rooted extracted teeth were included. For this study, the canals were enlarged up to an apical size of ISO#50 file. Laser irradiation was performed with six different settings. Specimens were irradiated at 0.6-1 W output power at the distal end of the fiber and about 1-1.5 W output power in the continuous mode (CW) as two groups. In the third group, 0.6-1 W output power, 10 ms pulse length (PL) and 10 ms interval duration (ID) were selected. In three other groups 1-1.5 W output power were used with different PL and ID as following: PL 10 and ID 10 ms, PL 10 and ID 20 ms and PL 20 and ID 20 ms. The total irradiation time was from 5 to 20 s per canal with a 200 mum in diameter and 25 mm long tip. After laser treatment, the temperature changes at the outer root surface were registered by means of NiCr-Ni measuring sensors and a T 202 thermometer. The safe temperature threshold for applying this diode laser in root canal is considered as 7 degrees C increase. To avoid increasing the temperature changes at the outer root surface related to this threshold, following total irradiation times were found: 0.6-1 W output power (10 ms PL/10 ms ID): 20 s (s), 1-1.5 W output power (10 ms/10 ms and 20 ms/20 ms): 15 s, 0.6-1 W output power CW and 1-1.5 W output power (20 ms PL/10 ms ID): 10 s and 1-1.5 W output power CW: 5 s. In the first three groups, 5 s irradiation and 5 s rest period avoided a temperature increase above the threshold of 7 degrees C).

1.5  kW efficient CW Nd:YAG planar waveguide MOPA laser.

PubMed

Wang, Juntao; Wu, Zhenhai; Su, Hua; Zhou, Tangjian; Lei, Jun; Lv, Wenqiang; He, Jing; Xu, Liu; Chen, Yuejian; Wang, Dan; Tong, Lixin; Hu, Hao; Gao, Qingsong; Tang, Chun

2017-08-15

In this Letter, we report a 1064 nm continuous wave Nd:YAG planar waveguide laser with an output power of 1544 W based on the structure of the master oscillator power amplification. A fiber laser is used as the master oscillator, and diode laser arrays are used as the pump source of the waveguide laser amplifier. The dimension of the waveguide is 1  mm (T)×10  mm (W)×60  mm (L), and the dual end oblique pumping is adopted with different angles. After a single-pass amplification, the power is scaled from 323 to 1544 W with the pump power of 2480 W, leading to an optical-to-optical efficiency of 49%. At the maximum output, the beam quality M 2 are measured to be 2.8 and 7.0 in the guided direction and the unguided direction, respectively. To the best of our knowledge, this is the highest output power of a Nd:YAG planar waveguide laser to date.

12W laser amplification at 1427nm on the 4F 3/2 to 4I 13/2 spectral line in an Nd 3+ doped fused silica optical fiber

DOE PAGES

Dawson, Jay W.; Pax, Paul H.; Allen, Graham S.; ...

2016-12-08

A 9.3dB improvement in optical gain and a 100x improvement in total optical power over prior published experimental results from the 4F 3/2 to 4I 13/2 transition in an Nd 3+ doped fused silica optical fiber is demonstrated. This is enabled via an optical fiber waveguide design that creates high spectral attenuation in the 1050-1120nm-wavelength range, a continuous spectral filter for the primary 4F 3/2 to 4I 11/2 optical transition. A maximum output power at 1427nm of 1.2W was attained for 43mW coupled seed laser power and 22.2W of coupled pump diode laser power at 880nm a net optical gainmore » of 14.5dB. Reducing the coupled seed laser power to 2.5mW enabled the system to attain 19.3dB of gain for 16.5W of coupled pump power. Four issues limited results; non-optimal seed laser wavelength, amplified spontaneous emission on the 4F 3/2 to 4I 9/2 optical transition, low absorption of pump light from the cladding and high spectral attenuation in the 1350-1450nm range. Lastly, future fibers that mitigate these issues should lead to significant improvements in the efficiency of the laser amplifier, though the shorter wavelength region of the transition from 1310nm to >1350nm is still expected to be limited by excited state absorption.« less

12W laser amplification at 1427nm on the 4F 3/2 to 4I 13/2 spectral line in an Nd 3+ doped fused silica optical fiber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dawson, Jay W.; Pax, Paul H.; Allen, Graham S.

A 9.3dB improvement in optical gain and a 100x improvement in total optical power over prior published experimental results from the 4F 3/2 to 4I 13/2 transition in an Nd 3+ doped fused silica optical fiber is demonstrated. This is enabled via an optical fiber waveguide design that creates high spectral attenuation in the 1050-1120nm-wavelength range, a continuous spectral filter for the primary 4F 3/2 to 4I 11/2 optical transition. A maximum output power at 1427nm of 1.2W was attained for 43mW coupled seed laser power and 22.2W of coupled pump diode laser power at 880nm a net optical gainmore » of 14.5dB. Reducing the coupled seed laser power to 2.5mW enabled the system to attain 19.3dB of gain for 16.5W of coupled pump power. Four issues limited results; non-optimal seed laser wavelength, amplified spontaneous emission on the 4F 3/2 to 4I 9/2 optical transition, low absorption of pump light from the cladding and high spectral attenuation in the 1350-1450nm range. Lastly, future fibers that mitigate these issues should lead to significant improvements in the efficiency of the laser amplifier, though the shorter wavelength region of the transition from 1310nm to >1350nm is still expected to be limited by excited state absorption.« less

Resonantly diode-pumped eye-safe Er:YAG laser with fiber-shaped crystal

NASA Astrophysics Data System (ADS)

Němec, Michal; Šulc, Jan; Hlinomaz, Kryštof; Jelínková, Helena; Nejezchleb, Karel; Čech, Miroslav

2018-02-01

Solid-state eye-safe lasers are interesting sources for various applications, such as lidar, remote sensing, and ranging. A resonantly diode-pumped Er:YAG laser could be one of them allowing to reach a tunable laser emission in 1.6 μm spectral region. To overcome low pump absorption and poor pumping beam quality generated by commercially available laser diode, an active medium could be formed to long and thin laser rod guiding pumping radiation. Such an effective cooling during a high power pumping, which is a "crystal-fiber" benefit, may be useful for "standard" crystal active medium. The main goal of this work was to investigate the laser characteristics of new developed Er:YAG crystal with a special shape for diode-pumping. Er:YAG fiber-shape crystal with square cross-section (1x1mm) and 40mm in length was doped by 0.1% Er3+ ions. All sides of this crystal were polished and in addition the end-faces of it were antireflection coatings for the wavelength 1470 and 1645 nm. As a pump system, a fiber coupled laser diode (f = 10 Hz, t = 10 ms) emitting radiation at 1465 nm wavelength was used. Er:YAG fiber-shape crystal was placed onto a copper holder in the 85 mm long plan-concave resonator consisting of a pump flat mirror and output curved (r = 150 mm) coupler with a reflectivity of 96 % @ 1645 nm. The dependence of the output peak power on absorbed pump power was investigated and the maximum 0.8 W was obtained. The corresponding slope efficiency was 14.5 %. The emitting wavelength was equaled to 1645 nm (4 nm linewidth, FWHM). The spatial beam structure was close to the Gaussian mode.

Blue 450nm high power semiconductor continuous wave laser bars exceeding rollover output power of 80W

NASA Astrophysics Data System (ADS)

König, H.; Lell, A.; Stojetz, B.; Ali, M.; Eichler, C.; Peter, M.; Löffler, A.; Strauss, U.; Baumann, M.; Balck, A.; Malchus, J.; Krause, V.

2018-02-01

Industrial material processing like cutting or welding of metals is rather energy efficient using direct diode or diode pumped solid state lasers. However, many applications cannot be addressed by established infrared laser technology due to fundamental material properties of the workpiece: For example materials like copper or gold have too low absorption in the near infrared wavelength range to be processed efficiently by use of existing high power laser systems. The huge interest to enable high power kW systems with more suitable wavelengths in the blue spectral range triggered the German funded research project 'BLAULAS': Therein the feasibility and capability of CW operating high power laser bars based on the GaN material system was investigated by Osram and Laserline. High performance bars were enabled by defeating fundamental challenges like material quality as well as the chip processes, both of which differ significantly from well-known IR laser bars. The research samples were assembled on actively cooled heat sinks with hard solder technology. For the first time an output power of 98W per bar at 60A drive current was achieved. Conversion efficiency as high as 46% at 50W output power was demonstrated.

Power balance on a multibeam laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sampat, Sid; Kelly, John H.; Kosc, Tanya Z.

Inertial confinement fusion (ICF) cryogenic experiments on the 60-beam OMEGA laser have strict requirements for the laser energy delivered on target to be power balanced in order to maximize target-irradiation uniformity. For OMEGA, this quantity (power balance) is inferred from measurements of the time-integrated energy and time-resolved, spatially integrated temporal profile of each of the 60 beams at the output of the laser. The work presented here proposes a general definition of power balance as measured at the laser output and discusses the conditions that are fundamental to achieving laser power balance. Power balance necessitates equal gain across all stagesmore » of amplification, equal net losses across each amplifier stage, equal frequency conversion (from 1053 nm to 351 nm) of all 60 beams, and equal beam path lengths (beam timing). Typical OMEGA ICF laser pulse shapes consist of one or more short (100-ps) “pickets” followed by a shaped “drive” pulse of 1 to 2 ns. For these experiments, power balance is assessed for the pickets and the drive independently, with the ultimate goal of achieving root-mean-square (rms) imbalance across all 60 beams of less than 2% rms on both. Our work presents a comprehensive summary of laser shot campaigns conducted to significantly improve laser power balance from typical rms values of 4.7% and 5.2%, respectively, to the 3% level for both features along with a discussion of future work required to further reduce the rms power imbalance of the laser system.« less

Power balance on a multibeam laser

NASA Astrophysics Data System (ADS)

Sampat, S.; Kelly, J. H.; Kosc, T. Z.; Rigatti, A. L.; Kwiatkowski, J.; Donaldson, W. R.; Romanofsky, M. H.; Waxer, L. J.; Dean, R.; Moshier, R.

