Sample records for diode laser pumped

  1. Diode-pumped dye laser

    Burdukova, O. A.; Gorbunkov, M. V.; Petukhov, V. A.; Semenov, M. A.


    This letter reports diode pumping for dye lasers. We offer a pulsed dye laser with an astigmatism-compensated three-mirror cavity and side pumping by blue laser diodes with 200 ns pulse duration. Eight dyes were tested. Four dyes provided a slope efficiency of more than 10% and the highest slope efficiency (18%) was obtained for laser dye Coumarin 540A in benzyl alcohol.

  2. Diode Pumped Fiber Laser.


    FIBER LASERS I. Nd:YAG FIBER LASER FABRICATION .............. 5 A. FIBER GROWTH .......................... 5 B. FIBER PROCESSING 7...1.32 pm FIBER LASERS I. Nd:YAG FIBER LASER FABRICATION A. FIBER GROWTH The single crystal fibers used in this work were grown at Stanford University

  3. Materials for diode pumped solid state lasers

    Chase, L. L.; Davis, L. E.; Krupke, W. F.; Payne, S. A.


    The advantages of semiconductor diode lasers and laser arrays as pump sources for solid state lasers are reviewed. The properties that are desirable in solid state laser media for various diode pumping applications are discussed, and the characteristics of several promising media are summarized.

  4. New laser materials for laser diode pumping

    Jenssen, H. P.


    The potential advantages of laser diode pumped solid state lasers are many with high overall efficiency being the most important. In order to realize these advantages, the solid state laser material needs to be optimized for diode laser pumping and for the particular application. In the case of the Nd laser, materials with a longer upper level radiative lifetime are desirable. This is because the laser diode is fundamentally a cw source, and to obtain high energy storage, a long integration time is necessary. Fluoride crystals are investigated as host materials for the Nd laser and also for IR laser transitions in other rare earths, such as the 2 micron Ho laser and the 3 micron Er laser. The approach is to investigate both known crystals, such as BaY2F8, as well as new crystals such as NaYF8. Emphasis is on the growth and spectroscopy of BaY2F8. These two efforts are parallel efforts. The growth effort is aimed at establishing conditions for obtaining large, high quality boules for laser samples. This requires numerous experimental growth runs; however, from these runs, samples suitable for spectroscopy become available.

  5. Diode-pumped laser altimeter

    Welford, D.; Isyanova, Y.


    TEM(sub 00)-mode output energies up to 22.5 mJ with 23 percent slope efficiencies were generated at 1.064 microns in a diode-laser pumped Nd:YAG laser using a transverse-pumping geometry. 1.32-micron performance was equally impressive at 10.2 mJ output energy with 15 percent slope efficiency. The same pumping geometry was successfully carried forward to several complex Q-switched laser resonator designs with no noticeable degradation of beam quality. Output beam profiles were consistently shown to have greater than 90 percent correlation with the ideal TEM(sub 00)-order Gaussian profile. A comparison study on pulse-reflection-mode (PRM), pulse-transmission-mode (PTM), and passive Q-switching techniques was undertaken. The PRM Q-switched laser generated 8.3 mJ pulses with durations as short as 10 ns. The PTM Q-switch laser generated 5 mJ pulses with durations as short as 5 ns. The passively Q-switched laser generated 5 mJ pulses with durations as short as 2.4 ns. Frequency doubling of both 1.064 microns and 1.32 microns with conversion efficiencies of 56 percent in lithium triborate and 10 percent in rubidium titanyl arsenate, respectively, was shown. Sum-frequency generation of the 1.064 microns and 1.32 microns radiations was demonstrated in KTP to generate 1.1 mJ of 0.589 micron output with 11.5 percent conversion efficiency.

  6. Diode pumped Nd:YAG laser development

    Reno, C. W.; Herzog, D. G.


    A low power Nd:YAG laser was constructed which employs GaAs injection lasers as a pump source. Power outputs of 125 mW TEM CW with the rod at 250 K and the pump at 180 K were achieved for 45 W input power to the pump source. Operation of the laser, with array and laser at a common heat sink temperature of 250 K, was inhibited by difficulties in constructing long-life GaAs LOC laser arrays. Tests verified pumping with output power of 20 to 30 mW with rod and pump at 250 K. Although life tests with single LOC GaAs diodes were somewhat encouraging (with single diodes operating as long as 9000 hours without degradation), failures of single diodes in arrays continue to occur, and 50 percent power is lost in a few hundred hours at 1 percent duty factor. Because of the large recent advances in the state of the art of CW room temperature AlGaAs diodes, their demonstrated lifetimes of greater than 5,000 hours, and their inherent advantages for this task, it is recommended that these sources be used for further CW YAG injection laser pumping work.

  7. Diode-pumped laser with improved pumping system

    Chang, Jim J.


    A laser wherein pump radiation from laser diodes is delivered to a pump chamber and into the lasing medium by quasi-three-dimensional compound parabolic concentrator light channels. The light channels have reflective side walls with a curved surface and reflective end walls with a curved surface. A flow tube between the lasing medium and the light channel has a roughened surface.

  8. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)


    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  9. Tapered diode laser pumped 946 nm Nd:YAG laser

    Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Petersen, Paul Michael


    We successfully implemented a 946 nm Nd:YAG laser based on a 808 nm tapered diode pump laser. The tapered diode is developed at the Ferdinand-Braun-Institute fur Hochstfrequenztechnik in Germany. Figure 2 shows the experimental setup and results of each pump source coupled into a 1.5 mm crystal...... laser, we show that tapered diode laser pumping potentially increase the power of 946 nm lasers by a factor of two and reduce the threshold by a factor of three....

  10. Diode pumped solid-state laser oscillators for spectroscopic applications

    Byer, R. L.; Basu, S.; Fan, T. Y.; Kozlovsky, W. J.; Nabors, C. D.; Nilsson, A.; Huber, G.


    The rapid improvement in diode laser pump sources has led to the recent progress in diode laser pumped solid state lasers. To date, electrical efficiencies of greater than 10 percent were demonstrated. As diode laser costs decrease with increased production volume, diode laser and diode laser array pumped solid state lasers will replace the traditional flashlamp pumped Nd:YAG laser sources. The use of laser diode array pumping of slab geometry lasers will allow efficient, high peak and average power solid state laser sources to be developed. Perhaps the greatest impact of diode laser pumped solid state lasers will be in spectroscopic applications of miniature, monolithic devices. Single-stripe diode-pumped operation of a continuous-wave 946 nm Nd:YAG laser with less than 10 m/w threshold was demonstrated. A slope efficiency of 16 percent near threshold was shown with a projected slope efficiency well above a threshold of 34 percent based on results under Rhodamine 6G dye-laser pumping. Nonlinear crystals for second-harmonic generation of this source were evaluated. The KNbO3 and periodically poled LiNbO3 appear to be the most promising.

  11. "Diode Pumped Solid State Lasers At 2 And 3 µm"

    Esterowitz, Leon


    The most attractive alternative to flashlamp pumping of solid state lasers is the diode laser. In the past two decades numerous laboratory devices have been assembled which incorporated single diode lasers, small laser diode arrays or LED's for pumping of Nd:YAG, Nd:glass and a host of other Nd lasers. The low power output, low packaging density, and extremely high cost of diode lasers prevented any serious applications for laser pumping in the past. The reason for the continued interest in this area stems from the potential dramatic increase in system efficiency and component lifetime, and reduction of thermal load of the solid-state laser material. The latter not only will reduce thereto-optic effects and therefore lead to better beam quality but also will enable an increase in pulse repetition frequency. The attractive operating parameters combined with low voltage operation and the compactness of an all solid-state laser system have a potential high payoff. The high pumping efficiency compared to flashlamps stems from the good spectral match between the laser diode emission and the rare earth activator absorption bands. A significant advantage of laser diode pumping compared to arc lamps is system lifetime and reliability. Laser diode arrays have exhibited lifetimes on the order of 10,000 hours in cw operation and 109 shots in the pulsed mode. Flashlamp life is on the order of 107 shots, and about 200 hours for cw operation. In addition, the high pump flux combined with a substantial UV content in lamp pumped systems causes material degradation in the pump cavity and in the coolant. Such problems are virtually eliminated with laser diode pump sources. The absence of high voltage pulses, high temperatures and UV radiation encountered with arc lamps leads to much more benign operating features for solid state laser systems employing laser diode pumps. Laser diode technology dates back to 1962 when laser action in GaAs diodes was first demonstrated. However, it

  12. Investigation of radial temperature gradients in diode pumped alkali lasers using tunable diode laser absorption spectroscopy

    Fox, Charles D.; Perram, Glen P.


    Heat loads in Diode Pumped Alkali Lasers (DPAL) have been investigated using a diode laser to probe the radial dependence of the absorbance. A TiS pump laser heats the medium in a T=50-100°C cesium heat pipe with 5 Torr nitrogen used for quenching. A tunable diode laser probes the spectral absorbance of the cesium cell. Local alkali concentration, temperature, and saturation broadening modify Voigt lineshapes in the wing of the hyperfine split lines. The temperature within the pumped volume exceeds the wall temperature by almost 200 C.

  13. Free-running emerald laser pumped by laser diode

    Zhenqiang Chen; Ge Zhang


    Free-running emerald laser pumped by 660-nm laser diode (LD) was reported. Free-running output powerof 24 mW has been obtained with overall efficiency of 1.4% and slope efficiency of 11.9% when the LD incident power was 2.56 W. The laser threshold value of emerald crystal was estimated to be 0.7 W.

  14. High power diode lasers for solid-state laser pumps

    Linden, Kurt J.; McDonnell, Patrick N.


    The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

  15. Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers

    Deri, R J


    Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and production capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a {approx} 200 {micro}s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and

  16. Diode-pumped Alexandrite ring laser for lidar applications

    Munk, A.; Jungbluth, B.; Strotkamp, M.; Hoffmann, H.-D.; Poprawe, R.; Höffner, J.


    We present design and performance data of a diode-pumped Q-switched Alexandrite ring laser in the millijoule regime, which is longitudinally pumped by laser diode bar modules in the red spectral range. As a first step, a linear resonator was designed and characterized in qcw operation as well as in Q-switched operation. Based on these investigations, two separate linear cavities were set up, each with one Alexandrite crystal longitudinally pumped by one diode module. The two cavities are fused together and form a ring cavity which yields up to 6 mJ pulse burst energy in the qcw regime at 770 nm.

  17. Efficient potassium diode pumped alkali laser operating in pulsed mode.

    Zhdanov, Boris V; Rotondaro, Matthew D; Shaffer, Michael K; Knize, Randall J


    This paper presents the results of our experiments on the development of an efficient hydrocarbon free diode pumped alkali laser based on potassium vapor buffered by He gas at 600 Torr. A slope efficiency of more than 50% was demonstrated with a total optical conversion efficiency of 30%. This result was achieved by using a narrowband diode laser stack as the pump source. The stack was operated in pulsed mode to avoid limiting thermal effects and ionization.

  18. Laser Diode Pumped Solid State Lasers


    CRYSTAL ._____ ____ &m? * Deuterated • Potassium Dihydrogen . Phosphate - ’ KD PO (KD*P) ~ .~ ,_ .i-; Deuterated Ceslum 43ssI6 1 .. r., Dihydrogen a buffer layer to absorb the thermal strain differential between the diode and a copper heatsink has also been suggested in the past and a recent...Potassium Titanium d33829-3 0.16 *; . ~ Penta- Phosphate - ’(20 na) ;A.: KTiOPOi (KTP) - Barium Sodium d33 8 43 .0j 4 eNilhatsh RA.NaNhO

  19. Diode-pumped 1123-nm Nd:YAG laser

    Xiaoping Guo(郭晓萍); Meng Chen(陈檬); Gang Li(李港); Bingyuan zhang(张炳元); Jiandong Yang(杨建东); Zhigang Zhang(张志刚); Yonggang Wang(王勇刚)


    We demonstrated a diode-pumped Nd:YAG laser with a plano-concave resonator. When the pump power is 1.57 W, the output power of 1123-nm laser is 132 mW at the temperature of 20 ℃, and the power change is less than 2% in an hour. A periodically poled LiNbOa (PPLN) was used as outer cavity frequency-doubling crystal and 561-nm laser was observed.

  20. High brightness diode-pumped organic solid-state laser

    Zhao, Zhuang; Nafa, Malik; Chénais, Sébastien; Forget, Sébastien


    High-power, diffraction-limited organic solid-state laser operation has been achieved in a vertical external cavity surface-emitting organic laser (VECSOL), pumped by a low-cost compact blue laser diode. The diode-pumped VECSOLs were demonstrated with various dyes in a polymer matrix, leading to laser emissions from 540 nm to 660 nm. Optimization of both the pump pulse duration and output coupling leads to a pump slope efficiency of 11% for a DCM based VECSOLs. We report output pulse energy up to 280 nJ with 100 ns long pump pulses, leading to a peak power of 3.5 W in a circularly symmetric, diffraction-limited beam.

  1. High brightness diode-pumped organic solid-state laser

    Zhao, Zhuang; Mhibik, Oussama; Nafa, Malik; Chénais, Sébastien; Forget, Sébastien


    High-power, diffraction-limited organic solid-state laser operation has been achieved in a vertical external cavity surface-emitting organic laser (VECSOL), pumped by a low-cost compact blue laser diode. The diode-pumped VECSOLs were demonstrated with various dyes in a polymer matrix, leading to laser emissions from 540 nm to 660 nm. Optimization of both the pump pulse duration and output coupling leads to a pump slope efficiency of 11% for a DCM based VECSOLs. We report output pulse energy up to 280 nJ with 100 ns long pump pulses, leading to a peak power of 3.5 W in a circularly symmetric, diffraction-limited beam.

  2. Development of diode-pumped medical solid-state lasers

    Kim, Cheol Jung; Kim, Min Suk


    Two thirds of human body consists of water and the absorption of laser by water is an important factor in medical laser treatment. Er medical lasers have been used in the dermatology, ophthalmology and dental treatments due to its highest absorption by water. However, 2.9 um Er laser can not be transmitted through an optical fiber. On the other hand, Tm laser can be transmitted through an fiber and also has very high absorption by water. Therefore, Tm lasers are used in ophthalmology and heart treatment wherein the fiber delivery is very important for the treatment. Until now, mainly lamp-pumped solid-state lasers have been used in medical treatments, but the lamp-pumped solid-state lasers are being replaced with the diode-pumped solid-state lasers because the diode-pumped solid-state lasers are more compact and much easier to maintain. Following this trend, end-pumped Er and side-pumped Tm lasers have been developed and the output power of 1 W was obtained for Er and Tm respectively.

  3. Dichroic mirror for diode pumped YAG:Nd-laser

    Dinca, Andreea; Skettrup, Torben; Lupei, V.


    The paper describes the design and realization of a dichroic mirror for a diode pumped YAG:Nd laser. The mirror is deposed on an optical glass substrate and works in optical contact with the laser crystal. The design was performed by admittance matching of the basic stack with the adjacent media...

  4. Wave optics simulation of diode pumped alkali laser (DPAL)

    Endo, Masamori; Nagaoka, Ryuji; Nagaoka, Hiroki; Nagai, Toru; Wani, Fumio


    A numerical simulation code for a diode pumped alkali laser (DPAL) was developed. The code employs the Fresnel- Kirchhoff diffraction integral for both laser mode and pump light propagations. A three-dimensional rate equation set was developed to determine the local gain. The spectral divergence of the pump beam was represented by a series of monochromatic beams with different wavelengths. The calculated results showed an excellent agreements with relevant experimental results. It was found that the main channel of the pump power drain is the spontaneous emission from the upper level of the lasing transition.

  5. Tapered Diode-pumped continuous-wave alexandrite laser


    Tapered diode-pumped continuous-wave alexandrite laser Ersen Beyatli,1 Ilyes Baali,2 Bernd Sumpf,3 Götz Erbert,3 Alfred Leitenstorfer,4 Alphan Sennaroglu,1 and Umit Demirbas2,4,* 1Laser Research Laboratory, Departments of Physics and Electrical-Electronics Engineering, Koç University, Rumelifeneri, Sariyer, Istanbul 34450, Turkey 2Laser Technology Laboratory, Department of Electrical and Electronics Engineering, Antalya International University, 07190 Dosemealti, Antalya,...

  6. Experimental study of the diode pumped alkali laser (DPAL)

    Endo, Masamori; Nagaoka, Ryuji; Nagaoka, Hiroki; Nagai, Toru; Wani, Fumio


    A small-scale cesium diode-pumped alkali laser (DPAL) apparatus has been developed for fundamental researches. A commercial laser diode with volume Bragg grating outcoupler is used to pump the gain cell longitudinally. Both windows of the gain cell are set at Brewster's angle for minimum loss and maximum durability. Output coupling coefficient is continuously variable from 13% to 85% by the slanted quartz plate outcoupler inserted in the optical resonator. Small signal gain is measured with a laser diode probe at various gain cell temperatures. A 6.5 W continuouswave output with 56% optical-to-optical conversion efficiency (based on the absorbed power) has been achieved. A numerical simulation code is developed and its calculation results are in good agreement with the experiments.

  7. Plasma formation in diode pumped alkali lasers sustained in Cs

    Markosyan, Aram H.; Kushner, Mark J.


    In diode pumped alkali lasers (DPALs), lasing action occurs on the resonant lines of alkali atoms following pumping by broadband semiconductor lasers. The goal is to convert the efficient but usually poor optical quality of inexpensive diode lasers into the high optical quality of atomic vapor lasers. Resonant excitation of alkali vapor leads to plasma formation through the excitation transfer from the 2P states to upper lying states, which then are photoionized by the pump and intracavity radiation. A first principles global model was developed to investigate the operation of the He/Cs DPAL system and the consequences of plasma formation on the efficiency of the laser. Over a range of pump powers, cell temperatures, excitation frequency, and mole fraction of the collision mixing agent (N2 or C2H6), we found that sufficient plasma formation can occur that the Cs vapor is depleted. Although N2 is not a favored collisional mixing agent due to large rates of quenching of the 2P states, we found a range of pump parameters where laser oscillation may occur. The poor performance of N2 buffered systems may be explained in part by plasma formation. We found that during the operation of the DPAL system with N2 as the collisional mixing agent, plasma formation is in excess of 1014-1015 cm-3, which can degrade laser output intensity by both depletion of the neutral vapor and electron collisional mixing of the laser levels.

  8. Laser-diode-pumped 1319-nm monolithic non-planar ring single-frequency laser

    Qing Wang(王青); Chunqing Gao(高春清); Yan Zhao(赵严); Suhui Yang(杨苏辉); Guanghui Wei(魏光辉); Dongmei Hong(洪冬梅)


    Single-frequency 1319-nm laser was obtained by using a laser-diode-pumped monolithic Nd:YAG crystalwith a non-planar ring oscillator (NPRO). When the NPRO laser was pumped by an 800-μm fiber coupledlaser diode, the output power of the single-frequency 1319-nm laser was 220 mW, and the slope efficiencywas 16%. With a 100-μm fiber coupled diode laser pumped, 99-mW single-frequency 1319-nm laser wasobtained with a slope efficiency of 29%.

  9. Method and system for homogenizing diode laser pump arrays

    Bayramian, Andrew James


    An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

  10. 980nm diode laser pump modules operating at high temperature

    Campbell, Jenna; Semenic, Tadej; Leisher, Paul; Bhunia, Avijit; Mashanovitch, Milan; Renner, Daniel


    Existing thermal management technologies for diode laser pumps place a significant load on the size, weight and power consumption of High Power Solid State and Fiber Laser systems, thus making current laser systems very large, heavy, and inefficient in many important practical applications. This problem is being addressed by the team formed by Freedom Photonics and Teledyne Scientific through the development of novel high power laser chip array architectures that can operate with high efficiency when cooled with coolants at temperatures higher than 50 degrees Celsius and also the development of an advanced thermal management system for efficient heat extraction from the laser chip array. This paper will present experimental results for the optical, electrical and thermal characteristics of 980 nm diode laser pump modules operating effectively with liquid coolant at temperatures above 50 degrees Celsius, showing a very small change in performance as the operating temperature increases from 20 to 50 degrees Celsius. These pump modules can achieve output power of many Watts per array lasing element with an operating Wall-Plug-Efficiency (WPE) of >55% at elevated coolant temperatures. The paper will also discuss the technical approach that has enabled this high level of pump module performance and opportunities for further improvement.

  11. Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika


    electro-optical efficiency of the diode laser. Autocorrelation measurements show that pulse widths of less than 20 fs can be expected with an average power of 52 mW when using our laser. These results indicate the high potential of direct diode laser pumped Ti: sapphire lasers to be used in applications...... like retinal optical coherence tomography (OCT) or pumping of photonic crystal fibers for CARS (coherent anti-stokes Raman spectroscopy) microscopy....

  12. Analysis of Thermal Effects in Laser Rod Pumped by Repetitively Pulsed Laser Diode Array

    DAI Qin; LI Xin-zhong; WU Ri-na; WANG Xi-jun


    Based on some assumptions, the numerical model of thermal distribution in solid state laser crystal pumped by pulsed laser diode is set up due to the pumped intensity distribution. Taking into account the property of YAG materials that varies with temperature, the transient temperature distribution of the laser crystal is calculated using finite element method on condition that K is a constant and a function of temperature. Then, the influence of the pumping parameters on the thermal effect in laser crystal is also discussed. This study is helpful to optimize the design of the diode side pumped solid state lasers.

  13. Frequency-doubled diode laser for direct pumping of Ti:sapphire lasers

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika


    A single-pass frequency doubled high-power tapered diode laser emitting nearly 1.3 W of green light suitable for direct pumping of Ti:sapphire lasers generating ultrashort pulses is demonstrated. The pump efficiencies reached 75 % of the values achieved with a commercial solid-state pump laser....... However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20...... fs are measured. These results open the opportunity of establishing diode laser pumped Ti:sapphire lasers for e.g. biophotonic applications like retinal optical coherence tomography or pumping of photonic crystal fibers for CARS microscopy....

  14. 946 nm Diode Pumped Laser Produces 100mJ

    Axenson, Theresa J.; Barnes, Norman P.; Reichle, Donald J., Jr.


    An innovative approach to obtaining high energy at 946 nm has yielded 101 mJ of laser energy with an optical-to-optical slope efficiency of 24.5%. A single gain module resonator was evaluated, yielding a maximum output energy of 50 mJ. In order to obtain higher energy a second gain module was incorporated into the resonator. This innovative approach produced un-surprised output energy of 101 mJ. This is of utmost importance since it demonstrates that the laser output energy scales directly with the number of gain modules. Therefore, higher energies can be realized by simply increasing the number of gain modules within the laser oscillator. The laser resonator incorporates two gain modules into a folded "M-shaped" resonator, allowing a quadruple pass gain within each rod. Each of these modules consists of a diode (stack of 30 microlensed 100 Watt diode array bars, each with its own fiber lens) end-pumping a Nd:YAG laser rod. The diode output is collected by a lens duct, which focuses the energy into a 2 mm diameter flat to flat octagonal pump area of the laser crystal. Special coatings have been developed to mitigate energy storage problems, including parasitic lasing and amplified spontaneous emission (ASE), and encourage the resonator to operate at the lower gain transition at 946 nm.

  15. Neodymium YAG lasers pumped by light-emitting diodes

    Bilak, V.I.; Goldobin, I.S.; Zverev, G.M.; Kuratev, I.I.; Pashkov, V.A.; Stel' makh, M.F.; Tsvetkov, Y.V.; Solov' eva, N.M.


    The results are presented of theoretical and experimental investigations of room-temperature YAG:Nd lasers pumped by light-emitting diodes. The lasing characteristics of a laser operated at the 1.06 and 1.32 wavelengths were investigated in the cw and pulsed regimes and dependences of its parameters on the temperature, pulse repetition frequency, and other factors were studied. In the pulsed regime the laser efficiency was 0.2% and in the cw regime the radiation power reached 50 and 17 mW at the 1.06 and 1.32 wavelengths, respectively.

  16. A Laser-Diode End-Pumped Nd:YVO4 Slab Laser at 1342 nm

    YAN Ying; ZHANG Heng-Li; LIU Yang; XING Ji-Chuan; XIN Jian-Guo


    A laser-diode end-pumped Nd:YV04 slab laser with a fiat-concave stable cavity at 1342nm is demonstrated. Under the pumping power of 92 W, a cw laser of output 17.8 W is obtained with the slope efficiency of 25.6%.

  17. Diode-pumped Yb3+:KYF4 femtosecond laser.

    Coluccelli, Nicola; Galzerano, Gianluca; Tonelli, Mauro; Laporta, Paolo; Svelto, Orazio


    Passive mode locking of a diode-pumped Yb(3+):KYF(4) laser is demonstrated using a semiconductor saturable absorber mirror. A high-stability, transform-limited pulse train with a repetition rate of 57 MHz is generated. Solitonlike pulses with maximum average output power of 250 mW, minimum pulse duration of 170 fs, and rms time jitter of 360 fs were obtained.

  18. Narrow line diode laser stacks for DPAL pumping

    Koenning, Tobias; Irwin, David; Stapleton, Dean; Pandey, Rajiv; Guiney, Tina; Patterson, Steve


    Diode pumped alkali metal vapor lasers (DPALs) offer the promise of scalability to very high average power levels while maintaining excellent beam quality, making them an attractive candidate for future defense applications. A variety of gain media are used and each requires a different pump wavelength: near 852nm for cesium, 780nm for rubidium, 766nm for potassium, and 670nm for lithium atoms. The biggest challenge in pumping these materials efficiently is the narrow gain media absorption band of approximately 0.01nm. Typical high power diode lasers achieve spectral widths around 3nm (FWHM) in the near infrared spectrum. With state of the art locking techniques, either internal to the cavity or externally mounted gratings, the spectral width can typically be reduced to 0.5nm to 1nm for kW-class, high power stacks. More narrow spectral width has been achieved at lower power levels. The diode's inherent wavelength drift over operating temperature and output power is largely, but not completely, eliminated. However, standard locking techniques cannot achieve the required accuracy on the location of the spectral output or the spectral width for efficient DPAL pumping. Actively cooled diode laser stacks with continuous wave output power of up to 100W per 10mm bar at 780nm optimized for rubidium pumping will be presented. Custom designed external volume holographic gratings (VHGs) in conjunction with optimized chip material are used to narrow and stabilize the optical spectrum. Temperature tuning on a per-bar-level is used to overlap up to fifteen individual bar spectra into one narrow peak. At the same time, this tuning capability can be used to adjust the pump wavelength to match the absorption band of the active medium. A spectral width of <0.1nm for the entire stack is achieved at <1kW optical output power. Tuning of the peak wavelength is demonstrated for up to 0.15nm. The technology can easily be adapted to other diode laser wavelengths to pump different materials.

  19. Diode-Pumped Mode-Locked LiSAF Laser



    Under this contract we have developed Cr{sup 3+}:LiSrAlF{sub 6} (Cr:LiSAF, LiSAF) mode-locked lasers suitable for generation of polarized electrons for CEBAF. As 670 nm is an excellent wavelength for optical pumping of Cr:LiSAF, we have used a LIGHTWAVE developed 670 nm diode pump module that combines the output of ten diode lasers and yields approximately 2 Watts of optical power. By the use of a diffraction limited pump beam however, it is possible to maintain a small mode size through the length of the crystal and hence extract more power from Cr:LiSAF laser. For this purpose we have developed a 1 Watt, red 660nm laser (LIGHTWAVE model 240R) which serves as an ideal pump for Cr:LiSAF and is a potential replacement of costly and less robust krypton laser. This new system is to compliment LIGHTWAVE Series 240, and is currently being considered for commercialization. Partially developed under this contract is LIGHTWAVEs product model 240 which has already been in our production lines for a few months and is commercially available. This laser produces 2 Watts of output at 532 nm using some of the same technology developed for production of the 660nm red system. It is a potential replacement for argon ion lasers and has better current and cooling requirements and is an excellent pump source for Ti:Al{sub 2}O{sub 3}. Also, as a direct result of this contract we now have the capability of commercially developing a mode-locked 100MHz Cr:LiSAF system. Such a laser could be added to our 100 MHz LIGHTWAVE Series 131. The Series 131 lasers provide pico second pulses and were originally developed under another DOE SBIR. Both models of LIGHTWAVE Series 240 lasers, the fiber coupled pump module and the 100MHz LiSAF laser of Series 131 have been partially developed under this contract, and are commercially competitive products.

  20. Polarization/Spatial Combining of Laser-Diode Pump Beams

    Gelsinger, Paul; Liu, Duncan


    A breadboard version of an optical beam combiner is depicted which make it possible to use the outputs of any or all of four multimode laser diodes to pump a non-planar ring oscillator (NPRO) laser. The output of each laser diode has a single-mode profile in the meridional plane containing an axis denoted the 'fast' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis. One of the purposes served by the beam-combining optics is to reduce the fast-axis numerical aperture (NA) of the laser-diode output to match the NA of the optical fiber. Along the slow axis, the unmodified laser-diode NA is already well matched to the fiber optic NA, so no further slow-axis beam shaping is needed. In this beam combiner, the laser-diode outputs are collimated by aspherical lenses, then half-wave plates and polarizing beam splitters are used to combine the four collimated beams into two beams. Spatial combination of the two beams and coupling into the optical fiber is effected by use of anamorphic prisms, mirrors, and a focusing lens. The anamorphic prisms are critical elements in the NA-matching scheme, in that they reduce the fast-axis beam width to 1/6 of its original values. Inasmuch as no slow-axis beam shaping is needed, the collimating and focusing lenses are matched for 1:1 iumaging. Because these lenses are well corrected for infinite conjugates the combiner offers diffraction-limited performance along both the fast and slow axes.

  1. Four-Pass Coupler for Laser-Diode-Pumped Solid-State Laser

    Coyle, Donald B.


    A four-pass optical coupler affords increased (in comparison with related prior two-pass optical couplers) utilization of light generated by a laser diode in side pumping of a solid-state laser slab. The original application for which this coupler was conceived involves a neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal slab, which, when pumped by a row of laser diodes at a wavelength of 809 nm, lases at a wavelength of 1,064 nm. Heretofore, typically, a thin laser slab has been pumped in two passes, the second pass occurring by virtue of reflection of pump light from a highly reflective thin film on the side opposite the side through which the pump light enters. In two-pass pumping, a Nd:YAG slab having a thickness of 2 mm (which is typical) absorbs about 84 percent of the 809-nm pump light power, leaving about 16 percent of the pump light power to travel back toward the laser diodes. This unused power can cause localized heating of the laser diodes, thereby reducing their lifetimes. Moreover, if the slab is thinner than 2 mm, then even more unused power travels back toward the laser diodes. The four-pass optical coupler captures most of this unused pump light and sends it back to the laser slab for two more passes. As a result, the slab absorbs more pump light, as though it were twice as thick. The gain and laser cavity beam quality of a smaller laser slab in conjunction with this optical coupler can thus be made comparable to those of a larger two-pass-pumped laser slab.

  2. High-efficiency diode-pumped femtosecond Yb:YAG ceramic laser

    Zhou, Binbin; Wei, Z.Y.; Zou, Y.W.


    A highly efficient diode-end-pumped femtosecond Yb:yttrium aluminum garnet (YAG) ceramic laser was demonstrated. Pumped by a 968 nm fiber-coupled diode laser, 1.9 W mode-locked output power at a repetition rate of 64.27 MHz was obtained with 3.5 W absorbed pump power, corresponding to a slope...

  3. Diode pumped erbium cascade fiber lasers

    Jackson, Stuart D.; Pollnau, Markus; Li, Jianfeng

    Cascading the 4I11/2 -> 4I13/2 transition at 2.8 μm and 4I13/2 -> 4I15/2 transition at 1.6 μm offers a solution to the thermal management of high power Er3+-doped fluoride fiber lasers. We demonstrate an output power of 8.2 W at 2.8 μm from an Er3+-doped fluorozirconate fiber laser with 56 W of

  4. Diode-pumped all-solid-state lasers and applications

    Parsons-Karavassilis, D


    This thesis describes research carried out by the within the Physics Department at Imperial College that was aimed at developing novel all-solid-state laser sources and investigating potential applications of this technology. A description of the development, characterisation and application of a microjoule energy level, diode-pumped all-solid-state Cr:LiSGAF femtosecond oscillator and regenerative amplifier system is presented. The femtosecond oscillator was pumped by two commercially available laser diodes and produced an approx 80 MHz pulse train of variable pulse duration with approx 30 mW average output power and a tuning range of over approx 60 nm. This laser oscillator was used to seed a regenerative amplifier, resulting in adjustable repetition rate (single pulse to 20 kHz) approx 1 mu J picosecond pulses. These pulses were compressed to approx 150 fs using a double-pass twin-grating compressor. The amplifier's performance was investigated with respect to two different laser crystals and different pul...

  5. Analysis of Laser Diode Pumped Solid-State Laser Resonator by the Transform Circle Approach

    SONG Feng; ZHANG Guang-Yin; XU Jing-Jun; ZHANG Chao-Bo


    The typical laser characteristics of a laser diode pumped solid-state laser with a Z-type resonator structure are analyzed by the transform circle approach. Laser waists change with the thermal focus length of the lasing medium so that the output power becomes unstable. In particular, there is a very unstable operation region when the pump power is of medium magnitude. A method is put forward to avoid this situation.

  6. The analytical investigation of temperature distribution in off-central diode-pumped lasers

    P Ealhi; A Taghavi; A Gharaati


    The influence of displacement of the pump source with respect to the crystal center on the thermal behavior of the laser crystal is studied analytically. We consider the pump energy to be deposited into the pump region which has been slightly displaced with respect to the crystal center. An analytical expression for temperature distribution for such off-central diode-pumped laser is investigated. The results are then applied to the Nd :YAG and Nd :YVO4 laser crystals and compared with the conventional diode-pumped lasers. We showed that in this special case, the temperature distribution equation in the off-central pumping convert to the conventional central pump scheme.

  7. Optimized high-power diode laser, laser arrays, and bars for pump applications

    Hülsewede, R.; Schulze, H.; Sebastian, J.; Schröder, D.; Meusel, J.; Wolf, J.; Hennig, P.


    Broad area diode laser and diode laser bars are the most efficient light sources. In comparison to solid state laser or gas laser systems the over all beam quality of the diode laser is poor. Thus most application of diode laser bars is high efficient pumping of solid state lasers converting the beam quality and scaling the power of laser systems within the kW range. The pump efficiency and the beam coupling efficiency of the diode laser pumped systems has to be increased to meet the increasing laser market demands for reduced costs. JENOPTIK Diode Lab GmbH (JDL) has optimized their high power brilliance bars to enable reliable high power operation especially, for the 9xx nm wavelength range and low far field divergences. Superior reliability with long operation time of 13,000 hours and high power operation of 200 W are demonstrated for high power bars high filling factor mounted on passively cooled heat sinks. Smaller far field divergence at high power levels requires longer cavity length and higher efficiencies in the beam coupling needs requires lower filling factors. The new high brilliance bars and arrays with 20% filling factor are showing high power operation up to 95 W and a slow axis beam divergence of less than 8° (95% power content).

  8. Polarization properties of laser-diode-pumped micro-grained Nd:YAG ceramic lasers

    Otsuka, Kenju


    Detailed polarization properties have been examined in laser-diode-pumped (LD-pumped) micro-grained ceramic Nd:YAG lasers in different microchip cavity configurations. Stable linearly-polarized single-frequency oscillations, whose polarization direction coincides with that of an LD pump light, were observed in an external cavity scheme. While, in the case of a thin-slice laser scheme with coated reflective ends, elliptically-polarized single-frequency operations took place in the low pump-power regime and dynamic instabilities appeared, featuring self-induced antiphase modulations among counter-rotating circularly-polarized components belonging to the same longitudinal mode, with increasing the pump power

  9. Stable 811.53 nm diode laser pump source for optically pumped metastable Ar laser

    Gao, Jun; Zuo, Duluo; Zhao, Jun; Li, Bin; Yu, Anlan; Wang, Xinbing


    A stable external cavity diode laser coupled with volume Bragg grating for metastable argon atoms pumping is presented. The measured maximum output power of the continuous wave is 6.5 W when the spectral width (FWHM) is less than 21 pm around 811.53 nm and the power efficiency is 68%. The tuning range of the emission wavelength is bigger than 270 pm. The calculated deviation in relative absorption efficiency caused by the fluctuations of wavelength and power is less than 4%.