2018-02-01

Inertial confinement fusion (ICF) cryogenic experiments on the 60-beam OMEGA laser have strict requirements for the laser energy delivered on target to be power balanced in order to maximize target-irradiation uniformity. For OMEGA, this quantity (power balance) is inferred from measurements of the time-integrated energy and time-resolved, spatially integrated temporal profile of each of the 60 beams at the output of the laser. The work presented here proposes a general definition of power balance as measured at the laser output and discusses the conditions that are fundamental to achieving laser power balance. Power balance necessitates equal gain across all stages of amplification, equal net losses across each amplifier stage, equal frequency conversion (from 1053 nm to 351 nm) of all 60 beams, and equal beam path lengths (beam timing). Typical OMEGA ICF laser pulse shapes consist of one or more short (100-ps) "pickets" followed by a shaped "drive" pulse of 1 to 2 ns. For these experiments, power balance is assessed for the pickets and the drive independently, with the ultimate goal of achieving root-mean-square (rms) imbalance across all 60 beams of less than 2% rms on both. This work presents a comprehensive summary of laser shot campaigns conducted to significantly improve laser power balance from typical rms values of 4.7% and 5.2%, respectively, to the 3% level for both features along with a discussion of future work required to further reduce the rms power imbalance of the laser system.

Power balance on a multibeam laser

DOE PAGES

Sampat, Sid; Kelly, John H.; Kosc, Tanya Z.; ...

2018-02-15

Inertial confinement fusion (ICF) cryogenic experiments on the 60-beam OMEGA laser have strict requirements for the laser energy delivered on target to be power balanced in order to maximize target-irradiation uniformity. For OMEGA, this quantity (power balance) is inferred from measurements of the time-integrated energy and time-resolved, spatially integrated temporal profile of each of the 60 beams at the output of the laser. The work presented here proposes a general definition of power balance as measured at the laser output and discusses the conditions that are fundamental to achieving laser power balance. Power balance necessitates equal gain across all stagesmore » of amplification, equal net losses across each amplifier stage, equal frequency conversion (from 1053 nm to 351 nm) of all 60 beams, and equal beam path lengths (beam timing). Typical OMEGA ICF laser pulse shapes consist of one or more short (100-ps) “pickets” followed by a shaped “drive” pulse of 1 to 2 ns. For these experiments, power balance is assessed for the pickets and the drive independently, with the ultimate goal of achieving root-mean-square (rms) imbalance across all 60 beams of less than 2% rms on both. Our work presents a comprehensive summary of laser shot campaigns conducted to significantly improve laser power balance from typical rms values of 4.7% and 5.2%, respectively, to the 3% level for both features along with a discussion of future work required to further reduce the rms power imbalance of the laser system.« less

Nonlinear frequency conversion of radiation from a copper-vapor laser

NASA Astrophysics Data System (ADS)

Polunin, Iu. P.; Troitskii, V. O.

1987-11-01

The nonlinear frequency conversion of copper-vapor laser radiation in a KDP crystal was studied experimentally. Output powers of 600 mW and 120 mW were obtained at wavelengths of 271 nm (the sum frequency) and 289 nm (the second harmonic of the yellow line), respectively. The conversion efficiency in both cases was about 3 percent; when selector losses were taken into accounted, the efficiency amounted to 5 percent.

Generation of high-power subpicosecond pulses at 155 nm.

PubMed

Mossavi, K; Fricke, L; Liu, P; Wellegehausen, B

1995-06-15

Subpicosecond vacuum-ultraviolet radiation at 155 nm with pulse energies above 0.2 mJ has been obtained by near-resonant four-wave difference-frequency mixing in a Xe gas jet. Laser fields for the mixing process have been generated by a short-pulse KrF dye excimer laser system and a Raman converter. The process permits tuning in a broad vacuum-ultraviolet range and can be scaled up to higher output energies.

High energy supercontinuum sources using tapered photonic crystal fibers for multispectral photoacoustic microscopy.

PubMed

Bondu, Magalie; Brooks, Christopher; Jakobsen, Christian; Oakes, Keith; Moselund, Peter Morten; Leick, Lasse; Bang, Ole; Podoleanu, Adrian

2016-06-01

We demonstrate a record bandwidth high energy supercontinuum source suitable for multispectral photoacoustic microscopy. The source has more than 150  nJ/10  nm bandwidth over a spectral range of 500 to 1600 nm. This performance is achieved using a carefully designed fiber taper with large-core input for improved power handling and small-core output that provides the desired spectral range of the supercontinuum source.

Design of micro-second pulsed laser mode for ophthalmological CW self-raman laser

NASA Astrophysics Data System (ADS)

Mota, Alessandro D.; Rossi, Giuliano; Ortega, Tiago A.; Costal, Glauco Z.; Fontes, Yuri C.; Yasuoka, Fatima M. M.; Stefani, Mario A.; de Castro N., Jarbas C.; Paiva, Maria S. V.

2011-02-01

This work presents the mechanisms adopted for the design of micro-second pulsed laser mode for a CW Self-Raman laser cavity in 586nm and 4W output power. The new technique for retina disease treatment discharges laser pulses on the retina tissue, in laser sequences of 200 μs pulse duration at each 2ms. This operation mode requires the laser to discharge fast electric pulses, making the system control velocity of the electronic system cavity vital. The control procedures to keep the laser output power stable and the laser head behavior in micro-second pulse mode are presented.

5  W output power from a double-clad hybrid fiber with Yb-doped phosphate core and silicate cladding.

PubMed

Wang, Longfei; He, Dongbing; Zhang, Lei; Yu, Chunlei; Feng, Suya; Wang, Meng; Chen, Danping; Hu, Lili

2017-08-01

For the first time, to the best of our knowledge, we report on the realization of a laser from a Yb-doped phosphate core/silicate cladding double-clad hybrid fiber. 5 W output power was extracted with 14.6% slope efficiency and a laser spectrum of a 1027 nm central wavelength from a 20 cm long single-mode fiber with a ∼10  μm core diameter in a 20%-4% laser cavity. The laser efficiency can be significantly enhanced by correspondingly adjusting and optimizing the laser oscillator.

Optimized design and performance of a shared pump single clad 2 μm TDFA

NASA Astrophysics Data System (ADS)

Tench, Robert E.; Romano, Clément; Delavaux, Jean-Marc

2018-05-01

We report the design, experimental performance, and simulation of a single stage, co- and counter-pumped Tm-doped fiber amplifier (TDFA) in the 2 μm signal wavelength band with an optimized 1567 nm shared pump source. We investigate the dependence of output power, gain, and efficiency on pump coupling ratio and signal wavelength. Small signal gains of >50 dB, an output power of 2 W, and small signal noise figures of <3.5 dB are demonstrated. Simulations of TDFA performance agree well with the experimental data. We also discuss performance tradeoffs with respect to amplifier topology for this simple and efficient TDFA.

1.9 W continuous-wave single transverse mode emission from 1060 nm edge-emitting lasers with vertically extended lasing area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miah, M. J., E-mail: jarez.miah@tu-berlin.de; Posilovic, K.; Kalosha, V. P.

2014-10-13

High-brightness edge-emitting semiconductor lasers having a vertically extended waveguide structure emitting in the 1060 nm range are investigated. Ridge waveguide (RW) lasers with 9 μm stripe width and 2.64 mm cavity length yield highest to date single transverse mode output power for RW lasers in the 1060 nm range. The lasers provide 1.9 W single transverse mode optical power under continuous-wave (cw) operation with narrow beam divergences of 9° in lateral and 14° (full width at half maximum) in vertical direction. The beam quality factor M{sup 2} is less than 1.9 up to 1.9 W optical power. A maximum brightness of 72 MWcm{sup −2}sr{supmore » −1} is obtained. 100 μm wide and 3 mm long unpassivated broad area lasers provide more than 9 W optical power in cw operation.« less

Stable and wavelength-tunable silicon-micro-ring-resonator based erbium-doped fiber laser.

PubMed

Yang, L G; Yeh, C H; Wong, C Y; Chow, C W; Tseng, F G; Tsang, H K

2013-02-11

In this work, we propose and demonstrate a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser. Here, a silicon-on-insulator (SOI)-based silicon-micro-ring-resonator (SMRR) is used as the wavelength selective element inside the fiber ring cavity. A uniform period grating coupler (GC) is used to couple between the SMRR and single mode fiber (SMF) and serves also as a polarization dependent element in the cavity. The output lasing wavelength of the proposed fiber laser can be tuned at a tuning step of 2 nm (defined by the free spectral range (FSR) of the SMRR) in a bandwidth of 35.2 nm (1532.00 to 1567.20 nm), which is defined by the gain of the EDF. The optical-signal-to-noise-ratio (OSNR) of each lasing wavelength is larger than 42.0 dB. In addition, the output stabilities of power and wavelength are also discussed.