  10. Continuously tunable solution-processed organic semiconductor DFB lasers pumped by laser diode

    Klinkhammer, Sönke; Liu, Xin; Huska, Klaus


    solutions on cm-scale surface gratings of different periods. We report optically pumped continuously tunable laser emission of 13 nm in the blue, 16 nm in the green and 19 nm in the red spectral region on a single chip respectively. Tuning behavior can be described with the Bragg-equation and the measured...... thickness profile. The laser threshold is low enough that inexpensive laser diodes can be used as pump sources....

  11. High efficient diode-pumped Tm:YAP laser at room temperature

    Yufeng Li; Baoquan Yao; Yuezhu Wang; Youlun Ju; Guangjun Zhao; Yanhua Zong; Jun Xu


    A high efficient diode-pumped Tm:YAP laser is reported. The maximum output power at 1981 nm is 5.2 W and the slope efficiency is 30%. Unpolarized absorption near 800 nm and unpolarized fluorescence spectra near 1800 nm pumped by laser diode (LD) are measured. In addition, the relationship between operation temperature and output power is discussed.

  12. Single-frequency operation of a diode-pumped green laser using multi-Brewster plates

    Quan Zheng(郑权); Ling Zhao(赵岭); Longsheng Qian(钱龙生)


    In a diode-pumped, KTP intracavity frequency-doubled green laser, multi-Brewster plates are used toachieve high power single-frequency operation. With a simple experimental setup, single-frequency opera-tion of the diode-pumped green laser with output of 46 and 218 mW is obtained by one and three Brewsterplate, respectively.

  13. Laser-diode and Flash Lamp Pumped Solid-State Lasers

    Garrec, Bruno Le


    Since the early 80's, most authors are considering that to enable high-average-power operation at the highest laser efficiency, it is necessary to replace flash lamp pumped solid-state lasers with laser-diode pumped solid-state lasers. This assumption is based on the fact that diode pumping has many advantages compared to flash lamp pumping that is seen as an old technology. Although it is very difficult to get true numbers, we shall show that Diode Pumped Solid State Lasers nearby the kW level have a moderate efficiency (Flash lamp pumped fusion lasers are still in the run with a low efficiency but can access high beam quality and high harmonic generation efficiency. For the ELI project, we believe that considering a flash lamp pumped laser makes sense when the amplifier can run at 1 shot/mn to delivering 200J of green light. We shall show that it is an engineering problem to be solved with the help of: adaptive optic and large non linear crystals.

  14. High power pump laser diodes for 2μm fibre laser

    Pawlik, S.; Todt, R.; Moser, M.; Romero, O.; Lichtenstein, N.


    We report on our recent developments at II-VI Laser Enterprise of laser diode sources for the 79x nm range. High power conversion efficiency in excess of 62% was demonstrated. For high power applications like Thulium fiber laser pumping we have achieved an output power of more than 12.5W in CW operation for 94 μm wide broad-area single-emitters. We added the functionality of wavelength stabilization to the laser diodes by using a distributed feedback grating (DFB). Locking has been obtained over the full current range between 1A and 4A tested so far with some margin for temperature variation. For efficient fiber laser pumping the laser diodes were integrated in a multi-emitter platform, achieving 38 W out of a 105 μm fiber within 0.15 NA.

  15. Challenges of high power diode-pumped lasers for fusion energy

    Bruno; Le; Garrec


    This paper reviews the different challenges that are encountered in the delivery of high power lasers as drivers for fusion energy.We will focus on diode-pumped solid-state lasers and we will highlight some of the main recent achievements when using ytterbium,cryogenic cooling and ceramic gain media.Apart from some existing fusion facilities and some military applications of diode-pumped solid-state lasers,we will show that diode-pumped solid-state lasers are scalable to inertial fusion energy(IFE)’s facility level and that the all-fiber laser scheme is very promising.

  16. Comparison of different side-pumping configurations for high power laser diode pumped solid-state laser

    Junqing Meng(孟俊清); Weibiao Chen(陈卫标); Xia Hou(侯霞); Qiquan Hu(胡企铨)


    Ray-tracing method is used to simulate the distribution of absorption in crystal rod for different sidepumping configuration. The distribution of pumping power and absorption efficiency is compared, and the numerical results are presented. The results show that the more uniform pumping and the higher absorption coefficient are obtained with a diffuse cavity. And the method of the slow axis of laser diode stack perpendicular to the axis of lasing gives the higher central pumping density.

  17. Pump polarization insensitive and efficient laser-diode pumped Yb:KYW ultrafast oscillator.

    Wang, Sha; Wang, Yan-Biao; Feng, Guo-Ying; Zhou, Shou-Huan


    We theoretically and experimentally report and evaluate a novel split laser-diode (LD) double-end pumped Yb:KYW ultrafast oscillator aimed at improving the performance of an ultrafast laser. Compared to a conventional unpolarized single-LD end-pumped ultrafast laser system, we improve the laser performance such as absorption efficiency, slope efficiency, cw mode-locking threshold, and output power by this new structure LD-pumped Yb:KYW ultrafast laser. Experiments were carried out with a 1 W output fiber-coupled LD. Experimental results show that the absorption increases from 38.7% to 48.4%, laser slope efficiency increases from 18.3% to 24.2%, cw mode-locking threshold decreases 12.7% from 630 to 550 mW in cw mode-locking threshold, and maximum output-power increases 28.5% from 158.4 to 221.5 mW when we switch the pump scheme from an unpolarized single-end pumping structure to a split LD double-end pumping structure.

  18. High-Efficiency High-Power Nd:YAG Laser under 885 nm Laser Diode Pumping

    LI Fang-Qin; ZHANG Xiao-Fu; ZONG Nan; YANG Jing; PENG Qin-Jun; CUI Da-Fu; XU Zu-Yan


    A high-efficiency high-power Nd:YAG laser under 885 nm laser diode (LD) pumping is demonstrated. The laser crystal is carefully designed, and the overlapping between the pump modes and the laser modes is optimized. The maximum output power at 1064 nm is 87 W under the absorbed pump power 127.7 W, corresponding to a slope efficiency of 72.4% and an optical-optical efficiency of 68.1%. The optical-optical efficiency is 58.4% for the pump power emitted directly from the LD. To our best knowledge, this is the maximal optical-optical conversion efficiency obtained for the LD end-pumped Nd:YAG lasers so far.

  19. Investigation of laser diode face-pumped high average power heat capacity laser

    Shenjin Zhang; Shouhuan Zhou; Xiaojun Tang; Guojiang Bi; Huachang LV


    The three-dimensional (3D) pump intensity distribution in medium of the laser diode (LD) pumped highaverage power heat capacity laser is simulated by the ray tracing method, and the divergence characteristicsof fast axis and slow axis of LD are simultaneously considered. The transient 3D temperature and stressdistributions are also simulated by the finite element method (FEM) with considering the uneven heatsource distribution in medium. A LD face-pumped Nd:GGG heat capacity laser is designed. The averageoutput power is 1.49 kW with an optical-optical efficiency of 24.1%.

  20. Continuously tunable solution-processed organic semiconductor DFB lasers pumped by laser diode.

    Klinkhammer, Sönke; Liu, Xin; Huska, Klaus; Shen, Yuxin; Vanderheiden, Sylvia; Valouch, Sebastian; Vannahme, Christoph; Bräse, Stefan; Mappes, Timo; Lemmer, Uli


    The fabrication and characterization of continuously tunable, solution-processed distributed feedback (DFB) lasers in the visible regime is reported. Continuous thin film thickness gradients were achieved by means of horizontal dipping of several conjugated polymer and blended small molecule solutions on cm-scale surface gratings of different periods. We report optically pumped continuously tunable laser emission of 13 nm in the blue, 16 nm in the green and 19 nm in the red spectral region on a single chip respectively. Tuning behavior can be described with the Bragg-equation and the measured thickness profile. The laser threshold is low enough that inexpensive laser diodes can be used as pump sources.

  1. High repetition rate femtosecond dye amplifier using a laser diode pumped neodymium:YAG laser

    Zysset, B.; LaGasse, M.J.; Fujimoto, J.G.; Kafka, J.D.


    A high repetition rate femtosecond dye amplifier is demonstrated using a laser diode pumped Q-switched Nd:YAG laser. Amplification of wavelength tunable 300 fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  2. High repetition rate femtosecond dye amplifier using a laser diode pumped neodymium:YAG laser

    Zysset, B.; LaGasse, M. J.; Fujimoto, J. G.; Kafka, J. D.


    A high repetition rate femtosecond dye amplifier is demonstrated using a laser diode pumped Q-switched Nd:YAG laser. Amplification of wavelength tunable 300 fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  3. Quasi-CW Diode Laser End-pumped Yb3+∶GlassMicrochip Laser

    DAI Shixun; HU Lili; LIU Zhuping; HUANG Guosong; JIANG Zhonghong; YASUKAZU Izawa


    Quasi-CW diode-pumped Yb3+∶borate glass and Yb3+∶phosphate glass microchip lasers have been reported. From Yb3+∶phosphate glass laser, the maximum average output power was 31 mW and the optical-optical conversion efficiency was 5%.The maximum average output power was 18 mW, and optical-optical conversion efficiency was 3% for Yb3+∶borate glass laser.

  4. Improving Lifetime of Quasi-CW Laser Diode Arrays for Pumping 2-Micron Solid State Lasers

    Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Singh, Upendra N.; Kavaya, Michael J.


    Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data on the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

  5. Fibre-coupled red diode-pumped Alexandrite TEM00 laser with single and double-pass end-pumping

    Arbabzadah, E. A.; Damzen, M. J.


    We report the investigation of an Alexandrite laser end-pumped by a fibre-coupled red diode laser module. Power, efficiency, spatial, spectral, and wavelength tuning performance are studied as a function of pump and laser cavity parameters. It is the first demonstration, to our knowledge, of greater than 1 W power and also highest laser slope efficiency (44.2%) in a diode-pumped Alexandrite laser with diffraction-limited TEM00 mode operation. Spatial quality was excellent with beam propagation parameter M 2 ~ 1.05. Wavelength tuning from 737-796 nm was demonstrated using an intracavity birefringent tuning filter. Using a novel double pass end-pumping scheme to get efficient absorption of both polarisation states of the scrambled fibre-delivered diode pump, a total output coupled power of 1.66 W is produced in TEM00 mode with 40% slope efficiency.

  6. High-average-power diode-pumped Yb: YAG lasers

    Avizonis, P V; Beach, R; Bibeau, C M; Emanuel, M A; Harris, D G; Honea, E C; Monroe, R S; Payne, S A; Skidmore, J A; Sutton, S B


    A scaleable diode end-pumping technology for high-average-power slab and rod lasers has been under development for the past several years at Lawrence Livermore National Laboratory (LLNL). This technology has particular application to high average power Yb:YAG lasers that utilize a rod configured gain element. Previously, this rod configured approach has achieved average output powers in a single 5 cm long by 2 mm diameter Yb:YAG rod of 430 W cw and 280 W q-switched. High beam quality (M{sup 2} = 2.4) q-switched operation has also been demonstrated at over 180 W of average output power. More recently, using a dual rod configuration consisting of two, 5 cm long by 2 mm diameter laser rods with birefringence compensation, we have achieved 1080 W of cw output with an M{sup 2} value of 13.5 at an optical-to-optical conversion efficiency of 27.5%. With the same dual rod laser operated in a q-switched mode, we have also demonstrated 532 W of average power with an M{sup 2} < 2.5 at 17% optical-to-optical conversion efficiency. These q-switched results were obtained at a 10 kHz repetition rate and resulted in 77 nsec pulse durations. These improved levels of operational performance have been achieved as a result of technology advancements made in several areas that will be covered in this manuscript. These enhancements to our architecture include: (1) Hollow lens ducts that enable the use of advanced cavity architectures permitting birefringence compensation and the ability to run in large aperture-filling near-diffraction-limited modes. (2) Compound laser rods with flanged-nonabsorbing-endcaps fabricated by diffusion bonding. (3) Techniques for suppressing amplified spontaneous emission (ASE) and parasitics in the polished barrel rods.

  7. Diode-pumped Q-switched Nd{sup 3+} : YAG laser operating in a wide temperature range without thermal stabilisation of pump diodes

    Vainshenker, A E; Vilenskiy, A V; Kazakov, A A; Lysoy, B G; Mikhailov, L K; Pashkov, V A [Open Joint-Stock Company ' M.F. Stel' makh Polyus Research and Development Institute' , Moscow (Russian Federation)


    A model sample of a compact low-power-consumption Nd{sup 3+} : YAG laser emitting 20-mJ pulses with a pulse repetition rate up to 20 Hz (in cyclic duty) at a wavelength of 1064 nm is developed and studied. The laser is designed for operating at external temperatures from -40 to +50 deg C. This was achieved by using quasi-end diode pumping without thermal stabilisation of pump diodes. (laser optics 2012)

  8. New class of compact diode pumped sub 10 fs lasers for biomedical applications

    Le, T.; Mueller, A.; Sumpf, B.;


    -laser. In this work we present an alternative method by deploying frequency-doubled IR diodes with good beam qualities to pump fs-lasers. The revolutionary approach allows choosing any pump wavelengths in the green region and avoids complicated relay optics for the diodes. For the first time we show results...... of a diode-pumped 10 fs-laser and how a single diode setup can be integrated into a 30 x 30 cm(2) fs-laser system generating sub 20 fs laser pulses with output power towards half a Watt. This technology paves the way for a new class of very compact and cost-efficient fs-lasers for life science and industrial...... applications....

  9. Spherical distribution structure of the semiconductor laser diode stack for pumping

    Zhao Tianzhuo; Yu Jin; Liu Yang; Zhang Xue; Ma Yunfeng; Fan Zhongwei


    A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling efficiency.The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium.The efficiency of the hollow light pipe,which is used for semiconductor laser diode stack coupling,is analyzed by geometric optics and ray tracing.Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure.Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system,and guides parameter optimization.Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency,reduce the optimum duct length and improve the output energy field distribution.

  10. High-temperature diode laser pumps for directed energy fiber lasers (Conference Presentation)

    Kanskar, Manoj; Bao, Ling; Chen, Zhigang; DeVito, Mark; Dong, Weimin; Grimshaw, Mike P.; Guan, Xinguo; Hemenway, David M.; Martinsen, Robert; Zhang, Jim; Zhang, Shiguo


    Kilowatt-class fiber lasers and amplifiers are becoming increasingly important building blocks for power-scaling laser systems in various different architectures for directed energy applications. Currently, state-of-the-art Yb-doped fiber lasers operating near 1060 nm operate with optical-to-optical power-conversion efficiency of about 66%. State-of-the-art fiber-coupled pump diodes near 975 nm operate with about 50% electrical-to-fiber-coupled optical power conversion efficiency at 25C heatsink temperature. Therefore, the total system electrical-to-optical power conversion efficiency is about 33%. As a result, a 50-kW fiber laser will generate 75 kW of heat at the pump module and 25 kW at the fiber laser module with a total waste heat of 100 kW. It is evident that three times as much waste heat is generated at the pump module. While improving the efficiency of the diodes primarily reduces the input power requirement, increasing the operating temperature primarily reduces the size and weight for thermal management systems. We will discuss improvement in diode laser design, thermal resistance of the package as well as improvement in fiber-coupled optical-to-optical efficiency to achieve high efficiency at higher operating temperature. All of these factors have a far-reaching implication in terms of significantly improving the overall SWAP requirements thus enabling DEW-class fiber lasers on airborne and other platforms.

  11. 550-W diode-pumped Nd:YAG disk laser

    Zhenyu Yao; Jianfeng Jiang; Bo Tu; Tangjian Zhou; Lingling Cui


    When a thin laser crystal disk is used with a nearly flat-top pump profile, the heat flux can be considered to be one-dimensional. This results in a homogeneous temperature and stress profile within the laser medium leading to reduction of thermal effects. A nearly flat-top pump profile is achieved with a two-pass cylindrical-lens coupling system. An average output power of 550 W is obtained by an average pumping

  12. Functional possibilities for forming different inverse population distributions in diode-side-pumped laser heads

    Grechin, S G; Nikolaev, P P; Sharandin, E A [N.E. Bauman Moscow State Technical University, Moscow (Russian Federation)


    The functional possibilities of diode-side-pumped laser heads of solid-state lasers for forming inverse population distributions of different types are analysed. The invariants determining the relationship between the laser head parameters upon scaling are found. The results of comparative experimental studies are presented. (lasers)

  13. Methane-based in situ temperature rise measurement in a diode-pumped rubidium laser.

    Wang, Rui; Yang, Zining; Wang, Hongyan; Xu, Xiaojun


    We measured active zone temperature rise of an operational diode-pumped rubidium laser non-perturbatively with methane-based near-infrared tunable diode laser spectroscopy (TDLAS). For a Rb+ methane diode-pumped alkali laser (DPAL), the temperature rise was obtained. Especially, the temperature differences (∼10  K) between lasing and un-lasing cases were well identified, which demonstrated a high sensitivity of the method. To our knowledge, this is the first demonstration of extending the methane-based TDLAS method to DPAL study.

  14. Improved performance of high average power semiconductor arrays for applications in diode pumped solid state lasers

    Beach, R.; Emanuel, M.; Benett, W.; Freitas, B.; Ciarlo, D.; Carlson, N.; Sutton, S.; Skidmore, J.; Solarz, R.


    The average power performance capability of semiconductor diode laser arrays has improved dramatically over the past several years. These performance improvements, combined with cost reductions pursued by LLNL and others in the fabrication and packaging of diode lasers, have continued to reduce the price per average watt of laser diode radiation. Presently, we are at the point where the manufacturers of commercial high average power solid state laser systems used in material processing applications can now seriously consider the replacement of their flashlamp pumps with laser diode pump sources. Additionally, a low cost technique developed and demonstrated at LLNL for optically conditioning the output radiation of diode laser arrays has enabled a new and scalable average power diode-end-pumping architecture that can be simply implemented in diode pumped solid state laser systems (DPSSL`s). This development allows the high average power DPSSL designer to look beyond the Nd ion for the first time. Along with high average power DPSSL`s which are appropriate for material processing applications, low and intermediate average power DPSSL`s are now realizable at low enough costs to be attractive for use in many medical, electronic, and lithographic applications.

  15. Diode-pumped double passively Q-switched Nd:GdVO4 laser

    LIU Min; LIU Shu-shan; LI Lei; WANG Wei-wei; CHEN Fei; LIU Jie


    Through using both Cr4+:YAG and GaAs saturable absorbers, a diode-pumped double passively Q-switched Nd:GdVO4 laser is realized and compared with a single passively Q-switched laser. This laser can generate symmetric pulse temporal profiles and shorter pulses. A laser pulse width of 17 ns has been achieved with the incident pump power of 8.5 W.

  16. High Efficient Continuous-Wave Ho: YAG Laser Pumped by a Diode-pumped Tm: YLF Laser at Room Temperature

    DUAN Xiao-Ming; YAO Bao-Quan; ZHANG Yun-Jun; SONG Cheng-Wei; GAO Jing; JU You-Lun; WANG Yue-Zhu


    We present a high efficient continuous wave Ho:YAG laser pumped by a diode-pumped Tm:YLF laser with a Fabry-Perot etalon tuning at 1.91 μm. The maximum output power reaches 7.2 W when the absorbed pump power is 10.8 W.The slope efficiency (relative to the absorbed power) is 74.1%,and the Tm:YLF to Ho:YAG optical conversion efficiency of 60%,then the diode-to-Holmium optical conversion efficiency achieved is 21.0%.The wavelength is 2090 nm when the transmission of output coupler is larger than 20%.The beam quality factor is M2 ~ 1.15 measured by the travelling knife-edge method.

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

    Juárez-Hernández, M.; Mejía, E. B.


    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.

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

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


    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.

  19. Transverse modes of a diode-laser pumped monolithic unidirectional non-planar ring laser

    Keying Wu(吴克瑛); Suhui Yang(杨苏辉); Guanghui Wei(魏光辉)


    Diode-laser pumped monolithic single-frequency non-planar ring laser has the advantages of compactness,reliability and high efficiency. But when the pump power is high enough, the thermal effect will be seriousand the high-order transverse modes will appear. Therefore the single-mode output power is limited. Inthis paper, the mechanism of generating the high-order transverse modes in the monolithic unidirectionalnon-planar ring cavity is analyzed using ray tracing method. The calculated results are in agreement withthe experiments.

  20. 28W average power hydrocarbon-free rubidium diode pumped alkali laser.

    Zweiback, Jason; Krupke, William F


    We present experimental results for a high-power diode pumped hydrocarbon-free rubidium laser with a scalable architecture. The laser consists of a liquid cooled, copper waveguide which serves to both guide the pump light and to provide a thermally conductive surface near the gain volume to remove heat. A laser diode stack, with a linewidth narrowed to approximately 0.35 nm with volume bragg gratings, is used to pump the cell. We have achieved 24W average power output using 4 atmospheres of naturally occurring helium ((4)He) as the buffer gas and 28W using 2.8 atmospheres of (3)He.

  1. Diffractive Combiner of Single-Mode Pump Laser-Diode Beams

    Liu, Duncan; Wilson, Daniel; Qiu, Yueming; Forouhar, Siamak


    An optical beam combiner now under development would make it possible to use the outputs of multiple single-mode laser diodes to pump a neodymium: yttrium aluminum garnet (Nd:YAG) nonplanar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. Heretofore, an Nd:YAG NPRO like the present one has been pumped by a single multimode laser-diode beam delivered via an optical fiber. It would be desirable to use multiple pump laser diodes to increase reliability beyond that obtainable from a single pump laser diode. However, as explained below, simplistically coupling multiple multimode laser-diode beams through a fiber-optic combiner would entail a significant reduction in coupling efficiency, and lasing would occur at one or more other frequencies in addition to the single desired frequency. Figure 1 schematically illustrates the principle of operation of a laser-diode-pumped Nd:YAG NPRO. The laser beam path is confined in a Nd:YAG crystal by means of total internal reflections on the three back facets and a partial-reflection coating on the front facet. The wavelength of the pump beam - 808 nm - is the wavelength most strongly absorbed by the Nd:YAG crystal. The crystal can lase at a wavelength of either 1,064 nm or 1,319 nm - which one depending on the optical coating on the front facet. A thermal lens effect induced by the pump beam enables stable lasing in the lowest-order transverse electromagnetic mode (the TEM00 mode). The frequency of this laser is very stable because of the mechanical stability of the laser crystal and the unidirectional nature of the lasing. The unidirectionality is a result of the combined effects of (1) a Faraday rotation induced by an externally applied magnetic field and (2) polarization associated with non-normal incidence and reflection on the front facet.

  2. New class of compact diode pumped sub 10 fs lasers for biomedical applications

    Le, T.; Mueller, A.; Sumpf, B.;


    Diode-pumping Ti: sapphire lasers promises a new approach to low-cost femtosecond light sources. Thus in recent years much effort has been taken just to overcome the quite low power and low beam qualities of available green diodes to obtain output powers of several hundred milliwatts from a fs-la...

  3. Laser-diode pumped Nd:GdVO4 ultraviolet laser with LBO frequency tripling

    WANG Yun; FAN Xiu-wei; PENG Qian-qian; LIU Jie; HE Jing-liang


    We have demonstrated a laser-diode pumped Nd:GdVO4 extra-cavity frequency tripling ultraviolet laser with a LBO crystal in this paper.Under the acousto-optic (A-O) Q-switched operation,we have obtained 355 nm ultraviolet laser,with pulse width of 25 ns and pulse repetition rate of 20 kHz.By using a type Ⅰ non-critical phase-matched LBO crystal,the SHG output power of 822 mW is achieved at the incident pump power of 16 W. The output power of 355nm UV laser is 260mW with a type Ⅱ phase-matched LBO crystal,and the conversion efficiency (1 064 nm-355 nm ) is 5.9 %.The power stability of 355 nm laser is 1.7% in 1 h.

  4. High-Power Continuous-Wave Directly-Diode-Pumped Fiber Raman Lasers

    Tianfu Yao


    Full Text Available We describe novel fiber Raman lasers pumped directly by spectrally combined high power multimode laser diodes at 975 nm and emitting at 1019 nm. With a commercial multimode graded-index fiber, we reached 20 W of laser output power with a record slope efficiency of 80%. With an in-house double-clad fiber, the beam quality improved to M2 = 1.9, albeit with lower output power and slope efficiency due to higher fiber loss. We believe this is the first publication of a fiber Raman laser cladding-pumped directly by diodes.

  5. Femtosecond laser pumped by high-brightness coherent polarization locked diodes.

    Purnawirman; Phua, P B


    We demonstrate, for the first time to our knowledge, the use of a coherent polarization locked diode as the high-brightness pump source for a femtosecond laser. Four diode emitters are coherently locked to produce more than 5 W linearly polarized, narrow linewidth, and single-lobed pump beam. This gives >10× brightness improvement over the conventional diode array. The diode beam is then used to pump a Yb:KYW laser to obtain 2 W output with 57% slope efficiency in cw laser operation. By using a saturable absorber mirror, we achieved cw mode-locking operation with a 177 fs pulse width at an average power of 0.55 W.

  6. Diode-pumped, All-solid-state Cr: LiSGaF Laser

    DAI Jianming; ZHANG Lizhe; ZHANG Weili; CHAI Lu; WANG Yong; XING Qirong; WANG Qingyue


    A compact and efficient CW Cr: LiSGaF laser pumped by two 670 nm laser diodes was reported. Average power as high as 125 mW was generated with a absorbed pump power of 800 mW. The slope efficiency was 17.2%, and the threshold was 72 mW. The tunability of the laser in detail was investigated and a tuning range of 100 nm from 790 to 890 nm was obtained.

  7. Diode Stack End-Pumped Nd:GdVO4 Continuous Wave Slab Laser

    ZHANG Heng-Li; ZHANG Huai-Jin; LI Dai-Jun; WANG Ji-Yang; SHI Peng; Haas Rüdiger; LI Hong-Xia; JIANG Min-Hua; DU Keming


    @@ We report a diode stack end-pumped Nd:GdVO4 slab laser with a near-diffraction-limited beam. The output power of 45.8 W at 1064nm is obtained under the pumping power of 147W, with the optical-optical conversion efficiency of 31.2%, and the slope efficiency is 39.6%.

  8. Investigation of Diode Pumped Alkali Laser Atmospheric Transmission Using Tunable Diode Laser Absorption Spectroscopy


    House Appropriations hearing on May 20th, 2010 where Robert Gates, then U.S. Secretary of Defense, said the following in answer to a question from Rep...Henry, B. P. Wert, T. Gilpin , and J. R. Drummond. “Tunable diode laser absorption spectrometer for ground-based measurements of formaldehyde”. Journal...spectroscopy (TDLAS) at 1.37 µm”. Applied Physics B: Lasers and Optics, 92(3):393–401, 2008. 43. Kormann, Robert , Horst Fischer, and Frank G. Wienhold

  9. Spatial Combining of Laser-Diode Beams for Pumping an NPRO

    Gelsinger, Paul; Liu, Duncan; Mulder, Jerry; Aguayo, Francisco


    A free-space optical beam combiner now undergoing development makes it possible to use the outputs of multiple multimode laser diodes to pump a neodymium-doped yttrium aluminum garnet (Nd:YAG) non-planar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. Heretofore, a Nd:YAG NPRO like the present one has been pumped by a single multimode laser-diode beam delivered via an optical fiber. It would be desirable to use multiple pump laser diodes to increase reliability beyond that obtainable from a single pump laser diode. However, as explained in this article, simplistically coupling multiple multimode laser-diode beams through a fiber-optic combiner would entail a significant reduction in coupling efficiency, and lasing would occur at one or more other frequencies in addition to the single desired frequency. To minimize coupling loss, one must ensure that the NA (approximately equal to 0.3) of the combined laser-diode beams is less than the NA of the fiber. The A(Omega) of the laser-diode beam in the slow-axis plane is 1/1.3 as large as that of the fiber. This A(Omega) is small enough to enable efficient coupling of light into the optical fiber, but too large for combining of beams in the slow-axis plane. Therefore, a pair of cylindrical lenses is used to cancel the slow-axis plane magnification introduced by the on-cylindrical lenses used to effect magnification in the fast-axis plane.

  10. Nd:YAG solid-state ring laser pumped by a light-emitting diode

    Belozerov, S.A.; Kornienko, L.S.; Kravtsov, N.V.; Kuratev, I.I.; Rusakov, S.I.; Stel' makh, M.F.; Shelaev, A.A.; Shelaev, A.I.


    This letter reports lasing in an Nd:YAG solid-state laser (lambda = 1.06 pumped either in pulses or continuously by a light-emitting diode. We report the first experimental results on this laser.(AIP)

  11. Room-temperature diode-pumped Yb:KYF(4) laser.

    Galzerano, Gianluca; Laporta, Paolo; Sani, Elisa; Bonelli, Lucia; Toncelli, Alessandra; Tonelli, Mauro; Pesatori, Alessandro; Svelto, Cesare


    Continuous-wave laser action has been demonstrated in a diode-pumped Yb:KYF(4) crystal. Crystal growth, spectroscopic measurements, and laser results are presented. A maximum output power of 505 mW, a slope efficiency of 43%, and a continuous wavelength tunability range of 65nm, from 1013 to 1078 nm, have been obtained at room temperature.

  12. Diode-pumped 1.7-W erbium 3-µm fiber laser

    Jackson, S.D.; King, T.A.; Pollnau, M.


    Utilizing lifetime quenching of the Er3+ lower laser level by energy transfer to a Pr3+ co-dopant, 1.7 W output power and 17% slope efficiency are demonstrated from a double-clad diode-pumped 2.7-µm Er3+,Pr3+:ZBLAN fiber laser.

  13. Discrete excitation of mode pulses using a diode-pumped solid-state digital laser

    Ngcobo, Sandile


    Full Text Available In this paper, we experimentally demonstrate novel method of generating discrete excitation of on-demand Lagaurre-Gaussian (LG) mode pulses, in a diode pumped solid-state digital laser. The digital laser comprises of an intra-cavity spatial light...


    D. A. Arkhipov


    Full Text Available Subject of Research. Thermophysical and optical techniques of parameter regulation for diode pumped solid-state laser are studied as applied to space laser communication and laser ranging lines. Methods. The investigations are carried out on the base of the original design of diode pumped solid-state laser module that includes the following: Nd:YAG slab element, diode pumped by 400W QCW produced by NORTHROP GRUMMAN; two-pass unstable resonator with rotation of the laser beam aperture about its axis through 1800; the output mirror of the resonator with a variable reflection coefficient; hyperthermal conductive plates for thermal stabilization of the laser diode generation modes. The presence of thermal conductive plates excludes conventional running water systems applied as cooling systems for solid-state laser components. The diodes temperature stabilization is achieved by applying the algorithm of pulse-width modulation of power of auxiliary electric heaters. To compensate for non-stationary thermal distortions of the slab refractive index, the laser resonator scheme comprises a prism reflector with an apex angle of 1200. Narrow sides of the prism are covered with reflective coating, and its wide side is sprayed with antireflection coating. The beam aperture is turned around its axis through 1800 because of triple reflection of the beam inside the prism. The turning procedure leads to compensating for the output beam phase distortions in view of symmetric character of the aberrations of slab refractive index. To suppress parasitic oscillations inside the slab, dielectric coatings of wide sides of the slab are used. Main Results. We have demonstrated theoretically and experimentally that the usage of hyperthermal conductive plates together with the algorithm of pulse-width modulation provides stabilizing of the diode substrate temperature accurate within ± 0.1 °С and smoothing the temperature distribution along the plate surface accurate

  15. Reducing temperature dependence of the output energy of a quasi-continuous wave diode-pumped Nd:YAG laser.

    Lee, Kangin; Kim, Youngjung; Lee, Sijin; Kwon, Jin Hyuk; Gwak, Jin Seog; Yi, Jonghoon


    It is demonstrated by numerical modeling that spectrally dispersed compound pumping diodes and low-loss pumping chamber reduced the temperature dependence of the output energy of quasi-continuous wave diode-pumped Nd:YAG lasers considerably. Several compound diodes with different spectral profiles were tested for pumping. The laser energy was calculated as a function of diode temperature from -30°C to 60°C. When a compound diode with a flat-top spectrum was used for pumping, the mean laser energy was 83% of the maximum energy of a Nd:YAG laser pumped by a diode with a narrow bandwidth. In addition, a compound diode with three emission lines was tested for pumping. When the wavelength gap between the adjacent emission lines of the pumping diode was in the range of 3-10 nm, the mean energy of the Nd:YAG laser became similar to that of a Nd:YAG laser pumped by a diode with a flat-top spectrum.

  16. 5kW GTWave fiber amplifier directly pumped by commercial 976nm laser diodes.

    Zhan, Huan; Liu, Qinyong; Wang, Yuying; Ke, Weiwei; Ni, Li; Wang, Xiaolong; Peng, Kun; Gao, Cong; Li, Yuwei; Lin, Honghuan; Wang, Jianjun; Jing, Feng; Lin, Aoxiang


    With home-made fiber perform and special fiber drawing & coating technique, a new-type of (3 + 1) GTWave fiber theoretically designed for bi-directional pump method, was successfully fabricated and justified of integrating multi-kW pump energy from commercial 976nm laser diodes. This (3 + 1) GTWave fiber amplifier demonstrated uniform absorption of pump light and easy thermal management characteristics along the whole fiber length. This amplifier is capable of simultaneously aggregating 5.19kW pump power at 976nm and finally generating 5.07kW laser output at 1066.5nm with an optical-to-optical efficiency of 74.5%, the first publically-reported multi-kW GTWave fiber directly pumped with commercial 976nm laser diodes to the best of our knowledge. No power roll-over was found at 5kW level and further power scaling can be expected with more pump power. The results indicate that GTWave fiber is a competitive integrated fiber device to collect enough pump energy from low-cost commercial laser diodes for multi-kW fiber laser development.


    P. A. Loiko


    Full Text Available An experimental setup was developed for thermal lensing measurements in the anisotropic diode-pumped laser crystals. The studied crystal is placed into the stable two-mirror laser cavity operating at the fundamental transversal mode. The output beam radius is measured with respect to the pump intensity for different meridional planes (all these planes contain the light propagation direction. These dependencies are fitted using the ABCD matrix method in order to obtain the sensitivity factors showing the change of the optical power of thermal lens due to variation of the pump intensity. The difference of the sensitivity factors for two mutually orthogonal principal meridional planes describes the thermal lens astigmatism degree. By means of this approach, thermal lensing was characterized in the diode-pumped monoclinic Np-cut Nd:KGd(WO42 laser crystal at the wavelength of 1.067 μm for light polarization E || Nm.

  18. Ho:KLuW microchip laser intracavity pumped by a diode-pumped Tm:KLuW laser

    Serres, J. M.; Loiko, P. A.; Mateos, X.; Yumashev, K. V.; Kuleshov, N. V.; Petrov, V.; Griebner, U.; Aguiló, M.; Díaz, F.


    A compact intracavity-pumped microchip Ho laser is realized using stacked Tm:KLuW/Ho:KLuW crystals pumped by a laser diode at 805 nm; both crystals are cut for light propagation along the N g optical indicatrix axis and emit with polarization along the N m axis. Maximum CW output power of 285 mW is achieved at a wavelength of 2080 nm for 5.6 W absorbed pump power in the Tm:KLuW crystal with a maximum slope efficiency of 8.3 %. Maximum total (Tm3+ and Ho3+ emission) output of 887 mW with a slope efficiency of 23 % is achieved. Laser operation is obtained in the 1867-1900 nm spectral range corresponding to the Tm emission, while Ho emits at 2078-2100 nm, depending on the output coupling. The microchip Ho laser generates a near-circular output beam with M 2 < 1.1. The compact laser setup with plane-plane cavity provides automatic mode-matching condition for the Tm and Ho laser modes.

  19. Diode-pumped tunable laser with dual Cri:LiSAF rods

    Xie Guo-Qiang; Wang Tao; Zhu He-Yuan; Qian Lie-Jia


    We propose and demonstrate a simple approach to lower the thermal quenching effect and improve the output power of Cr:LiSAF lasers, which is accomplished by employing two laser rods. The resonator contains two laser rods and is designed by using two "X" folding cavities in cascade. A tunable laser output of ~ 180 mW has been achieved with the pump of single-striped laser diodes. Compared with lasers using single gain rod, the laser with dual rods shows less severe thermal effect and increases the output by more than two times.

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

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


    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.

  1. High-power diode-pumped AlGaAs surface-emitting laser.

    Holm, M A; Burns, D; Cusumano, P; Ferguson, A I; Dawson, M D


    We report the development and characterization of an efficient diode-pumped surface-emitting semiconductor laser operating at approximately 870 nm. By using a semiconductor Bragg reflector stack/multiple GaAs quantum well structure, mounted within a conventional laser cavity, we achieved single transverse mode laser output powers of 153 mW. Self-tuning over a 15-nm spectral range has been obtained.

  2. Laser Diode Pumped 1.54μm Er:Yb:Phosphate Glass Continuous Wave Compact Laser

    孟凡臻; 宋峰; 张潮波; 丁欣; 商美茹; 张光寅


    We report a cw Er3+ :Yb3+ co-doped phosphate glass laser pumped by a laser diode. The maximum output power of 78.3mW and a slope efficiency of 15.25% were achieved. The laser spectral region was from 1532nm to 1535nm, with the peak laser wavelength at 1534nm. The laser modes and time stability were also measured.The thermal effect had little influence on the output in our experiment.

  3. High energy diode-pumped solid-state laser development at the Central Laser Facility

    Mason, Paul D.; Banerjee, Saumyabrata; Ertel, Klaus; Phillips, P. Jonathan; Butcher, Thomas; Smith, Jodie; De Vido, Mariastefania; Chekhlov, Oleg; Hernandez-Gomez, Cristina; Edwards, Chris; Collier, John


    In this paper we review the development of high energy, nanosecond pulsed diode-pumped solid state lasers within the Central Laser Facility (CLF) based on cryogenic gas cooled multi-slab ceramic Yb:YAG amplifier technology. To date two 10J-scale systems, the DiPOLE prototype amplifier and an improved DIPOLE10 system, have been developed, and most recently a larger scale system, DiPOLE100, designed to produce 100 J pulses at up to 10 Hz. These systems have demonstrated amplification of 10 ns duration pulses at 1030 nm to energies in excess of 10 J at 10 Hz pulse repetition rate, and over 100 J at 1 Hz, with optical-to-optical conversion efficiencies of up to 27%. We present an overview of the cryo-amplifier concept and compare the design features of these three systems, including details of the amplifier designs, gain media, diode pump lasers and the cryogenic gas cooling systems. The most recent performance results from the three systems are presented along with future plans for high energy DPSSL development within the CLF.

  4. Plasma Formation During Operation of a Diode Pumped Alkali Laser (DPAL) in Cs

    Babaeva, Natalia Yu.; Zatsarinny, Oleg; Bartschat, Klaus; Kushner, Mark J.


    Diode pumped Alkali Lasers (DPALs) produce laser action on the resonant lines of alkali atoms. Diode lasers resonantly pump the 2P3/2 state of the alkali atom which is collisionally relaxed to the 2P3/2 state which then lases to the ground state 2S1/2. The low optical quality of high power semiconductor diode lasers is converted into high optical quality laser radiation from the alkali vapor. The Cs DPAL system using Ar/Cs/C2H6 mixtures has shown promising results. (C2H6 is the collisional relaxant.) In other studies, resonant excitation of alkali vapor by low power lasers has been used to produce highly ionized channels, initiated through associative ionization and superelastic electron heating. The issue then arises if plasma formation occurs during DPAL by similar mechanisms which would be detrimental to laser performance. In this paper, we report on results from a computational study of a DPAL using Cs vapor. The global model addresses quasi-cw pumping of the Cs(2P3/2) state by laser diodes, and includes a full accounting of the resulting electron kinetics. To enable this study, the B-spline R-matrix (BSR) with pseudostates method was employed to calculate electron impact cross sections for Cs. We found that for pump rates of many to 10 kW/cm2, plasma densities approaching 1013 cm-3 occur during laser oscillation with higher values in the absence of laser oscillation. Supported by DoD High Energy Laser Mult. Res. Initiative and NSF.

  5. Dynamics of Efficiency Change by Temperature in Diode Pumped Nd:YAG Heat Capacity Laser

    WANG Xiao-Jun; TANG Bing; SHU Xiao-Jian


    We investigate the influence of temperature on the efficiency of diode pumped Nd:YAG heat capacity laser is studied. It is shown that the efficiency of such a laser system is greatly reduced at higher temperature. This bad behaviour is mainly caused by the doped-ion redistribution among various Stark levels of the ground state, and by a thermal equilibrium between the upper laser level and the pump level. Meanwhile, the thermal excitations from the ground state to the lower laser level also play a role. We derive a model to describe those effects, with the considerations of emission spectrum of laser diodes, the subtle Stark structures and the linewidth of absorption and of simulated-emission.

  6. Efficient Diode-Pumped Passively Q-Switched Nd:GdVO4 Lasers

    刘杰; 贾玉磊; 杨济民; 杜鹃; 何京良


    An efficient diode-pumped Nd:GdVO4 laser passively Q-switched by a Cr4+ :YAG has been developed as a saturable absorber. A KTP crystal is used for the extra-cavity second-harmonic generation and a BBO crystal for the sum frequency mixing. The green output power is 172mW at incident pump power of 8 W. The ultraviolet (UV) output power is measured to be 20mW at the same pump power. The peak power of the UV laser is 143 W with the pulse repetition rate of 14 kHz and pulse width of 10 ns.

  7. Picosecond pulse generation from a synchronously pumped mode-locked semiconductor laser diode

    Auyeung, J. C.; Johnston, A. R.


    A semiconductor laser diode was mode locked in an external cavity when synchronously pumped with 90-ps current pulses. Transform-limited optical pulses with a 10-ps pulse width and a peak power of 160 mW were produced. Operating characteristics of such a system are described.

  8. Pump Diode Characterization for an Unstable Diode-Pumped Alkali Laser Resonator


    narrowed linewidth. Learning how to control the tuning range of the VBG will permit the fine-tuning of the output frequency of the pump to match the...of commands and their descriptions HINDI get/set toggle indicators on/off HMODEL get harmonic model HO get/set harmonic options HQ get has Q‐switch

  9. Diode-pumped 1.7-W erbium 3-µm fiber laser

    Jackson, Stuart D.; King, Terence A.; Pollnau, Markus


    We report what is to our knowledge the first 3-mm fiber laser of the 1-W class. 1.7 W of output power and 17.3% slope eff iciency (with respect to the launched pump power) at a wavelength of 2.71 mm are demonstrated from a double-clad erbium-doped ZBLAN fiber diode pumped at 790 nm. Energy transfer

  10. Passive mode locking of a Nd:KGW laser with hot-band diode pumping

    Eibna Halim, M. Z.; Talukder, R. C.; Waritanant, T.; Major, A.


    Passive mode locking of a Nd:KGW laser with hot-band diode pumping at 910 nm was demonstrated. A semiconductor saturable absorber mirror was used as a mode locking mechanism. The laser generated 2.4 ps pulses at a repetition rate of ~83.8 MHz. An average output power of 87 mW was obtained at 1067 nm. To the best of our knowledge, this is the first report on passive mode locking of a Nd:KGW laser with low quantum defect pumping which holds great promise for further output power scaling.

  11. 1-kilowatt CW all-fiber laser oscillator pumped with wavelength-beam-combined diode stacks.

    Xiao, Y; Brunet, F; Kanskar, M; Faucher, M; Wetter, A; Holehouse, N


    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.

  12. Heat generation and thermo-mechanical effect modeling in longitudinally diode-pumped solid state lasers

    Lakhdari, Fouad; Osmani, Ismahen; Tabet, Saida


    Thermal management in solid state laser is a challenge to the high power laser industry's ability to provide continued improvements in device and system performance. In this work an investigation of heat generation and thermo-mechanical effect in a high-power Nd:YAG and Yb:YAG cylindrical-type solid state laser pumped longitudinally with different power by fibre coupled laser diode is carried out by numerical simulation based on the finite element method (FEM). Impact of the dopant concentration on the power conversion efficiency is included in the simulation. The distribution of the temperature inside the lasing material is resolute according to the thermal conductivity. The thermo-mechanical effect is explored as a function of pump power in order to determine the maximum pumping power allowed to prevent the crystal's fracture. The presented simulations are in broad agreement with analytical solutions; provided that the boundary condition of the pump induced heat generation is accurately modelled.

  13. Short-pulse generation in a diode-end-pumped solid-state laser

    Ngcobo, S


    Full Text Available in the picosecond region with a maximum average output power of 2.8W. Passive modelocking of the Nd:YVO4 laser has been demonstrated using a semiconductor saturable absorber mirror (SESAM). THEORETICAL ANALYSIS Ultra-fast solid state lasers are a key component... theoretical PQSML,th of 2.08W. Short-Pulse Generation in a Diode-End-Pumped Solid-State Laser S. Ngcobo1,2, C. Bollig1 and H. Von Bergmann2 1CSIR National Laser Centre, PO Box 395, Pretoria, 0001, South Africa 2Laser Research Center, University...

  14. A Laser-Diode-Pumped Widely Tunable Single-Longitude-Mode Tm:YAP Laser at Room Temperature

    LI Yu-Feng; JU You-Lun; YAO Bao-Quan; WANG Yue-Zhu; Sergii Ubizskii


    A laser-diode-pumped widely tunable single-longitude-mode Tm:YAP laser in 2μm eye-safe region is built. Continuous tunable range from 1899nm to 2025nm is achieved with the maximum laser output power of 225 m W at 1989nm. In addition, the Tm:YAP laser operating under multimode and single-mode conditions is discussed.

  15. Tm:GGAG crystal for 2μm tunable diode-pumped laser

    Šulc, Jan; Boháček, Pavel; Němec, Michal; Fibrich, Martin; Jelínková, Helena; Trunda, Bohumil; Havlák, Lubomír.; Jurek, Karel; Nikl, Martin


    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.

  16. Laser emission from diode-pumped Nd:YAG ceramic waveguide lasers realized by direct femtosecond-laser writing technique.

    Salamu, Gabriela; Jipa, Florin; Zamfirescu, Marian; Pavel, Nicolaie


    We report on realization of buried waveguides in Nd:YAG ceramic media by direct femtosecond-laser writing technique and investigate the waveguides laser emission characteristics under the pump with fiber-coupled diode lasers. Laser pulses at 1.06 μm with energy of 2.8 mJ for the pump with pulses of 13.1-mJ energy and continuous-wave output power of 0.49 W with overall optical efficiency of 0.13 were obtained from a 100-μm diameter circular cladding waveguide realized in a 0.7-at.% Nd:YAG ceramic. A circular waveguide of 50-μm diameter yielded laser pulses at 1.3 μm with 1.2-mJ energy.

  17. Frequency-stabilized diode-pumped Nd:YAG laser of high power

    Taccheo, S.; Laporta, P.; Longhi, S. [CNR, Milano (Italy). Centro di Elettronica Quantistica e Strumentazione Elettronica]|[Politecnico di Milano (Italy). Dipt. di Fisica; Svelto, C. [Politecnico di Milano (Italy). Dipt. di Elettronica e Informazione


    The authors describe a frequency-stabilized diode-pumped Nd:YAG laser of high power whose single-mode operation is obtained by suppressing the spatial hole burning through the twisted-mode technique. Active frequency stabilization is achieved by fringe side locking the laser beam to a reference Fabry-Perot cavity. Output power up to 800 mW in single-transverse and -longitudinal mode operation with a linewidth of less than 20 kHz is obtained.

  18. Basic studies on laser-assisted phacoemulsification using diode-pumped Er:YAG laser

    Hausladen, Florian; Wurm, Holger; Stock, Karl


    The aim of this study was to determine the potential of a novel diode-pumped Er:YAG laser for phacoemulsification in basic experimental investigations. An appropriate experimental setup was created, including a translation stage for sample movement, a sample holder, a water spray for sample humidification and a surgical microscope with a CCD camera for video documentation. The analysis of the laser cuts and histological sections was done by light microscopy. As samples porcine eye lenses hardened by formalin were used. In ablation experiments with different spot diameters and radiant powers and a constant repetition rate νr = 200 Hz the maximum ablation depths of (4.346 +/- 0.044) mm have reached at (Ø = 480 μm, Φ = 24.15 W) with a maximum extend of thermal damage of (0.165 +/- 0.030) mm. The average ablation efficiency is 0.241 mm3/J. With a spot diameter of 308 μm the maximum ablation depth is (4.238 +/- 0.040) mm at 24.65 W with a mean ablation efficiency of 0.293 mm3/J. The extend of the thermally damaged region is (0.171 +/- 0.024) mm at this laser power. Using a sapphire cylinder with a diameter of 412 μm (length 38.5 mm) in direct tissue contact with water spray for sample humidification the ablation depth reaches (1.017 +/- 0.074) mm at 4.93 W and (1.840 +/- 0.092) mm at 9.87 W with a mean efficiency of 0.261 mm3/J. A thermal damage zone of (0.064 +/-0.024) mm at 9.87 W was measured. Additionally, at this high power, a progressive contamination and destruction of the cylinder end facet was observed. In conclusion, the investigations show that the diode-pumped Er:YAG laser has considerable potential for cataract surgery.

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

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


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

  20. Narrow-line, tunable, high-power diode laser pump for DPAL applications

    Pandey, Rajiv; Merchen, David; Stapleton, Dean; Irwin, David; Humble, Chuck; Patterson, Steve; Kissel, Heiko; Biesenbach, Jens


    We report on a high-power diode laser pump source for diode-pumped alkali lasers (DPAL), specifically rubidium alkali vapor lasers at 780nm, delivering up to 100W/bar with FWHM spectral line width of 0.06nm (~30GHz). This pump is based on a micro-channel water-cooled stack with collimation in both-axes. Wavelength-locking of the output spectrum allows absorption in one of the very narrow resonance lines of the atomic rubidium alkali vapor. To achieve these results, research was conducted to deliver the highest performance on all key components of the product from the diode laser bar which produces the optical power at 780nm to the external Bragg gratings which narrow the spectrum line width. We highlight the advancements in the epitaxy, device design, beam collimation, grating selection, alignment, tunability and thermal control that enable realization of this novel pump-source for DPALs. Design trade-offs will be presented.

  1. A Continuous-Wave Diode-Side-Pumped Tm:YAG Laser with Output 51 W

    ZHANG Xiao-Fu; CUI DaFu; XU Zu-Yan; XU Yi-Ting; LI Cheng-Ming; ZONG Nan; XU Jia-Lin; CUI Qian-Jin; LU Yuan-Fu; BO Yong; PENG Qin-Jun


    A compact diode-side-pumped Tm:YAG laser is presented, which can output 51 W of cw power at 2.02μm. The Tm:YAG rod is side pumped by nine diode arrays with the central wavelength of 783nm and the with bandwidth of about 2.5 nm at 25℃. To decrease the thermal effect on the both ends and dissipate the heat effectively, one composite Tm:YAG rod with the undoped YAG end caps and the screw threads on the side surface of the rod is used as the laser crystal. The maximum optical-to-optical conversion efficiency of the 2.02-μm laser output is 14.2%, with a slope efficiency of 26.8%.

  2. Modeling of static and flowing-gas diode pumped alkali lasers

    Barmashenko, Boris D.; Auslender, Ilya; Yacoby, Eyal; Waichman, Karol; Sadot, Oren; Rosenwaks, Salman


    Modeling of static and flowing-gas subsonic, transonic and supersonic Cs and K Ti:Sapphire and diode pumped alkali lasers (DPALs) is reported. A simple optical model applied to the static K and Cs lasers shows good agreement between the calculated and measured dependence of the laser power on the incident pump power. The model reproduces the observed threshold pump power in K DPAL which is much higher than that predicted by standard models of the DPAL. Scaling up flowing-gas DPALs to megawatt class power is studied using accurate three-dimensional computational fluid dynamics model, taking into account the effects of temperature rise and losses of alkali atoms due to ionization. Both the maximum achievable power and laser beam quality are estimated for Cs and K lasers. The performance of subsonic and, in particular, supersonic DPALs is compared with that of transonic, where supersonic nozzle and diffuser are spared and high power mechanical pump (needed for recovery of the gas total pressure which strongly drops in the diffuser), is not required for continuous closed cycle operation. For pumping by beams of the same rectangular cross section, comparison between end-pumping and transverse-pumping shows that the output power is not affected by the pump geometry, however, the intensity of the output laser beam in the case of transverse-pumped DPALs is strongly non-uniform in the laser beam cross section resulting in higher brightness and better beam quality in the far field for the end-pumping geometry where the intensity of the output beam is uniform.

  3. Frequency-doubled DBR-tapered diode laser for direct pumping of Ti:sapphire lasers generating sub-20 fs pulses.

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika; Le, Tuan; Stingl, Andreas; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E; Petersen, Paul Michael


    For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (mode-locked) respectively at 1.2 W of pump power. This corresponds to a reduction in optical conversion efficiencies to 75% of the values achieved with a commercial diode pumped solid-state laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser when pumped with our diode laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs can therefore be expected.

  4. High-repetition-rate femtosecond dye amplifier using a laser-diode-pumped neodymium:YAG laser

    Zysset, B.; LaGasse, M.J.; Fujimoto, J.G.; Kafka, J.D.


    A high-repetition-rate femotosecond dye amplifier is demonstrated using a laser-diode-pumped Q-switched Nd:YAG laser. Amplification of wavelength-tunable 300-fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  5. Gigahertz frequency comb from a diode-pumped solid-state laser.

    Klenner, Alexander; Schilt, Stéphane; Südmeyer, Thomas; Keller, Ursula


    We present the first stabilization of the frequency comb offset from a diode-pumped gigahertz solid-state laser oscillator. No additional external amplification and/or compression of the output pulses is required. The laser is reliably modelocked using a SESAM and is based on a diode-pumped Yb:CALGO gain crystal. It generates 1.7-W average output power and pulse durations as short as 64 fs at a pulse repetition rate of 1 GHz. We generate an octave-spanning supercontinuum in a highly nonlinear fiber and use the standard f-to-2f carrier-envelope offset (CEO) frequency fCEO detection method. As a pump source, we use a reliable and cost-efficient commercial diode laser. Its multi-spatial-mode beam profile leads to a relatively broad frequency comb offset beat signal, which nevertheless can be phase-locked by feedback to its current. Using improved electronics, we reached a feedback-loop-bandwidth of up to 300 kHz. A combination of digital and analog electronics is used to achieve a tight phase-lock of fCEO to an external microwave reference with a low in-loop residual integrated phase-noise of 744 mrad in an integration bandwidth of [1 Hz, 5 MHz]. An analysis of the laser noise and response functions is presented which gives detailed insights into the CEO stabilization of this frequency comb.

  6. Diode laser pumped solid state laser. Part IV. ; Noise analysis. Handotai laser reiki kotai laser. 4. ; Noise kaiseki

    Sakurai, H.; Seno, T.; Tanabe, Y. (Asahi Glass Co. Ltd., Tokyo (Japan))


    Concerning the second harmonic generation(SHG) of diode laser pumped solid state laser using a nonlinear optical material, the researches are carried out to pracitically apply to the optical pickup. Therefore, the reduction of output optical noise has become the important researching subject. The theoretical and experimental analyses of noise generating mechanism were carried out for the system in which Nd;YAG as the laser diode and KTP (KTiOPO {sub 4}) as the nonlinear optical crystal were used. The following findings for the noise generating mechanism could be obtained: The competitive interaction between the polarization modes was dominant noise mechanism in the high frequency range from 1 to 20MHz and the noise could be removed sufficiently by using the QWP(quarter wave plate). On the other hand, the noise observed in the low frequency range from 100 to 200kHz depended on the resonance length, agreed qualitatively with the theoretical analysis of the noise to the competitive longitudinal modes and agreed quantitatively with the noise generating frequency range. 10 refs., 13 figs., 1 tab.

  7. Efficient quasi-three-level Nd:YAG laser at 946 nm pumped by a tunable external cavity tapered diode laser

    Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter;


    Using a tunable external cavity tapered diode laser (ECDL) pumped quasi-three-level Nd:YAG laser, a fivefold reduction in threshold and twofold increase in slope efficiency is demonstrated when compared to a traditional broad area diode laser pump source. A TEM00 power of 800 mW with 65% slope...... efficiency is obtained, the highest reported TEM00 power from any 946 nm Nd:YAG laser pumped by a single emitter diode laser pump source. A quantum efficiency of 0.85 has been estimated from experimental data using a simple quasi-three-level model. The reported value is in good agreement with published...... values, suggesting that the model is adequate. Improvement of the 946 nm laser due to the ECDL's narrow spectrum proves to be less significant when compared to its spatial quality, inferring a broad spectrum tapered diode laser pump source may be most practical. Experimental confirmation of such setup...

  8. Selective removal of dental caries with a diode-pumped Er:YAG laser

    Yan, Ruth; Chan, Kenneth H.; Tom, Henry; Simon, Jacob C.; Darling, Cynthia L.; Fried, Daniel


    Selective removal of caries lesions with high precision is best accomplished using lasers operating at high pulse repetition rates utilizing small spot sizes. Conventional flash-lamp pumped Er:YAG lasers are poorly suited for this purpose, but new diode-pumped Er:YAG lasers have become available operating at high pulse repetition rates. The purpose of this study was to measure the ablation rate and selectivity of sound and demineralized enamel and dentin for a 30 W diode-pumped Er:YAG laser operating with a pulse duration of 20-30-μs and evaluate it's potential for the selective removal of natural occlusal lesions on extracted teeth. Microradiography was used to determine the mineral content of the demineralized enamel and dentin of 300-μm thick sections with natural caries lesions prior to laser ablation. The ablation rate was calculated for varying mineral content. In addition, near-IR reflectance measurements at 1500-1700- nm were used to guide the laser for the selective ablation of natural occlusal caries lesions on extracted teeth.

  9. Diode end-pumped 1123-nm Nd:YAG laser with 2.6-W output power

    Zhiqiang Cai; Meng Chen; Zhigang Zhang; Rui Zhou; Wuqi Wen; Xin Ding; Jianquan Yao


    We present a compact and high output power diode end-pumped Nd:YAG laser which operates at the wavelength of 1123 nm. Continuous wave (CW) laser output of 2.6 W was achieved at the incident pump power of 15.9 W, indicating an overall optical-optical conversion efficiency of 16.4%, and the slope efficiency was 18%.

  10. High-Power Diode-Side-Pumped Intracavity-Frequency-Doubled Continuous Wave 532 nm Laser

    ZHANG Yu-Ping; ZHANG Hui-Yun; ZHONG Kai; LI Xi-Fu; WANG Peng; YAO Jian-Quan


    @@ An efficient and high-power diode-side-pumped cw 532nm green laser based on a V-shaped cavity geometry, and capable of generating 22.7 W green radiation with optical conversion efficiency of 8.31%, has been demonstrated. The laser is operated with rms noise amplitude of less than 1% and with M2-parameter of about 6.45 at the top of the output power. This laser has the potential for scaling to much higher output power.

  11. High power CW diode-side-pumped Nd:YAG rod laser

    Hailin Wang(王海林); Weiling Huang(黄维玲); Zhuoyou Zhou(周卓尤); Hongbing Cao(曹红兵)


    We report on the characterization of a diode-side-pumped Nd:YAG rod laser operating at high CW output power. A four-fold pump configuration is designed and the pump light is directly coupled into the Nd:YAG rod without the help of any cylindrical lenses. The distribution of pump light in the Nd:YAG rod has been calculated by using ray tracing program. The thermal lens effect of the Nd:YAG rod has been experimentally measured. A maximum output power of 800 W at 1064 nm in multimode operation is obtained for a pump power of 2400 W with 33% optical-optical efficiency. At the same time, the maximum beam parameter product of 25 mm.mrad is achieved.

  12. Compact, diode-pumped, solid-state lasers for next generation defence and security sensors

    Silver, M.; Lee, S. T.; Borthwick, A.; McRae, I.; Jackson, D.; Alexander, W.


    Low-cost semiconductor laser diode pump sources have made a dramatic impact in sectors such as advanced manufacturing. They are now disrupting other sectors, such as defence and security (D&S), where Thales UK is a manufacturer of sensor systems for application on land, sea, air and man portable. In this talk, we will first give an overview of the market trends and challenges in the D&S sector. Then we will illustrate how low cost pump diodes are enabling new directions in D&S sensors, by describing two diode pumped, solid- state laser products currently under development at Thales UK. The first is a new generation of Laser Target Designators (LTD) that are used to identify targets for the secure guiding of munitions. Current systems are bulky, expensive and require large battery packs to operate. The advent of low cost diode technology, merged with our novel solid-state laser design, has created a designator that will be the smallest, lowest cost, STANAG compatible laser designator on the market. The LTD delivers greater that 50mJ per pulse up to 20Hz, and has compact dimensions of 125×70×55mm. Secondly, we describe an ultra-compact, eye-safe, solid-state laser rangefinder (LRF) with reduced size, weight and power consumption compared to existing products. The LRF measures 100×55×34mm, weighs 200g, and can range to greater than 10km with a single laser shot and at a reprate of 1Hz. This also leverages off advances in laser pump diodes, but also utilises low cost, high reliability, packaging technology commonly found in the telecoms sector. As is common in the D&S sector, the products are designed to work in extreme environments, such as wide temperature range (-40 to +71°C) and high levels of shock and vibration. These disruptive products enable next- generation laser sensors such as rangefinders, target designators and active illuminated imagers.

  13. Carrier-Envelope Offset Stabilized Ultrafast Diode-Pumped Solid-State Lasers

    Stéphane Schilt


    Full Text Available Optical frequency combs have been revolutionizing many research areas and are finding a growing number of real-world applications. While initially dominated by Ti:Sapphire and fiber lasers, optical frequency combs from modelocked diode-pumped solid-state lasers (DPSSLs have become an attractive alternative with state-of-the-art performance. In this article, we review the main achievements in ultrafast DPSSLs for frequency combs. We present the current status of carrier-envelope offset (CEO frequency-stabilized DPSSLs based on various approaches and operating in different wavelength regimes. Feedback to the pump current provides a reliable scheme for frequency comb CEO stabilization, but also other methods with faster feedback not limited by the lifetime of the gain material have been applied. Pumping DPSSLs with high power multi-transverse-mode diodes enabled a new class of high power oscillators and gigahertz repetition rate lasers, which were initially not believed to be suitable for CEO stabilization due to the pump noise. However, this challenge has been overcome, and recently both high power and gigahertz DPSSL combs have been demonstrated. Thin disk lasers have demonstrated the highest pulse energy and average power emitted from any ultrafast oscillator and present a high potential for the future generation of stabilized frequency combs with hundreds of watts average output power.

  14. Diode-pumped Yb,Y:CaF2 laser mode-locked by monolayer graphene

    Zhu, Hongtong; Liu, Jie; Jiang, Shouzhen; Xu, Shicai; Su, Liangbi; Jiang, Dapeng; Qian, Xiaobo; Xu, Jun


    The large-area and high-quality monolayer graphene saturable absorber with a sandwich structure is prepared by the chemical vapor deposition technique. Using graphene saturable absorber, the mode locking operation of a diode-pumped Yb,Y:CaF2 laser is demonstrated. Without extra negative dispersion elements, 4.8 ps pulses are yielded at 1051 nm. The pulse repetition rate is 60 MHz.

  15. Diode-pumped Solid-state Cr4+∶Nd∶YAG/KTP Green Laser

    YU Ting; CUI Junwen; LU Yutian; HU Qiquan


    A diode-pumped solid-state Cr4+∶Nd∶YAG/KTP green laser with intracavity second harmonic generation is reported. Stable quasi-cw output of 1.03 W in average power, 100 kHz of repetition rate and about 25 ns of pulse width were obtained. Repetition rate and pulse width were studied experimentally and analyzed under different conditions.

  16. Development of laser diode-pumped high average power solid-state laser for the pumping of Ti:sapphire CPA system

    Maruyama, Yoichiro; Tei, Kazuyoku; Kato, Masaaki; Niwa, Yoshito; Harayama, Sayaka; Oba, Masaki; Matoba, Tohru; Arisawa, Takashi; Takuma, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment


    Laser diode pumped all solid state, high repetition frequency (PRF) and high energy Nd:YAG laser using zigzag slab crystals has been developed for the pumping source of Ti:sapphire CPA system. The pumping laser installs two main amplifiers which compose ring type amplifier configuration. The maximum amplification gain of the amplifier system is 140 and the condition of saturated amplification is achieved with this high gain. The average power of fundamental laser radiation is 250 W at the PRF of 200 Hz and the pulse duration is around 20 ns. The average power of second harmonic is 105 W at the PRF of 170 Hz and the pulse duration is about 16 ns. The beam profile of the second harmonic is near top hat and will be suitable for the pumping of Ti:sapphire laser crystal. The wall plug efficiency of the laser is 2.0 %. (author)

  17. Study of diode-pumped Yb:YAG disk lasers at low temperature

    Jianlei Wang; Zhenhua Zhang; Xiaojin Cheng; Lei Li; Xiangchun Shi; Xiaolei Zhu; Weibiao Chen


    A Yb:YAG disk laser with V-shaped stable resonator and active-mirror configuration, end-pumped by a 940-nm InGaAs laser diode array, is demonstrated. Performances and optimization of the disk laser at low temperature over a range of 130-200 K are investigated theoretically and experimentally. Laser output energy of 1.46 J/pulse operating at 10-Hz repetition rate is obtained with the optimum output coupler transmission of 30%, and the corresponding optical-to-optical efficiency is 48.7%.%Yb:YAG[1-4],by virtue of its high quantum efficiency (>90%),long life time,no concentration quenching,no excite-state absorption,and no upconversion effect,has recently been considered as a suitable candidate for lasers with high average power and high efficiency[5-7].Due to their wide absorption band centered at 941 nm,Yb:YAG lasers are more acceptable for variation of pump laser diode (LD) wavelength.

  18. Effects of Plasma Formation on the Cesium Diode (DPAL) and Excimer (XPAL) Pumped Alkali Laser

    Markosyan, Aram H.; Kushner, Mark J.


    Diode pumped alkali lasers (DPALs) and excimer pumped alkali lasers (XPALs) are being investigated as a means to convert optical pumps having poor optical quality to laser radiation having high optical quality. DPALs sustained in Cs vapor are pumped on the D2(852.35 nm), Cs(62S1/2) --> Cs(62P3/2) , transition and lase on the D1(894.59 nm) transition, Cs(62P1/2) --> Cs(62S1/2) . Collisional mixing (spin orbit relaxation) of the Cs(62P3/2) and Cs(62P1/2) levels is a key part of this three-level (in fact, a quasi-two-level) laser scheme. In the five-level XPAL pumping scheme, the CsAr(B2Σ1/ 2 +) state is optically pumped by 836.7 nm pulses, which later dissociates and produces Cs(62P3/2) . As in DPAL, a collisional relaxant transfers the population of Cs(62P3/2) to Cs(62P1/2) , which enables lasing on D1 transition. A first principals global computer model has been developed for both systems to investigate the effects of plasma formation on the laser performance. Argon is used as a buffer gas and nitrogen or ethane are used as a collisional relaxant at total pressure of 600 Torr at temperatures of 350-450 K, which produces vapor pressures of Cs of systems, a plasma formation in excess of 1014 - 1016cm-3 occurs, which potentially reduces laser output power by electron collisional mixing of upper and lower laser levels. Work supported by DoD High Energy Laser Multidisc, Res. Initiative.

  19. Design of a device for pumping a double-clad fiber laser with a laser-diode bar.

    Zenteno, L A


    Pumping rare-earth-doped double-clad fiber lasers with GaAlAs laser-diode bars typically requires one to transform a 1-cm-long one-dimensional linear array of tens of multimode laser-diode sources into atwo-dimensional oblong cross section that approximately matches the fiber's first cladding shape. I describe the design of a device, henceforth called a high-brightness geometric transformer, that uses a cylindrical microlens to image the laser-diode bar near field onto a linear array of soft-glass, thin-clad, rectangular fibers. In turn, the fibers output ends are arranged to form a stack that matches the required first cladding shape. For a typical laser-diode bar with a brightness of 25 mW·µm(-2)·sr(-1), the geometric transformer output brightness is 0.6 mW·µm(-2)·sr(-1), i.e., there is a 40× intermediate loss of brightness. If the output of the geometric transformer is used to pump a Nd-doped double-clad fiber laser, anoverall brightness gain of 340× can be achieved.

  20. Reviews of a Diode-Pumped Alkali Laser (DPAL): a potential high powered light source

    Cai, He; Wang, You; Han, Juhong; An, Guofei; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Zhou, Jie; Gao, Ming; Jiang, Zhigang


    Diode pumped alkali vapor lasers (DPALs) were first developed by in W. F. Krupke at the beginning of the 21th century. In the recent years, DPALs have been rapidly developed because of their high Stokes efficiency, good beam quality, compact size and near-infrared emission wavelengths. The Stokes efficiency of a DPAL can achieve a miraculous level as high as 95.3% for cesium (Cs), 98.1% for rubidium (Rb), and 99.6% for potassium (K), respectively. The thermal effect of a DPAL is theoretically smaller than that of a normal diode-pumped solid-state laser (DPSSL). Additionally, generated heat of a DPAL can be removed by circulating the gases inside a sealed system. Therefore, the thermal management would be relatively simple for realization of a high-powered DPAL. In the meantime, DPALs combine the advantages of both DPSSLs and normal gas lasers but evade the disadvantages of them. Generally, the collisionally broadened cross sections of both the D1 and the D2 lines for a DPAL are much larger than those for the most conventional solid-state, fiber and gas lasers. Thus, DPALs provide an outstanding potentiality for realization of high-powered laser systems. It has been shown that a DPAL is now becoming one of the most promising candidates for simultaneously achieving good beam quality and high output power. With a lot of marvelous merits, a DPAL becomes one of the most hopeful high-powered laser sources of next generation.

  1. Selective removal of dental composite with a diode-pumped Er:YAG laser

    Fried, William A.; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel


    Selective removal of dental composite with high precision is best accomplished using lasers operating at high pulse repetition rates focused to a small spot size. Conventional flash-lamp pumped Er:YAG lasers are poorly suited for this purpose, but new diode-pumped Er:YAG lasers have become available operating at high pulse repetition rates. The purpose of this study was to compare the ablation rates and selectivity of enamel and composite for a 30 W diode-pumped Er:YAG laser operating with a pulse duration of 30-50-μs and evaluate it's suitability for the selective removal of composite from tooth surfaces. The depth of ablation and changes in surface morphology were assessed using digital microscopy. The fluence range of 30-50 J/cm2 appeared optimal for the removal of composite, and damage to sound enamel was limited to less than 100-μm after the removal of composite as thick as 700-800-μm. Future studies will focus on the use of methods of feedback to further increase selectivity.

  2. High-efficiency Tm-doped yttrium aluminum garnet laser pumped with a wavelength-locked laser diode

    Huang, H. Z.; Huang, J. H.; Liu, H. G.; Dai, S. T.; Weng, W.; Zheng, H.; Ge, Y.; Li, J. H.; Deng, J.; Yang, X.; Lin, W. X.


    We first demonstrate a high-efficiency composite Tm-doped yttrium aluminum garnet laser end-pumped with a narrow-linewidth laser diode, which was locked at a wavelength of 784.9 nm with volume Bragg gratings. The locked pump wavelength was experimentally determined by the excitation peak, which was also the absorption peak of a 3.5 at.% Tm:YAG crystal around 785 nm, for the improvement of laser efficiency under high-intensity pumping. Under an absorbed pump power of 24.64 W, a maximum output power of 11.12 W at 2018 nm was obtained, corresponding to an optical to optical conversion efficiency of 45.1% and a slope efficiency of 52.4%.