Extreme triple asymmetric (ETAS) epitaxial designs for increased efficiency at high powers in 9xx-nm diode lasers

NASA Astrophysics Data System (ADS)

Kaul, T.; Erbert, G.; Maaßdorf, A.; Martin, D.; Crump, P.

2018-02-01

Broad area lasers that are tailored to be most efficient at the highest achievable optical output power are sought by industry to decrease operation costs and improve system performance. Devices using Extreme-Double-ASymmetric (EDAS) epitaxial designs are promising candidates for improved efficiency at high optical output powers due to low series resistance, low optical loss and low carrier leakage. However, EDAS designs leverage ultra-thin p-side waveguides, meaning that the optical mode is shifted into the n-side waveguide, resulting in a low optical confinement in the active region, low gain and hence high threshold current, limiting peak performance. We introduce here explicit design considerations that enable EDAS-based devices to be developed with increased optical confinement in the active layer without changing the p-side layer thicknesses. Specifically, this is realized by introducing a third asymmetric component in the vicinity of the quantum well. We call this approach Extreme-Triple-ASymmetric (ETAS) design. A series of ETAS-based vertical designs were fabricated into broad area lasers that deliver up to 63% power conversion efficiency at 14 W CW optical output power from a 100 μm stripe laser, which corresponds to the operation point of a kW optical output power in a laser bar. The design process, the impact of structural changes on power saturation mechanisms and finally devices with improved performance will be presented.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji Wang; Yunjun Zhang; Aotuo Dong

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 energymore » 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)« less

High-power, high-repetition-rate performance characteristics of β-BaB₂O₄ for single-pass picosecond ultraviolet generation at 266 nm.

PubMed

Kumar, S Chaitanya; Casals, J Canals; Wei, Junxiong; Ebrahim-Zadeh, M

2015-10-19

We report a systematic study on the performance characteristics of a high-power, high-repetition-rate, picosecond ultraviolet (UV) source at 266 nm based on β-BaB2O4 (BBO). The source, based on single-pass fourth harmonic generation (FHG) of a compact Yb-fiber laser in a two-crystal spatial walk-off compensation scheme, generates up to 2.9 W of average power at 266 nm at a pulse repetition rate of ~80 MHz with a single-pass FHG efficiency of 35% from the green to UV. Detrimental issues such as thermal effects have been studied and confirmed by performing relevant measurements. Angular and temperature acceptance bandwidths in BBO for FHG to 266 nm are experimentally determined, indicating that the effective interaction length is limited by spatial walk-off and thermal gradients under high-power operation. The origin of dynamic color center formation due to two-photon absorption in BBO is investigated by measurements of intensity-dependent transmission at 266 nm. Using a suitable theoretical model, two-photon absorption coefficients as well as the color center densities have been estimated at different temperatures. The measurements show that the two-photon absorption coefficient in BBO at 266 nm is ~3.5 times lower at 200°C compared to that at room temperature. The long-term power stability as well as beam pointing stability is analyzed at different output power levels and focusing conditions. Using cylindrical optics, we have circularized the generated elliptic UV beam to a circularity of >90%. To our knowledge, this is the first time such high average powers and temperature-dependent two-photon absorption measurements at 266 nm are reported at repetition rates as high as ~80 MHz.

Ultrafast Airy beam optical parametric oscillator

PubMed Central

Apurv Chaitanya, N.; Kumar, S. Chaitanya; Aadhi, A.; Samanta, G. K.; Ebrahim-Zadeh, M.

2016-01-01

We report on the first realization of an ultrafast Airy beam optical parametric oscillator (OPO). By introducing intracavity cubic phase modulation to the resonant Gaussian signal in a synchronously-pumped singly-resonant OPO cavity and its subsequent Fourier transformation, we have generated 2-dimensional Airy beam in the output signal across a 250 nm tuning range in the near-infrared. The generated Airy beam can be tuned continuously from 1477 to 1727 nm, providing an average power of as much as 306 mW at 1632 nm in pulses of ~23 ps duration with a spectral bandwidth of 1.7 nm. PMID:27476910

One joule output from a diode-array-pumped Nd:YAG laser with side-pumped rod geometry

NASA Technical Reports Server (NTRS)

Kasinski, Jeffrey J.; Hughes, Will; Dibiase, Don; Bournes, Patrick; Burnham, Ralph

1992-01-01

Output of 1.25 J per pulse (1.064 micron) with an absolute optical efficiency of 28 percent and corresponding electrical efficiency of 10 percent was demonstrated in a diode-array-pumped Nd:YAG laser using a side-pumped rod geometry in a master-oscillator/power-amplifier configuration. In Q-switched operation, an output of 0.75 J in a 17-ns pulse was obtained. The fundamental laser output was frequency doubled in KTP with 60 percent conversion efficiency to obtain 0.45 J in a 16-ns pulse at 532 nm. The output beam had high spatial quality with pointing stability better than 40 microrad and a shot-to-shot pulse energy fluctuation of less than +/-3 percent.

High-power and highly efficient diode-cladding-pumped Ho3+-doped silica fiber lasers.

PubMed

Jackson, Stuart D; Bugge, Frank; Erbert, Götz

2007-11-15

We demonstrate high-power operation from a singly Ho3+-doped silica fiber laser that is cladding pumped directly with diode lasers operating at 1150 nm. Internal slope efficiencies approaching the Stokes limit were produced, and the maximum output power was 2.2W. This result was achieved using a low Ho3+-ion concentration and La3+-ion codoping, which together limit the transfer of energy between excited Ho3+ ions.

Metasurface-assisted orbital angular momentum carrying Bessel-Gaussian Laser: proposal and simulation.

PubMed

Zhou, Nan; Wang, Jian

2018-05-23

Bessel-Gaussian beams have distinct properties of suppressed diffraction divergence and self-reconstruction. In this paper, we propose and simulate metasurface-assisted orbital angular momentum (OAM) carrying Bessel-Gaussian laser. The laser can be regarded as a Fabry-Perot cavity formed by one partially transparent output plane mirror and the other metasurface-based reflector mirror. The gain medium of Nd:YVO 4 enables the lasing wavelength at 1064 nm with a 808 nm laser serving as the pump. The sub-wavelength structure of metasurface facilitates flexible spatial light manipulation. The compact metasurface-based reflector provides combined phase functions of an axicon and a spherical mirror. By appropriately selecting the size of output mirror and inserting mode-selection element in the laser cavity, different orders of OAM-carrying Bessel-Gaussian lasing modes are achievable. The lasing Bessel-Gaussian 0 , Bessel-Gaussian 01 + , Bessel-Gaussian 02 + and Bessel-Gaussian 03 + modes have high fidelities of ~0.889, ~0.889, ~0.881 and ~0.879, respectively. The metasurface fabrication tolerance and the dependence of threshold power and output lasing power on the length of gain medium, beam radius of pump and transmittance of output mirror are also discussed. The obtained results show successful implementation of metasurface-assisted OAM-carrying Bessel-Gaussian laser with favorable performance. The metasurface-assisted OAM-carrying Bessel-Gaussian laser may find wide OAM-enabled communication and non-communication applications.

Tunable triple-wavelength mode-locked fiber laser with topological insulator Bi2Se3 solution

NASA Astrophysics Data System (ADS)

Guo, Bo; Yao, Yong

2016-08-01

We experimentally demonstrated a tunable triple-wavelength mode-locked erbium-doped fiber laser with few-layer topological insulator: Bi2Se3/polyvinyl alcohol solution. By properly adjusting the pump power and the polarization state, the single-, dual-, and triple-wavelength mode-locking operation could be stably initiated with a wavelength-tunable range (˜1 nm) and a variable wavelength spacing (1.7 or 2 nm). Meanwhile, it exhibits the maximum output power of 10 mW and pulse energy of 1.12 nJ at the pump power of 175 mW. The simple, low-cost triple-wavelength mode-locked fiber laser might be applied in various potential fields, such as optical communication, biomedical research, and sensing system.

MoS2-based passively Q-switched diode-pumped Nd:YAG laser at 946 nm

NASA Astrophysics Data System (ADS)

Lin, Haifeng; Zhu, Wenzhang.; Xiong, Feibing; Cai, Lie

2017-06-01

We demonstrate a passively Q-switched Nd: YAG quasi-three-level laser operating at 946 nm using MoS2 as saturable absorber. A maximum average output power of 210 mW is achieved at an absorbed pump power of 6.67 W with a slope efficiency of about 5.8%. The shortest pulse width and maximum pulse repetition frequency are measured to be 280 ns and 609 kHz, respectively. The maximum pulse energy and maximum pulse peak power are therefore estimated to be about 0.35 μJ and 1.23 W, respectively. This work represents the first MoS2-based Q-switched laser operating at 0.9 μm spectral region.

Passively Q-switched Tm:BaY2F8 lasers

NASA Astrophysics Data System (ADS)

Yu, Haohai; Veronesi, Stefano; Mateos, Xavier; Petrov, Valentin; Griebner, Uwe; Parisi, Daniela; Tonelli, Mauro

2013-07-01

We demonstrate passive Q-switching (PQS) of the Tm-doped BaY2F8 (Tm:BYF) laser for the first time. The Tm:BYF laser is diode-pumped using an L-shaped hemispherical resonator. In the cw regime, the maximum output power with an 18% Tm-doped BYF crystal reached 1.12 W at ~1920 nm for an absorbed pump power of 3.06 W. In the PQS regime, maximum pulse energy (720 μJ) and peak power (17.1 kW) were obtained with an 8% Tm-doped BYF crystal and a Cr:ZnS saturable absorber with 92% low-signal transmission, again near 1920 nm, for a pulse width of ~40 ns and a repetition rate of 50 Hz.