  3. High-power diode-end-pumped Tm:YLF slab laser delivering 189 W at 1890 nm

    Koen, W


    Full Text Available The authors present a high-power Tm:YLF slab laser double-end-pumped by two 300 W laser diode stacks. The resonator was designed such that the laser emitted at 1890 nm instead of the conventional operating wavelength of 1912 nm. At full incident...

  4. Novel Single-Frequency Diode Pumped Solid-State Lasers and Their Applications in Laser Ranging and Velocimetry

    杨苏辉; 吴克瑛; 魏光辉


    Two models of laser diode pumped unidirectional single-frequency ring lasers with maximum single-frequency output powers of 1 W and 780mW are investigated. The statistical linewidth of the free-run laser is measured to be 2.1 kHz within 5μs by using a single-mode fibre link. We use the monolithic laser to measure the angular speed of a spinning motor and simulate a linearly frequency modulated continuous-wave ladar system in the laboratory.

  5. Qualification Testing of Laser Diode Pump Arrays for a Space-Based 2-micron Coherent Doppler Lidar

    Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Singh, Upendra N.; Kavaya, Michael J.


    The 2-micron thulium and holmium-based lasers being considered as the transmitter source for space-based coherent Doppler lidar require high power laser diode pump arrays operating in a long pulse regime of about 1 msec. Operating laser diode arrays over such long pulses drastically impact their useful lifetime due to the excessive localized heating and substantial pulse-to-pulse thermal cycling of their active regions. This paper describes the long pulse performance of laser diode arrays and their critical thermal characteristics. A viable approach is then offered that allows for determining the optimum operational parameters leading to the maximum attainable lifetime.


    A. V. Belikov


    Full Text Available Subject of Study. The paper discusses the breadboarding results of compact diode pumped laser. The laser is based on Yb,Er:glass slab active element and frustrated total internal reflection (FTIR shutter and features of the impact of generated pulses at the water-containing media. The transmitter working in cavity dumping mode provides generation of single microsecond pulses or regular trains of these pulses with peak power up to 100 kW and average output power up to 8 W. The laser allows varying output parameters of radiation in wide range and is designed for the usage in technology and biomedical applications. The possibilities of the laser radiation parameters adapting for application in a compact laser cataract extraction complex are examined. Method. The energy efficient for three level active medium method of lasing pulses repetition rate increasing was investigated, which comprises the generation of pulse trains by several FTIR shutter switching on one pump pulse. We carried out analysis of application possibility for microsecond laser pulses with peak power of tens of kilowatts at wavelength of 1,54 μm in the processing of water-containing tissues. The acoustic response on the interaction of radiation with a model environment was studied. Main Results. In the modulation mode of useful (active losses lasing pulses have been obtained with microsecond duration and energy more than 100 mJ and trains of pulses with total energy of 0,5 J at the effective pulse repetition rate of more than 50 Hz. The minimal permissible period of laser pulses in train (300 μs has been established experimentally on the basis of optoacoustic studies. It meets the criteria of operation noninvasiveness consisting in prevention of the risk of posterior lens capsule damage with laser radiation. Practical Relevance. The results obtained with the layout of diode pumped Yb,Er:glass laser with cavity dumping and slab active element are presently record for diode-pumped

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

    Poberezhskiy, Ilya Y; Chang, Daniel H.; Erlig, Herman


    Optical metrology system reliability during a prolonged space mission is often limited by the reliability of pump laser diodes. We developed a metrology laser pump module architecture that meets NASA SIM Lite instrument optical power and reliability requirements by combining the outputs of multiple single-mode pump diodes in a low-loss, high port count fiber coupler. We describe Monte-Carlo simulations used to calculate the reliability of the laser pump module and introduce a combined laser farm aging parameter that serves as a load-sharing optimization metric. Employing these tools, we select pump module architecture, operating conditions, biasing approach and perform parameter sensitivity studies to investigate the robustness of the obtained solution.

  8. Stable,efficient diode-pumped femtosecond Yb:KGW laser through optimization of energy density on SESAM

    Jinfeng Li; Xiaoyan Liang; Jinping He; Hua Lin


    An efficient high-power diode-pumped femtosecond Yb:KGW laser is repored.Through optimization of energy density by semiconductor saturable absorber mirror,output power achieved 2.4 W with pulse duration of 350 fs and repetition rate of 53 MHz at a pump power of 12.5 W,corresponding to an optical-to-optical efficiency of 19.2%. We believe that it is the highest optical-to-optical efficiency for single-diode-pumped bulk Yb:KGW femtosecond lasers to date.

  9. Gigahertz dual-comb modelocked diode-pumped semiconductor and solid-state lasers

    Link, S. M.; Mangold, M.; Golling, M.; Klenner, A.; Keller, U.


    We present a simple approach to generate simultaneously two gigahertz mode-locked pulse trains from a single gain element. A bi-refringent crystal in the laser cavity splits the one cavity beam into two cross-polarized and spatially separated beams. This polarization-duplexing is successfully demonstrated for both a semiconductor disk laser (i.e. MIXSEL) and a diode-pumped solid-state Nd:YAG laser. The beat between the two beams results in a microwave frequency comb, which represents a direct link between the terahertz optical frequencies and the electronically accessible microwave regime. This dual-output technique enables compact and cost-efficient dual-comb lasers for spectroscopy applications.

  10. Micro-Welding of Copper Plate by Frequency Doubled Diode Pumped Pulsed Nd:YAG Laser

    Nakashiba, Shin-Ichi; Okamoto, Yasuhiro; Sakagawa, Tomokazu; Takai, Sunao; Okada, Akira

    A pulsed laser of 532 nm wavelength with ms range pulse duration was newly developed by second harmonic generation of diode pumped pulsed Nd:YAG laser. High electro-optical conversion efficiency more than 13% could be achieved, and 1.5 kW peak power green laser pulse was put in optical fiber of 100 μm in diameter. In micro- welding of 1.0 mm thickness copper plate, a keyhole welding was successfully performed by 1.0 kW peak power at spot diameter less than 200 μm. The frequency doubled pulsed laser improved the processing efficiency of copper welding, and narrow and deep weld bead was stably obtained.

  11. Novel pressure sensor by diode-pumped birefringent Nd:YAG dual-frequency laser

    Huang, Chunning; Li, Yan; Zhang, Shulian; Guo, Hui


    The prototype of a novel sensor based on laser frequency splitting technology is presented in this paper and the results of a series of experiments are reported. A scheme of the novel pressure sensor by diode-pumped birefringent Nd:YAG dual-frequency laser is brought forward. As a result of the stress birefringence the laser's longitudinal mode is split to two with frequency difference. Both the theoretical analysis and the experiments indicate that there is a direct ratio relation between the frequency difference and the pressure imposed on the Nd:YAG crystal. Therefore when the external pressure is sensed by the Nd:YAG dual-frequency laser and the beat frequency is measured by the frequency counter, the pressure value can be obtained from the magnitude of the beat frequency. The laser can operate under single mode or complex modes with little error to the experiment results. Some research work under different pumping ways is finished and it indicates that the beat frequency has little relation with pumping ways. The experiment has a good linearity (R greater than 0.999) with satisfied precision, sensitivity (5.27 MHz/kPa) and stability, which provides a good academic and experimental foundation for further research.

  12. Dynamics of an erbium-doped fiber laser subjected to harmonic modulation of a diode pump laser

    Pisarchik, Alexander N.; Kir'yanov, Alexander V.; Barmenkov, Yuri O.; Reategui, R. J.


    An erbium-doped fiber laser is shown to operate as a bistable or multistable nonlinear system under harmonic modulation of the diode pump laser. Phase- and frequency-dependent states are demonstrated both experimentally and in numerical simulations through codimensional-one and codimensional-two bifurcation diagrams in the parameter space of the modulation frequency and amplitude. In particular, generalized bistability results in doubling of saddle-node bifurcation lines where different coexisting attractors born. The laser model describes well all experimental features.

  13. Diode-Pumped Nanosecond Pulsed Laser with Pulse-Transmission-Mode Q-Switch

    CHEN Fei; HUO Yu-Jing; HE Shu-Fang; FENG Li-Chun


    Q-switched pulses at 1.064μm with a peak power of 5.02kW and a pulse width of2.8ns were obtained which were pumped by a 1 W laser diode on the Nd:YVO4 microchip at the 1 kHz repetition rate. These values were achieved by combining the techniques of aconsto-optic Q-switching and electro-optic pulse-transmission-mode Q-switching. The temporal characteristics of the pulses were analysed numerically. The experimental results are shown to be in good agreement with theoretical predictions.

  14. Diode-end-pumped electro-optically Q-switched Nd:YLF slab laser.

    Zhang, Hengli; Du, Keming; Li, Daijun; Shi, Peng; Wang, Yongdong; Diart, Robert


    We report a very compact Nd:YLF slab laser that is end pumped by a quasi-continuous-wave diode stack. A hybrid resonator is used to generate high output power in a near-diffraction-limited beam (i.e., a beam propogation M2 factor of less than 1.2). A pulse energy of 14.3 mJ was obtained with a pulse width of 8.5 ns at a repetition rate of 500 Hz, which corresponds to a Q-switched peak power of 1.68 MW.

  15. Search and Characterization of Optical Ceramics and Crystals for Diode-pumped Laser Oscillations


    Higher microhardness ; - No cleavage planes; - Large size; Also for some experiments, the optical quality of the resultant ceramic material was...samples to lase was tested in the setup shown in Fig.19. The samples were pumped with a 967 nm fiber coupled (fiber core 120 m) 10 W laser diode with...Because of low levels of heating, testing of the CaF2:Yb 3+ ceramics could be performed in the continuous wave (CW) mode of operation. In Fig.23

  16. Near-field dynamics of broad area diode laser at very high pump levels

    Martin Hempel


    Full Text Available Near-field properties of the emission of broad area semiconductor diode lasers under extremely high pumping of up to ∼50 times the threshold are investigated. A transition from a gain to thermally-induced index guiding is shown under operation with single pulses of 300 ns duration. At highest output powers, catastrophic optical damage is observed which is studied in conjunction with the evolution of time-averaged filamentary near-field properties. Dynamics of the process is resolved on a picosecond time scale.


    K. N. Gorbachenya


    Full Text Available Diode-pumped passively Q-switched microchip Er,Yb:YAl3(BO34 laser for range-finding has been demonstrated. By using a Co2+:MgAl2O4 as a saturable absorber TEM00–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.

  18. Low threshold Nd3+:KY(WO4)2 laser operated at 1072 nm pumped by diode

    Lang Lin; Zhenqiang Chen; Ge Zhang; Rugang Wang; Zhen Li; Jingzhao Li


    @@ The diode-pumped Nd:KYW laser operated in the free-running mode at 1072 nm is demonstrated at room temperature. The laser output power of 102.6 mW with 12.07% optical-to-optical conversion efficiency and 13.16% slope efficiency is obtained.

  19. Multiwavelength picosecond pulse generation with diode-pumped Nd:GAGG and Nd:LGGG lasers

    Agnesi, A.; Pirzio, F.; Reali, G.; Arcangeli, A.; Tonelli, M.; Jia, Z.; Tao, X.; Zhang, J.


    Laser operation near 1.06 μm by diode-pumped Nd:(LuxGd1-x)3Ga5O12 (Nd:LGGG, with x = 0.1) and Gd3AlxGa5-xO12 (GAGG, with x = 1) disordered crystals has been investigated. Cw oscillation with a slope efficiency as high as 61% and 230 mW output power was achieved with 400 mW absorbed power from a 1-W laser diode in Nd:LGGG. Under the same pumping conditions cw oscillation with a slope efficiency as high as 55% and 255 mW output power was achieved with 500 mW absorbed power in Nd:GAGG. Stable passive mode-locking with single- or multi-wavelength spectrum was obtained with a semiconductor saturable absorber mirror (SAM) and a single-prism, dispersion-compensated cavity with both the samples. Fourier-limited pulses with duration ~ 4-9 ps and output power ~ 40 mW were generated at three well-defined laser transitions in the range 1062-1067 nm with ND:GLGG. Two-color mode-locking regime well described by Fourier-limited synchronized pulses with duration ~ 3.7 and 5.9 ps and output power ~ 65 mW, with wavelength separation of 1.3 nm around 1062 nm was obtained with Nd:GAGG.

  20. Dual wavelength operation in diode-end-pumped hybrid vanadate laser

    A J Singh; S K Sharma; P K Mukhopadhyay; S M Oak


    Dual wavelength operation at 1062.8 nm and 1064.1 nm in a diode-pumped hybrid laser comprising of Nd3+-doped birefringent YVO4 and GdVO4 crystals is demon-strated. A detailed characterization of the laser is performed under CW and pulsed operation. Under Q-switching, 4 W of average power at 5 kHz repetition rate is obtained with 32 ns FWHM pulse duration corresponding to 25 kW of the peak power. The intensity and the polarization of the individual spectral components can be easily controlled by changing the relative gain and the relative orientation of the two crystals. The resulting pulsed dual-wavelength laser has the potential to be used as a source for generating terahertz radiation.

  1. 80-W cw TEM{sub 00} IR beam generation by use of a laser-diode-side-pumped Nd:YAG rod laser

    Konno, Susumu; Fujikawa, Shuichi; Yasui, Koji [Mitsubishi Electric Corp. Amagasaki, Hyogo (Japan). Advanced Technology R and D Center


    We have demonstrated high-efficient and high-power operation of a diode-side-pumped Nd:YAG rod laser. The laser has a simple and scalable configuration consisting of a diffusive pumping reflector and an advanced cavity configuration for polarization-dependent bifocusing compensation. (author)

  2. 16.6 J chirped femtosecond laser pulses from a diode-pumped Yb:CaF2 amplifier.

    Kessler, Alexander; Hornung, Marco; Keppler, Sebastian; Schorcht, Frank; Hellwing, Marco; Liebetrau, Hartmut; Körner, Jörg; Sävert, Alexander; Siebold, Mathias; Schnepp, Matthias; Hein, Joachim; Kaluza, Malte C


    We report the amplification of laser pulses at a center wavelength of 1034 nm to an energy of 16.6 J from a fully diode-pumped amplifier using Yb:CaF2 as the active medium. Pumped by a total optical power of 300 kW from high-power laser diodes, a gain factor of g=6.1 was achieved in a nine-pass amplifier configuration agreeing with numerical simulations. A measured spectral bandwidth of 10 nm full width at half-maximum promises a bandwidth-limited compression of the pulses down to a duration of 150 fs. These are, to our knowledge, the most energetic laser pulses achieved from a diode-pumped chirped-pulse amplifier so far.

  3. Investigation of diode-laser pumped thulium-doped fluoride lasers; Investigacao de lasers de floureto dopados com tulio e bombeados por diodo-laser

    Matos, Paulo Sergio Fabris de


    Tunable lasers emitting around 2.3 mum region are important in many areas, like gas detection, remote sensing and medical applications. Thulium has a large emission spectra around 2.3 mum with demonstrated tuning range of 2.2-2.45 mum using the YLF host. For efficient pump absorption, a high concentration sensitizer like ytterbium can be used. We demonstrate quasi-cw operation of the Yb:Tm:YLF laser, pumped at 960 nm with a 20 W diode bar achieving the highest output power reported so far of 620 mW. Simultaneous pumping of the 2.3 mm Yb:Tm:YLF laser at 685 nm and 960 nm is demonstrated, showing higher slope efficiency than 960 nm alone. Numerical simulations and analytical models show the best ratio of pump power between both wavelengths. (author)

  4. Scaling output energy in a diode-end-pumped passively Q-switched laser with a flat-flat resonator

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


    The spatial and temporal behaviors in a diode-end-pumped passively Q-switched laser with a flat-flat resonator are systematically explored as a function of the cavity length. A Nd:YAG/Cr4+:YAG miniature laser is experimentally used to show that the scale-up of the pulse energy without the higher-order transverse modes can be practically realized by optimizing the cavity length as a function of the pump size. A theoretical analysis is performed to confirm the experimental results. The extracavity second harmonic generation is experimentally conducted to demonstrate the usefulness of the laser design. PACS number(s): 42.60.Gd Q-switching; 42.55.Xi Diode-pumped lasers; 42.55.-f Lasers; 42.65.Sf Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatiotemporal dynamics.

  5. Diode-double-face-pumped Nd:YAG ceramic slab laser amplifier with low depolarization loss

    Chen, Yanzhong; Fan, Zhongwei; Guo, Guangyan; Jia, Dan; He, Jianguo; Lang, Ye; Qiu, Jisi; Kang, Zhijun; Zhao, Tianzhuo; Lin, Weiran; Wang, Jiang; Xie, Tengfei; Li, Jiang; Kou, Huamin; Pan, Yubai


    A diode-double-face-pumped Nd:YAG ceramic slab laser amplifier with uniform gain distribution and low depolarization loss was presented. Energy storage of 2.6 J was achieved at 1064 nm with a repetition rate of 200 Hz and a pulse width of 200 us from a 140 mm × 40 mm × 7 mm ceramic slab at a total pump power of 1215 W, corresponding to an optical-to-optical efficiency of 42.8%. An average small signal gain of 5.45 was achieved with a standard deviation of only 0.09 in the cross section, which shown good concentration uniformity. An average depolarization loss of 2.6% at different positions of the slab was obtained due to small thermal gradient of the zigzag configuration.

  6. Compact intra-cavity frequency doubled line beam green laser by a laser diode array pumped

    Yan, Boxia; Qi, Yan; Wang, Yanwei


    Compact, high power, and low-cost green laser light sources are needed in projection-related applications such as digital cinema, rear-projection television, simulators, and command and control stations. We report a LD array directly pumped intracavity SHG Nd:YVO4/PPMgLN laser without lens or waveguide in this letter. A compact 3.12 W green laser was demonstrated by intra-cavity frequency doubled using a PPMgLN bulk crystal by a 19-emitter LD array pumped(single bar), the conversion efficiency from input LD array was 9.2%. A line-beam output suitable for laser projectors was generated, which has the potential to be scalable to small volumes and low costs for laser projection displays.

  7. High power 355 nm diode-pumped solid-state laser

    Yu, Yang; Cheng, Chee Yuen; Peng, Xiaoyuan; Yong, Saw Soon


    This paper reported a high-power diode-pumped solid-state laser for material processing applications with a target of more than 60 ns pulse width at 355 nm. As known, long pulse width IR laser (around 70-100 ns) is difficult to get high conversion efficiency to UV since the peak power is more than 2 times lower than 20-30 ns laser. However, the unique long pulse width characteristic makes the laser an ideal tool for flexible PCB drilling with 30-50 μm holes and for cutting portable devices. Up to 52.2% IR to UV conversion efficiency was obtained by our novel intra-cavity harmonic generation cavity design. A 9.3W UV output at 30 kHz was demonstrated with compact intra-cavity sum frequency design. Special conduction cooling-designed LD side-pumped module provided 17.8 W fundamental IR output power with AOM q-switching. The UV output pulse width is 76 ns at 30 kHz and 140 ns at 70 kHz. The type I and type II phase matching LBOs were used for intra-cavity harmonic generations of 355 nm. The output characteristics of the IR and the harmonic generations varying with the pulse repetition rate were also investigated. The experimental results are in agreement with the theoretical modelling. This system will also be useful for many material processing applications such as PCB cutting and wafer scribing.

  8. Room-temperature cw operation of an efficient miniaturized Nd:YAG laser end-pumped by a superluminescent diode

    Washio, K.; Iwamoto, K.; Inoue, K.; Hino, I.; Matsumoto, S.; Saito, F.


    A miniaturized Nd:YAG laser is described, in which a 3-mm-diam x 5.4-mm-long laser rod is end-pumped by a single Al/sub x/Ga/sub 1-x/As superluminescent diode (SLD) having x 1.4-nm stripe geometry. A 4.5-mW laser power was obtained at room temperature in a 1-ms pulse operation. Emitted power from the SLD was 50 mW with 1.7% external power efficiency. When continuously pumped, a 1.5-mW laser power was obtained at room temperature. (AIP)

  9. Diode-pumped Er:CaF2 ceramic 2.7 μm tunable laser.

    Sulc, Jan; Němec, Michal; Svejkar, Richard; Jelínková, Helena; Doroshenko, Maxim E; Fedorov, Pavel P; Osiko, Vyacheslav V


    Spectroscopic and laser properties of a newly developed high optical quality Er:CaF2 hot-formed ceramic were investigated. Under pulsed 968 nm laser diode pumping, the mid-infrared (2.7 μm) radiation was obtained with a slope efficiency of 3%. Laser tunability was reached using a birefringent filter and the laser tuning range of 118 nm, from 2687 up to 2805 nm, was demonstrated. The maximal output energy reached was 0.48 mJ at 2730 nm for the absorbed pumping energy 34 mJ.

  10. Near-diffraction-limited,35.4 W laser-diode end-pumped Nd:YVO4 slab laser operating at 1342 nm.

    Yan, Ying; Zhang, Hengli; Liu, Yang; Yu, Xilong; Zhang, Huaijin; He, Jingliang; Xin, Jianguo


    A diode stack end-pumped Nd:YVO4 slab laser at 1342 nm with near-diffraction-limited beam quality by using a hybrid resonator was presented. At a pump power of 139.5 W, laser power of 35.4 W was obtained with a conversion efficiency of 25.4% of the laser diode to laser output. The beam quality M2 factors were measured to be 1.2 in the unstable direction and 1.3 in the stable direction at the output power of 29 W.

  11. Robust modeling and performance analysis of high-power diode side-pumped solid-state laser systems.

    Kashef, Tamer; Ghoniemy, Samy; Mokhtar, Ayman


    In this paper, we present an enhanced high-power extrinsic diode side-pumped solid-state laser (DPSSL) model to accurately predict the dynamic operations and pump distribution under different practical conditions. We introduce a new implementation technique for the proposed model that provides a compelling incentive for the performance assessment and enhancement of high-power diode side-pumped Nd:YAG lasers using cooperative agents and by relying on the MATLAB, GLAD, and Zemax ray tracing software packages. A large-signal laser model that includes thermal effects and a modified laser gain formulation and incorporates the geometrical pump distribution for three radially arranged arrays of laser diodes is presented. The design of a customized prototype diode side-pumped high-power laser head fabricated for the purpose of testing is discussed. A detailed comparative experimental and simulation study of the dynamic operation and the beam characteristics that are used to verify the accuracy of the proposed model for analyzing the performance of high-power DPSSLs under different conditions are discussed. The simulated and measured results of power, pump distribution, beam shape, and slope efficiency are shown under different conditions and for a specific case, where the targeted output power is 140 W, while the input pumping power is 400 W. The 95% output coupler reflectivity showed good agreement with the slope efficiency, which is approximately 35%; this assures the robustness of the proposed model to accurately predict the design parameters of practical, high-power DPSSLs.

  12. High-power diode-pumped Tm:YLF slab laser

    Schellhorn, M


    Full Text Available The aim is to develop a high-power Tm:YLF slab laser which can be utilized to pump a Ho slab laser. A 68 W Tm:YLF slab laser was recently presented in [1] pumped from one end by a single 6-bar stack delivering ~300 W of pump power. In this work, we...

  13. An 80-W Laser Diode Array with 0.1 nm Linewidth for Rubidium Vapor Laser Pumping

    YANG Zi-Ning; WANG Hong-Yan; LU Qi-Sheng; HUA Wei-Hong; XU Xiao-Jun


    The spectral linewidth of a 64-emitter laser-diode array is effectively suppressed by using a volume Bragg grating (VBG) based external cavity.At a maximal driven current of 90 A,the device produces a cw output of 80 W with 1.2 W/A slope efficiency and 0.1 nm spectral linewidth (FWHM) centered at 780 nm.The power extraction efficiency reaches 90% as compared with the free running case.The central wavelength of the narrowed spectrum is tuned over a 0.3nm range by adjusting the VBG's temperature.The absorption of 45% laser radiation by a 5-mm-long rubidium vapor cell with 150Torr ethane and 450 Torr helium at 383K is demonstrated.Diode pumped alkali vapor lasers (DPALs) have attracted much attention and have developed quickly in recent years due to their great potential in the high power laser field.[1-4] The efficient operation of DPALs requires pump sources with a linewidth that matches the pressure-broadened absorption band of alkali atoms.In moderate (~5 atm buffer gas) and low (~1 atm buffer gas) pressure operating regimes,the required pump linewidths should be 0.4 nm and less than 0.1 nm,respectively,[5] while the typical linewidth of commercial laser diode arrays (LDAs) is 2-4 nm.%The spectral linewidth of a 64-emitter laser-diode array is effectively suppressed by using a volume Bragg grating (VBG) based external cavity. At a maximal driven current of 90 A, the device produces a cw output of80W with 1.2 W/A slope efficiency and 0.1 nm spectral linewidth (FWHM) centered at 780 nm. The power extraction efficiency reaches 90% as compared with the free running case. The central wavelength of the narrowed spectrum is tuned over a 0.3nm range by adjusting the VBG's temperature. The absorption of 45% laser radiation by a 5-mm-long rubidium vapor cell with 150 Torr ethane and 450 Torr helium at 383 K is demonstrated.

  14. 3.1 kW monolithic MOPA configuration fibre laser bidirectionally pumped by non-wavelength-stabilized laser diodes

    Yan, Ping; Huang, Yusheng; Sun, Junyi; Li, Dan; Wang, Xuejiao; Gong, Mali; Xiao, Qirong


    We report an all-fibre monolithic master oscillator power amplifier configuration fibre laser bidirectionally pumped by non-wavelength-stabilized laser diodes. The Raman Effect and thermal problems can be effectively suppressed by the bidirectional pumping configuration. A small core diameter double-clad ytterbium-doped fibre is utilized in the amplifier for a refined beam quality control. As a result, a maximum output power of 3122 W and an optical-to-optical efficiency of 81.4% are achieved with near-diffraction-limitation beam quality. No mode instability was detected via a photodiode. Also, the output power instability was measured to be less than 0.6% during a continuous operation of 2 h.

  15. 300 W laser-diode dual-end-pumped Nd:YVO4 Innoslab laser

    Duan, Yabo; Song, Chengtian; Mao, Yefei


    We demonstrate a continuous wave neodymium-doped vanadate (Nd:YVO4) experiment with the laser diode dual end pumped directly in the band at 880 nm. Due to the advantage of the Innoslab laser, a 22 mm  ×  10 mm  ×  1 mm Nd:YVO4 crystal was used. By using a positive confocal unstable-stable hybrid fold resonator, a maximum power of 330 W was obtained at the absorbed pump power of 725 W. The corresponding optical-to-optical efficiency and slope efficiency were 45.5% and 55.8%, respectively. At an output power of 300 W, the beam quality factors M 2 in the unstable direction and stable direction were 1.7 and 2.1, respectively.

  16. Algorithm for Evaluation of Temperature 3D-Distribution of a Vapor Cell in a Diode End-pumped Alkali Laser System

    Han, J. H.; Wang, Y.; Cai, H.; An, G. F.; Rong, K. P.; Yu, H.; Wang, S. Y.; Wang, H. Y.; Zhang, W.; Xue, L. P.; Zhou, J.


    We develop a new 3D-model to evaluate the light characteristics and the thermal features of a cesium-vapor laser end-pumped by a laser diode. The theoretical model is based on the principles of both heat transfer and laser kinetics. The 3-dimensional population density distribution and temperature distribution are both systematically obtained and analyzed. The methodology is thought to be useful for realization of a high-powered diode-pumped alkali laser (DPAL) in the future.

  17. Spectroscopic and laser properties of SrMoO4:Tm3+ crystal under 1700-nm laser diode pumping

    Doroshenko, M. E.; Papashvili, A. G.; Dunaeva, E. E.; Ivleva, L. I.; Osiko, V. V.; Jelinkova, H.; Sulc, J.; Nemec, M.


    Spectroscopic and laser properties of Tm3+ ions under 1700 nm excitation in SrMoO4 crystal are investigated. Negligible effect of cross-relaxation process (3H4sbnd 3F4, 3H6sbnd 3F4) on population of 3F4 level for thulium concentrations up to 0.25 at.% was demonstrated. Efficient lasing with slope efficiency up to 18% and broadband (over 100 nm) tuning at room temperature under 1700 nm diode pumping were obtained.

  18. Efficient Laser-Diode End-Pumped Passively Q-Switched Mode-Locked Yb:LYSO Laser Based on SESAM

    XU Shi-Xiang; LI Wen-Xue; HAO Qiang; ZHAI Hui; ZENG He-Ping


    We report an eddicient Q-switched laser action based on a semiconductor saturable absorber mirrors(SESAMs)as passively Q-switched laser starter and a Yb:LYSO alloyed crystal as gain material pumped directly by 974nm In GaAs laser diodes.The output pulse duration is measured to be about 7μs,while the average power and the repetition rate of the pulse chain are about 0.92 W and 6.2kHz.respectively,under 12.5 W absorbed pumping power.The Q-switched mode-locked pulse train is also observed in this setup.The laser performance shows that Yb:LYSO is a promising laser gain medium for laser-diode pumped compact solid-state lasers.

  19. DPAL: a new class of CW near-infrared high-power diode-pumped alkali (vapor) lasers

    Krupke, William F.; Beach, Raymond J.; Kanz, Vernon K.; Payne, Stephen A.


    DPAL, a new class of diode pumped alkali vapor lasers, offers the prospect for high efficiency cw laser radiation at near-infrared wavelengths: cesium 895 nm, rubidium 795 nm, and potassium 770 nm. The physics of DPAL lasers are outlined, and the results of laboratory demonstrations using a titanium sapphire surrogate pump are summarized, along with benchmarked device models. DPAL electrical efficiencies of 25-30% are projected and near-diffraction-limited DPAL device power scaling into the multi-kilowatt regime from a single aperture is also projected.

  20. Computer modelling and numerical simulation of the solid state diode pumped Nd:YAG laser with intracavity saturable absorber

    Yashkir, Yuriy


    Stimulated emission in the Nd:YAG laser with a saturable absorber Cr:YAG is modelled as a superposition of interacting optical modes which are stable in a given optical cavity. The interaction of the active laser crystal and a passive Q-switch with diode pump and optical cavity modes is modelled with account of transversal two-dimentional variation of the pump field and of all participating optical modes. Each elementary volume of an active laser crystal and the Q-switching crystal in...

  1. Continuous-wave Raman generation in a diode-pumped Nd3+:KGd(WO4)2 laser.

    Demidovich, A A; Grabtchikov, A S; Lisinetskii, V A; Burakevich, V N; Orlovich, V A; Kiefer, W


    Continuous-wave Raman generation in a compact solid-state laser system pumped by a multimode diode laser is demonstrated. The Stokes radiation of stimulated Raman scattering at 1.181 microm is generated as a result of self-frequency conversion of the 1.067 microm laser radiation in Nd3+:KGd(WO4)2 crystal placed in the cavity. The Raman threshold was measured at 1.15 W of laser diode power. The highest output power obtained at the Stokes wavelength was 54 mW. The anomalous delay of Raman generation relative to the start of laser generation (the oscillation buildup) due to slow accumulation of Stokes photons in the cavity at low Raman gain and Raman threshold dependence not only on the laser intensity but also on the time of laser action are observed.

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

    HE Jin-Ping; LIANG Xiao-Yan; LI Jin-Feng; ZHENG Li-He; SU Liang-Bi; XU Jun


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

  3. A diode-pumped Tm:CaYAlO4 laser at 1851 nm

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


    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.

  4. Spatial and polarization entanglement of lasing patterns and related dynamic behaviors in laser-diode-pumped solid-state lasers.

    Otsuka, K; Chu, S-C; Lin, C-C; Tokunaga, K; Ohtomo, T


    To provide the underlying physical mechanism for formations of spatial- and polarization-entangled lasing patterns (namely, SPEPs), we performed experiments using a c-cut Nd:GdVO(4) microchip laser with off-axis laser-diode pumping. This extends recent work on entangled lasing pattern generation from an isotropic laser, where such a pattern was explained only in terms of generalized coherent states (GCSs) formed by mathematical manipulation. Here, we show that polarization-resolved transverse patterns can be well explained by the transverse mode-locking of distinct orthogonal linearly polarized Ince-Gauss (IG) mode pairs rather than GCSs. Dynamic properties of SPEPs were experimentally examined in both free-running and modulated conditions to identify long-term correlations of IG mode pairs over time. The complete chaos synchronization among IG mode pairs subjected to external perturbation is also demonstrated.

  5. Green-diode-pumped femtosecond Ti:Sapphire laser with up to 450 mW average power.

    Gürel, K; Wittwer, V J; Hoffmann, M; Saraceno, C J; Hakobyan, S; Resan, B; Rohrbacher, A; Weingarten, K; Schilt, S; Südmeyer, T


    We investigate power-scaling of green-diode-pumped Ti:Sapphire lasers in continuous-wave (CW) and mode-locked operation. In a first configuration with a total pump power of up to 2 W incident onto the crystal, we achieved a CW power of up to 440 mW and self-starting mode-locking with up to 200 mW average power in 68-fs pulses using semiconductor saturable absorber mirror (SESAM) as saturable absorber. In a second configuration with up to 3 W of pump power incident onto the crystal, we achieved up to 650 mW in CW operation and up to 450 mW in 58-fs pulses using Kerr-lens mode-locking (KLM). The shortest pulse duration was 39 fs, which was achieved at 350 mW average power using KLM. The mode-locked laser generates a pulse train at repetition rates around 400 MHz. No complex cooling system is required: neither the SESAM nor the Ti:Sapphire crystal is actively cooled, only air cooling is applied to the pump diodes using a small fan. Because of mass production for laser displays, we expect that prices for green laser diodes will become very favorable in the near future, opening the door for low-cost Ti:Sapphire lasers. This will be highly attractive for potential mass applications such as biomedical imaging and sensing.

  6. 1.34μm Nd:YVO4 high efficiency laser end-pumped by diode-laser of flat-concave cavity type

    Shang Lian-Ju; Ning Ji-Ping


    The parameters of 1.34μm Nd:YVO4 laser end-pumped with flat-concave cavity are theoretically analysed. The analysis in this paper may be helpful to the designing of kindred lasers. The operation of 1.34μm Nd:YVO4 laser end-pumped by a diode-laser with flat-concave cavity is achieved. The output power of 3.51W at 1.34μm and optical to optical conversion efficiency of 39.0% are obtained at the pump power of 9.0W.

  7. Self-Mode-Locking in a Diode-Pumped Self-Q-Switched Nd3+,Cr4+:YAG Laser

    杨林; 冯宝华; 张治国; Volker Gaebler; 刘百宁; Hans J. Eichler; 张世文


    We report for the first time on the observation of self-mode-locking in a diode pumped self-Q-switched (SQS)Nd3+,Cr4+ : YA G laser. This phenomenon results from significant excited state absorption of the Cr4+ ions in theco-doped host during the SQS laser pulses. The self-mode-locking occurs already slightly above the SQS laserthreshold. Experiments using relatively low saturable intensity achieved a modulation depth of more than 40%.

  8. Continuously tunable solution-processed organic semiconductor DFB lasers pumped by laser diode

    Klinkhammer, Sönke; Liu, Xin; Huska, Klaus


    The fabrication and characterization of continuously tunable, solution-processed distributed feedback (DFB) lasers in the visible regime is reported. Continuous thin film thickness gradients were achieved by means of horizontal dipping of several conjugated polymer and blended small molecule...... solutions on cm-scale surface gratings of different periods. We report optically pumped continuously tunable laser emission of 13 nm in the blue, 16 nm in the green and 19 nm in the red spectral region on a single chip respectively. Tuning behavior can be described with the Bragg-equation and the measured...