Electroabsorption-modulated widely tunable DBR laser transmitter for WDM-PONs.

PubMed

Han, Liangshun; Liang, Song; Wang, Huitao; Qiao, Lijun; Xu, Junjie; Zhao, Lingjuan; Zhu, Hongliang; Wang, Baojun; Wang, Wei

2014-12-01

We present an InP based distributed Bragg reflector (DBR) laser transmitter which has a wide wavelength tuning range and a high chip output power for wavelength division multiplexing passive optical network (WDM-PON) applications. By butt-jointing InGaAsP with 1.45 µm emission wavelength as the material of the grating section, the laser wavelength can be tuned for over 13 nm by the DBR current. Accompanied by varying the chip temperature, the tuning range can be further enlarged to 16 nm. With the help of the integrated semiconductor optical amplifier (SOA), the largest chip output power is over 30 mW. The electroabsorption modulator (EAM) is integrated into the device by the selective-area growth (SAG) technique. The 3 dB small signal modulation bandwidth of the EAM is over 13 GHz. The device has both a simple tuning scheme and a simple fabrication procedure, making it suitable for low cost massive production which is desirable for WDM-PON uses.

Ca3La2(BO3)4 crystal: a new candidate host material for the ytterbium ion

NASA Astrophysics Data System (ADS)

Wang, Yeqing; You, Zhenyu; Zhu, Zhaojie; Xu, Jinlong; Li, Jianfu; Wang, Yan; Wang, Hongyan; Tu, Chaoyang

2013-10-01

A disordered laser crystal Yb3+-doped Ca3La2(BO3)4 crystal was grown by the Czochralski technique. The characterized room temperature polarized spectra, re-absorption possibility and laser performance showed that this crystal should be a promising gain material, not only suitable for diode pumping, but also a good candidate for the generation of tunable and short pulse lasers. End pumped by a diode laser at 976 nm in plano-concave and plano-plano cavity, a 3.65 W output power with a slope efficiency of 65% was achieved by using a c-cut Yb3+:Ca3La2(BO3)4 crystal. The output laser wavelength shifted from 1042 to 1062 nm.

Graphene mode-lockers for fiber lasers functioned with evanescent field interaction

NASA Astrophysics Data System (ADS)

Song, Yong-Won; Jang, Sung-Yeon; Han, Won-Suk; Bae, Mi-Kyung

2010-02-01

Employing graphene as an intracavity passive power modulating element, we demonstrate the efficient laser pulsation in high pulse-energy regime with evanescent field interaction between the propagating light and graphene layer. Graphene is prepared by the solution based reduction of graphene oxide, and dispersed homogeneously into the water for spray onto an all-fiber substrate, side-polished fiber. With the intracavity power up to 21.41 dBm, we ensure the robust high-energy operation without any thermal damage of graphene. Resultant output pulses have center wavelength, spectral width, and repetition rate of 1561.6 nm, 1.96 nm, and 6.99 MHz, respectively.

Managing SRS competition in a miniature visible Nd:YVO4/BaWO4 Raman laser.

PubMed

Li, Xiaoli; Lee, Andrew J; Huo, Yujing; Zhang, Huaijin; Wang, Jiyang; Piper, James A; Pask, Helen M; Spence, David J

2012-08-13

We demonstrate the operation of a compact and efficient continuous wave (CW) self-Raman laser utilizing a Nd:YVO4 gain crystal and BaWO4 Raman crystal, generating yellow emission at 590 nm. We investigate the competition that occurs between Stokes lines in the Nd:YVO4 and BaWO4 crystals, and within the BaWO4 crystal itself. Through careful consideration of crystal length and orientation, we are able to suppress competition between Stokes lines, and generate pure yellow emission at 590 nm with output power of 194 mW for just 3.8 W pump power.

Comparison of tunable lasers based on diode pumped Tm-doped crystals

NASA Astrophysics Data System (ADS)

Šulc, Jan; Jelínková, Helena; Koranda, Petr; Černý, Pavel; Jabczyński, Jan K.; Żendzian, Waldemar; Kwiatkowski, Jacek; Urata, Yoshiharu; Higuchi, Mikio

2008-12-01

We report on continuously tunable operation of a diode pumped lasers based on Tm-doped materials, emitting in the 1.8 - 2.μ1 m spectral band. In our study we compare results obtained with three various single crystals doped by Tm3+ ions: Yttrium Aluminum perovskite YAP (YAlO3), Gadolinium orthovanadate GdVO4, and Yttrium Lithium Fluoride YLF (YLiF4). Following samples were available: the 3mm long a-cut crystal rod of Tm:YAP with 4% at. Tm/Y (diameter 3 mm); the 8mm long b-cut crystal rod of Tm:YLF with 3.5% at. Tm/Y (diameter 3 mm); the 2.7mm long a-cut crystal block of Tm:GdVO4 with 2% at. Tm/Gd (crystal face 5×3 mm). For active medium pumping, the laser diode radiation was used. Because the tested samples differs significantly in absorption spectra, two fibre-coupled (core diameter 400 µm) temperature-tuned laser diodes were used: first operating at wavelength 793nm was used for Tm:YAP and Tm:YLF; the second operating at wavelength 802nm was used for Tm:GdVO4. In both cases, the continuous power up to 20W was available for pumping. The diode radiation was focused into the active crystal by two achromatic doublet lenses with the focal length f = 75 mm. The measured radius of pumping beam focus inside the crystal was 260 µm. The longitudinally diode pumped crystals were tested in linear, 80mm long, hemispherical laser cavity. The curved (radius 150mm) output coupler reflectivity was ~ 97 % in range from 1.8 up to 2.1 μm. The pumping flat mirror had maximal reflectivity in this range and it had high transmission around 0.8 μm. A 1.5mm thick birefringent plate made from quartz (Lyot filter) inserted under a Brewster's angle was used as a tuning element. This plate was placed inside the resonator between the crystal and the output coupler. Using Tm:YAP crystal, the maximal output power of 2.8W in this set-up was obtained. The laser could be tuned from 1865nm up to 2036nm with a maximum at 1985 nm. Laser based on Tm:YLF crystal was tunable from 1835nm up to 2010nm with a maximum at 1928 nm (3.0W was reached). Using the Tm:GdVO4 tunable operation with greater that 1W output at 1920nm and 130nm tuning range (1842-1972 nm) was demonstrated. The overall reached tuning range of over 200nm covers many important atmospheric absorption lines and contains also the local absorption peak of liquid water, making them attractive for applications such as high resolution spectroscopy, atmospheric remote sensing, laser radar, and laser microsurgery.

Comparative study of high power Tm:YLF and Tm:LLF slab lasers in continuous wave regime.

PubMed

Berrou, Antoine; Collett, Oliver J P; Morris, Daniel; Esser, M J Daniel

2018-04-16

We report on Tm:YLF and Tm:LLF slab lasers (1.5 x 11 x 20 mm 3 ) end pumped from one end with a high-brightness 792 nm laser diode stack. These two lasers are compared under identical pump conditions in continuous-wave regime. A stronger negative thermal lens in Tm:LLF than in Tm:YLF is highlighted, making it more difficult to operate the Tm:LLF laser under stable lasing conditions. In a configuration where the high reflectivity cavity mirror has a radius of curvature of r = 150 mm, the Tm:YLF (Tm:LLF) laser produces a maximum output power of 150 W (143 W) for 428 W of incident pump power (respectively). For a second cavity configuration where the high reflectivity cavity mirror has a radius of curvature of r = 500 mm, the Tm:YLF laser produces a maximum output power of 164 W for 412 W of incident pump power and a 57% slope efficiency with respect to the absorbed pump power. The emitted wavelength of these two lasers are measured as a function of the output coupler reflectivity and it shows that Tm:LLF laser emits at a longer wavelength than Tm:YLF.

Ultra-long fiber Raman lasers: design considerations

NASA Astrophysics Data System (ADS)

Koltchanov, I.; Kroushkov, D. I.; Richter, A.

2015-03-01

In frame of the European Marie Currie project GRIFFON [http://astonishgriffon.net/] the usage of a green approach in terms of reduced power consumption and maintenance costs is envisioned for long-span fiber networks. This shall be accomplished by coherent transmission in unrepeatered links (100 km - 350 km) utilizing ultra-long Raman fiber laser (URFL)-based distributed amplification, multi-level modulation formats, and adapted Digital Signal Processing (DSP) algorithms. The URFL uses a cascaded 2-order pumping scheme where two (co- and counter-) ˜ 1365 nm pumps illuminate the fiber. The URFL oscillates at ˜ 1450 nm whereas amplification is provided by stimulated Raman scattering (SRS) of the ˜ 1365 nm pumps and the optical feedback is realized by two Fiber Bragg gratings (FBGs) at the fiber ends reflecting at 1450 nm. The light field at 1450 nm provides amplification for signal waves in the 1550 nm range due to SRS. In this work we present URFL design studies intended to characterize and optimize the power and noise characteristics of the fiber links. We use a bidirectional fiber model describing propagation of the signal, pump and noise powers along the fiber length. From the numerical solution we evaluate the on/off Raman gain and its bandwidth, the signal excursion over the fiber length, OSNR spectra, and the accumulated nonlinearities. To achieve best performance for these characteristics the laser design is optimized with respect to the forward/backward pump powers and wavelengths, input/output signal powers, reflectivity profile of the FBGs and other parameters.