  9. Diode Laser Pumped Alkali Vapor Lasers with Exciplex-Assisted Absorption


    Torr of Helium in the discharge is similar to the DPAL systems, o 13 = 7.2 x 10’ 13 cm2. The state degeneracy’s of, g3 =7, g2 =3 and g1 = 5 are more...krypton and helium was used . These gases were further purified by passage through molecular sieve traps that were immersed in liquid nitrogen. The total...was produced from a dye laser pumped by the 308 nm output of an excimer laser running at 10 Hz (Lambda Physik EMG201/FL3002). The linewidth was

  10. Theoretical and experimental investigations of quasi-continuous wave diode arrays side-pumped Yb:YAG slab laser

    Wu Hai-Sheng; Yan Ping; Gong Ma-Li; Liu Qiang


    An analytical model of quasi-continuous wave (quasi-CW) diode array side-pumped slab laser for Yb:YAG oscillator in long-pulse free-running has been developed based on the CW model. In this model we first introduce a new parameter,pump pulse width, and make the model available for use in the quasi-CW model. We also give an analytical equation of laser delay time to calculate the laser pulse width. A detailed model is also presented for a new structure laser design, taking account of the geometry of Yb:YAG slab. A quasi-CW diode array side-pumped Yb:YAG slab laser is investigated theoretically and experimentally. Experiments yield a quasi-CW output energy up to 20.36 mJ with the laser pulse width of 654.55μs at 1049 nm when the diode arrays operate at 25 Hz and 1 ms pulse width. The crystal dimensions are 3 mm×8 mm× 1 mm and the doping density is 10 at.%. The experimental results are in good agreement with the predictions of the theoretical model.

  11. Activation of theMercury Laser System: A Diode-Pumped Solid-State Laser Driver for Inertial Fusion

    Bayramian, A J; Beach, R J; Bibeau, C; Ebbers, C A; Freitas, B L; Kanz, V K; Payne, S A; Schaffers, K I; Skulina, K M; Smith, L K; Tassano, J B


    Initial measurements are reported for the Mercury laser system, a scalable driver for rep-rated inertial fusion energy. The performance goals include 10% electrical efficiency at 10 Hz and 100 J with a 2-10 ns pulse length. We report on the first Yb:S-FAP crystals grown to sufficient size for fabricating full size (4 x 6 cm) amplifier slabs. The first of four 160 kW (peak power) diode arrays and pump delivery systems were completed and tested with the following results: 5.5% power droop over a 0.75 ms pulse, 3.95 nm spectral linewidth, far field divergence of 14.0 mrad and 149.5 mrad in the microlensed and unmicrolensed directions respectively, and 83% optical-to-optical transfer efficiency through the pump delivery system.

  12. Primary investigations on the potential of a novel diode pumped Er:YAG laser system for middle ear surgery

    Stock, Karl; Wurm, Holger; Hausladen, Florian


    Flashlamp pumped Er:YAG lasers are successfully used clinically for both precise soft and hard tissue ablation. Since several years a novel diode pumped Er:YAG laser system (Pantec Engineering AG) is available, with mean laser power up to 40 W and pulse repetition rate up to 1 kHz. The aim of the study was to investigate the suitability of the laser system specifically for stapedotomy. Firstly an experimental setup was realized with a beam focusing unit and a computer controlled translation stage to move the samples (slices of porcine bone) with a defined velocity while irradiation with various laser parameters. A microphone was positioned in a defined distance to the ablation point and the resulting acoustic signal of the ablation process was recorded. For comparison, measurements were also performed with a flash lamp pumped Er:YAG laser system. After irradiation the resulting ablation quality and efficacy were determined using light microscopy. Using a high speed camera and "Töpler-Schlierentechnik" the cavitation bubble in water after perforation of a bone slice was investigated. The results show efficient bone ablation using the diode pumped Er:YAG laser system. Also a decrease of the sound level and of the cavitation bubble volume was observed with decreasing pulse duration. Higher repetition rates lead to a slightly increase of thermal side effects but have no influence on the ablation efficiency. In conclusion, these first experiments demonstrate the high potential of the diode pumped Er:YAG laser system for use in middle ear surgery.

  13. Diode-pumped CW Tm:GdVO4 laser at 1.9 μm

    Yufeng Li; Baoquan Yao; Yuezhu Wang


    @@ A high power cryogenic cooling Tm-doped (2%) GdVO4 laser double-end-pumped by fiber-coupled-diode with the center wavelength of 804.5 nm at 21 ℃ is reported. The highest continuous-wave (CW) power of 2.35 W at 1903 nm is attained at pump power of 24 W. The slope efficiency is 12.5% and the threshold is 3.2 W. Single- and double-end-pumped types are investigated.

  14. Green-diode-pumped femtosecond Ti:Sapphire laser with up to 450 mW average power

    Gürel, Kutan; Wittwer, Valentin J; Hoffmann, Martin; Saraceno, Clara J.; Hakobyan, Sargis; Resan, B; Rohrbacher, A; Weingarten, K.; Schilt, Stéphane; Südmeyer, Thomas


    We investigate power-scaling of green-diode-pumped Ti:Sapphire lasers in continuous-wave (CW) and mode-locked operation. In a first configuration with a total pump power of up to 2 W incident onto the crystal, we achieved a CW power of up to 440 mW and self-starting mode-locking with up to 200 mW average power in 68-fs pulses using semiconductor saturable absorber mirror (SESAM) as saturable absorber. In a second configuration with up to 3 W of pump power incident onto the crystal, we achieve...

  15. Efficient intracavity frequency doubling of a high-repetition-rate diode-pumped Nd:YAG laser.

    Hanson, F; Poirier, P


    Efficient operation of a pulsed, high-repetition-rate diode-pumped and intracavity frequency-doubled Nd:YAG laser is reported. A 3-mm-diameter laser rod was side-pumped with a 5-bar stack of high-duty-cycle 1-cm diodearrays. The average Q-switched power at 1.06microum was 3.8 W at 1.33 kH(z), and more than 4 W at 0.532 ,microm wasobtained through intracavity frequency doubling with LiB(3)O(5).

  16. 340 W average power output of diode-pumped composite ceramic YAG/Nd:YAG disk laser

    Jia, Kai; Jiang, Yong; Yang, Feng; Deng, Bo; Hou, Tianjin; Guo, Jiawei; Chen, Dezhang; Wang, Hongyuan; Yang, Chuang; Peng, Chun


    We report on a diode-pumped composite ceramic disk laser in this paper. The composite ceramic YAG/Nd:YAG disk consists of 4 mm thick pure YAG and 2 mm thick Nd:YAG with 1.0 at.% doping concentration. The slope efficiency of the composite ceramic disk laser is 36.6% corresponding to the maximum optical-optical efficiency of 29.2%. Furthermore, 340 W average power output was achieved at the absorbed pump power of 1290 W.

  17. Low threshold diode-pumped picosecond mode-locked Nd:YAG laser with a semiconductor saturable absorber mirror

    Eshghi, M. J.; Majdabadi, A.; Koohian, A.


    In this paper, a low threshold diode pumped passively mode-locked Nd:YAG laser has been demonstrated by using a semiconductor saturable absorber mirror. The threshold power for continuous-wave mode-locking is relatively low, about 3.2 W. The resonator stability across the pump power has been analytically examined. Moreover, the mode overlap between the pump beam and the laser fundamental mode has been simulated by MATLAB software. Adopting Z-shaped resonator configuration and suitable design of the resonator’s arm lengths, has enabled the author to prepare mode-locking conditions, and obtain 40 ps pulses with 112 MHz pulse repetition rate. The laser output was stable without any Q switched instability. To the best of our knowledge, this is the lowest threshold for CW mode-locking operation of a Nd:YAG laser.

  18. Spontaneous Generation of Vortex Array Beams from a Thin-Slice Solid-State Laser with Wide-Aperture Laser-Diode Pumping

    Otsuka, Kenju


    We studied complex lasing pattern formations in a thin-slice solid-state laser with wide-aperture laser-diode end-pumping. Radial and rectangular vortex arrays were found to be formed in a controlled fashion with symmetric and asymmetric pump beam profiles, respectively. Most of these vortices exhibited single-frequency oscillations arising from a spontaneous process of transverse mode locking of nearly degenerate modes assisted by the laser nonlinearity. Single-frequency rectangular array beams consisting of a large number of vortices, e.g., closely packed 36 or 46 vortex pixels, were generated, originating from Ince-Gaussian modes excited by the asymmetric pumping.

  19. Continuous-wave laser operation of diode-pumped Tm-doped Gd3Ga5O12 crystal

    Wang, Yi; Lan, Jinglong; Zhou, Zhiyong; Guan, Xiaofeng; Xu, Bin; Xu, Huiying; Cai, Zhiping; Wang, Yan; Tu, Chaoyang


    We report on a diode-pumped Tm:Gd3Ga5O12 (GGG) laser at 2004 nm operated in continuous-wave mode with two-mirror linear cavity configuration. The maximum output power reaches 0.58 W with laser threshold absorbed pump power of about 0.39 W and overall slope efficiency of about 18.4%, which is believed to be the highest output power for Tm:GGG laser up to now. The Tm:GGG laser shows obvious thermally induced saturation of the output power, which indicated that power and efficiency scaling could be furtherly realized by more efficient thermal removal of the laser crystal.

  20. Influence of the laser-diode temperature on crystal absorption and output power in an end-pumped Nd:YVO4 laser

    Ebrahim Safari


    In this work, we studied the influence of heat loaded into the laser crystal in an endpumped solid-state Nd:YVO4 high power laser. We have shown experimentally that the optimum value of the laser-diode temperature for the maximum pump power absorption by the Nd:YVO4 crystal and the maximum Nd:YVO4 laser output power are approximately similar to that of a system of the low power type, but by increasing the pump power, different values can be obtained.

  1. Widely Tunable cw Diode-Pumped 1.9-μm Tm:GdVO4 Laser at Room Temperature

    LI Yu-Feng; YAO Bao-Quan; LIU Yan-Mei; WANG Yue-Zhu; JU You-Lun


    A widely tunable cw diode-pumped room-temperature Tm:GdVO4 laser is built. Output power of 2.8 W and a slope efficiency of 22% pumped by a 18 W Fibre-coupled diode laser at 795nm have been obtained. Continuous tunability from 1820nm to 1946nm is achieved. In addition, the factors that contribute to the efficiency of oscillation are studied.

  2. Highly efficient diode-stack, end-pumped Nd:YAG slab laser with symmetrized beam quality.

    Liao, Y; Du, K; Falter, S; Zhang, J; Quade, M; Loosen, P; Poprawe, R


    An efficient high-power cw Nd:YAG slab laser, partially end pumped by diode-laser stacks, and a novel beam-shaping technique are reported. The optical efficiency amounted to 44 %, and the slope efficiency amounted to 55 %. Introducing an intracavity Brewster plate to polarize the laser beam, we obtained an optical efficiency of 35 % and a slope efficiency of 41 %. The output beam was rectangular and the beam quality asymmetric in two orthogonal directions. To equalize the beam quality, we introduced a step-mirror beam-shaping technique. The beam-shaping technique and the results obtained are discussed.

  3. Frequency stabilization to a molecular line of a diode-pumped Er{endash}Yb laser at 1533-nm wavelength

    Taccheo, S.; Longhi, S.; Pallaro, L.; Laporta, P. [Centro di Elettronica Quantistica e Strumentazione Elettronica del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica del Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Svelto, C.; Bava, E. [Dipartimento di Elettronica e Informazione del Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano (Italy)


    Two identical diode-pumped bulk Er:Yb:glass lasers, operating at 1533-nm wavelength, have been locked independently to the {ital P}(13) vibrational{endash}rotational line of an acetylene molecule. A long-term frequency stability over a 4-h period of better than 1.5 MHz and a short-term laser linewidth narrower than 50 kHz have been obtained by measurement of the beat note between the two lasers. {copyright} {ital 1995 Optical Society of America.}

  4. Efficient Ho:LuLiF4 laser diode-pumped at 1.15 μm.

    Wang, Sheng-Li; Huang, Chong-Yuan; Zhao, Cheng-Chun; Li, Hong-Qiang; Tang, Yu-Long; Yang, Nan; Zhang, Shuai-Yi; Hang, Yin; Xu, Jian-Qiu


    We report the first laser operation based on Ho(3+)-doped LuLiF(4) single crystal, which is directly pumped with 1.15-μm laser diode (LD). Based on the numerical model, it is found that the "two-for-one" effect induced by the cross-relaxation plays an important role for the laser efficiency. The maximum continuous wave (CW) output power of 1.4 W is produced with a beam propagation factor of M(2) ~2 at the lasing wavelength of 2.066 μm. The slope efficiency of 29% with respect to absorbed power is obtained.

  5. >220W output power at 355nm from a Q-switched diode-pumped solid-state laser

    Hay, Nick; Slavinskis, Nerijus; Rodin, Aleksej M.; Kwon, Young Key


    We demonstrate 220 W average power at 355 nm from a diode-pumped acousto-optically Q-switched Nd:YAG laser using intracavity second harmonic generation and sum frequency mixing in a nested sub-cavity design. The laser generates linearly polarised pulses with duration 65 ns at repetition rate 10 kHz. Polarisation multiplexing is used to combine two orthogonal beams giving total output pulse energy 22 mJ with peak power cost of ownership DPSS lasers for high-throughput industrial processes in the UV.

  6. Stability of a Laser-diode-pumped Cr4+∶YAG Passively Q-switched Nd3+∶YAG Laser

    ZHANG Xingyu; ZHAO Shengzhi; WANG Qingpu; ZHANG Qidi; B. Ozygus; M. Weber


    In this paper, the stability of a laser-diode-pumped Cr4+∶YAG passively Nd3+∶YAG Q-switched laser and the influence of the transversal mode structure on the stability are investigated. With the laser operating in TEM00 mode, the pulse energy fluctuation and the repetition rate fluctuation as functions of the repetition rate are measured, and semi-quantitatively and qualitatively analyzed, respectively.

  7. Intensity noise in diode-pumped single-frequency Nd:YAG lasers and its control by electronic feedback

    Kane, Thomas J.


    The power spectrum of the relative intensity noise (RIN) of single-frequency diode-pumped Nd:YAG lasers is observed to be shot-noise limited at frequencies above 20 MHz for a photocurrent of up to 4.4 mA. Relaxation oscillations result in noise 60-70 dB above shot noise at a few hundred kHz. These relaxation oscillations have been suppressed using electronic feedback.

  8. Laser-diode pumped self-mode-locked praseodymium visible lasers with multi-gigahertz repetition rate.

    Zhang, Yuxia; Yu, Haohai; Zhang, Huaijin; Di Lieto, Alberto; Tonelli, Mauro; Wang, Jiyang


    We demonstrate efficient laser-diode pumped multi-gigahertz (GHz) self-mode-locked praseodymium (Pr3+) visible lasers with broadband spectra from green to deep red for the first time to our knowledge. With a Pr3+-doped GdLiF4 crystal, stable self-mode-locked visible pulsed lasers at the wavelengths of 522 nm, 607 nm, 639 nm, and 720 nm have been obtained with the repetition rates of 2.8 GHz, 3.1 GHz, 3.1 GHz, and 3.0 GHz, respectively. The maximum output power was 612 mW with the slope efficiency of 46.9% at 639 nm. The mode-locking mechanism was theoretically analyzed. The stable second-harmonic mode-locking with doubled repetition frequency was also realized based on the Fabry-Perot effect formed in the laser cavity. In addition, we find that the polarization directions were turned with lasing wavelengths. This work may provide a new way for generating efficient ultrafast pulses with high- and changeable-repetition rates in the visible range.

  9. Diode-pumped low noise CW 355-nm intra-cavity tripled laser up to 20 mW

    Aubert, Nicolas; Georges, Thierry; Chauzat, Corinne; Le Bras, Raymond; Féron, Patrice


    Low noise lasers in the UV spectrum (355 nm) are important for many applications like spectroscopy, confocal microscopy, flow cytometry, cell sorting, CD mastering, semiconductor inspection and reprographics. The UV CW laser sources currently commercially available, are restricted to excimers lasers, gas ions lasers which suffer from low power efficiency (0.01% or less), high electrical consumption and bulky dimensions. These products, which are expensive, are still waiting for practical replacements. To our best knowledge, we report in this paper the first efficient low noise diode-pumped neodymium doped solid-state laser operating at 355 nm by intra-cavity third harmonic generation (THG). The fundamental infrared laser light is generated by a diode-pumped Nd:YVO 4 crystal optically contacted with others components of the laser cavity. Intra-cavity SHG and THG are achieved with a KTP and LBO respectively. Several configurations have led to low noise 355 nm single-frequency operation at a power exceeding 10 mW. We believe that this power can still be improved.

  10. A Compact 532-nm Source by Frequency Doubling of a Diode Stack End-Pumped Nd:YAG Slab Laser

    ZHANG Heng-Li; LIU Xiao-Meng; LI Dai-Jun; SHI Peng; Alex Schell; Claus Rüdige Haas; Du Ke-Ming


    A near-diffraction-limited green source is generated at 1 kHz repetition rate by frequency doubling ofa diode stack end-pumped electro-optically Q-switched Nd:YAG slab laser. We obtain 9.7mJ green light with pulse width of 12.2ns at a repetition rates of 1 kHz. The pump to green optical conversion efficiency is 12.9%. The energy pulse stability at 532nm is about 0.8%.

  11. Q-switched mode-locked diode-pumped Nd:YVO4 laser with a saturable Bragg reflector

    Juan Du(杜鹃); Jingliang He(何京良); Jie Liu(刘杰); Qiuxia Jiang(姜秋霞); Sheng Liu(刘胜); Huitian Wang(王慧田)


    We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of ~230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of ~150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.

  12. Q-switched mode-locked diode-pumped Nd:YVO4 laser with a saturable Bragg reflector

    杜鹃; 何京良; 刘杰; 姜秋霞; 刘胜; 王慧田


    We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of ~230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of ~150kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.

  13. Power scaling of a wavelength-narrowed diode laser system for pumping alkali vapors

    Hersman, F. W.; Distelbrink, J. H.; Ketel, J.; Wilson, J.; Watt, D. W.


    We report a method for locking the output wavelength and reducing the spectral linewidth of diode lasers by feeding back light to the emitters from a wavelength selective external optical cavity. Ten years ago our team developed a stepped-mirror that allowed a single external cavity to lock the wavelength of a stack of diode array bars by equalizing path lengths between each emitter and the grating. Here we report combining one such step-mirror external cavity with an array of power dividers, each sending a portion of this feedback power to a separate diode array bar stack.

  14. A 46-W Laser Diode Stack End-Pumped Slab Amplifier with a Pulse Duration of Picoseconds

    YAN Ying; FAN Zhong-Wei; NIU Gang; YU Jin; ZHANG Heng-Li


    A 46-W laser diode end-pumped amplifier is demonstrated by using a SESAM passively mode-locked oscillator and a compact LD stack end-pumped slab amplifier.For the oscillator,a 5-W picosecond mode-locked laser with a repetition frequency of 79MHz is obtained with beam quality factors of M2 < 1.3.A beam shaping system made up of cylindrical lens is designed according to different sizes of the active medium in both directions,and a plane-plane cavity is used in the amplifier for high efficiency.At the absorbed pumping power of 174 W,the highest output power of 46 W is obtained with the slope efficiency of 29.5%.The beam quality factors M2 in both directions are measured to be 1.43 and 1.76,respectively.

  15. Welding Stainless Steels and Refractory Metals Using Diode-Pumped Continuous Wave Nd:YAG Lasers

    Palmer, T A; Elmer, J W; Pong, R; Gauthier, M D


    This report provides an overview of a series of developmental welding studies performed on a 2.2 kW Rofin Sinar DY-022 Diode Pumped Continuous Wave (CW) Nd:YAG welder at Lawrence Livermore National Laboratory (LLNL). Several materials systems, ranging from refractory metals, such as commercially pure tantalum and vanadium, to austenitic stainless steels, including both 304L and 21-6-9 grades, are examined. Power input and travel speed are systematically varied during the welding of each materials system, and the width, depth, and cross sectional area of the resulting weld fusion zones are measured. These individual studies are undertaken in order to characterize the response of the welder to changes in these welding parameters for a range of materials and to determine the maximum depth of penetration of which this welder is capable in each materials system. The maximum weld depths, which are on the order of 5.4 mm, are observed in the 21-6-9 austenitic stainless steel at the maximum laser power setting (2200 W) and a slow travel speed (6.4 mm/sec). The next highest weld depth is observed in the 304L stainless steel, followed by that observed in the vanadium and, finally, in the tantalum. Porosity, which is attributed to the collapse of the keyhole during welding, is also observed in the welds produced in tantalum, vanadium, and 304L stainless steel. Only the 21-6-9 austenitic stainless steel welds displayed little or no porosity over the range of welding parameters. Comparisons with similar laser welding systems are also made for several of these same materials systems. When compared with the welds produced by these other systems, the LLNL system typically produces welds of an equivalent or slightly higher depth.

  16. 2.05 µm holmium-doped all-fiber laser diode-pumped at 1.125 µm

    Kir'yanov, A. V.; Barmenkov, Y. O.; Villegas Garcia, I.


    We report a holmium-doped all-fiber laser oscillating at ~2.05 µm in continuous wave at direct in-core pumping by a 1.125 µm laser diode. Two types of home-made holmium-doped alumino-germano-silicate fiber (HDF), differentiated in the Ho3+ doping level, were fabricated to implement the laser, for revealing the effect of Ho3+ concentration upon the laser output. Firstly, the fibers were characterized thoroughly from the material and optical viewpoints. Then, laser action with both HDFs was assessed using the simplest Fabry-Perot cavity, assembled by a couple of spectrally adjusted fiber Bragg gratings, also made-in-house. In the best case, when using the lower-doped HDF of proper length (1.4 m), low threshold (~370 mW) and moderate slope efficiency (~13%) of ~2.05 µm lasing were obtained at 1.125 µm diode pumping. Long-term stability, high brightness, low noise, and purely CW operation are shown to be the laser’s attractive features. Yet, when utilizing the heavier-doped HDF, laser output is revealed to be overall worse, with a possible reason being the deteriorating Ho3+ concentration-related effects.

  17. Investigations on the potential of a novel diode pumped Er:YAG laser system for dental applications

    Stock, Karl; Hausladen, Florian; Hibst, Raimund


    The successful clinical application of the Er:YAG-laser in dentistry is well known, documented by numerous published studies. These lasers are flash lamp pumped systems and emit pulses of typically some 100 μs duration with energies of up to 1 J. Pulse repetition rates can reach up to 100Hz, and mean powers are up to about 8W. As an alternative to these laser systems recently a novel diode pumped Er:YAG laser system (Pantec Engineering AG) became available. This laser can provide a pulse repetition rate up to 2kHz and a mean laser power up to 15W. The aim of the presented study is to investigate the effect of this laser system on dental hard and soft tissue at various irradiation parameters, particular at repetition rates more than 100 Hz. At first an appropriate experimental set-up was realized with a beam delivery and focusing unit, a computer controlled stepper unit with sample holder, and a shutter unit. The stepper unit allows to move the samples (dentin or enamel slides of extracted human teeth, chicken breast, pig bone) with a defined velocity during irradiation by various laser parameters. For rinsing the sample surface a water spray was also included. The laser produced grooves and cuts were analyzed by light microscopy and laser scanning microscopy regarding to the ablation quality, geometry, ablation efficacy, and thermal effects. The grooves in dentin and enamel show a rough surface, typical for Er:YAG laser ablation. The craters are slightly cone shaped with sharp edges on the surface. Water cooling is essential to prevent thermal injury. The ablation efficacy in dentin is comparable to literature values of the flash lamp pumped Er:YAG laser. The cutting of bone and soft tissue is excellent and appears superior to earlier results obtained with flash lamp pumped system. As a further advantage, the broad range of repetition rates allows to widely vary the thermal side effects. In conclusion, these first experiments with a diode pumped Er:YAG laser

  18. Influence of absorbed pump profile on the temperature distribution within a diode side-pumped laser rod



    In this paper, an analytical model for temperature distribution of the side-pumped laser rod is extracted. This model can be used for side-pumped laser rods whose absorbed pump profile is a Gaussian profile. Then, it is validated by numerical results which exhibit a good agreement with the analytical results. Afterwards, by considering a general expression for super-Gaussian and top-hat profiles, and solving the heat equation, the influence of profile width and super-Gaussian exponent of the profile on temperature distribution are investigated.Consequently, the profile width turns out to have a greater influence on the temperature compared to the type of the profile.

  19. Influence of absorbed pump profile on the temperature distribution within a diode side-pumped laser rod

    Moghtader Dindarlu, M. H.; Tehrani, M. Kavosh; Saghafifar, H.; Maleki, A.; Solookinejad, Gh; Jabbari, M.


    In this paper, an analytical model for temperature distribution of the side-pumped laser rod is extracted. This model can be used for side-pumped laser rods whose absorbed pump profile is a Gaussian profile. Then, it is validated by numerical results which exhibit a good agreement with the analytical results. Afterwards, by considering a general expression for super-Gaussian and top-hat profiles, and solving the heat equation, the influence of profile width and super-Gaussian exponent of the profile on temperature distribution are investigated. Consequently, the profile width turns out to have a greater influence on the temperature compared to the type of the profile.

  20. 1.8kW laser diode pumped YAG laser; Shutsuryoku 1.8kW no handotai laser reiki YAG laser



    Toshiba Corporation, as a participant in Ministry of International Trade and Industry`s `photon measurement and processing technology project` since August, 1997, is engaged in the development of an energy-efficient LD (laser diode) pumped semiconductor YAG (yttrium-aluminum-garnet) laser device to be used for welding and cutting. It is a 5-year project and the goal is a mean output of 10kW and efficiency of 20%. In this article, a simulation program is developed which carries out calculation about element technology items such as the tracking of the beam from the pumping LD and the excitation distribution, temperature distribution, thermal stress distribution, etc., in the YAG rod. An oscillator is constructed, based on the results of the simulation, and it exhibits a world-high class continuous laser performance of a 1.8kW output and 13% efficiency. The record of 13% efficiency is five times higher than that achieved by the conventional lamp-driven YAG laser device. (translated by NEDO)

  1. Header For Laser Diode

    Rall, Jonathan A. R.; Spadin, Paul L.


    Header designed to contain laser diode. Output combined incoherently with outputs of other laser diodes in grating laser-beam combiner in optical communication system. Provides electrical connections to laser diode, cooling to thermally stabilize laser operation, and optomechanical adjustments that steer and focus laser beam. Range of adjustments provides for correction of worst-case decentering and defocusing of laser beam encountered with laser diodes. Mechanical configuration made simple to promote stability and keep cost low.

  2. Epi-detecting label-free multimodal imaging platform using a compact diode-pumped femtosecond solid-state laser

    Andreana, Marco; Le, Tuan; Hansen, Anders Kragh


    We have developed an epi-detected multimodal nonlinear optical microscopy platform based on a compact and cost-effective laser source featuring simultaneous acquisition of signals arising from hyperspectral coherent anti-Stokes Raman scattering (CARS), two-photon fluorescence, and second harmonic...... for these three modalities, achieving sufficient spectral resolution for CARS in the lipid region. The experimental results on a biological tissue reveal that the combination of the epi-detection scheme and the use of a compact diode-pumped femtosecond solid-state laser in the nonlinear optical microscope...

  3. Passive Q-switching of diode-pumped Yb:YAG microchip laser with ion-implanted GaAs

    Yonggang Wang(王勇刚); Xiaoyu Ma(马骁宇); Bin Zhong(钟斌); Desong Wang(王德松); Qiulin Zhang(张秋琳); Baohua Feng(冯宝华)


    We reported a passive Q-switched diode laser pumped Yb:YAG microchip laser with an ion-implanted semiinsulating GaAs wafer. The wafer was implanted with 400-kev As+ in the concentration of 1016 ions/cm2.To decrease the non-saturable loss, we annealed the ion-implanted GaAs at 500 ℃ for 5 minutes and coated both sides of the ion-implanted GaAs with antireflection (AR) and high reflection (HR) films,respectively. Using GaAs wafer as an absorber and an output coupler, we obtained 52-ns pulse duration of single pulse.

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

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


    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%.

  5. Full characterization of the amplified spontaneous emission from a diode-pumped high-power laser system.

    Keppler, S; Hornung, M; Bödefeld, R; Sävert, A; Liebetrau, H; Hein, J; Kaluza, M C


    We present the first complete temporal and spatial characterization of the amplified spontaneous emission (ASE) of laser radiation generated by a diode-pumped high-power laser system. The ASE of the different amplifiers was measured independently from the main pulse and was characterized within a time window of -10ms ≤ t ≤ 10ms and an accuracy of up to 15fs around the main pulse. Furthermore, the focusability and the energy of the ASE from each amplifier was measured after recompression. Using our analysis method, the laser components, which need to be optimized for a further improvement of the laser contrast, can be identified. This will be essential for laser-matter interaction experiments requiring a minimized ASE intensity or fluence.

  6. Reducing Thermal Effect in End-Diode-Pumped Laser Crystal by Using a Novel Resonator

    YAO Ai-Yun; HOU Wei; LI Hui-Qing; BI Yong; LIN Xue-Chun; GENG Ai-Cong; KONG Yu-Peng; CUI Da-Fu; XU Zu-Yan


    @@ We report a new way, i.e. double-end-pumping, to extend the stability range of a laser resonator, in advantage of making the thermal loading be effectively divided between the ends of the laser crystal to reduce the thermal effect, thus to extend the stability range.

  7. High Average Power Diode Pumped Solid State Lasers: Power Scaling With High Spectral and Spatial Coherence


    sensing and coherent LIDAR systems, will require kW class lasers in the near future. The zigzag slab architecture [2], with its nearly one-dimensional... photodetectors ; PM1, PM2, PM3: thermal power meters; HBS1: 1064 nm holographic beam sampler; HBS2: 532-nm holographic beam sampler; LD: laser diode; CCD: charge...recombining pairs is measured by a photodetector . This measurement shows higher PL intensity as the material is improved by reducing defect density. We tried

  8. A compact diode-pumped pulsed Nd:YAG slab laser based on a master oscillator power amplifier configuration

    Maleki, A.; Kavosh Tehrani, M.; Saghafifar, H.; Moghtader Dindarlu, M. H.; Ebadian, H.


    In this paper, the design and construction of a pulsed Nd:YAG laser is described. The structure of this laser is based on a master oscillator power amplifier system. A master oscillator is an electro-optical Q-switched Nd:YAG rod laser. Face-pumping is used for the excitation of the slab structure, and a double-pass method is designed for the amplification stages. Two Nd:YAG zigzag slabs are utilized as power amplification stages in this laser. The laser diodes are stacked in a compact configuration and are used for rod and slabs pumping. The total pump energy in the amplifier stages is 3200 mJ at 808 nm. The output pulse energy achieved at 1064 nm is about 850 mJ of 10 ns pulse duration corresponding to 26.5% optical-to-optical conversion efficiency. Moreover, this laser can generate pulse energies around 430 mJ at 532 nm. The dependence of the output energy of MOPA and second harmonic generation operations on different pulse repetition rates (PRRs) from 1 to 100 Hz has been investigated. Experimental results show that the maximum fluctuations of the output energies are about 2.5 and 4% for 1064 and 532 nm, respectively.

  9. Nanoimprinted organic semiconductor laser pumped by a light-emitting diode.

    Tsiminis, Georgios; Wang, Yue; Kanibolotsky, Alexander L; Inigo, Anto R; Skabara, Peter J; Samuel, Ifor D W; Turnbull, Graham A


    An organic semiconductor laser, simply fabricated by UV-nanoimprint lithography (UV-NIL), that is pumped with a pulsed InGaN LED is demonstrated. Molecular weight optimization of the polymer gain medium on a nanoimprinted polymer distributed feedback resonator enables the lowest reported UV-NIL laser threshold density of 770 W cm(-2) , establishing the potential for scalable organic laser fabrication compatible with mass-produced LEDs.

  10. Continuous-Wave Green Laser of 9.9W by Intracavity Frequency Doubling in Laser Diode Single-End-Pumped Nd:YVO4/LBO

    BAI Yang; LI Long; CHEN Hao-Wei; YANG Zhi; BAI Jin-Tao


    @@ A maximum of 9.9 W cw TEM00 output at 532nm laser has been obtained by intracavity frequency doubling with LBO in laser-diode single-end-pumped Nd:YVO4. The Nd:YVO4/LBO green laser has a simple three mirror V-fold cavity structure. The optical-optical conversion efficiency was 34.8%. Based on the equation of thermal conduction, a general solution for the laser-crystal interior temperature distribution is obtained by the semi-analytical thermal analysis method.

  11. Diode-pumped Q-switched Nd:YLF laser at 1313 nm

    Xu, Shan; Gao, Shufang; Zheng, Chunyan


    In this letter, we describe the operation of an end-pumped acousto-optic Q-switched Nd:YLF laser. According to the theoretical analysis and calculation for Nd:YLF crystal, the thermal focal length of σ-polarized laser is positive in plane-parallel resonator, while that of π-polarized laser is negative. Hence laser operation at σ-polarized 1313 nm should be stable in plane-parallel cavity. When absorbed pump power is 12.45 W and the pulse repetition frequency is 10 kHz, 3.1 W output laser at 1313 nm is achieved. As a result, the optical-optical conversion efficiency is 25.4 % and slope efficiency is 31.2 %, respectively.

  12. Kerr-Lens Mode-Locked Femtosecond Yb:GdYSiO5 Laser Directly Pumped by a Laser Diode

    Jiangfeng Zhu


    Full Text Available We demonstrate the first Kerr-lens mode-locked operation in a diode-pumped Yb:GdYSiO5 oscillator. Under a diode pump power of 5 W, 141 fs pulses with an average power of 237 mW were obtained at a repetition rate of 118 MHz. The central wavelength was at 1094 nm with a bandwidth of 10.1 nm. Shorter pulses were obtained by adjusting the cavity to operate at a shorter wavelength, resulting in 55 fs pulse duration at the central wavelength of 1054 nm with a bandwidth of 23.5 nm.

  13. Diode-pumped optical parametric oscillator.

    Geiger, A R; Hemmati, H; Farr, W H; Prasad, N S


    Diode-pumped optical parametric oscillation has been demonstrated for the first time to our knowledge in a single Nd:MgO:LiNbO(3) nonlinear crystal. The crystal is pumped by a semiconductor diode laser array at 812 nm. The Nd(3+) ions absorb the 812-nm radiation to generate 1084-nm laser oscillation. On internal Q switching the 1084-nm radiation pumps the LiNbO(3) host crystal that is angle cut at 46.5 degrees and generates optical parametric oscillation. The oscillation threshold that is due to the 1084-nm laser pump with a pulse length of 80 ns in a 1-mm-diameter beam was measured to be approximately 1 mJ and produced 0.5-mJ output at 3400-nm signal wavelength.

  14. 80-fs Nd:silicate glass laser pumped by a single-mode 200-mW diode.

    Agnesi, Antonio; Greborio, Alessandro; Pirzio, Federico; Reali, Giancarlo


    A Nd(3+)-doped Schott LG680 silicate glass laser was pumped with a single-mode 200-mW diode. Efficient cw operation was demonstrated with 37.5 mW output power and 36% slope efficiency. Passive mode-locking with a semiconductor saturable absorber mirror yielded 80-fs pulses with a two-prism setup. Alternatively, pulses of approximately 200-fs, tunable over the range 1058-1076 nm, were obtained with either slit-tuning or a single-prism dispersive resonator. Output powers from 6 to 14 mW have been measured.

  15. Diode-pumped cw and femtosecond laser operations of a hetero-composite crystal YAG||SYS:Yb

    Druon, Frédéric; Chenais, Sébastien; Balembois, François; Georges, Patrick; Gaume, R.; Viana, Bruno


    International audience; We report cw and femtosecond laser operations under diode pumping of a diffusion-bonding heterocomposite Yb-doped crystal: Yb3+:SrY4sSiO4d3OiY2Al5O12sYAGiSYS:Ybd. To show the advantages of this heterocomposite crystal over classical Yb:SYS crystal, we first investigate the high-power cw regime. A cw power of 4.3 W is demonstrated. The femtosecond regime is also investigated, and 1-W-average-power, 130-fs pulses at 1070 nm are produced, which represents, to our knowledg...

  16. Direct comparison of the thermal lenses of diode-end-pumped Nd:YVO4 and Nd:GdVO4 lasers using a simple evaluation technique

    Esser, MJD


    Full Text Available In this work, the thermal lenses generated in diode-end-pumped Nd:YVO4 and Nd:GdVO4 lasers were evaluated and compared using a simple technique based on the stability criteria of a plane-parallel laser resonator [example 1], as shown in the top...

  17. Glass marking with diode-pumped Nd:YLF laser; Handotai reiki Nd:YLF laser ni yoru glass marking

    Sakai, F.; Hayashi, K. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)


    The compact marking system based on a beam scanning system in which the fourth harmonic (FHG: 262 nm in wavelength) of a diode-pumped Nd:YLF (Nd:LiYf4) laser is used for the source of ultraviolet light is described. The result of application to the glass marking that caused a problem due to the generation of cracks is also explained. The machining characteristics significantly vary depending on the type of glass. During actual marking, sample processing must be beforehand carried out to optimize the processing conditions after confirming that there is no problem in practical use. For marking on the glass used for liquid-crystal board, it is valid to improve the density of a dot and increase the number of shots per dot for obtaining high visibility. However, cracks may occur in the clearance of each dot because of the thermal effect. Therefore, the processing conditions must be optimized according to the glass type and crack generation state. The generation of cracks can be suppressed by setting the processing conditions to the optimum level. As a result, satisfactory marking is obtained. 8 refs., 6 figs.

  18. Diode end-pumped self-Q-switched and mode-locked Nd,Cr:YAG/KTP green laser

    Du Shi-Feng; Wang Su-Mei; Zhang Dong-Xiang; Feng Bao-Hua; Zhang Chun-Yu; Zhang Ling; Zhang Zhi-Guo; Zhang Shi-Wen


    We first experimentally demonstrate a laser-diode end-pumped self-Q-switched and mode-locked Nd,Cr:YAG green laser with a KTP crystal as the intra- cavity frequency doubler. The device produces an average output power of 680 mW at 532 nm. The corresponding pulse width of the Q-switched envelope of the green laser is 170 ± 20 ns. The mode-locked pulses have a repetition rate of approximately 183 MHz and the average pulse duration is estimated to be around sub-nanosecond. It is found that the intra-cavity frequency doubling greatly improves the modulation depth and stability of the mode-locked pulses within the Q-switched envelope.

  19. Structure of picosecond pulses of a Q-switched and mode-locked diode-pumped Nd:YAG laser

    Donin, V I; Yakovin, D V; Gribanov, A V [Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)


    The pulse duration of a diode-pumped Nd:YAG laser, in which Q-switching with mode-locking (QML regime) is achieved using a spherical mirror and a travelling-wave acousto-optic modulator, is directly measured with a streak camera. It is found that the picosecond pulses can have a non-single-pulse structure, which is explained by excitation of several competing transverse modes in the Q-switching regime with a pulse repetition rate of 1 kHz. In the case of cw mode-locking (without Q-switching), a new (auto-QML) regime is observed, in which the pulse train repetition rate is determined by the frequency of the relaxation oscillations of the laser field while the train contains single picosecond pulses. (control of laser radiation parameters)

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

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


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

  1. High Power Diode-End-Pumped Nd:YAG 946-nm Laser and Its Efficient Frequency Doubling

    ZHOU Rui; ZHAO Shi-Yong; CAI Zhi-Qiang; ZHANG Qiang; WEN Wu-Qi; DING Xin; WANG Peng; DING Li-Li; YAO Jian-Quan


    @@ We report a high power operation of the 4F3/2 → 4I9/2 transition in diode-end-pumped laser at 946nm. The maximum output of5.1 W is obtained with a short linear plano-concave cavity, and the slope efficiency is 24.5%at incident pump power of 23.3 W. To our knowledge, this is the highest value of the LD-pumped Nd:YAG 946nm lasers that employ the conversional Nd:YAG rod as the gain medium. By intracavity frequency doubling with an LBO crystal, up to 982mW cw output power in the blue spectral range at 473nm is achieved at an incident pump power of 10.9 W with a compact three-element cavity, leading to optical-to-optical conversion efficiency of 9%. The conversion efficiency should be increased to 15.1%, if the rather low absorption coefficient of this Nd:YAG is considered.

  2. Efficient and high-power laser-diode single-end-pumped Nd:YVO4 continuous wave laser at 1342 nm

    Zhang Yu-Ping; Zheng Yi; Zhang Hui-Yun; Wang Peng; Yao Jian-Quan


    A compact, efficient and high-power laser diode (LD) single-end-pumped Nd:YVO4 laser with continuous-wave emission at 1342 nm is reported. With a single crystal single-end-pumped by fibre-coupled LD array, an output power of 7.36W is obtained from the laser cavity of concave-convex shape, corresponding to an optical-to-optical efficiency of 32.8%. The laser is operated in TEM00 mode with small rms amplitude noise of 0.3%. The influences of the Nd concentration, transmissivity of the output mirror and the cavity length on the output power have been studied experimentally.

  3. 3.6-W cryogenic Tm,Ho:YLF laser pumped by fiber-coupled diodes module

    Baoquan Yao; Youlun Ju; Yuezhu Wang; Wanjun He; Yufeng Li


    In this paper, we report a high power cryogenic cooling Tm(6 at.-%),Ho(0.5 at.-%):YLF laser end-pumped by a 19-fiber-coupled-diodes module with the central wavelength of 792 nm at 20°. The highest continuouswave power of 3.6 W at 2.051 μm is attained under pumping power of 13.6 W, corresponding to opticaloptical conversion efficiency of 26%, and the slope efficiency is larger than 30%. The threshold power is only about 0.16 W because of the long lifetime, large effective emission cross section, and low re-absorption in Tm,Ho:YLF crystal.

  4. Passively Q-switched diode-pumped Cr4+:YAG/Nd3+:GdVO4 monolithic microchip laser

    Forget, S; Balembois, F; Georges, P; Landru, N; Feve, J P; Lin, J; Weng, Z; Forget, Sebastien; Druon, Frederic; Balembois, Francois; Georges, Patrick; Landru, Nicolas; Feve, Jean Philippe; Lin, Jiali; Weng, Zhiming


    the realization of high repetition rate passively Q-switched monolithic microlaser is a challenge since a decade. To achieve this goal, we report here on the first passively Q-switched diode-pumped microchip laser based on the association of a Nd:GdVO4 crystal and a Cr4+:YAG saturable absorber. The monolithic design consists of 1 mm long 1% doped Nd:GdVO4 optically contacted on a 0.4 mm long Cr4+:YAG leading to a plano-plano cavity. A repetition rate as high as 85 kHz is achieved. The average output power is approximately 400 mW for 2.2 W of absorbed pump power and the pulse length is 1.1 ns.

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

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


    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).

  6. Laser Diode Ignition (LDI)

    Kass, William J.; Andrews, Larry A.; Boney, Craig M.; Chow, Weng W.; Clements, James W.; Merson, John A.; Salas, F. Jim; Williams, Randy J.; Hinkle, Lane R.


    This paper reviews the status of the Laser Diode Ignition (LDI) program at Sandia National Labs. One watt laser diodes have been characterized for use with a single explosive actuator. Extensive measurements of the effect of electrostatic discharge (ESD) pulses on the laser diode optical output have been made. Characterization of optical fiber and connectors over temperature has been done. Multiple laser diodes have been packaged to ignite multiple explosive devices and an eight element laser diode array has been recently tested by igniting eight explosive devices at predetermined 100 ms intervals.

  7. Efficient second harmonic generation of a diode-laser-pumped CW Nd:YAG laser using monolithic MgO:LiNbO3 external resonant cavities

    Kozlovsky, William J.; Nabors, C. D.; Byer, Robert L.


    56-percent efficient external-cavity-resonant second-harmonic generation of a diode-laser pumped, CW single-axial-mode Nd:YAG laser is reported. A theory of external doubling with a resonant fundamental is presented and compared to experimental results for three monolithic cavities of nonlinear MgO:LiNbO3. The best conversion efficiency was obtained with a 12.5-mm-long monolithic ring cavity doubler, which produced 29.7 mW of CW, single-axial model 532-nm radiation from an input of 52.5 mW.

  8. Mode-locked and Q-switched operation of a diode laser pumped Nd:YAG laser operating at 1.064 µm

    Maker, G. T.; Keen, S. J.; Ferguson, A. I.


    We describe the performance of a mode-locked and Q-switched Nd:YAG laser operating at 1.064 μm, optically pumped by a 500 mW diode laser. The cw mode-locked system provides bandwidth-limited pulses of 55 ps duration, with a corresponding peak power of 3.3 W. When Q-switched the energy within the 100 ns pulse envelope is 10 μJ giving a peak power in the largest pulse of 7 kW. Preliminary results for operation at 1.32 μm are also reported.

  9. Efficient second harmonics generation of a laser-diode-pumped Nd:YAG laser and its applications. Laser diode reiki Nd:YAG laser no kokoritsu daini kochoha hassei to sono oyo

    Kubota, S.; Oka, M. (Sony Corp., Tokyo (Japan))


    Stabilization of the second harmonics in a laser-diode-pumped Nd:YAG laser and its application are described. The laser is a quantum noise limiting laser, in which a mode competing noise is generated from an interaction between the laser medium Nd:YAG and the type II nonlinear optical crystal KTiOPO{sub 4} when generating a second harmonics in the resonator. However, the quantum noise limiting second harmonics was obtained by means of inserting (1/4) wave length plate in the resonator to release the bond between two intersecting inherent polarization modes. This stabilized green laser is of a single lateral mode is nearly free of aberration. Therefore, an optical disc prototype having three times as much of the currently used density was made using an objective lens having high number of openings to collect lights, which was verified capable of regeneration at a high signal to noise ratio. In addition, higher output is possible by means of parallelizing the excitation, and high output is realized from edge excitation at a fiber bundle. 18 refs., 3 figs.

  10. Analysis of the thermal effects in diode-pumped Tm:YAG ceramic slab lasers

    Cheng, Xiaojin; Shang, Jianhua; Jiang, Benxue


    Tm:YAG ceramics with a quasi-three-level system are sensitive to temperature. The optical and thermodynamic properties of Tm:YAG ceramics can change with changing temperature, and this affects the output power stability and beam quality of lasers. Thus temperature control is a key and difficult problem for Tm:YAG lasers, especially for high power laser output. In combination with slab structure and grad-doping techniques for composite ceramics, the temperature distributions of Tm:YAG ceramics are analyzed. It is found that the temperature difference of a rationally designed grad-doping Tm:YAG ceramic can be reduced significantly with the same absorption pump power, which results in higher output power and beam quality.

  11. Micromachining of liquid crystal polymer film with frequency converted diode-pumped Nd:YVO4 laser

    Li, Mingwei; Hix, Ken; Dosser, Larry R.; Hartke, Kevin; Blackshire, Jim


    Liquid crystal polymer (LCP) is a new and innovative material being used as an alternative to polyimide in the flexible circuit industry. LCP has many intrinsic benefits over polyimide including lower moisture absorption and improved dimensional stability. However, LCP is very resistant to chemical milling or etching. As a result, other methods for processing the material are being investigated including laser micromachining. In this paper, three frequency converted diode-pumped solid-state (DPSS) Nd:YVO4 lasers at 355 nm were used to micromachine a LCP film and a copper/LCP laminate. Of them, two are Q-switched lasers operating in the nanosecond regime and the other a mode-locked laser in the picosecond regime. The Q-switched lasers can be operated at pulse repetition rates of 1 to 300 kHz while the mode-locked system is operated at 80 MHz. The micromachining experiments consisted of cutting the 50 μm thick LCP film, cutting the 18 μm thick copper on the film, and drilling micro-vias through both the copper coating and the film substrate. The laser/material interactions and processing speeds were studied and compared. The results show that, compared to polyimide film of the same thickness, LCP film can be more efficiently processed by laser micromachining. In addition, each laser has a unique advantage in processing LCP based flexible circuit materials. The Q-switched lasers are more capable of processing the copper coating while the mode-locked laser can cut LCP film faster with the smallest kerf width.

  12. Status of the High Average Power Diode-Pumped Solid State Laser Development at HiLASE

    Ondřej Novák


    Full Text Available An overview of the latest developments of kilowatt-level diode pumped solid state lasers for advanced applications at the HiLASE Centre is presented. An overview of subcontracted and in-house-developed laser beamlines is presented. The aim of development is to build kW-class beamlines delivering picosecond pulses between 1- and 100-kHz repetition rates and high-energy nanosecond pulses at 10 Hz. The picosecond beamlines are based on Yb:YAG thin-disk amplifiers and chirped pulse amplification. The current status of the beamlines’ performance is reported. The advantages of zero-phonon line and pulsed pumping are demonstrated with respect to efficiency, thin disk temperature and beam quality. New diagnostics methods supporting the high average power lasers’ development, such as the high-resolution spectroscopy of Yb-doped materials, in situ thin disk deformation measurements, single-shot M2 measurement, realization of wavefront correction by a deformable mirror and the laser performance of a new mixed garnet ceramics, are described. The energetic, thermal and fluid-mechanical numerical modeling for the optimization of the multi-slab amplifiers is also described.

  13. Lighting with laser diodes

    Basu, Chandrajit; Meinhardt-Wollweber, Merve; Roth, Bernhard


    Contemporary white light-emitting diodes (LEDs) are much more efficient than compact fluorescent lamps and hence are rapidly capturing the market for general illumination. LEDs are also replacing halogen lamps or even newer xenon based lamps in automotive headlamps. Because laser diodes are inherently much brighter and often more efficient than corresponding LEDs, there is great research interest in developing laser diode based illumination systems. Operating at higher current densities and with smaller form factors, laser diodes may outperform LEDs in the future. This article reviews the possibilities and challenges in the integration of visible laser diodes in future illumination systems.

  14. One-Watt level mid-IR output, singly resonant, continuous-wave optical parametric oscillator pumped by a monolithic diode laser

    Nieuwenhuis, Albert F.; Lee, Christopher James; Sumpf, Bernd; van der Slot, Petrus J.M.; Erbert, Götz; Boller, Klaus J.


    We report more than 1.1 Watt of idler power at 3373 nm in a singly resonant optical parametric oscillator (SRO), directly pumped by a single-frequency monolithic tapered diode laser. The SRO is based on a periodically poled MgO:LiNbO3 crystal in a four mirror cavity and is excited by 8.05 W of 1062

  15. Influence of the intracavity second harmonic generation on the mode competition in a double-mode diode-pumped Nd : YAG laser

    Yermachenko, VM; Karle, RA; Petrovskiy, VN; Protsenko, ED


    The influence of intracavity second harmonic generation on the mode competition in a double-mode diode-pumped Nd:YAG laser is studied theoretically and experimentally. Various configurations of the optical cavity with II-type phase-matching frequency-doubling crystals are considered. The conditions

  16. Diode-pumped Nd : YAG laser with linear and orthogonal polarized components of a radiation at the wavelength 0.532 mu m

    Petrovskiy, V. N.; Prokopova, N. M.; Protesenko, E. D.; Yermachenko, V. M.


    A diode-pumped continuous-wave Nd:YAG laser with two linear and mutually orthogonal polarized components of radiation at a wavelength 0.532 mu m is studied theoretically and experimentally. The cavity confirmation for the realization of generation in this region is suggested. Stable lasting wit two

  17. 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.

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


    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.

  18. High-power diode-pumped Q-switched Er3+:YAG single-crystal fiber laser for active imaging system

    Martial, Igor; Balembois, François; Georges, Patrick


    We describe an efficient laser emission from a directly grown Er3+:YAG single-crystal fiber that is resonantly pumped using a continuous-wave (CW) laser diode at 1532 nm. In a longitudinal pumping, it emits 12.5 W at 1645 nm with a slope efficiency of 32%, which is the highest ever reported for a directly grown Er:YAG single-crystal fiber laser. Using an off-axis pumping scheme, CW output powers up to 7.3 W can be reached and in Q-switched operation, the laser produces 2 mJ pulses with a duration of 38 ns at the repetition rate of 1 kHz with an M^{2} factor below 1.8. To our knowledge this is the first directly grown Er3+:YAG single-crystal fiber Q-switched laser. In dual-side pumping scheme a laser emission at 1617 nm is achieved with output powers up to 5.7 W representing the highest output power ever achieved by a diode-pumped Er:YAG laser at this wavelength.

  19. 15 mJ single-frequency Ho:YAG laser resonantly pumped by a 1.9 µm laser diode

    Na, Q. X.; Gao, C. Q.; Wang, Q.; Zhang, Y. X.; Gao, M. W.; Ye, Q.; Li, Y.


    A 2.09 µm injection-seeded single-frequency Ho:YAG laser resonantly pumped by a 1.91 µm laser diode is demonstrated for the first time. The seed laser is a continuous wave (CW) Ho:YAG non-planar ring oscillator. 15.15 mJ single-frequency output energy is obtained from the injection-seeded Q-switched Ho:YAG laser, with a pulse repetition rate of 200 Hz and a pulse width of 109 ns. The half-width of the pulse spectrum is measured to be 4.19 MHz by using the heterodyne technique. The fluctuation of the center frequency of the single-frequency pulses is 1.52 MHz (root mean square (RMS)) in 1 h.

  20. Design of a stacked diode array pumped Nd:YAG laser with a truncated compound parabolic concentrator and a diffusive optical cavity

    Lee, S M; Yun, M J; Cha, B H; Lee, J M


    We designed and analyzed a new Nd:YAG laser which employs a combination of a truncated compound parabolic concentrator (CPC) and a diffusive optical pump cavity for pumping with a stacked diode array. A design code based on a ray-tracing algorithm was developed to analyze the Nd:YAG laser system. The optimum truncated CPC profile was determined from analyses of the dependences of the pump-beam distribution and the total absorbed power in the laser crystal upon the acceptance angle and the slit width of the CPC. In addition, the analyses show the importance of the acceptance angle in designing an efficient laser system with a truncated CPC. Using conservative design parameters, the design code predicted a Nd:YAG laser output of 130 W with a corresponding optical slope efficiency of 44%.

  1. Short pulse diode-pumped Tm:YAG slab laser electro-optically Q-switched by RbTiOPO4 crystal

    Jin, Lin; Liu, Pian; Huang, Haitao; Liu, Xuan; Shen, Deyuan


    In this paper, a laser diode end pumped RbTiOPO4 (RTP) electro-optically Q-switched Tm:YAG slab laser was demonstrated. Stable Q-switched pulse with the shortest pulse width of 58 ns and an average output power of 7.5 W were realized at the repetition rate of 1 KHz, corresponding to the slope efficiency of 21.7%.


    Mircea UDREA


    Full Text Available Preliminary results obtained in developing a visualisation technique for non-invasive analysis of air flow inside INCAS subsonic wind tunnel and its appendages are presented. The visualisation technique is based on using a green light sheet generated by a continuous wave (cw longitudinally diode pumped and frequency doubled Nd:YAG laser. The output laser beam is expanded on one direction and collimated on rectangular direction. The system is tailored to the requirements of qualitative analysis and vortex tracking requirements inside the INCAS 2.5m x 2.0m subsonic wind tunnel test section, for measurements performed on aircraft models. Also the developed laser techniques is used for non-invasive air flow field analysis into environmental facilities settling room (air flow calming area. Quantitative analysis is enabled using special image processing tools upon movies and pictures obtained during the experiments. The basic experimental layout in the wind tunnel takes advantage of information obtained from the investigation of various aircraft models using the developed visualisation technique. These results are further developed using a Particle Imaging Velocimetry (PIV experimental technique.The focus is on visualisation techniques to be used for wind flow characterization at different altitudes in indus-trial and civil buildings areas using a light sheet generated by a Nd:YAG cw pumped and doubled laser at 532 nm wave-length. The results are important for prevention of biological/chemical disasters such as spreading of extremely toxic pol-lutants due to wind. Numerical simulations of wind flow and experimental visualisation results are compared. A good agreement between these results is observed.

  3. High Power Continuous-Wave Diode-End-Pumped 1.34-μm Nd:GdVO4 Laser

    ZHOU Rui; RUAN Shuang-Chen; DU Chen-Lin; YAO Jian-Quan


    @@ A high power cw all-solid-state 1.34-μm Nd:GdVO4 laser is experimentally demonstrated. With a diode-doubleend-pumped configuration and a simple plane-parallel cavity, a maximum output power of 27.9 W is obtained at incident pump power of 96 W, introducing a slope efficiency of 35.4%. To the best of our knowledge, this is the highest output power of diode-end-pumped 1.3-gin laser. With the experimental data, the thermal-stress-resistance figure of merit of Nd:GdVO4 crystal with 0.3at% Nd3+ doped level is calculated to be larger than 9.94 W/cm.

  4. Compact and highly efficient laser pump cavity

    Chang, Jim J. (Dublin, CA); Bass, Isaac L. (Castro Valley, CA); Zapata, Luis E. (Livermore, CA)


    A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

  5. 575 nm laser oscillation in Dy3+-doped waterproof fluoro-aluminate glass fiber pumped by violet GaN laser diodes

    Fujimoto, Yasushi; Ishii, Osamu; Yamazaki, Masaaki


    We successfully drew a low-loss Dy-doped optical fiber (0.3dB/m at 532nm) of a waterproof fluoro-aluminate glass system and demonstrated yellow laser oscillation in the Dy3+-doped fluoride fiber pumped by a 398.8-nm GaN laser diode. The maximum output power was 10.3 mW and the slope efficiency was 17.1% at 575 nm. Since the fluoro-aluminate- glass system has a remarkable water resistance advantage compared to ZBLAN glass, Dy-doped fluoro-aluminate glass fiber is expected to contribute to making a solid-state yellow fiber laser with high chemical durability without a frequency doubling technique.

  6. Investigation on 447.3 nm blue-violet laser by extra-cavity frequency doubling of a diode-pumped cesium vapor laser

    Xu, Dongdong; Chen, Fei; Guo, Jin; Shao, Mingzhen; Xie, Jijiang


    447.3 nm blue-violet lasers are investigated by extra-cavity single-pass second harmonic generation (SHG) of diode-pumped cesium vapor lasers (Cs-DPALs) using a LBO crystal. Two types of 894.6 nm Cs-DPAL are constructed, and the beam quality factors are Mx2=1.02, My2=1.13 and Mx2=2.13, Mx2=2.66, respectively. The maximum output powers for the two types of Cs-DPAL operating in pulsed mode are 0.692 W and 2.6 W, and the corresponding maximum second harmonics (SH) powers are 9.5 μW and 11.2 μW at optimal focusing parameter of 1.68, respectively. The relative insensitivity of SH power to the LBO crystal temperature and the influence of Cs laser beam quality on the SHG efficiency are analyzed qualitatively.

  7. Compact green-diode-based lasers for biophotonic bioimaging

    Jensen, Ole Bjarlin; Hansen, Anders Kragh; Petersen, Paul Michael


    Diode lasers simultaneously offer tunability, high-power emission, and compact size at fairly low cost and are increasingly preferred for pumping titanium:sapphire lasers.......Diode lasers simultaneously offer tunability, high-power emission, and compact size at fairly low cost and are increasingly preferred for pumping titanium:sapphire lasers....

  8. Diode-Pumped Passive Q-Switched 946-nm Nd:YAG Laser with 2.1-W Average Output Power

    ZHANG Ling; LI Chun-Yong; FENG Bao-Hua; WEI Zhi-Yi; LI De-Hua; FU Pan-Ming; ZHANG Zhi-Guo


    @@ We demonstrate a diode-pumped passive Q-switched 946nm Nd:YAG laser with a diffusion-bonded composite laser rod and a co-doped Nd, Cr:YAG as saturable absorber. The average output power of 2.1 W is generated at an incident pump power of 14.3 W. The peak power of the Q-switched pulse is 643 W with 80 kHz repetition rate and 40.8ns pulse width. The slope efficiency and optical conversion efficiency are 17.6% and 14.7%, respectively.

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

    Newburgh, G. A.; Dubinskii, M.


    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.

  10. A high-power high-stability Q-switched green laser with intracavity frequency doubling using a diode-pumped composite ceramic Nd:YAG laser

    Wang Yu-Ye; Xu De-Gang; Liu Chang-Ming; Wang Wei-Peng; Yao Jian-Quan


    We successfully obtain a high-average-power high-stability Q-switched green laser based on diode-side-pumped composite ceramic Nd:YAG in a straight plano-concave cavity. The temperature distribution in composite ceramic Nd:YAG crystal is numerically analyzed and compared with that of conventional Nd:YAG crystal.By using a composite ceramic Nd:YAG rod and a type-Ⅱ high gray track resistance KTP (HGTR-KTP) crystal,a green laser with an average output power of 165 W is obtained at a repetition rate of 25 kHz,with a diode-to-green optical conversion of 14.68%,and a pulse width of 162 ns.To the best of our knowledge,both the output power and optical-to-optical efficiency are the highest values for green laser systems with intracavity frequency doubling of this novel composite ceramic Nd:YAG laser to date.The power fluctuation at around 160 W is lower than 0.3% in 2.5 hours.

  11. Laser Diode-Pumped Four Nd∶YAG Disks Laser%激光二极管抽运四片串联Nd∶YAG薄片激光器

    刘洋; 王超; 唐晓军; 徐鎏婧; 梁兴波; 刘刚; 赵鸿


    针对四薄片串联结构,利用ABCD传输矩阵方法对谐振腔进行优化设计.采用四片Nd∶YAG薄片串联,谐振腔采用双凹对称腔,实现了2.15 kW的激光输出,验证了激光二极管(LD)抽运薄片激光器的定标放大能力.%The resonator is optimally designed for the construction of four disks in series, using the method of ABCDtransmission matrix. With four Nd:YAG disks in the concave-concave symmetrical resonator, the output power of2.15 kW is obtained, which proves that the laser diode-pumped disk laser has the ability of output scaling andamplification.

  12. High-intensity, high-contrast laser pulses generated from the fully diode-pumped Yb:glass laser system POLARIS.

    Hornung, Marco; Keppler, Sebastian; Bödefeld, Ragnar; Kessler, Alexander; Liebetrau, Hartmut; Körner, Jörg; Hellwing, Marco; Schorcht, Frank; Jäckel, Oliver; Sävert, Alexander; Polz, Jens; Arunachalam, Ajay Kawshik; Hein, Joachim; Kaluza, Malte C


    We report on the first generation of high-contrast, 164 fs duration pulses from the laser system POLARIS reaching focused peak intensities in excess of 2×10(20) W/cm2. To our knowledge, this is the highest peak intensity reported so far that has been achieved with a diode-pumped, solid-state laser. Several passive contrast enhancement techniques have been specially developed and implemented, achieving a relative prepulse intensity smaller than 10(-8) at t=-30 ps before the main pulse. Furthermore a closed-loop adaptive-optics system has been installed. Together with angular chirp compensation, this method has led to a significant reduction of the focal spot size and an increase of the peak intensity.

  13. Design of a Compact Diode-Pumped Intracavity-Doubled Nd:GdVO4 Laser with 820-mW Red Light

    ZHANG Ling; LI De-Hua; WEI Zhi-Yi; FENG Bao-Hua; FU Pan-Ming; ZHANG Zhi-Guo


    @@ We report a design of diode-pumped high power Nd:GdVO4/LBO red laser with a compact linear cavity, which can output 820-Mw red light at 670nm with an optical conversion efficiency of 9.6%. The maximum output power of the fundamental light at 1.34μm was 4 W with a slope efficiency of 45%.

  14. Continuous-wave and Q-switched operation of a compact, diode-pumped Yb3+:KY(WO4)2 planar waveguide laser.

    Bain, F M; Lagatsky, A A; Kurilchick, S V; Kisel, V E; Guretsky, S A; Luginets, A M; Kalanda, N A; Kolesova, I M; Kuleshov, N V; Sibbett, W; Brown, C T A


    A diode-pumped LPE-grown Yb:KYW planar waveguide laser is demonstrated in a microchip monolithic cavity configuration. Output powers as high as 148 mW and thresholds as low as 40 mW were demonstrated during continuous-wave operation. Pulses of 170 ns duration with maximum pulse energy of 44 nJ at a 722 kHz repetition rate were generated when Q-switched using a semiconductor saturable absorber mirror.

  15. A Passively Mode-Locked Diode-End-Pumped Nd:YAG Laser with a Semiconductor Saturable Absorber Mirror Grown by Metal Organic Chemical Vapour Deposition

    王勇刚; 马骁宇; 李春勇; 张治国; 张丙元; 张志刚


    We report the experimental results of a mode-locked diode-end-pumped Nd:YAG laser with a semiconductor saturable absorber mirror(SESAM)from which we achieved a 10ps pulse duration at 150MHz repetition rate.The SESAM was grown by metal organic chemical vapour deposition at low temperature.The recovery time was measured to be 0.5 ps,indicating the potential pulse compression to sub-picoseconds.

  16. Spectroscopic analysis and efficient diode-pumped 1.9 μm Tm3+-doped β'-Gd2(MoO4)3 crystal laser.

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


    Tm3+-doped β'-Gd2(MoO4)3 single crystal was grown by the Czochralski method. Spectroscopic analysis was carried out along different polarizations. End-pumped by a quasi-cw diode laser at 795 nm in a plano-concave cavity, an average laser output power of 58 mW around 1.9 μm was achieved in a 0.93-mm-thick crystal when the output coupler transmission was 7.1%. The absorbed pump threshold was 8 mW and the slope efficiency of the laser was 57%. This crystal has smooth and broad gain curve around 1.9 μm, which shows that it is also a potential gain medium for tunable and short pulse lasers.

  17. LD泵浦Nd∶YAG薄片激光器技术研究%Study of laser diode-pumped Nd∶YAG disk laser

    刘洋; 王超; 唐晓军; 徐鎏婧; 梁兴波; 刘刚; 吕华昌


    报道了二极管泵浦的大功率薄片激光器.通过合理设计四通耦合系统,实现了泵浦光在方形薄片晶体上的均匀泵浦;采用两块方形Nd∶ YAG薄片串联,实现了1.32 kW的激光输出,光-光转换效率达32.1%;通过干涉条纹法测量增益介质受热后造成的光学畸变小于10 λ.%A laser diode-pumped Nd:YAC disk laser with an average output power of 1.32 kW is reported in this paper. A nearly uniform pump profile is achieved with a good design of the four-pass optical coupling system. An average output power of 1.32 kW is obtained form two square Nd:YAG disks in a stable resonator. The optical efficiency of the laser system is about 32.1%. Using the method of interferogram, the distortion of gain medium is measured and it is less than 10 λ.

  18. Diode Pumped Alkaline Laser System: A High Powered, Low SWaP Directed Energy Option for Ballistic Missile Defense High-Level Summary - April 2017

    Wisoff, P. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The Diode-Pumped Alkali Laser (DPAL) system is an R&D effort funded by the Missile Defense Agency (MDA) underway at Lawrence Livermore National Laboratory (LLNL). MDA has described the characteristics needed for a Boost Phase directed energy (DE) weapon to work against ICBM-class threat missiles. In terms of the platform, the mission will require a high altitude Unmanned Aerial Vehicle (UAV) that can fly in the “quiet” stratosphere and display long endurance – i.e., days on station. In terms of the laser, MDA needs a high power, low size and weight laser that could be carried by such a platform and deliver lethal energy to an ICBM-class threat missile from hundreds of kilometers away. While both the military and industry are pursuing Directed Energy for tactical applications, MDA’s objectives pose a significantly greater challenge than other current efforts in terms of the power needed from the laser, the low size and weight required, and the range, speed, and size of the threat missiles. To that end, MDA is funding two R&D efforts to assess the feasibility of a high power (MWclass) and low SWaP (size, weight and power) laser: a fiber combining laser (FCL) project at MIT’s Lincoln Laboratory, and LLNL’s Diode-Pumped Alkali Laser (DPAL) system.

  19. 8-mJ TEM(00) diode-end-pumped frequency-quadrupled Nd:YAG laser.

    Feugnet, G; Pocholle, J P


    A frequency-quadrupled Nd:YAG laser pumped by a commercially available high-brightness stack is described. A master oscillator power amplifier configuration was implanted, and the laser delivered energy of 8 mJ at 0.266microm . The laser was air cooled for easy use.

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

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


    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 ...

  1. Diode-pumped, Cr:YAG passively Q-switched and mode-locked Nd:YVO4/KTP green laser

    Junying Wang(王军营); Quan Zheng(郑权); Qinghua Xue(薛庆华); Huiming Tan(檀慧明)


    The phenomena of simultaneous Q-switching and mode-locking in a diode-pumped Nd:YVO4/Cr:YAG/KTP green laser are reported and discussed in this paper. With 5.3-W pump power, by using a nearlyhemispherical cavity (the cavity length is only 97 mm), the results of modulation depth of 70% and theperiod of 0.6 ns are obtained, the output power and the repetitive frequency of Q-switched pulse are 90mW and 12 kHz, respectively.

  2. Diode-pumped passively dual-wavelength Q-switched Nd:GYSGG laser using graphene oxide as the saturable absorber.

    Song, Qi; Wang, Guoju; Zhang, Bingyuan; Wang, Wenjun; Wang, Minghong; Zhang, Qingli; Sun, Guihua; Bo, Yong; Peng, Qinjun


    The performance of a diode end-pumped passively Q-switched dual-wavelength Nd:GYSGG laser operating at 1057.28 and 1060.65 nm with graphene oxide as the saturable absorber was demonstrated. The maximum dual-wavelength average output power of 521 mW was achieved under the absorbed pump power of 5.4 W, corresponding to the optical-to-optical conversion and slope efficiency of 9.8% and 21%, respectively. The minimum pulse width was 115 ns with a pulse repetition rate of 338 kHz.

  3. Blue diode-pumped solid-state-laser based on ytterbium doped laser crystals operating on the resonance zero-phonon transition

    Krupke, William F. (Pleasanton, CA); Payne, Stephen A. (Castro Valley, CA); Marshall, Christopher D. (Livermore, CA)


    The invention provides an efficient, compact means of generating blue laser light at a wavelength near .about.493+/-3 nm, based on the use of a laser diode-pumped Yb-doped laser crystal emitting on its zero phonon line (ZPL) resonance transition at a wavelength near .about.986+/-6 nm, whose fundamental infrared output radiation is harmonically doubled into the blue spectral region. The invention is applied to the excitation of biofluorescent dyes (in the .about.490-496 nm spectral region) utilized in flow cytometry, immunoassay, DNA sequencing, and other biofluorescence instruments. The preferred host crystals have strong ZPL fluorecence (laser) transitions lying in the spectral range from .about.980 to .about.992 nm (so that when frequency-doubled, they produce output radiation in the spectral range from 490 to 496 nm). Alternate preferred Yb doped tungstate crystals, such as Yb:KY(WO.sub.4).sub.2, may be configured to lase on the resonant ZPL transition near 981 nm (in lieu of the normal 1025 nm transition). The laser light is then doubled in the blue at 490.5 nm.

  4. High pulse energy passive Q-switching of a diode-pumped Tm:YLF laser by Cr:ZnSe

    Korenfeld, Arik; Sebbag, Daniel; Ben-Ami, Udi; Shalom, Eran; Marcus, Gilad; Noach, Salman


    A passively Q-switched diode-pumped Tm:YLF laser with polycrystalline Cr:ZnSe as the saturable absorber is demonstrated for the first time, to the best of our knowledge. By using saturable absorbers with different initial transmission, the maximum pulse energy reached 4.22 mJ with peak power of 162.3 kW for a pulse duration of 26 ns. The maximum output average power amounted to 2.2 W. These results constitute significant improvement from the highest average power, pulse energy and peak power results for the PQS Tm:YLF laser to date.

  5. Effect of Nd3+ concentration on CW and pulsed performance of fiber-coupled diode laser pumped Nd:YVO4 laser at 1064 nm

    Pranab K Mukhopadhyay; K Ranganathan; Jogy George; S K Sharma; T P S Nathan


    The effect of Nd3+ concentration on the CW and Q-switched laser performances at 1064 nm from Nd : YVO4 has been studied under diode laser pumping in identical laser configuration. The Nd3+ concentrations used were 1, 2 and 3 at. % in YVO4 crystals. Under the CW operations we have compared the thermal lensing effect, slope efficiencies and also the beam quality at the fourth-order degeneracy configuration. Q-switching was done with the help of an acousto-optic modulator and we have compared the pulses obtained from Nd : YVO4 laser with different doping concentration. It was found that the 1 at.%-doped crystal is the best, offering highest optical-to-optical conversion efficiency (55%), lowest fractional heat load (24%), highest pulse energy (80 J) and shortest pulse width (20 ns). It was also found that there was not much difference in performances for 2 and 3 at. %-doped crystals both in CW and Q-switched configurations.