Normal dispersion femtosecond fiber optical parametric oscillator.

PubMed

Nguyen, T N; Kieu, K; Maslov, A V; Miyawaki, M; Peyghambarian, N

2013-09-15

We propose and demonstrate a synchronously pumped fiber optical parametric oscillator (FOPO) operating in the normal dispersion regime. The FOPO generates chirped pulses at the output, allowing significant pulse energy scaling potential without pulse breaking. The output average power of the FOPO at 1600 nm was ∼60  mW (corresponding to 1.45 nJ pulse energy and ∼55% slope power conversion efficiency). The output pulses directly from the FOPO were highly chirped (∼3  ps duration), and they could be compressed outside of the cavity to 180 fs by using a standard optical fiber compressor. Detailed numerical simulation was also performed to understand the pulse evolution dynamics around the laser cavity. We believe that the proposed design concept is useful for scaling up the pulse energy in the FOPO using different pumping wavelengths.

Low-Power and High-Speed Technique for logic Gates in 20nm Double-Gate FinFET Technology

NASA Astrophysics Data System (ADS)

Priydarshi, A.; Chattopadhyay, M. K.

2016-10-01

The FinFET is the leading example of multigate MOSFETS to substitute conventional single gate MOSFETs for ultimate scaling [1], The FinFET structure is a combination of a thin channel region and a double gate to suppress the short channel effects (SCEs) and Vthvariation [2], By using FinFET,figure of merits viz, ION, IOFF, output resistance, propagation delay, noise margin and leakage power, can be improved for ultra low power and high performance applications[3]. In this paper, a new high speed low power dynamic circuit design technique has been proposed using 20nm FinFETs. By applying the appropriate clock and sleep signal to the back gates of the FinFETs, the proposed circuit can efficiently control the dynamic power, During the pre-charging period, Vth of PMOS is controlled low so that a fast precharging can occur;

Highly efficient X-range AlGaN/GaN power amplifier

NASA Astrophysics Data System (ADS)

Tural'chuk, P. A.; Kirillov, V. V.; Osipov, P. E.; Vendik, I. B.; Vendik, O. G.; Parnes, M. D.

2017-09-01

The development of microwave power amplifiers (PAs) based on transistors with an AlGaN/GaN heterojunction are discussed in terms of the possible enhancement of their efficiency. The main focus is on the synthesis of the transforming circuits, which ensure the reactive load at the second- and third-harmonic frequencies and complex impedance at the fundamental frequency. This makes it possible to optimize the complex operation mode of a PA; i.e., to reduce the scattering power and enhance the efficiency. A microwave PA based on the Schottky-barrier-gate field-effect transistor with 80 electrodes based on the GaN pHEMT transistor with a gate length of 0.25 nm and a gate width of 125 nm is experimentally investigated. The amplifier has a pulse output power of 35 W and a power-added efficiency of at least 50% at a working frequency of 9 GHz.

Design considerations of 10 kW-scale extreme ultraviolet SASE FEL for lithography

NASA Astrophysics Data System (ADS)

Pagani, C.; Saldin, E. L.; Schneidmiller, E. A.; Yurkov, M. V.

2001-05-01

The semiconductor industry growth is driven to a large extent by steady advancements in microlithography. According to the newly updated industry roadmap, the 70 nm generation is anticipated to be available in the year 2008. However, the path to get there is not obvious. The problem of construction of Extreme Ultraviolet (EUV) quantum laser for lithography is still unsolved: progress in this field is rather moderate and we cannot expect a significant break through in the near future. Nevertheless, there is clear path for optical lithography to take us to sub- 100 nm dimensions. Theoretical and experimental work in free electron laser (FEL) and accelerator physics and technology over the last 10 years has pointed to the possibility of generation of high-power optical beams with laser-like characteristics in the EUV spectral range. Recently, there have been important advances in demonstrating a high-gain self-amplified spontaneous emission (SASE) FEL at 100 nm wavelength (Andruszkov et al., Phys. Rev. Lett. 85 (2000), 3825). In the SASE FEL powerful, coherent radiation is produced by the electron beam during single-pass of the undulator, thus there are no apparent limitations which would prevent operation at very short wavelength range and to increase the average output power of this device up to 10 kW level. The use of superconducting energy-recovery linac could produce a major, cost-effective facility with wall plug power to output optical power efficiency of about 1%. A 10-kW-scale transversely coherent radiation source with narrow bandwidth (0.5%) and variable wavelength could be an excellent tool for manufacturing computer chips with the minimum feature size below 100 nm. All components of the proposed SASE FEL equipment (injector, driver accelerator structure, energy-recovery system, undulator, etc.) have been demonstrated in practice. This is guaranteed success in the time schedule requirement.

Efficient Single-Frequency Thulium Doped Fiber Laser Near 2-micrometers

NASA Technical Reports Server (NTRS)

Geng, Jihong; Wu, Jianfeng; Jiang, Shibin; Yu, Jirong

2007-01-01

We demonstrate highly efficient diode-pumped single-frequency fiber laser with 35% slope efficiency and 50mW output power operating near 2 micrometers, which generated from a 2-cm long piece of highly Tm(3+)-doped germanate glass fiber pumped at 800nm.

Comparative experimental and simulation studies of high-power AlGaN-based 353 nm ultraviolet flip-chip and top-emitting LEDs

NASA Astrophysics Data System (ADS)

Liu, Mengling; Zhou, Shengjun; Liu, Xingtong; Gao, Yilin; Ding, Xinghuo

2018-03-01

Experimental and simulation studies of high-power AlGaN-based 353 nm ultraviolet (UV) flip-chip (FC) and top-emitting (TE) light-emitting diodes (LEDs) are performed here. To improve the optical and electrical properties of ultraviolet LEDs, we fabricate high-power FC-UV LEDs with Ta2O5/SiO2 distributed Bragg reflectors (DBRs) and a strip-shaped SiO2 current blocking layer (CBL). The reflectance of fourteen pairs of Ta2O5/SiO2 DBRs is 96.4% at 353 nm. The strip-shaped SiO2 CBL underneath the strip-shaped p-electrode can prevent the current concentrating in regions immediately adjacent to the p-electrode where the overlying opaque p-electrode metal layer absorbs the emitted UV light. Moreover, two-level metallization electrodes are used to improve current spreading. Our numerical results show that FC-UV LED has a more favorable current spreading uniformity than TE-UV LED. The light output power of 353 nm FC-UV LED was 23.22 mW at 350 mA, which is 24.7% higher than that of TE-UV LED.

Efficient blue conversion from a 1064 nm microchip laser in long photonic crystal fiber tapers for fluorescence microscopy.

PubMed

Kudlinski, A; Lelek, M; Barviau, B; Audry, L; Mussot, A

2010-08-02

Using a low-cost microchip laser and a long photonic crystal fiber taper, we report a supercontinuum source with a very efficient visible conversion, especially in the blue region (around 420 nm). About 30 % of the total average output power is located in the 350-600 nm band, which is of primary importance in a number of biophotonics applications such as flow cytometry or fluorescence imaging microscopy for instance. We successfully demonstrate the use of this visible-enhanced source for a three-color imaging of HeLa cells in wide-field microscopy.

Diode-pumped passively Q-switched Nd:YAG ceramic laser with a gold nanotriangles saturable absorber at 1 µm

NASA Astrophysics Data System (ADS)

Bai, Jinxi; Li, Ping; Chen, Xiaohan; Guo, Lei; Wang, Lili; Liu, Binghai

2017-08-01

Passively Q-switched Nd:YAG ceramic lasers at 1064 and 1123 nm are demonstrated based on a gold nanotriangles saturable absorber (GNTs-SA) for the first time. The maximum average output power reaches 226 mW at 1064 nm and 172 mW at 1123 nm with corresponding shortest pulse widths and maximum pulse repetition rates of (179 ns, 320 kHz) and (231 ns, 457 kHz), respectively. Our results prove that the GNTs-SA is a promising saturable absorber around the 1-µm region.

Highly efficient 400  W near-fundamental-mode green thin-disk laser.

PubMed

Piehler, Stefan; Dietrich, Tom; Rumpel, Martin; Graf, Thomas; Ahmed, Marwan Abdou

2016-01-01

We report on the efficient generation of continuous-wave, high-brightness green laser radiation. Green lasers are particularly interesting for reliable and reproducible deep-penetration welding of copper or for pumping Ti:Sa oscillators. By intracavity second-harmonic generation in a thin-disk laser resonator designed for fundamental-mode operation, an output power of up to 403 W is demonstrated at a wavelength of 515 nm with almost diffraction-limited beam quality. The unprecedented optical efficiency of 40.7% of green output power with respect to the pump power of the thin-disk laser is enabled by the intracavity use of a highly efficient grating waveguide mirror, which combines the functions of wavelength stabilization and spectral narrowing, as well as polarization selection in a single element.