  6. Modeling of time evolution of power and temperature in single-pulse and multi-pulses diode-pumped alkali vapor lasers.

    Shen, Binglin; Huang, Jinghua; Xu, Xingqi; Xia, Chunsheng; Pan, Bailiang


    A physical model combining rate, power propagation, and transient heat conduction equations for diode-pumped alkali vapor lasers (DPAL) is applied to a pulsed Rb-CH4 DPAL, which agrees well with the time evolution of laser power and temperature measured by K absorption spectroscopy. The output feature and temperature rise of a multi-pulse DPAL are also calculated in the time domain, showing that if we energize the pump light when the temperature rise decays to 1/2, rather than 1/e of its maximum, we can increase the duty cycle and obtain more output energy. The repetition rate of >100Hz is high enough to achieve QCW (quasi-continuous-wave) laser pulses.

  7. Generation of Laguerre-Gaussian Beams Using a Diode Pumped Solid-State Digital Laser

    Bell, Teboho


    Full Text Available The solid state digital laser was used in generation of Laguerre-Gaussian modes, LGpl, of different orders. This work demonstrates that we can generate high-order Laguerre-Gaussian modes with high purity using a digital laser....

  8. Diode-end-pumped Tm:GdVO4 laser operating at 1818 and 1915 nm

    Esser, MJD


    Full Text Available High power operation at 1818 and 1915 nm has been demonstrated from a Tm:GdVO4 laser operating in quasi-continuous-wave mode with a maximum measured power of 8.7Wand a laser output energy of 175 mJ was observed in a 20 ms pulse at 1.9 µm...

  9. High power CW and Q-switched operation of a diode-side-pumped Nd: YAG 1319-nm laser

    Yunfang Wan; Kezhen Han; Yun Wang; Jingliang He


    We demonstrated the highly efficient continuous wave(CW)and Q-switched infrared laser from a diodeside-pumped Nd:YAG crystal.A CW output as high as 66 W at 1319 nm was achieved under the pump power of 460 W,corresponding to a coversion efficiency of 14.3%.A maximum average power of 8.9 W of TEM00 mode was obtained in Q-switched operation at the repetition rate of 8 kHz.The performance of the laser considering the thermal lens effect induced by pump power Was also analyzed.

  10. Diode array pumped, non-linear mirror Q-switched and mode-locked Nd : YVO4 laser – a good tool for powder SHG measurement

    P K Datta; Chandrajit Basu; S Mukhopadhyay; S K Das; G K Samanta; Antonio Agnesi


    A non-linear mirror consisting of a lithium triborate crystal and a dichroic output coupler are used to mode-lock (passively) an Nd : YVO4 laser, pumped by a diode laser array. The laser can operate both in cw mode-locked and simultaneously Q-switched and mode-locked (QML) regime. The peak power of the laser while operating in QML regime is much higher but pulses suffers from poor amplitude stability. The incorporation of an acousto-optic modulator as an active Q-switch enhances the stability of the QML pulse envelope. The second-order non-linearity of powdered crystalline urea is conclusively measured with respect to KDP while the laser is operating in passively Q-switched and passively mode-locked regime as well as in actively Q-switched and passively mode-locked regime.

  11. Ablation studies using a diode-pumped Nd:YVO4 micro-laser

    Pervolaraki, M.; Dyer, P. E.; Monk, P.

    We report an investigation of ablating several materials using a nanosecond pulse duration Nd:YVO4 micro-laser operating at wavelengths of 1064 and 532 nm and high pulse-repetition rate (ballistic pendulum measurements and scanning electron microscopy are used to characterise the interaction. It is shown that good-quality micro-scale features can be produced in polyimide, gold foils and silicon targets by ablation using this laser.

  12. Cladding For Transversely-Pumped Laser Rod

    Byer, Robert L.; Fan, Tso Yee


    Combination of suitable dimensioning and cladding of neodymium:yttrium aluminum garnet of similar solid-state laser provides for more efficient utilization of transversely-incident pump light from diode lasers. New design overcomes some of limitations of longitudinal- and older transverse-pumping concepts and promotes operation at higher output powers in TEM00 mode.

  13. The route toward a diode-pumped 1-W erbium 3-µm fiber laser

    Pollnau, Markus


    A rate-equation analysis of the erbium 3-um ZBLAN fiber laser is performed. The computer calculation includes the longitudinal spatial resolution of the host material. It considers ground-state bleaching, excited-state absorption (ESA), interionic processes, lifetime quenching by co-doping, and stim

  14. 540 nm diode-pumped passively Nd:SSO/KTP green laser with a single-walled carbon nanotube saturable absorber

    Cheng, K.; Zhao, S. Z.; Yang, K. J.; Li, G. Q.; Li, D. C.; Zhang, G.; Wang, Y. G.; Zheng, L. H.; Wu, F.; Su, L. B.; Xu, J.


    The fluorescence spectrum of the Nd:Sc2SiO5 (Nd:SSO) crystal is measured. The central wavelength of the fluorescence band is 1080.1 nm with a full width at half-maximum (FWHM) of 3.4 nm. By using a single-walled carbon nanotube saturable absorber as a passive Q-switcher, a diode-pumped passively Q-switched intracavity frequency doubling Nd:Sc2SiO5/KTP green laser operating at 540 nm is demonstrated for the first time. The maximum average output power is 0.89 W at an incident pump power of 11.8 W, corresponding to an optical conversion efficiency of 7.5% and a slope efficiency of 10.2%. At the same incident pump power, a minimum pulse width of 94.8 ns and a maximum peak power of 19.1 W can be obtained.

  15. Generation of 30  fs pulses from a diode-pumped graphene mode-locked Yb:CaYAlO4 laser.

    Ma, Jie; Huang, Haitao; Ning, Kaijie; Xu, Xiaodong; Xie, Guoqiang; Qian, Liejia; Loh, Kian Ping; Tang, Dingyuan


    Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical vapor deposited monolayer graphene as the saturable absorber. The mode-locked 8.43 optical-cycle pulses have a spectral bandwidth of ∼50  nm and a pulse repetition frequency of ∼113.5  MHz. To the best of our knowledge, this is the shortest pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped bulk lasers. Our experimental results demonstrate that graphene mode locking is a very promising practical technique for directly generating few-cycle optical pulses from a laser oscillator.

  16. Generation of 30 fs pulses from a diode-pumped graphene mode-locked Yb:CaYAlO_4 laser

    Ma, Jie; Huang, Haitao; Ning, Kaijie; Xu, Xiaodong; Xie, Guoqiang; Qian, Liejia; Loh, Kian Ping; Tang, Dingyuan


    Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical vapor deposited monolayer graphene as the saturable absorber. The mode locked 8.43 optical-cycle pulses have a spectral bandwidth of ~ 50 nm and a pulse repetition frequency of ~ 113.5 MHz. To our knowledge, this is the shortest pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped bulk lasers. Our experimental results demonstrate that graphene mode locking is a very promising practical technique to generate few-cycle optical pulses directly from a laser oscillator.

  17. Generation of 30-fs pulses from a diode-pumped graphene mode-locked Yb:CaYAlO4 laser

    Ma, Jie; Ning, Kaijie; Xu, Xiaodong; Xie, Guoqiang; Qian, Liejia; Loh, Kian Ping; Tang, Dingyuan


    Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical vapor deposited monolayer graphene as the saturable absorber. The mode locked 8.43 optical-cycle pulses have a spectral bandwidth of ~ 50 nm and a pulse repetition frequency of ~ 113.5 MHz. To our knowledge, this is the shortest pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped bulk lasers. Our experimental results demonstrate that graphene mode locking is a very promising practical technique to generate few-cycle optical pulses directly from a laser oscillator.

  18. Stable High Power and High Beam Quality Diode-Side-Pumped Continuous-Wave Intracavity Frequency-Doubled Nd:YAG Laser

    CHENG Xian-Kun; ZHOU Yong; CUI Qian-Jin; YANG Feng; BO Yong; PENG Qin-Jun; CUI Da-Fu; XU Zu-Yan


    We report a stable high power and high beam quality diode-side-pumped cw green laser from intracavity frequency-doubled Nd:YAG laser with KTP.By using a L-shaped concave-convex resonator,designed with two Nd:YAG rods birefringence compensation,a large fundamental mode size in the laser crystal arid a tight focus in the nonlinear crystal could be obtained simultaneously.The green laser delivers a maximum 532nm output power of 23.2 W.Under 532 nm output power of 20.9 W,the beam quality factor is measured to be 4.1,and the fluctuation of the output power is less than 1.4% in an hour.

  19. Simultaneous Q-switching and Frequency-doubling by a Single KTP Crystal in a Diode-pumped Nd: YVO4 Laser

    CHEN Fei; HUO Yujing; HE Shufang; FENG Lichun


    The interrelation between the phase matching condition for second harmonic generation (SHG) and the electro-optic Q-switching in KTP was numerically analyzed. A diode-pumped Q-switched Nd: YVO4/KTP green laser was reported, where the KTP crystal was simultaneously used as both an electrooptic Q-switcher and a frequency-doubling crystal in type Ⅱ phase matching.Compared with the conventional frequency-doubling and Q-switching configuration, low loss and high efficiency characteristics were realized by using a single KTP crystal. The Q-switched green laser pulse with a peak power of 762 W and a pulse width of 12 ns was obtained with 1 W pump power.

  20. Efficient stable simultaneous CW dual-wavelength diode-end-pumped Nd :YAG laser operating at 1.319 and 1.338 μm

    Rui Zhou; Wuqi Wen; Zhiqiang Cai; Xin Ding; Peng Wang; Jianquan Yao


    An efficient, stable diode-end-pumped simultaneous continuous-wave (CW) dual-wavelength laser operating at 1.319 and 1.338 μm in a Nd:YAG crystal has been demonstrated. A total output power of 6.3 W is achieved at an absorbed pump power of 15 W, with a slope efficiency of 43.5%. The instability of output power is less than 1%. With a type Ⅱ critical phase-matched KTP crystal inserted into the cavity as frequency doubler, a maximum output power of 200 mW in red region is acquired. In addition, a sixwavelength laser operation at 1.319 μm, 1.338 μm, 1.356 μm, 659.5 nm, 669 nm, and 678 nm is observed.

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

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


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

  2. Prospects for diode-pumped alkali-atom-based hollow-core photonic-crystal fiber lasers.

    Sintov, Yoav; Malka, Dror; Zalevsky, Zeev


    By employing large hollow-core Kagome fiber in a double-clad configuration, the performance of a potentially rubidium vapor-based fiber laser is explored. The absorbed power and laser efficiency versus pump power are calculated utilizing a simple laser model. Our results show that a Kagome-based high-power fiber laser is feasible provided that the value of the collisional fine-structure mixing rate will be elevated by increasing the ambient temperature or by increasing the helium pressure.

  3. Diode-pumped continuous wave tunable and graphene Q-switched Tm:LSO lasers.

    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


    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.

  4. A compact spin-exchange optical pumping system for 3He polarization based on a solenoid coil, a VBG laser diode, and a cosine theta RF coil

    Lee, Sungman; Kim, Jongyul; Moon, Myung Kook; Lee, Kye Hong; Lee, Seung Wook; Ino, Takashi; Skoy, Vadim R.; Lee, Manwoo; Kim, Guinyun


    For use as a neutron spin polarizer or analyzer in the neutron beam lines of the HANARO (High-flux Advanced Neutron Application ReactOr) nuclear research reactor, a 3He polarizer was designed based on both a compact solenoid coil and a VBG (volume Bragg grating) diode laser with a narrow spectral linewidth of 25 GHz. The nuclear magnetic resonance (NMR) signal was measured and analyzed using both a built-in cosine radio-frequency (RF) coil and a pick-up coil. Using a neutron transmission measurement, we estimated the polarization ratio of the 3He cell as 18% for an optical pumping time of 8 hours.

  5. Theoretical simulations of protective thin film Fabry-Pérot filters for integrated optical elements of diode pumped alkali lasers (DPAL

    L. Quarrie


    Full Text Available The lifetime of Diode-Pumped Alkali Lasers (DPALs is limited by damage initiated by reaction of the glass envelope of its gain medium with rubidium vapor. Rubidium is absorbed into the glass and the rubidium cations diffuse through the glass structure, breaking bridging Si-O bonds. A damage-resistant thin film was developed enhancing high-optical transmission at natural rubidium resonance input and output laser beam wavelengths of 780 nm and 795 nm, while protecting the optical windows of the gain cell in a DPAL. The methodology developed here can be readily modified for simulation of expected transmission performance at input pump and output laser wavelengths using different combination of thin film materials in a DPAL. High coupling efficiency of the light through the gas cell was accomplished by matching the air-glass and glass-gas interfaces at the appropriate wavelengths using a dielectric stack of high and low index of refraction materials selected to work at the laser energies and protected from the alkali metal vapor in the gain cell. Thin films as oxides of aluminum, zirconium, tantalum, and silicon were selected allowing the creation of Fabry-Perot optical filters on the optical windows achieving close to 100% laser transmission in a solid optic combination of window and highly reflective mirror. This approach allows for the development of a new whole solid optic laser.

  6. Theoretical simulations of protective thin film Fabry-Pérot filters for integrated optical elements of diode pumped alkali lasers (DPAL)

    Quarrie, L.


    The lifetime of Diode-Pumped Alkali Lasers (DPALs) is limited by damage initiated by reaction of the glass envelope of its gain medium with rubidium vapor. Rubidium is absorbed into the glass and the rubidium cations diffuse through the glass structure, breaking bridging Si-O bonds. A damage-resistant thin film was developed enhancing high-optical transmission at natural rubidium resonance input and output laser beam wavelengths of 780 nm and 795 nm, while protecting the optical windows of the gain cell in a DPAL. The methodology developed here can be readily modified for simulation of expected transmission performance at input pump and output laser wavelengths using different combination of thin film materials in a DPAL. High coupling efficiency of the light through the gas cell was accomplished by matching the air-glass and glass-gas interfaces at the appropriate wavelengths using a dielectric stack of high and low index of refraction materials selected to work at the laser energies and protected from the alkali metal vapor in the gain cell. Thin films as oxides of aluminum, zirconium, tantalum, and silicon were selected allowing the creation of Fabry-Perot optical filters on the optical windows achieving close to 100% laser transmission in a solid optic combination of window and highly reflective mirror. This approach allows for the development of a new whole solid optic laser.

  7. Theoretical simulations of protective thin film Fabry-Pérot filters for integrated optical elements of diode pumped alkali lasers (DPAL)

    Quarrie, L., E-mail:, E-mail: [New Mexico Institute of Mining and Technology, Department of Materials Engineering, 801 LeRoy Place, Socorro, NM 87801 (United States); Air Force Research Laboratory, AFRL/RDLC Laser CoE, 3550 Aberdeen Avenue SE, Kirtland AFB, NM 87117-5776 (United States)


    The lifetime of Diode-Pumped Alkali Lasers (DPALs) is limited by damage initiated by reaction of the glass envelope of its gain medium with rubidium vapor. Rubidium is absorbed into the glass and the rubidium cations diffuse through the glass structure, breaking bridging Si-O bonds. A damage-resistant thin film was developed enhancing high-optical transmission at natural rubidium resonance input and output laser beam wavelengths of 780 nm and 795 nm, while protecting the optical windows of the gain cell in a DPAL. The methodology developed here can be readily modified for simulation of expected transmission performance at input pump and output laser wavelengths using different combination of thin film materials in a DPAL. High coupling efficiency of the light through the gas cell was accomplished by matching the air-glass and glass-gas interfaces at the appropriate wavelengths using a dielectric stack of high and low index of refraction materials selected to work at the laser energies and protected from the alkali metal vapor in the gain cell. Thin films as oxides of aluminum, zirconium, tantalum, and silicon were selected allowing the creation of Fabry-Perot optical filters on the optical windows achieving close to 100% laser transmission in a solid optic combination of window and highly reflective mirror. This approach allows for the development of a new whole solid optic laser.

  8. Highly efficient dual-wavelength mid-infrared CW Laser in diode end-pumped Er:SrF2 single crystals

    Ma, Weiwei; Qian, Xiaobo; Wang, Jingya; Liu, Jingjing; Fan, Xiuwei; Liu, Jie; Su, Liangbi; Xu, Jun


    The spectral properties and laser performance of Er:SrF2 single crystals were investigated and compared with Er:CaF2. Er:SrF2 crystals have larger absorption cross-sections at the pumping wavelength, larger mid-infrared stimulated emission cross-sections and much longer fluorescence lifetimes of the upper laser level (Er3+:4I11/2 level) than those of Er:CaF2 crystals. Dual-wavelength continuous-wave (CW) lasers around 2.8 μm were demonstrated in both 4at.% and 10at.% Er:SrF2 single crystals under 972 nm laser diode (LD) end pumping. The laser wavelengths are 2789.3 nm and 2791.8 nm in the former, and 2786.4 nm and 2790.7 nm in the latter, respectively. The best laser performance has been demonstrated in lightly doped 4at.% Er:SrF2 with a low threshold of 0.100 W, a high slope efficiency of 22.0%, an maximum output power of 0.483 W.

  9. Two-beam combined 3.36  J, 100  Hz diode-pumped high beam quality Nd:YAG laser system.

    Qiu, J S; Tang, X X; Fan, Z W; Wang, H C; Liu, H


    In this paper, we develop a diode-pumped all-solid-state high-energy and high beam quality Nd:YAG laser system. A master oscillator power amplifier structure is used to provide a high pulse energy laser output with a high repetition rate. In order to decrease the amplifier working current so as to reduce the impact of the thermal effect on the beam quality, a beam splitting-amplifying-combining scheme is adopted. The energy extraction efficiency of the laser system is 50.68%. We achieve 3.36 J pulse energy at a 100 Hz repetition rate with a pulse duration of 7.1 ns, a far-field beam spot 1.71 times the diffraction limit, and 1.07% energy stability (RMS).

  10. Comparative studies of semiconductor saturable absorber mirror mode-locking dynamics in pulsed diode-end-pumped picosecond Nd:GdVO4 and Nd:YAG lasers

    Bingyuan Zhang; Gang Li; Meng Chen; Guoju Wang; Yonggang Wang


    Ultrashort pulses were generated in passively mode-locked Nd:YAG and Nd:GdVO4 lasers pumped by a pulsed laser diode with 10-Hz repetition rate. Stable mode-locked pulse trains were produced with the pulse width of 10 ps. The evolution of the mode-locked pulse was observed in the experiment and was discussed in detail. Comparing the pulse evolutions of Nd:YAG and Nd:GdVO4 lasers, we found that the buildup time of the steady-state mode-locking with semiconductor saturable absorber mirrors (SESAMs) was relevant to the upper-state lifetime and the emission cross-section of the gain medium.

  11. Simultaneous tri-wavelength laser operation at 916, 1086, and 1089 nm of diode-pumped Nd:LuVO4 crystal

    Shen, Bingjun; Jin, Lihong; Zhang, Jiajia; Tian, Jian


    We report a diode-pumped continuous-wave tri-wavelength Nd:LuVO4 laser operating at 916, 1086, and 1089 nm. A theoretical analysis has been introduced to determine the threshold conditions for simultaneous tri-wavelength laser operation. Using a T-shaped cavity, we realized efficient tri-wavelength operation at 4F3/2  →  4I9/2 and 4F3/2  →  4I11/2 transitions for Nd:LuVO4 crystal, simultaneously. The maximum output power was 2.8 W, which included 916, 1086, and 1089 nm, and the optical conversion efficiency was 15.1%. To our knowledge, this is the first work that realizes simultaneous tri-wavelength Nd:LuVO4 laser operation.

  12. Endoscopic cystoventriculostomy and ventriculocysternostomy using a recently developed 2.0-micron fiber-guided high-power diode-pumped solid state laser in children with hydrocephalus

    Ludwig, Hans C.; Kruschat, Thomas; Knobloch, Torsten; Rostasy, Kevin; Buchfelder, Michael


    Preterm infants have a high incidence of post hemorrhagic or post infectious hydrocephalus often associated with ventricular or arachnoic cysts which carry a high risk of entrapment of cerebrospinal fluid (CSF). In these cases fenestration and opening of windows within the separating membranes are neurosurgical options. Although Nd:YAG- and diode-lasers have already been used in neuroendoscopic procedures, neurosurgeons avoid the use of high energy lasers in proximity to vital structures because of potential side effects. We have used a recently developed diode pumped solid state (DPSS) laser emitting light at a wavelength of 2.0 μm (Revolix TM LISA laser products, Katlenburg, Germany), which can be delivered through silica fibres towards endoscopic targets. From July 2002 until June 2004 fourteen endoscopic procedures in 12 consecutive patients (age 3 months to 12 years old) were performed. Most children suffered from complex post hemorrhagic and post infectious hydrocephalus, in whom ventriculoperitoneal shunt devices failed to restore a CSF equilibrium due to entrapment of CSF pathways by the cysts. We used two different endoscopes, a 6 mm Neuroendoscope (Braun Aesculap, Melsungen, Germany; a 4 mm miniature Neuroscope (Storz, Tuttlingen, Germany). The endoscopes were connected to a standard camera and TV monitor, the laser energy was introduced through a 365 μm core diameter bare ended silica fibre (PercuFib, LISA laser products, Katlenburg, Germany) through the endoscope"s working channel. The continuous wave laser was operated at power levels from 5 to 15 Watt in continuous and chopped mode. The frequency of the laser in chopped mode was varied between 5 and 20 Hz. All patients tolerated the procedure well. No immediate or long term side effects were noted. In 3 patients with cystic compression of the 4th ventricle, insertion of a shunt device could be avoided. The authors conclude that the use of the new RevolixTM laser enables safe and effective procedures

  13. Diode pumped solid state kilohertz disk laser system for time-resolved combustion diagnostics under microgravity at the drop tower Bremen

    Wagner, Volker; Paa, Wolfgang; Triebel, Wolfgang [Institute of Photonic Technology, Laser Diagnostics, Albert-Einstein-Str. 9, 07745 Jena (Germany); Eigenbrod, Christian; Klinkov, Konstantin [Center of Applied Space Technology and Microgravity, University Bremen, Am Fallturm, 28359 Bremen (Germany); Larionov, Mikhail; Giesen, Adolf; Stolzenburg, Christian [Institut für Strahlwerkzeuge (IFSW), Pfaffenwaldring 43, 70569 Stuttgart (Germany)


    We describe a specially designed diode pumped solid state laser system based on the disk laser architecture for combustion diagnostics under microgravity (μg) conditions at the drop tower in Bremen. The two-stage oscillator-amplifier-system provides an excellent beam profile (TEM{sub 00}) at narrowband operation (Δλ < 1 pm) and is tunable from 1018 nm to 1052 nm. The laser repetition rate of up to 4 kHz at pulse durations of 10 ns enables the tracking of processes on a millisecond time scale. Depending on the specific issue it is possible to convert the output radiation up to the fourth harmonic around 257 nm. The very compact laser system is integrated in a slightly modified drop capsule and withstands decelerations of up to 50 g (>11 ms). At first the concept of the two-stage disk laser is briefly explained, followed by a detailed description of the disk laser adaption to the drop tower requirements with special focus on the intended use under μg conditions. In order to demonstrate the capabilities of the capsule laser as a tool for μg combustion diagnostics, we finally present an investigation of the precursor-reactions before the droplet ignition using 2D imaging of the Laser Induced Fluorescence of formaldehyde.

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

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


    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.

  15. High-Power Continuous-Wave Diode-End-Pumped Intracavity Frequency Doubled Nd:YVO4 Laser at 671 nm with a Compact Three-Element Cavity

    ZHOU Rui; DING Xin; WEN Wu-Qi; CAI Zhi-Qiang; WANG Peng; YAO Jian-Quan


    @@ We report a high-power high-effcient continuous-wave (cw) diode-end-pumped Nd:YVO4 1342-nm laser with a short plane-parallel cavity and an efficient cw intracavity frequency-doubled red laser at 671 nm with a compact three-element cavity. At incident pump power of 20.6 W, a maximum output power of 7 W at 1342 nm is obtained with a slope efficiency of 37.3%. By inserting a type-I critical phase-matched LBO crystal as intracavity frequencydoubler, a cw red output as much as 2.85-W is achieved with an incident pump power of 16.9 W, inducing an optical-to-optical conversion efficiency of 16.9%. To the best of our knowledge, this is the highest output of diodepumped solid-state Nd:YVO4 red laser. During half an hour, the red output is very stable, and the instability of output power is less than 1%.

  16. Continuous-wave and Q-switched performance of an Yb:YAG/YAG composite thin disk ceramic laser pumped with 970-nm laser diode

    Hong Cai; Jun Zhou; Hongming Zhao; Yunfeng Qi; Qihong Lou; Jingxing Dong; Yunrong Wei


    Using front face-pumped compact active mirror laser (CAMIL) structure, we have demonstrated an Yb:YAG/YAG composite ceramic disk laser with pumping wavelength at 970 nm. The laser has been operated in both continuous-wave (CW) and Q-switching modes. Under CW operation, laser output power of 1.05 W with 2% transmission output coupler was achieved at the wavelength of 1031 nm. Qswitched laser output was gotten by using an acousto-optic Q-switch. The repetition rate ranged from 1 to 30 kHz and the pulse width varied from 166 to 700 ns.

  17. Diode Pumped Fiber Laser


    numerical aperture is assumed to be small, the fiber modes are taken to be of the LP-type, described for example by Marcuse (Reference 11). In an (x...Fort Washington, PA. 11. D. Marcuse in Theory of Dielectric Optical Waveguides, Quantum Electronics, Principles and Applications, (Academic...10, 2252-2258, October 1971. 17. D. Marcuse , "Gaussian approximation of the fundamental modes of graded- index fibers," J. Opt. Soc. Am., Vol

  18. Ultra-low phase-noise microwave generation using a diode-pumped solid-state laser based frequency comb and a polarization-maintaining pulse interleaver

    Portuondo-Campa, Erwin; Kundermann, Stefan; Balet, Laurent; Lecomte, Steve


    We report ultra-low phase-noise microwave generation at a 9.6 GHz carrier frequency from optical frequency combs based on diode-pumped solid-state lasers emitting at telecom wavelength and referenced to a common cavity-stabilized continuous-wave laser. Using a novel fibered polarization-maintaining pulse interleaver, a single-oscillator phase-noise floor of -171 dBc/Hz has been measured with commercial PIN InGaAs photodiodes, constituting a record for this type of detector. Also, a direct optical measurement of the stabilized frequency combs timing jitter was performed using a balanced optical cross correlator, allowing for an identification of the origin of the current phase-noise limitations in the system.

  19. Diode-pumped passively Q-switched and mode-locked Nd:YLF laser with Cr4+:YAG saturable absorber

    Shudi Pan; Kezhen Han; Hongmei Wang; Xiuwei Fan; Jingliang He


    @@ A diode-pumped passively Q-switched Nd:YLF laser was demonstrated by using saturable absorber of Cr4+:YAG. At the incident power of 7.74 W, pure passively Q-switched laser with per pulse energy of 210 Μj and pulse width of 19.6 ns at repetition rate of 1.78 kHz was obtained by using Cr4+:YAG with initial transmission of 80%. At the incident power of 8.70 W, a Q-switched mode-locking with average output power of 650 Mw was achieved, the overall slop efficiency was 16%, corresponding to the initial transmission of 85% of Cr4+ :YAG.

  20. kW-class direct diode laser for sheet metal cutting based on DWDM of pump modules by use of ultra-steep dielectric filters.

    Witte, U; Schneider, F; Traub, M; Hoffmann, D; Drovs, S; Brand, T; Unger, A


    A direct diode laser was built with > 800 W output power at 940 nm to 980 nm. The radiation is coupled into a 100 µm fiber and the NA ex fiber is 0.17. The laser system is based on pump modules that are wavelength stabilized by VBGs. Dense and coarse wavelength multiplexing are realized with commercially available ultra-steep dielectric filters. The electro-optical efficiency is above 30%. Based on a detailed analysis of losses, an improved e-o-efficiency in the range of 40% to 45% is expected in the near future. System performance and reliability were demonstrated with sheet metal cutting tests on stainless steel with a thickness of 4.2 mm.

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

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


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

  2. Ultra-low phase-noise microwave generation using a diode-pumped solid-state laser based frequency comb and a polarization-maintaining pulse interleaver.

    Portuondo-Campa, Erwin; Buchs, Gilles; Kundermann, Stefan; Balet, Laurent; Lecomte, Steve


    We report ultra-low phase-noise microwave generation at a 9.6 GHz carrier frequency from optical frequency combs based on diode-pumped solid-state lasers emitting at telecom wavelength and referenced to a common cavity-stabilized continuous-wave laser. Using a novel fibered polarization-maintaining pulse interleaver, a single-oscillator phase-noise floor of -171 dBc/Hz at 10 MHz offset frequency has been measured with commercial PIN InGaAs photodiodes, constituting a record for this type of detector. Also, a direct optical measurement of the stabilized frequency combs' timing jitter was performed using a balanced optical cross correlator, allowing for an identification of the origin of the phase-noise limitations in the system.

  3. Diode-end-pumped passively mode-locked Nd:GAGG laser at 1.3 μm with SESAM Diode-end-pumped passively mode-locked Nd:GAGG laser

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


    The performance of a passively mode-locked Nd:Gd3AlxGa5-xO12 (Nd:GAGG) laser at 1332 nm was experimentally investigated by using a semiconductor saturable absorber mirror (SESAM) for the first time. At the absorbed pump power of 6.7 W, the average output power was obtained to be 293 mW with the pulse duration of 6.3 ps and the repetition rate of 32.2 MHz. The corresponding single pulse energy and the peak power were determined to be 4.55 nJ and 722 W, respectively.

  4. Diode laser applications in urology

    Sam, Richard C.; Esch, Victor C.


    Diode lasers are air-cooled, efficient, compact devices which have the potential of very low cost when produced in quantity. The characteristics of diode lasers are discussed. Their applications in interstitial thermal treatment of the prostate, and laser ablation of prostate tissues, will be presented.

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

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


    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.

  6. Power scaling of blue-diode-pumped Pr:YLF lasers at 523.0, 604.1, 606.9, 639.4, 697.8 and 720.9 nm

    Luo, Saiyu; Yan, Xigun; Cui, Qin; Xu, Bin; Xu, Huiying; Cai, Zhiping


    We report a power scaled laser operation of diode-pumped Pr3+-doped LiYF4 crystal in single-end pumping geometry. Using a multi-mode InGaN diode laser, laser emissions at about 523.0, 604.1, 606.9, 639.4, 697.8 and 720.9 nm are achieved with maximum output power of 1.7, 0.6, 1.1, 2.3, 1.3 and 1 W, respectively. The corresponding slope efficiencies are found to be about 49%, 33%, 40%, 57%, 36% and 42%. Good laser beam qualities of these visible lasers are also found with measured beam propagation factors M2<1.8 for all of them.

  7. Nuclear-pumped lasers

    Prelas, Mark


    This book focuses on Nuclear-Pumped Laser (NPL) technology and provides the reader with a fundamental understanding of NPLs, a review of research in the field, and exploration of large scale NPL system design and applications. Early chapters look at the fundamental properties of lasers, nuclear-pumping and nuclear reactions that may be used as drivers for nuclear-pumped lasers. The book goes on to explore the efficient transport of energy from the ionizing radiation to the laser medium and then the operational characteristics of existing nuclear-pumped lasers. Models based on Mathematica, explanations and a tutorial all assist the reader’s understanding of this technology. Later chapters consider the integration of the various systems involved in NPLs and the ways in which they can be used, including beyond the military agenda. As readers will discover, there are significant humanitarian applications for high energy/power lasers, such as deflecting asteroids, space propulsion, power transmission and mining....

  8. Applications of microlens-conditioned laser diode arrays

    Beach, R.J.; Emanuel, M.A.; Freitas, B.L. [and others


    The ability to condition the radiance of laser diodes using shaped-fiber cylindrical-microlens technology has dramatically increased the number of applications that can be practically engaged by diode laser arrays. Lawrence Livermore National Laboratory (LLNL) has actively pursued optical efficiency and engineering improvements in this technology in an effort to supply large radiance-conditioned laser diode array sources for its own internal programs. This effort has centered on the development of a modular integrated laser diode packaging technology with the goal of enabling the simple and flexible construction of high average power, high density, two-dimensional arrays with integrated cylindrical microlenses. Within LLNL, the principal applications of microlens-conditioned laser diode arrays are as high intensity pump sources for diode pumped solid state lasers (DPSSLs). A simple end-pumping architecture has been developed and demonstrated that allows the radiation from microlens-conditioned, two-dimensional diode array apertures to be efficiently delivered to the end of rod lasers. To date, pump powers as high as 2.5 kW have been delivered to 3 mm diameter laser rods. Such high power levels are critical for pumping solid state lasers in which the terminal laser level is a Stark level lying in the ground state manifold. Previously, such systems have often required operation of the solid state gain medium at low temperature to freeze out the terminal laser Stark level population. The authors recently developed high intensity pump sources overcome this difficulty by effectively pumping to much higher inversion levels, allowing efficient operation at or near room temperature. Because the end-pumping technology is scalable in absolute power, the number of rare-earth ions and transitions that can be effectively accessed for use in practical DPSSL systems has grown tremendously.

  9. Generation of UV radiation at 335.5 nm based on frequency-quadrupling of a diode-pumped Nd:YVO4 laser

    Xiuwei Fan; Haitao Huang; Jijian Jiang; Jingliang He


    The generation of ultraviolet(UV)light at 335.5 nm based on frequency quadrupling of a diode-endpumped Q-switched Nd:YVO4 laser at 1342 nm was demonstrated.KTP crystal was used for generation of wavelength of 671 nm by intracavity doubling and LBO (BBO) crystal Was exploited for the subsequent external fourth harmonic generation(FHG).With 6.3-W absorbed pump power and 10-kHz frequency repetition rate,the UV output power of 35 and 63 mW were obtained by using LBO and BBO as frequency quadrupling nonlinear crystals, respectively. The experimenta results show that the conversion efficiency (red-UV)of 6.4% for BBO crystal is higher than that of 3.5% for LB0 crystal, but the UV beam quality obtained by LBO crystal is better than by BBO crystal.

  10. High-Reliability Pump Module for Non-Planar Ring Oscillator Laser

    Liu, Duncan T.; Qiu, Yueming; Wilson, Daniel W.; Dubovitsky, Serge; Forouhar, Siamak


    We propose and have demonstrated a prototype high-reliability pump module for pumping a Non-Planar Ring Oscillator (NPRO) laser suitable for space missions. The pump module consists of multiple fiber-coupled single-mode laser diodes and a fiber array micro-lens array based fiber combiner. The reported Single-Mode laser diode combiner laser pump module (LPM) provides a higher normalized brightness at the combined beam than multimode laser diode based LPMs. A higher brightness from the pump source is essential for efficient NPRO laser pumping and leads to higher reliability because higher efficiency requires a lower operating power for the laser diodes, which in turn increases the reliability and lifetime of the laser diodes. Single-mode laser diodes with Fiber Bragg Grating (FBG) stabilized wavelength permit the pump module to be operated without a thermal electric cooler (TEC) and this further improves the overall reliability of the pump module. The single-mode laser diode LPM is scalable in terms of the number of pump diodes and is capable of combining hundreds of fiber-coupled laser diodes. In the proof-of-concept demonstration, an e-beam written diffractive micro lens array, a custom fiber array, commercial 808nm single mode laser diodes, and a custom NPRO laser head are used. The reliability of the proposed LPM is discussed.