Influence of temperature on Yb:YAG/Cr:YAG microchip laser operation

NASA Astrophysics Data System (ADS)

Šulc, Jan; Eisenschreiber, Jan; Jelínková, Helena; Nejezchleb, Karel; Å koda, Václav

2017-02-01

The goal of this work was an investigation of the temperature influence (in range from 80 up to 320 K) on the laser properties of Yb:YAG/Cr:YAG Q-switched diode-pumped microchip laser. This laser was based on monolith crystal (diameter 3mm) which combines in one piece an active laser part (Yb:YAG crystal, 10 at.% Yb/Y, 3mm long) and saturable absorber (Cr:YAG crystal, 1.36mm long, initial transmission 90% @ 1031 nm). The laser resonator pump mirror (HT for pump radiation, HR for generated radiation) was directly deposited on the Yb:YAG monolith part. The output coupler with reflection 55% for the generated wavelength was placed on the Cr:YAG part. The microchip laser was placed in the temperature controlled cupreous holder inside vacuum chamber of the liquid nitrogen cryostat. For Yb:YAG part longitudinal pulsed pumping (pumping pulse length 2.5 ms, rep-rate 20 Hz, power amplitude 21W) a fibre coupled (core diameter 400 μm, NA= 0:22) laser diode, operating at wavelength 933 nm, was used. The microchip laser mean output power, pulse duration, repetition rate, emission wavelength, and laser beam profile were measured in dependence on temperature. The generated pulse length was in range from 2.2 ns to 1.1 ns (FWHM) with the minimum at 230 K. The single pulse energy was peaking (0.4 mJ) at 180 K. The highest peak power (325 kW) was obtained at 220 K. The highest pulse repetition rate (38 kHz) and output mean power (370mW) was reached for temperature 80 K.

UHF front-end feeding RFID-based body sensor networks by exploiting the reader signal

NASA Astrophysics Data System (ADS)

Pasca, M.; Colella, R.; Catarinucci, L.; Tarricone, L.; D'Amico, S.; Baschirotto, A.

2016-05-01

This paper presents an integrated, high-sensitivity UHF radio frequency identification (RFID) power management circuit for body sensor network applications. The circuit consists of a two-stage RF-DC Dickson's rectifier followed by an integrated five-stage DC-DC Pelliconi's charge pump driven by an ultralow start-up voltage LC oscillator. The DC-DC charge pump interposed between the RF-DC rectifier and the output load provides the RF to load isolation avoiding losses due to the diodes reverse saturation current. The RF-DC rectifier has been realized on FR4 substrate, while the charge pump and the oscillator have been realized in 180 nm complementary metal oxide semiconductor (CMOS) technology. Outdoor measurements demonstrate the ability of the power management circuit to provide 400 mV output voltage at 14 m distance from the UHF reader, in correspondence of -25 dBm input signal power. As demonstrated in the literature, such output voltage level is suitable to supply body sensor network nodes.

A highly stable monolithic enhancement cavity for second harmonic generation in the ultraviolet

NASA Astrophysics Data System (ADS)

Hannig, S.; Mielke, J.; Fenske, J. A.; Misera, M.; Beev, N.; Ospelkaus, C.; Schmidt, P. O.

2018-01-01

We present a highly stable bow-tie power enhancement cavity for critical second harmonic generation (SHG) into the UV using a Brewster-cut β-BaB2O4 (BBO) nonlinear crystal. The cavity geometry is suitable for all UV wavelengths reachable with BBO and can be modified to accommodate anti-reflection coated crystals, extending its applicability to the entire wavelength range accessible with non-linear frequency conversion. The cavity is length-stabilized using a fast general purpose digital PI controller based on the open source STEMlab 125-14 (formerly Red Pitaya) system acting on a mirror mounted on a fast piezo actuator. We observe 130 h uninterrupted operation without decay in output power at 313 nm. The robustness of the system has been confirmed by exposing it to accelerations of up to 1 g with less than 10% in-lock output power variations. Furthermore, the cavity can withstand 30 min of acceleration exposure at a level of 3 grms without substantial change in the SHG output power, demonstrating that the design is suitable for transportable setups.

High-power, highly stable KrF laser with a 4-kHz pulse repetition rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borisov, V M; El'tsov, A V; Khristoforov, O B

2015-08-31

An electric-discharge KrF laser (248 nm) with an average output power of 300 W is developed and studied. A number of new design features are related to the use of a laser chamber based on an Al{sub 2}O{sub 3} ceramic tube. A high power and pulse repetition rate are achieved by using a volume discharge with lateral preionisation by the UV radiation of a creeping discharge in the form of a homogeneous plasma sheet on the surface of a plane sapphire plate. Various generators for pumping the laser are studied. The maximum laser efficiency is 3.1%, the maximum laser energymore » is 160 mJ pulse{sup -1}, and the pulse duration at half maximum is 7.5 ns. In the case of long-term operation at a pulse repetition rate of 4 kHz and an output power of 300 W, high stability of laser output energy (σ ≤ 0.7%) is achieved using an all-solid-state pump system. (lasers)« less

A triple hybrid micropower generator with simultaneous multi-mode energy harvesting

NASA Astrophysics Data System (ADS)

Uluşan, H.; Chamanian, S.; Pathirana, W. P. M. R.; Zorlu, Ö.; Muhtaroğlu, A.; Külah, H.

2018-01-01

This study presents a triple hybrid energy harvesting system that combines harvested power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters into a single DC supply. A power management circuit is designed and implemented in 180 nm standard CMOS technology based on the distinct requirements of each harvester, and is terminated with a Schottky diode to avoid reverse current flow. The system topology hence supports simultaneous power generation and delivery from low and high frequency vibrations as well as temperature differences in the environment. The ultra-low DC voltage harvested from TE generator is boosted with a cross-coupled charge-pump driven by an LC oscillator with fully-integrated center-tapped differential inductors. The EM harvester output was rectified with a self-powered and low drop-out AC/DC doubler circuit. The PZT interface electronics benefits from peak-to-peak cycle of the harvested voltage through a negative voltage converter followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The hybrid system was tested with a wearable in-house EM energy harvester placed wrist of a jogger, a commercial low volume PZT harvester, and DC supply as the TE generator output. The system generates more than 1.2 V output for load resistances higher than 50 kΩ, which corresponds to 24 μW to power wearable sensors. Simultaneous multi-mode operation achieves higher voltage and power compared to stand-alone harvesting circuits, and generates up to 110 μW of output power. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.

Ground Demonstration of Planetary Gas Lidar Based on Optical Parametric Amplifier

NASA Technical Reports Server (NTRS)

Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephen R.; Krainak, Michael; Abshire, James

2012-01-01

We report on the development effort of a nanosecond-pulsed optical parametric amplifier (OPA) for remote trace gas measurements for Mars and Earth. The OPA output has high spectral purity and is widely tunable both at near-infrared and mid-infrared wavelengths, with an optical-optica1 conversion efficiency of up to approx 39 %. Using this laser source, we demonstrated open-path measurements of CH4 (3291 nm and 1651 nm), CO2 (1573 nm), H2O (1652 nm), and CO (4764 nm) on the ground. The simplicity, tunability. and power scalability of the OPA make it a strong candidate for general planetary lidar instruments, which will offer important information on the origins of the planet's geology, atmosphere, and potential for biology,

Efficient 2(nd) and 4(th) harmonic generation of a single-frequency, continuous-wave fiber amplifier.

PubMed

Sudmeyer, Thomas; Imai, Yutaka; Masuda, Hisashi; Eguchi, Naoya; Saito, Masaki; Kubota, Shigeo

2008-02-04

We demonstrate efficient cavity-enhanced second and fourth harmonic generation of an air-cooled, continuous-wave (cw), single-frequency 1064 nm fiber-amplifier system. The second harmonic generator achieves up to 88% total external conversion efficiency, generating more than 20-W power at 532 nm wavelength in a diffraction-limited beam (M(2) < 1.05). The nonlinear medium is a critically phase-matched, 20-mm long, anti-reflection (AR) coated LBO crystal operated at 25 degrees C. The fourth harmonic generator is based on an AR-coated, Czochralski-grown beta-BaB(2)O(4) (BBO) crystal optimized for low loss and high damage threshold. Up to 12.2 W of 266-nm deep-UV (DUV) output is obtained using a 6-mm long critically phase-matched BBO operated at 40 degrees C. This power level is more than two times higher than previously reported for cw 266-nm generation. The total external conversion efficiency from the fundamental at 1064 nm to the fourth harmonic at 266 nm is >50%.

The aging process of optical couplers by gamma irradiation

NASA Astrophysics Data System (ADS)

Bednarek, Lukas; Marcinka, Ondrej; Perecar, Frantisek; Papes, Martin; Hajek, Lukas; Nedoma, Jan; Vasinek, Vladimir

2015-08-01

Scientists have recently discovered that the ageing process of optical elements is faster than it was originally anticipated. It is mostly due to the multiple increases of the optical power in optical components, the introduction of wavelength division multiplexers and, overall, the increased flow of traffic in optical communications. This article examines the ageing process of optical couplers and it focuses on their performance parameters. It describes the measurement procedure followed by the evaluation of the measurement results. To accelerate the ageing process, gamma irradiation from 60Co was used. The results of the measurements of the optical coupler with one input and eight outputs (1:8) were summarized. The results gained by measuring of the optical coupler with one input and four outputs (1:4) as well as of the optical couplers with one input and two outputs (1:2) with different split ratios were also processed. The optical powers were measured on the input and the outputs of each branch of each optical coupler at the wavelengths of 1310 nm and 1550 nm. The parameters of the optical couplers were subsequently calculated according to the appropriate formulas. These parameters were the insertion loss of the individual branches, split ratio, total losses, homogeneity of the losses and directionalities alias cross-talk between the individual output branches. The gathered data were summarized before and after the first irradiation when the configuration of the couplers was 1:8 and 1:4. The data were summarized after the third irradiation when the configuration of the couplers was 1:2.

Low threshold L-band mode-locked ultrafast fiber laser assisted by microfiber-based carbon nanotube saturable absorber

NASA Astrophysics Data System (ADS)

Lau, K. Y.; Ng, E. K.; Abu Bakar, M. H.; Abas, A. F.; Alresheedi, M. T.; Yusoff, Z.; Mahdi, M. A.

2018-04-01

We demonstrate a passively mode-locked erbium-doped fiber laser in L-band wavelength region with low mode-locking threshold employing a 1425 nm pump wavelength. The mode-locking regime is generated by microfiber-based saturable absorber using carbon nanotube-polymer composite in a ring cavity. This carbon nanotube saturable absorber shows saturation intensity of 9 MW/cm2. In this work, mode-locking laser threshold is observed at 36.4 mW pump power. At the maximum pump power of 107.6 mW, we obtain pulse duration at full-width half-maximum point of 490 fs and time bandwidth product of 0.33, which corresponds to 3-dB spectral bandwidth of 5.8 nm. The pulse repetition rate remains constant throughout the experiment at 5.8 MHz due to fixed cavity length of 35.5 m. Average output power and pulse energy of 10.8 mW and 1.92 nJ are attained respectively through a 30% laser output extracted from the mode-locked cavity. This work highlights the feasibility of attaining a low threshold mode-locked laser source to be employed as seed laser in L-band wavelength region.

50W CW output power and 12mJ pulses from a quasi-2-level Yb:YAG ceramic rod laser end-pumped at the 969nm zero-phonon line

NASA Astrophysics Data System (ADS)

Fries, Christian; Weitz, Marco; Theobald, Christian; v. Löwis of Menar, Patric; Bartschke, Jürgen; L'huillier, Johannes A.

2015-02-01

With the advent of high power and narrow bandwidth 969 nm pump diodes, direct pumping into the upper laser level of Yb:YAG and hence quasi-2-level lasers became possible. Pumping directly into the emitting level leads to higher quantum efficiency and reduction of non-radiative decay. Consequently, thermal load, thermal lensing and risk of fracture are reduced significantly. Moreover pump saturation and thermal population of uninvolved energy-levels in ground and excited states are benefical for a homogenous distribution of the pump beam as well as the reduction of reabsorption loss compared to 3-level systems, which allows for high-power DPSS lasers. Beside continuous-wave (cw) operation, nanosecond pulses with a repetition rate between 1 and 5 kHz are an attractive alternative to flashlamp-pumped systems (10-100 Hz) in various measurement applications that require higher data acquisition rates because of new faster detectors. Based on measurements of the absorption and a detailed numerical model for pump beam distribution, including beam propagation and saturation factors, power-scaling of a ceramic rod Yb:YAG oscillator was possible. Finally a cw output power of 50 W with 33 % pump efficiency at 1030 nm has been demonstrated (M2 < 1.2). Nanosecond pulses have been produced by cavity-dumping of this system. The cavity-dumped setup allowed for 3-10 ns pulses with a pulse energy of 12.5 mJ at 1 kHz (M2 < 1.1). In order to achieve these results a systematic experimental and numerical investigation on gain dynamics and the identification of different stable operating regimes has been carried out.

Room temperature high power mid-IR diode laser bars for atmospheric sensing applications

NASA Astrophysics Data System (ADS)

Crump, Paul; Patterson, Steve; Dong, Weimin; Grimshaw, Mike; Wang, Jun; Zhang, Shiguo; Elim, Sandrio; Bougher, Mike; Patterson, Jason; Das, Suhit; Wise, Damian; Matson, Triston; Balsley, David; Bell, Jake; DeVito, Mark; Martinsen, Rob

2007-04-01

Peak CW optical power from single 1-cm diode laser bars is advancing rapidly across all commercial wavelengths and the available range of emission wavelengths also continues to increase. Both high efficiency ~ 50% and > 100-W power InP-based CW bars have been available in bar format around 1500-nm for some time, as required for eye-safe illuminators and for pumping Er-YAG crystals. There is increasing demand for sources at longer wavelengths. Specifically, 1900-nm sources can be used to pump Holmium doped YAG crystals, to produce 2100-nm emission. Emission near 2100-nm is attractive for free-space communications and range-finding applications as the atmosphere has little absorption at this wavelength. Diode lasers that emit at 2100-nm could eliminate the need for the use of a solid-state laser system, at significant cost savings. 2100-nm sources can also be used as pump sources for Thulium doped solid-state crystals to reach even longer wavelengths. In addition, there are several promising medical applications including dental applications such as bone ablation and medical procedures such as opthamology. These long wavelength sources are also key components in infra-red-counter-measure systems. We have extended our high performance 1500-nm material to longer wavelengths through optimization of design and epitaxial growth conditions and report peak CW output powers from single 1-cm diode laser bars of 37W at 1910-nm and 25W at 2070-nm. 1-cm bars with 20% fill factor were tested under step-stress conditions up to 110-A per bar without failure, confirming reasonable robustness of this technology. Stacks of such bars deliver high powers in a collimated beam suitable for pump applications. We demonstrate the natural spectral width of ~ 18nm of these laser bars can be reduced to < 3-nm with use of an external Volume Bragg Grating, as required for pump applications. We review the developments required to reach these powers, latest advances and prospects for longer wavelength, higher power and higher efficiency.

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.

Complete indium-free CW 200W passively cooled high power diode laser array using double-side cooling technology

NASA Astrophysics Data System (ADS)

Wang, Jingwei; Zhu, Pengfei; Liu, Hui; Liang, Xuejie; Wu, Dihai; Liu, Yalong; Yu, Dongshan; Zah, Chung-en; Liu, Xingsheng

2017-02-01

High power diode lasers have been widely used in many fields. To meet the requirements of high power and high reliability, passively cooled single bar CS-packaged diode lasers must be robust to withstand thermal fatigue and operate long lifetime. In this work, a novel complete indium-free double-side cooling technology has been applied to package passively cooled high power diode lasers. Thermal behavior of hard solder CS-package diode lasers with different packaging structures was simulated and analyzed. Based on these results, the device structure and packaging process of double-side cooled CS-packaged diode lasers were optimized. A series of CW 200W 940nm high power diode lasers were developed and fabricated using hard solder bonding technology. The performance of the CW 200W 940nm high power diode lasers, such as output power, spectrum, thermal resistance, near field, far field, smile, lifetime, etc., is characterized and analyzed.

Spectral and power characteristics of a 5% Tm : KLu(WO4)2 Nm-cut minislab laser passively Q-switched by a Cr2+ : ZnSe crystal

NASA Astrophysics Data System (ADS)

Vatnik, S. M.; Vedin, I. A.; Kurbatov, P. F.; Smolina, E. A.; Pavlyuk, A. A.; Korostelin, Yu. V.; Skasyrsky, Ya. K.

2017-12-01

Laser characteristics of a 5%Tm : KLu(WO4)2 Nm-cut minislab laser passively Q-switched by a Cr2+ : ZnSe saturable absorber are presented. At a pump power of 21 W, the average laser power at a wavelength of 1.91 μm was 3.2 W (pulse duration 35 ns, pulse energy 0.3 mJ). The maximum slope efficiency of the laser in the Q-switched regime was 31%; the loss in power with respect to the cw regime did not exceed 17%. At pump powers above 15 W, the dependence of the output power in the Q-switched regime on the pump power considerably differed from linear, which was explained by the formation of a thermal lens in the saturable absorber volume. The experimental energies and durations of laser pulses well agree with the values calculated from rate equations.

Traction Drives for Zero Stick-Slip Robots, and Reaction Free, Momentum Balanced Systems

NASA Technical Reports Server (NTRS)

Anderson, William J.; Shipitalo, William; Newman, Wyatt

1995-01-01

Two differential (dual input, single output) drives (a roller-gear and a pure roller), and a momentum balanced (single input, dual output) drive (pure roller ) were designed, fabricated, and tested. The differential drives are each rated at 295 rad/sec (2800 rpm) input speed, 450 N-m (4,000 in-lbf) output torque. The momentum balanced drive is rated at 302 rad/sec (2880 rpm) input speed, and dual output torques of 434N-m (3840 in-lbf). The Dual Input Differential Roller-Gear Drive (DC-700) has a planetary roller-gear system with a reduction ratio (one input driving the output with the second input fixed) of 29.23: 1. The Dual Input Differential Roller Drive (DC-500) has a planetary roller system with a reduction ratio of approximately 24:1. Each of the differential drives features dual roller-gear or roller arrangements consisting of a sun, four first row planets, four second row planets, and a ring. The Momentum Balanced (Grounded Ring) Drive (DC-400) has a planetary roller system with a reduction ratio of 24:1 with both outputs counterrotating at equal speed. Its single roller cluster consists of a sun, five first and five second row planets, a roller cage or spider and a ring. Outputs are taken from both the roller cage and the ring which counterrotate. Test results reported for all three drives include angular and torque ripple (linearity and cogging), viscous and Coulomb friction, and forward and reverse power efficiency. Of the two differential drives, the Differential Roller Drive had better linearity and less cogging than did the Differential Roller-Gear Drive, but it had higher friction and lower efficiency (particularly at low power throughput levels). Use of full preloading rather than a variable preload system in the Differential Roller Drive assessed a heavy penalty in part load efficiency. Maximum measured efficiency (ratio of power out to power in) was 95% for the Differential Roller-Gear Drive and 86% for the Differential Roller Drive. The Momentum Balanced (Grounded Ring) Drive performed as expected kinematically. Reduction r-atios to the two counterrotating outputs (design nominal=24:1) were measured to be 23.98:1 and 24.12:1 at zero load.. At 25ONm (2200 in-lbf) output torque the ratio changed 2% due to roller creep. This drive was the smoothest of all three as determined from linearity and cogging tests, and maximum measured efficiency (ratio of power out to power in) was 95%. The disadvantages of full preloading as comvared to variable preload were apparent in this drive as in the Differential Roller Drive. Efficiencies at part load were low, but improved dramatically with increases in torque. These were consistent with friction measurements which indicated losses primarily from Coulomb friction. The initial preload level setting was low so roller slip was encountered at higher torques during testing.

EMERGING TECHNOLOGY REPORT: DESTRUCTION OF ORGANIC CONTAMINANTS IN AIR USING ADVANCED ULTRAVIOLET FLASHLAMPS

EPA Science Inventory

This paper describes a new process for photo-oxidation of volatile organic compounds (VOCs) in air using an advanced ultraviolet source, a Purus xenon flashlamp. The flashlamps have greater output at 200-250 nm than medium-pressure mercury lamps at the same power and therefore ca...

Ultrahigh-brightness, spectrally-flat, short-wave infrared supercontinuum source for long-range atmospheric applications.

PubMed

Yin, Ke; Zhu, Rongzhen; Zhang, Bin; Jiang, Tian; Chen, Shengping; Hou, Jing

2016-09-05

Fiber based supercontinuum (SC) sources with output spectra covering the infrared atmospheric window are very useful in long-range atmospheric applications. It is proven that silica fibers can support the generation of broadband SC sources ranging from the visible to the short-wave infrared region. In this paper, we present the generation of an ultrahigh-brightness spectrally-flat 2-2.5 μm SC source in a cladding pumped thulium-doped fiber amplifier (TDFA) numerically and experimentally. The underlying physical mechanisms behind the SC generation process are investigated firstly with a numerical model which includes the fiber gain and loss, the dispersive and nonlinear effects. Simulation results show that abundant soliton pulses are generated in the TDFA, and they are shifted towards the long wavelength side very quickly with the nonlinearity of Raman soliton self-frequency shift (SSFS), and eventually the Raman SSFS process is halted due to the silica fiber's infrared loss. A spectrally-flat 2-2.5 μm SC source could be generated as the result of the spectral superposition of these abundant soliton pulses. These simulation results correspond qualitatively well to the following experimental results. Then, in the experiment, a cladding pumped large-mode-area TDFA is built for pursuing a high-power 2-2.5 μm SC source. By enhancing the pump strength, the output SC spectrum broadens to the long wavelength side gradually. At the highest pump power, the obtained SC source has a maximum average power of 203.4 W with a power conversion efficiency of 38.7%. It has a 3 dB spectral bandwidth of 545 nm ranging from 1990 to 2535 nm, indicating a power spectral density in excess of 370 mW/nm. Meanwhile, the output SC source has a good beam profile. This SC source, to the best of our knowledge, is the brightest spectrally-flat 2-2.5 μm light source ever reported. It will be highly desirable in a lot of long-range atmospheric applications, such as broad-spectrum LIDAR, free space communication and hyper-spectral imaging.

Diode-pumped continuous wave tunable and graphene Q-switched Tm:LSO lasers.

PubMed

Feng, T L; Zhao, S Z; Yang, K J; Li, G Q; Li, D C; Zhao, J; Qiao, W C; Hou, J; Yang, Y; He, J L; Zheng, L H; Wang, Q G; Xu, X D; Su, L B; Xu, J

2013-10-21

We have investigated the lasing characteristics of Tm:LSO crystal in three operation regimes: continuous wave (CW), wavelength tunable and passive Q-switching based on graphene. In CW regime, a maximum output power of 0.65 W at 2054.9 nm with a slope efficiency of 21% was achieved. With a quartz plate, a broad wavelength tunable range of 145 nm was obtained, corresponding to a FWHM of 100 nm. By using a graphene saturable absorber mirror, the passively Q-switched Tm:LSO laser produced pulses with duration of 7.8 μs at 2030.8 nm under a repetition rate of 7.6 kHz, corresponding to pulse energy of 14.0 μJ.

Kilohertz Pulse Repetition Frequency Slab Ti:sapphire Lasers with High Average Power (10 W)

NASA Astrophysics Data System (ADS)

Wadsworth, William J.; Coutts, David W.; Webb, Colin E.

1999-11-01

High-average-power broadband 780-nm slab Ti:sapphire lasers, pumped by a kilohertz pulse repetition frequency copper vapor laser (CVL), were demonstrated. These lasers are designed for damage-free power scaling when pumped by CVL s configured for maximum output power (of order 100 W) but with poor beam quality ( M 2 300 ). A simple Brewster-angled slab laser side pumped by a CVL produced 10-W average power (1.25-mJ pulses at 8 kHz) with 4.2-ns FWHM pulse duration at an absolute efficiency of 15% (68-W pump power). Thermal lensing in the Brewster slab laser resulted in multitransverse mode output, and pump absorption was limited to 72% by the maximum doping level for commercially available Ti:sapphire (0.25%). A slab laser with a multiply folded zigzag path was therefore designed and implemented that produced high-beam-quality (TEM 00 -mode) output when operated with cryogenic cooling and provided a longer absorption path for the pump. Excessive scattering of the Ti:sapphire beam at the crystal surfaces limited the efficiency of operation for the zigzag laser, but fluorescence diagnostic techniques, gain measurement, and modeling suggest that efficient power extraction ( 15 W TEM 00 , 23% efficiency) from this laser would be possible for crystals with an optical quality surface polish.

High efficiency, linearly polarized, directly diode-pumped Er:YAG laser at 1617  nm.

PubMed

Yu, Zhenzhen; Wang, Mingjian; Hou, Xia; Chen, Weibiao

2014-12-01

An efficient, directly diode-pumped Er:YAG laser at 1617 nm was demonstrated. A folding mirror with high reflectivity for the s-polarized light at the laser wavelength was used to achieve a linearly polarized laser. A maximum continuous-wave output power of 7.73 W was yielded under incident pump power of 50.57 W, and the optical conversion efficiency with respect to incident pump power was ∼15.28%, which was the highest optical conversion efficiency with directly diode-pumped Er:YAG lasers up to now; in Q-switched operation, the maximum pulse energy of 7.82 mJ was generated with pulse duration of about 80 ns at a pulse repetition frequency of 500 Hz.

Efficient yellow-green light generation at 561 nm by frequency-doubling of a QD-FBG laser diode in a PPLN waveguide.

PubMed

Fedorova, Ksenia A; Sokolovskii, Grigorii S; Khomylev, Maksim; Livshits, Daniil A; Rafailov, Edik U

2014-12-01

A compact high-power yellow-green continuous wave (CW) laser source based on second-harmonic generation (SHG) in a 5% MgO doped periodically poled congruent lithium niobate (PPLN) waveguide crystal pumped by a quantum-dot fiber Bragg grating (QD-FBG) laser diode is demonstrated. A frequency-doubled power of 90.11 mW at the wavelength of 560.68 nm with a conversion efficiency of 52.4% is reported. To the best of our knowledge, this represents the highest output power and conversion efficiency achieved to date in this spectral region from a diode-pumped PPLN waveguide crystal, which could prove extremely valuable for the deployment of such a source in a wide range of biomedical applications.

Optical fiber bundle displacement sensor using an ac-modulated light source with subnanometer resolution and low thermal drift

NASA Astrophysics Data System (ADS)

Shimamoto, Atsushi; Tanaka, Kohichi

1995-09-01

An optical fiber bundle displacement sensor with subnanometer order resolution and low thermal drift is proposed. The setup is based on a carrier amplifier system and involves techniques to eliminate fluctuation in the light power of the source. The achieved noise level of the sensor was 0.03 nm/ \\radical Hz \\end-radical . The stability was estimated by comparing the outputs of two different sensors from the same target for 4 ks (67 min). The relative displacements between the fiber bundle ends of the two sensors and the target surface varied in the area of 400 nm depending on the ambient temperature variation at 2 deg C. However, the difference in output between the two sensor systems is within 2 nm for more than 1 hour of measurement. It is expected that it would be reduced to within the area of 0.1 nm if the ambient temperature were controlled to within +/-0.1 deg C. It is concluded that the stability of the sensors is sufficiently good to be used with nanotechnological instruments.

In-band-pumped Ho:KLu(WO4)2 microchip laser with 84% slope efficiency.

PubMed

Loiko, Pavel; Serres, Josep Maria; Mateos, Xavier; Yumashev, Konstantin; Kuleshov, Nikolai; Petrov, Valentin; Griebner, Uwe; Aguiló, Magdalena; Díaz, Francesc

2015-02-01

We report on a continuous-wave Ho:KLu(WO4)2 (KLuW) microchip laser with a record slope efficiency of 84%, the highest value among the holmium inband-pumped lasers, delivering 201 mW output power at 2105 nm. The Ho laser operating at room temperature on the (5)I8→(5)I7 transition is in-band-pumped by a diode-pumped Tm:KLuW microchip laser at 1946 nm. Ho:KLuW laser operation at 2061 and 2079 nm is also demonstrated with a maximum slope efficiency of 79%. The microchip laser generates an almost diffraction-limited output beam with a Gaussian profile and a M2<1.1. The laser performance of the Ng-cut Ho:KLuW crystal is very similar for pump light polarizations ‖Nm and Np. The positive thermal lens plays a key role in the laser mode stabilization and proper mode-matching. The latter, together with the low quantum defect under in-band-pumping (∼0.08), is responsible for the extraordinary high slope efficiency.