  11. Electronically controlled heat sink for high-power laser diodes

    Vetrovec, John


    We report on a novel electronically controlled active heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink receives diode waste heat at high flux and transfers it at reduced flux to environment, coolant fluid, heat pipe, or structure. Thermal conductance of the heat sink is electronically adjustable, allowing for precise control of diode temperature and the diode light wavelength. When pumping solid-state or alkaline vapor lasers, diode wavelength can be precisely temperature-tuned to the gain medium absorption features. This paper presents the heat sink physics, engineering design, and performance modeling.

  12. Numerical simulation of pumping performance of diode side pumped thin disk laser%二极管侧面泵浦薄片激光器泵浦性能数值仿真

    郭渭荣; 李强; 冯驰; 晏乐伦; 王金国


    Taking advantage of the symmetry in the distribution of the absorbed pump power density of a diode side pumped thin disk laser, the pump uniformity could be described quantitively with a novel method that took values on key points of absorbed pump power density distribution into consideration. A pump performance index that considered both pump uniformity and absorption efficiency was introduced. Pump performance index within certain ranges of diode array distance, round thin disk radius and absorption coefficient were compared. Results of calculation show that the performance index reaches an optimized minimum of 0.1110 with the round thin disk radius of 13 mm, the diode array distance of 37 mm, and the absorption coefficient of 0.10 mm-1. A performance index near to the optimized value could be obtained with the parameters experimentally used. Tentative experiment measured the phase distortion on the thin disk caused by thermal effects. The computed phase distortion matches with experimentally measured phase distortion. Pump performance index and related calculation results presented in this paper presents a useful theoretical reference for research of diode side pumped composite thin disk lasers.%利用二极管侧面泵浦薄片激光器泵浦分布的对称性,通过泵浦分布中的特殊点对泵浦均匀性进行定量描述的方法,提出了由泵浦均匀性和吸收效率共同表征的泵浦性能指标,并使用该指标对一定范围内的阵列距离、圆薄片晶体尺寸和吸收系数的泵浦性能进行了对比.在一定取值范围内,当圆薄片晶体半径为13mm、阵列与晶体中心间距为37 mm、吸收系数为0.10 mm-1时,泵浦性能指标达到最小值0.1110.采用接近最优泵浦性能指标值的泵浦参数进行实验,初步测量了热效应造成的薄片相位畸变,根据泵浦分布计算出的相位畸变分布与实验结果基本相符.文中提出的泵浦性能指标和相应计算结果为薄片激光器的

  13. Continuous-wave Raman laser pumped within a semiconductor disk laser cavity.

    Parrotta, Daniele C; Lubeigt, Walter; Kemp, Alan J; Burns, David; Dawson, Martin D; Hastie, Jennifer E


    A KGd(WO₄)₂ Raman laser was pumped within the cavity of a cw diode-pumped InGaAs semiconductor disk laser (SDL). The Raman laser threshold was reached for 5.6 W of absorbed diode pump power, and output power up to 0.8 W at 1143 nm, with optical conversion efficiency of 7.5% with respect to the absorbed diode pump power, was demonstrated. Tuning the SDL resulted in tuning of the Raman laser output between 1133 and 1157 nm.

  14. Diode-pumped passively Q-switched Nd:GAGG laser at 938 nm with V3+:YAG saturable absorber

    Liu, S. D.; Zhang, B. T.; He, J. L.; Yang, H. W.; Xu, J. L.; Liu, F. Q.; Yang, J. F.; Yang, X. Q.; Huang, H. T.


    The continuous wave (CW) and passively Q-switched Nd:Gd3AlxGa5-xO12 (Nd:GAGG) laser operation at 938 nm have been realized for the first time. The maximum CW output power of 0.44 W was obtained under the absorbed pump power of 8.54 W, corresponding to the slope efficiency of 7.8% and optical-to-optical efficiency of 5.2% respectively. A V3+:YAG saturable absorber crystal with the initial transmission of 97% was used for the passive Q-switching regime. The maximum average output power of 0.19 W was achieved with the minimum pulse width of 358 ns and Q-switched repetition rate of 116 kHz. The corresponding single pulse energy and pulse peak power were determined to be 1.6 μJ and 4.6 W, respectively.

  15. Sodium temperature/wind lidar based on laser-diode-pumped Nd:YAG lasers deployed at Tromsø, Norway (69.6°N, 19.2°E).

    Kawahara, T D; Nozawa, S; Saito, N; Kawabata, T; Tsuda, T T; Wada, S


    An Nd:YAG laser-based sodium temperature/wind lidar was developed for the measurement of the northern polar mesosphere and lower thermosphere at Tromsø (69.6N, 19.2E), Norway. Coherent light at 589 nm is produced by sum frequency generation of 1064 nm and 1319 nm from two diode laser end-pumped pulsed Nd:YAG lasers. The output power is as high as 4W, with 4 mJ/pulse at 1000 Hz repetition rate. Five tilting Cassegrain telescopes enable us to make five-direction (zenith, north, south, east, west) observation for temperature and wind simultaneously. This highly stable laser system is first of its kind to operate virtually maintenance-free during the observation season (from late September to March) since 2010.

  16. The all-diode-pumped laser system POLARIS——an experimentalist’s tool generating ultra-high contrast pulses with high energy

    Marco; Hornung; Hartmut; Liebetrau; Andreas; Seidel; Sebastian; Keppler; Alexander; Kessler; Jrg; Krner; Marco; Hellwing; Frank; Schorcht; Diethard; Klpfel; Ajay; K.Arunachalam; Georg; A.Becker; Alexander; Svert; Jens; Polz; Joachim; Hein; Malte; C.Kaluza


    The development,the underlying technology and the current status of the fully diode-pumped solid-state laser system POLARIS is reviewed.Currently,the POLARIS system delivers 4 J energy,144 fs long laser pulses with an ultra-high temporal contrast of 5 × 1012 for the ASE,which is achieved using a so-called double chirped-pulse amplification scheme and cross-polarized wave generation pulse cleaning.By tightly focusing,the peak intensity exceeds 3.5 × 1020 W cm-2.These parameters predestine POLARIS as a scientific tool well suited for sophisticated experiments,as exemplified by presenting measurements of accelerated proton energies.Recently,an additional amplifier has been added to the laser chain.In the ramp-up phase,pulses from this amplifier are not yet compressed and have not yet reached the anticipated energy.Nevertheless,an output energy of 16.6 J has been achieved so far.

  17. Diode-pumped solid state laser. (Part V). ; Short pulse laser oscillation. Handotai laser reiki kotai laser. 5. ; Tan pulse hasshin

    Kuwabara, M.; Bando, N. (Asahi Glass Co. Ltd., Tokyo (Japan))


    A semiconductor laser (LD) excited solid state laser using an LD as an excited light source is under discussion for its practical applications to measurements, processing, communications, office automation, and medical areas. This paper describes the discussions given on the short pulse transmission using AOQ switching elements in the LD excited solid state laser with a long wave length band (1.3{mu}m), which is expected of its application in the communications and measurements area. Based on a possibility of raising a measurements resolution by making the pluses in the LD excited solid state laser, and experiments were performed using Nd:YLF as a laser host. as a results, it was found that the smaller the effective mode volume V {sub eff},the smaller the pulse width, and that the ratio of number of initial inversion distribution (N{sub i}/N{sub t}), an important parameter to determine pulse widths, can be obtained from the ratio of the LD exciting light to the input power (P{sub in}/P{sub t}). 7 refs., 14 figs., 2 tabs.

  18. Direct writing of micro/nano-scale patterns by means of particle lens arrays scanned by a focused diode pumped Nd:YVO4 laser

    Pena, Ana; Wang, Zengbo; Whitehead, David; Li, Lin


    A practical approach to a well-known technique of laser micro/nano-patterning by optical near fields is presented. It is based on surface patterning by scanning a Gaussian laser beam through a self-assembled monolayer of silica micro-spheres on a single-crystalline silicon (Si) substrate. So far, the outcome of this kind of near-field patterning has been related to the simultaneous, parallel surface-structuring of large areas either by top hat or Gaussian laser intensity distributions. We attempt to explore the possibility of using the same technique in order to produce single, direct writing of features. This could be of advantage for applications in which only some areas need to be patterned (i.e. local area selective patterning) or single lines are required (e.g. a particular micro/nano-fluidic channel). A diode pumped Nd:YVO4 laser system (wavelength of 532 nm, pulse duration of 8 ns, repetition rate of 30 kHz) with a computer-controlled 3 axis galvanometer beam scanner was employed to write user-defined patterns through the particle lens array on the Si substrate. After laser irradiation, the obtained patterns which are in the micro-scale were composed of sub-micro/micro-holes or bumps. The micro-pattern resolution depends on the dimension of both the micro-sphere’s diameter and the beam’s spot size. The developed technique could potentially be employed to fabricate photonic crystal structures mimicking nature’s butterfly wings and anti-reflective “moth eye” arrays for photovoltaic cells.

  19. A tunable diode laser with narrow linewidth for Rb vapor laser pumping%用于Rb蒸气激光泵浦的可调谐窄线宽半导体激光器

    李志永; 谭荣清; 徐程; 李琳; 张阔海


    Since the Rb vapor′s absorption line varies with the pressure of the buffer gas,it′s essential to make the pumping diode laser′s central wavelength tunable while the linewidth is narrowed with volume Bragg grating(VBG) at the same time.In our research,based on a domestic packaged CS mounted laser,by use of the thermal shift of VBG′s central wavelength,we achieve a tunable diode laser which could be tunable from 779.89 nm to 780.35 nm while the linewidth is no more than 0.3 nm.The diode laser could be used as the pump source of a rubidium vapor laser by means of stack.%由于Rb蒸气的吸收峰随缓冲气体气压存在漂移,利用体布拉格光栅(VBG)实现线宽压窄的同时,实现泵浦半导体激光器中心波长的可调谐也是十分必要的。本文采用国内封装的半导体激光阵列(LDA),利用VBG的温度特性,实现了线宽不大于0.3nm的同时,激光器中心波长从779.89nm到780.35nm可调谐。该激光器可以通过叠阵方式用于Rb蒸气的泵浦和激励。

  20. Modulated Pulse Generations in a Laser-diode-pumped Passively Q-switched Intracavity-frequency-doubling Nd∶YVO4 Laser

    郑加安; 赵圣之; 陈磊


    The investigative results of modulated pulse output from an LD end-pumped passively Q-switched intracavity-frequency-doubling Nd∶YVO4/KTP laser with Cr4+∶YAG saturable absorber are presented. The numerical stimulations of these modulated pulses are carried out basing on the rate equations. It indicated that the modulations are attribute to the frequency beating of two eigenstates of the resonant polarized modes. The theoretical calculations are in good agreement with the experimental observations.

  1. High contrast, 86  fs, 35  mJ pulses from a diode-pumped, Yb:glass, double-chirped-pulse amplification laser system.

    Liebetrau, Hartmut; Hornung, Marco; Keppler, Sebastian; Hellwing, Marco; Kessler, Alexander; Schorcht, Frank; Hein, Joachim; Kaluza, Malte C


    We demonstrate the generation of 86 fs, 35 mJ, high-contrast laser pulses at 1030 nm with a repetition rate of 1 Hz from a diode-pumped double chirped-pulse amplification setup. The pulses exhibit a spectral bandwidth exceeding 27 nm full width at half-maximum. This could be achieved by using a laser architecture comprising two stages of chirped pulse amplification with a cross-polarized wave generation filter in between, by applying spectral shaping and by increasing the spectral hard-clip of the second stretcher. These are, to the best of our knowledge, the shortest pulses at the mJ level with ultra-high contrast generated with a diode-pumped front end at 1030 nm.

  2. Efficient and high-power green beam generation by frequency doubling of acousto-optic Q-switched diode-side pumped Nd:YAG rod laser in a coupled cavity

    S K Sharma; A J Singh; P K Mukhopadhyay; S M Oak


    A 52-W green laser at 532 nm by extra-cavity second-harmonic generation in a coupled-cavity configuration is demonstrated. The fundamental laser is a diode-side-pumped acousto-optic (AO) Q-switched Nd:YAG rod laser producing 84 W of average power at 1064 nm at 8 kHz repetition rate. Type-II phase-matched polished KTP crystal is used as the nonlinear crystal for second-harmonic generation. The individual green pulse width is 50 ns and the fundamental to second harmonic conversion efficiency is 61.8%.

  3. Multiphoton imaging with a novel compact diode-pumped Ti:sapphire oscillator

    König, Karsten; Andersen, Peter E.; Le, Tuan;


    Multiphoton laser scanning microscopy commonly relies on bulky and expensive femtosecond lasers. We integrated a novel minimal-footprint Ti:sapphire oscillator, pumped by a frequency-doubled distributed Bragg reflector tapered diode laser, into a clinical multiphoton tomograph and evaluated its...

  4. Simulation and experimental results of kaleidoscope homogenizers for longitudinal diode pumping.

    Bartnicki, Eric; Bourdet, Gilbert L


    With the goal to set a homogenizer to allow coupling of a stack of diodes with a disk amplifier medium for a longitudinally pumped laser or amplifier, we report simulation and experimental results on homogenization of the light supplied by a large stack of diodes. We investigate various kaleidoscope cross-section shapes and various optical coupling configurations.

  5. Spontaneous generation of vortex and coherent vector beams from a thin-slice c-cut Nd:GdVO4 laser with wide-aperture laser-diode end pumping: application to highly sensitive rotational and translational Doppler velocimetry

    Otsuka, Kenju; Chu, Shu-Chun


    Selective excitation of Laguerre-Gauss modes (optical vortices: helical LG0,2 and LG0,1), reflecting their weak transverse cross-saturation of population inversions against a preceding higher-order Ince-Gauss (IG0,2) or Hermite-Gauss (HG2,1) mode, was observed in a thin-slice c-cut Nd:GdVO4 laser with wide-aperture laser-diode end pumping. Single-frequency coherent vector beams were generated through the transverse mode locking of a pair of orthogonally polarized IG2,0 and LG0,2 or HG2,1 and LG0,1 modes. Highly sensitive self-mixing rotational and translational Doppler velocimetry is demonstrated by using vortex and coherent vector beams.

  6. Local Effects on Lung Parenchyma Using a 600 µm Bare Fiber with the Diode-Pumped Nd:YAG Laser LIMAX® 120

    Peter Rexin


    Full Text Available Lung metastases are frequently removed with an Nd:YAG laser. The aim is to perform a non-anatomic resection of all intraoperatively palpable lung metastases completely in order to preserve the largest possible amount of healthy lung parenchyma. The surgeon can either work with a focusing handpiece or use a laser fiber of the so-called bare fiber with direct contact to the lung parenchyma. We currently use a 600 µm bare fiber for applications involving the lung parenchyma. Precise data on the local effect of the laser fiber on the lung parenchyma are not available, especially with regard to an increase in the laser energy. We want to study this question within the scope of an experimental model in pig lungs by means of systematic and reproducible tests. The lung lobes were removed from animals recently slaughtered in the abattoir and taken to the laboratory immediately, where the lobes were stored such that the surface of the lungs was parallel to the floor. A 600 µm bare fiber was attached to a mounting bracket vertically above the lung surface at a distance of either 0, 5, or 10 mm. This mounting bracket was in turn connected to a hydraulic feed motor. The feed motor is capable of moving the bare fiber forward across the lungs consistently at three different speeds (5 mm/s, 10 mm/s, or 20 mm/s. The bare fiber itself was connected to the diode-pumped Nd: YAG Laser LIMAX® 120 (Gebrüder Martin GmbH & Co KG, Tuttlingen, Germany. We carried out the tests using three different laser powers: 20 W, 60 W, and 120 W. The lung lesions caused by the laser in each of the lungs were resected and sent in for histological analysis. The exact size of the vaporization and coagulation zone was measured using the HE sections, and the respective mean values (with standard deviations were ascertained. For all laser powers, the extent of the vaporization was greatest with a motion speed of 5 mm/s for the respective laser power: 756.4 ± 1.2 µm (20 W, 1411.0 ± 2

  7. Coupled Resonator Vertical Cavity Laser Diodes

    Choquette, K.D.; Chow, W.W.; Fischer, A.J.; Allerman, A.A.; Hou, H.Q.; Geib, K.M.


    For many applications, the device performance of edge emitting semiconductor lasers can be significantly improved through the use of multiple section devices. For example, cleaved coupled cavity (C3) lasers have been shown to provide single mode operation, wavelength tuning, high speed switching, as well as the generation of short pulses via mode-locking and Q-switching [1]. Using composite resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the coupling between the monolithic cavities, incorporate passive or active resonators which are spectrally degenerate or detuned, and to fabricate these devices in 2-dimensional arrays. Composite resonator vertical cavity lasers (CRVCL) have been examined using optical pumping and electrical injection [2-5]. We report on CRVCL diodes and show that efficient modulation of the laser emission can be achieved by either forward or reverse biasing the passive cavity within a CRVCL.

  8. Laser brackets debonding: Tm:YAP, Nd:YAG, and GaAs diode lasers evaluation

    Dostálová, Tat'jana; Jelínková, Helena; Šulc, Jan; Koranda, Petr; Němec, Michal; Ivanov, Ilja; Miyagi, Mitsunobu; Iwai, Katsumasa


    The study demonstrates the possibility of using laser radiation for the ceramic bracket removing. Three laser radiations were examined for this effect and the removing possibility and velocity together with enamel and root damage were investigated. A diode pumped Tm:YAP microchip laser generating a wavelength 1.9 μm, diode pumped Nd:YAG laser with 1.44 μm wavelength, GaAs diode with 0.808 μm were used for the debonding purpose. The measurement of transmission and absorption of the basic element - bracket, adhesive resin, and enamel was also made with the goal to explain the source of the heat and bracket debonding. The explanation of the debonding effect is also presented. From the results it is possible to conclude that continuously running diode pumped microchip Tm:YAP laser having output power 1W can be a good candidate for ceramic bracket debonding procedure.

  9. Laser Diode Beam Basics, Manipulations and Characterizations

    Sun, Haiyin


    Many optical design technical books are available for many years which mainly deal with image optics design based on geometric optics and using sequential raytracing technique. Some books slightly touched laser beam manipulation optics design. On the other hand many books on laser diodes have been published that extensively deal with laser diode physics with little touching on laser diode beam manipulations and characterizations. There are some internet resources dealing with laser diode beams. However, these internet resources have not covered enough materials with enough details on laser diode beam manipulations and characterizations. A technical book concentrated on laser diode beam manipulations and characterizations can fit in to the open and provide useful information to laser diode users. Laser Diode Beam Basics, Manipulations and  Characterizations is concentrated on the very practical side of the subject, it only discusses the basic physics and mathematics that are necessary for the readers in order...

  10. Diode laser and endoscopic laser surgery.

    Sullins, Kenneth E


    Two functionally important differences exist between the diode laser and the carbon dioxide (CO2) laser (used more commonly in small animal surgery). Diode laser energy is delivered through a quartz fiber instead of being reflected through an articulated arm or waveguide. Quartz fibers are generally more flexible and resilient than waveguides and can be inserted through an endoscope for minimally invasive procedures. Laser-tissue interaction is the other significant difference. The CO2 laser is completely absorbed by water, which limits the effect to visible tissue. The diode wavelength is minimally absorbed by water and may affect tissue as deep as 10 mm below the surface in the free-beam mode. With proper respect for the tissue effect, these differences can be used to the advantage of the patient.

  11. Study on the Pulse Interval of Passively Q-Switched Laser Pumped by Diode Laser Pulse%脉冲抽运被动调Q激光器脉冲间隔特性研究

    许韬; 金光勇; 于永吉; 陈薪羽; 王超; 吴春婷


    采用数值模拟和实验相结合的方法对脉冲激光二极管(LD)抽运Nd:YAG被动调Q激光器输出脉冲间隔特性进行分析.从被动调Q速率方程出发,结合脉冲LD抽运的特点,考虑剩余反转粒子数密度的影响,推导出输出调Q脉冲间隔时间的计算公式.重点分析了抽运脉宽、输出镜反射率、抽运功率和Cr4+:YAG初始透射率对输出脉冲间隔时间的影响.结果表明,数值模拟与实验结果基本吻合.%A passively Q-switched Nd! YAG laser pumped by diode pulse is set up. The characteristics of the laser pulse intervals are analysed by combining numerical simulation and experimental method. Starting with the rate equation of passively Q-switching mode, the Q-switched pulse intervals are formulated in consideration of the feature of diode pulse pumping and the influence of surplus inverse population density. The in fluence of pumping current and pulse width, the reflectivity of output mirror and the initial transmission of Cr4+: YAG on pulse interval time is analysed enphatically. The result indicates that the numerical simulation of pulse interval time coincides with the experimental data.

  12. Highly-efficient high-power pumps for fiber lasers

    Gapontsev, V.; Moshegov, N.; Berezin, I.; Komissarov, A.; Trubenko, P.; Miftakhutdinov, D.; Berishev, I.; Chuyanov, V.; Raisky, O.; Ovtchinnikov, A.


    We report on high efficiency multimode pumps that enable ultra-high efficiency high power ECO Fiber Lasers. We discuss chip and packaged pump design and performance. Peak out-of-fiber power efficiency of ECO Fiber Laser pumps was reported to be as high as 68% and was achieved with passive cooling. For applications that do not require Fiber Lasers with ultimate power efficiency, we have developed passively cooled pumps with out-of-fiber power efficiency greater than 50%, maintained at operating current up to 22A. We report on approaches to diode chip and packaged pump design that possess such performance.

  13. All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

    Offerhaus, H.L.; Godfried, H.P.; Witteman, W.J.


    At the Nederlands Centrum voor Laser Research (NCLR) a 1 kHz diode-pumped Nd:YAG Master Oscillator Power Amplifier (MOPA) chain with a Stimulated Brillouin Scattering (SBS) Phase Conjugate mirror is designed and operated. A small Brewster angle Nd:YAG slab (2 by 2 by 20 mm) is side pumped with 200 μ

  14. Power and energy scaling of a diode-end-pumped Nd:YLF laser through gain optimization

    Bollig, C


    Full Text Available / Vol. 18, No. 13 / OPTICS EXPRESS 13997 0% 20% 40% 60% 80% 100% 0 0.5 1 1.5 2 w [mm] ?-polarisation only Q-switch loss to hold off Pthr (% of full pump power) Fig. 2. Solid line: Theoretical minimum single-pass Q-switch loss required...

  15. Quantum Noise in Laser Diodes

    Giacobino, E.; Marin, F.; Bramati, A.; Jost, V.; Poizat, J. Ph.; Roch, J.-F.; Grangier, P.; Zhang, T.-C.


    We have investigated the intensity noise of single mode laser diodes, either free-running or using different types of line narrowing techniques at room temperature. We have measured an intensity squeezing of 1.2 dB with grating-extended cavity lasers and 1.4 dB with injection locked lasers (respectively 1.6 dB and 2.3 dB inferred at the laser output). We have observed that the intensity noise of a free-running nominally single mode laser diode results from a cancellation effect between large anti-correlated fluctuations of the main mode and of weak longitudinal side modes. Reducing the side modes by line narrowing techniques results in intensity squeezing.

  16. Continuous-wave 1.55 $\\mu$m diode-pumped surface emitting semiconductor laser for broadband multiplex spectroscopy

    Jacquemet, M; Guelachvili, G; Picqué, N; Sagnes, I; Strassner, M; Symonds, C; Garnache, Arnaud; Guelachvili, Guy; Jacquemet, Mathieu; Picqu\\'{e}, Nathalie; Sagnes, Isabelle; Strassner, Martin; Symonds, Cl\\'{e}mentine


    A room temperature operating Vertical External Cavity Surface Emitting Laser is applied around 1550 nm to intracavity laser absorption spectroscopy analyzed by time-resolved Fourier transform interferometry. At an equivalent pathlength of 15 km, the high resolution spectrum of the semiconductor disk laser emission covers 17 nm simultaneously. A noise equivalent absorption coefficient at one second averaging equal to 1.5 10^{-10} cm^{-1}.Hz^{-1/2} per spectral element is reported for the 65 km longest path length employed.

  17. Diode-Pumped High Energy and High Average Power All-Solid-State Picosecond Amplifier Systems

    Jiaxing Liu


    Full Text Available We present our research on the high energy picosecond laser operating at a repetition rate of 1 kHz and the high average power picosecond laser running at 100 kHz based on bulk Nd-doped crystals. With diode-pumped solid state (DPSS hybrid amplifiers consisting of a picosecond oscillator, a regenerative amplifier, end-pumped single-pass amplifiers, and a side-pumped amplifier, an output energy of 64.8 mJ at a repetition rate of 1 kHz was achieved. An average power of 37.5 W at a repetition rate of 100 kHz pumped by continuous wave laser diodes was obtained. Compact, stable and high power DPSS laser amplifier systems with good beam qualities are excellent picosecond sources for high power optical parametric chirped pulse amplification (OPCPA and high-efficiency laser processing.

  18. High-Power, High-Efficiency 1.907nm Diode Lasers Project

    National Aeronautics and Space Administration — nLight developed high-power, high-efficiency laser diodes emitting at 1907nm for the pumping of solid-state lasers during the Phase I. The innovation brought to bear...

  19. Single-frequency operation of diode-pumped Nd YAG high-power lasers in rod and slab geometry

    Knoke, S


    transverse and longitudinal mode is reduced by aberrations of the thermal lens, investigations in the compensation of the thermooptical effects by the laser crystal geometry and the resonator configuration were performed. In addition to the conventional cylindrical rod geometry slab laser crystals with a square cross-section and an internal zig-zag-pass were investigated. Based on the results, the output power of Nd:YAG lasers both in rod and slab geometry could be scaled to more than 20W in single-frequency operation for the first time. A maximum output power of up to 45W was demonstrated with a Nd:YAG rod laser system. Finally principal power limitations of these laser systems could be determined. Laser radiation of high coherence and with diffraction limited beam quality opens up many opportunities for applications in optic metrology, fundamental physics and nonlinear frequency conversion. Light sources with high single-frequency output powers are employed in large Michelson-type interferometers with armle...

  20. Combless broadband terahertz generation with conventional laser diodes.

    Molter, D; Wagner, A; Weber, S; Jonuscheit, J; Beigang, R


    We present a novel technique to generate a continuous, combless broadband Terahertz spectrum with conventional low-cost laser diodes. A standard time-domain spectroscopy system using photoconductive antennas is pumped by the output of two tunable diode lasers. Using fine tuning for one laser and fine and coarse tuning for the second laser, difference frequency generation results in a continuous broadband THz spectrum. Fast coarse-tuning is achieved by a simple spatial light modulator introduced in an external cavity. The results are compared to multi-mode operation for THz generation.

  1. Diode-pumped Nd:LuAG ceramic laser on 4F3/2-4I13/2transition

    Xu, Changwen; Yang, Chengdong; Zhu, Haiyong; Ye, Yanlin; Duan, Yanmin; Wei, Pengfei; Zhang, Han; Zhang, Jian; Tang, Dingyuan


    Laser operation of Nd:LuAG ceramic on the 4F3/2-4I13/2 transition has been demonstrated for the first time, to the best of our knowledge. Different output couplers are used to optimize the laser performance and the highest slope efficiency of 18.0% as well as maximum output power of 3.05 W under the pump power of 21 W was obtained. The spectral characteristics of Nd:LuAG ceramic laser is carefully studied and compared with Nd:YAG ceramic laser's. In our experiment, it has been observed that the 1338 nm wavelength is always the initial and strongest oscillating spectral line when Nd:LuAG ceramic laser operates on the 4F3/2-4I13/2 transition, even though the pump level or intra-cavity loss changes greatly, which is quite different from the case of Nd:YAG ceramic laser.

  2. Ruggedized microchannel-cooled laser diode array with self-aligned microlens

    Freitas, Barry L.; Skidmore, Jay A.


    A microchannel-cooled, optically corrected, laser diode array is fabricated by mounting laser diode bars onto Si surfaces. This approach allows for the highest thermal impedance, in a ruggedized, low-cost assembly that includes passive microlens attachment without the need for lens frames. The microlensed laser diode array is usable in all solid-state laser systems that require efficient, directional, narrow bandwidth, high optical power density pump sources.

  3. Diode-Pumped Self Q-Switched and Mode-Locking Nd3+,Cr4+:YAG Laser

    LI Chun-Yong; LI Ping-Xue; LI De-Hua; FENG Bao-Hua; FU Pan-Ming; ZHANG Zhi-Guo; ZHANG Shi-Wen


    @@ Using Nd3+,Cr4+ : YAG as a laser crystal and saturable absorber simultaneously, we obtain a self-Q-switched and mode-locking laser at 1.06 μm with straight cavity structure. Self mode-locking phenomenon was observed at an intracavity intensity of only about 2000 W/cm2. More than 90% modulation depth is achieved at an intracavity intensity of less than 3.0 × 104 W/cm2 for the first time. The Q-switched pulse width and repetition rate are found to be connected with the cavity length and the output power.

  4. Enhanced 2.7 μm emission from Er{sup 3+} doped oxyfluoride tellurite glasses for a diode-pump mid-infrared laser

    Zhang, F. F.; Yuan, J.; Chen, D. D.; Qian, Q.; Zhang, Q. Y., E-mail: [State Key Laboratory of Luminescence Materials and Devices, and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China); Zhang, W. J. [Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022 (China)


    The influence of fluoride and shielding gas (O{sub 2} or Ar) on the physical and spectroscopic properties of Er{sup 3+} doped TeO{sub 2}-ZnO-ZnF{sub 2} glass system is investigated. The larger electronegativity of F than O accounts for the gradual decrease of refractive index, density, and J-O parameters with increasing ZnF{sub 2}. An analysis on Fourier transform infrared transmission spectra reveals that the absorption coefficient of OH{sup −} around 3 μm as low as 0.247 cm{sup −1} can be achieved when 30 mol% ZnF{sub 2} containing sample is treated with Ar gas during glass melting process. The reduction of OH{sup −} groups combined with the low multiphonon relaxation rate (207 s{sup −1}) contributes to the enhanced emissions at 1.5 and 2.7 μm, along with prolonged lifetimes of {sup 4}I{sub 11/2} and {sup 4}I{sub 13/2} levels. A high branching ratio (17.95%) corresponding to the Er{sup 3+}: {sup 4}I{sub 11/2} → {sup 4}I{sub 13/2} transition, the large absorption and emission cross section (0.44 × 10{sup −20} cm{sup 2} and 0.45 × 10{sup −20} cm{sup 2}), and good gain cross section demonstrate that oxyfluoride tellurite glass could be a promising material for a diode-pump 2.7 μm fiber laser.

  5. Q-Switched and Mode Locked Short Pulses from a Diode Pumped, YB-Doped Fiber Laser


    500fs.pdf. 43. H. Leblond, M. Salhi, A. Hideur, T. Chartier , M. Brunel, F. Sanchez, "Experimental and theoretical study of the passively mode...locked ytterbium-doped double-clad fiber laser", Physical Review A, Vol. 65 063811 (2002) pp 1-9. 44. B. Ortac, A. Hideur, M. Brunel, T. Chartier , M

  6. Investigation of a diode-pumped intracavity optical parametric oscillator in pulsed and continuous wave operation

    Jensen, Ole Bjarlin; Skettrup, Torben; Balle-Petersen, O.;


    Summary form only given. CW and pulsed compact tunable laser sources in the infrared have widespread scientific, medical and industrial applications. Such a laser source can be obtained by use of a diode-pumped intracavity optical parametric oscillator (IOPO). We report on a IOPO based on a Yb...

  7. Indirect solar-pumped laser diode using a solar cell; Taiyo denchi wo mochiita taiyoko kansetsu reikigata handotai laser no kaihatsu

    Kanamori, Y.; Yugami, H.; Naito, H.; Arashi, H. [Tohoku University, Sendai (Japan). Faculty of Engineering


    This paper describes the operating characteristics of a stabilizing circuit using commercial electricity, those of a stabilizing circuit using solar cells, relation between the quantity of solar radiation and the maximum output of a semiconductor laser diode (LD), and simulation results of annual LD output in Sendai City. The stabilizing circuit for the solar-cell driven LD was structured such that the output of the solar cell panels was guided to a DC/DC converter, that the voltage was set at a prescribed value and that the current was stabilized with the use of power MOSFET. The solar cells used in the experiment were monocrystal silicone solar cells with the maximum output of 53W each. In the experiment, the LD was protected by stabilizing the current at a set value when an excess current was supplied to the stabilizing circuit. As a result of the simulation of the annual LD output from the meteorological data of Sendai City, it was predicted that a solar cell of approximately 1kW was able to provide an annual output of 102MJ and that the efficiency was highest with four sheets of the solar cell. Consequently, consistency proved to be essential between the LD and the solar cell output. 3 refs., 7 figs.

  8. Green Output of 1.5 W from a Diode-Pumped Intracavity Frequency-Doubled Self-Q-Switched and Mode-Locked Cr,Nd:YAG Laser

    DU Shi-Feng; WANG Su-Mei; ZHANG Dong-Xiang; LI De-Hua; ZHANG Zhi-Guo; FENG Bao-Hua; ZHANG Shi-Wen


    We report a diode-pumped intracavity frequency-doubled self-Q-switched and mode-locked Cr,Nd:YAG/KTP green laser with a Z-type cavity, which produces 1.5 W of average power at 532 nm with incident pump power 14.2 W. The individual mode-locked green pulse duration is about 560ps with 149MHz repetition rate. Almost 100% modulation depth of the mode-locked green pulses is achieved at an incident pump power of 4.13 W. The maximum energy of Q-switched green pulse is 19.8 fiJ. The experimental results of pulse duration and pulse energy of Q-switched green pulse agree well with the theoretical calculations.

  9. Q-switched Ho:YLF laser pumped by a Tm:GdVO4 laser.

    Esser, MJD


    Full Text Available The authors have, through careful analysis of spectroscopic data, designed and demonstrated a diode-end-pumped, quasicontinuous wave Tm:GdVO4 laser operating at 1892 nm in order to pump a Q-switched Ho:YLF laser. The Ho:YLF maximum output energy...

  10. Wavelength stabilized multi-kW diode laser systems

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


    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.

  11. 407 W End-pumped Multi-segmented Nd:YAG Laser.

    Kracht, Dietmar; Wilhelm, Ralf; Frede, Maik; Dupré, Klaus; Ackermann, Lothar


    A composite crystalline Nd:YAG rod consisting of 5 segments with different dopant concentrations for high power diode end-pumping is presented. A maximum laser output power of 407 W with an optical-to-optical efficiency of 54 % was achieved by longitudinal pumping with a high power laser diode stack.

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

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


    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.

  13. Wavelength Stabilized High Brightness Direct Diode Pumps for Solid State LIDAR Systems at Eye-Safe Wavelengths Project

    National Aeronautics and Space Administration — Our proposed innovation is to design and fabricate a diode pumped Er:YAG micro-chip laser capable of varied repetition rates and high pulse energies using the single...

  14. Spectral narrowing of a 980 nm tapered diode laser bar

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Lucas Leclin, Gaëlle


    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...

  15. Lasers with nuclear pumping

    Melnikov, S P; Sizov, A N; Miley, George H


    This book covers the history of lasers with nuclear pumping (Nuclear Pumped Lasers, NPLs). This book showcases the most important results and stages of NPL development in The Russian Federal Nuclear Center (VNIIEF) as well as other Russian and international laboratories, including laboratories in the United States. The basic science and technology behind NPLs along with potential applications are covered throughout the book. As such, this book: ·         Contains a historical overview of the extensive information developed over the past 40 years of work on NPLs ·         Covers the most important results and stages of NPL development, not just in the Russian Federal Nuclear Center, VNIIEF, but also in other laboratories in Russia, the United States , and some other scattered international laboratories ·         Systematizes the fragmented information accumulated over these years of very active research and development As the first comprehensive discussion of NPLs, students, research...

  16. An experimental study of low-frequency amplitude noise in a fibre Bragg grating laser diode

    Zholnerov, V S [Russian Institute of Radionavigation and Time, St.Petersburg (Russian Federation); Ivanov, A V; Kurnosov, V D; Kurnosov, K V; Romantsevich, V I; Chernov, R V [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation)


    We have studied the amplitude noise in a fibre Bragg grating laser diode. It has been shown that discontinuities in noise characteristics correlate with those in the power – current and spectral characteristics of the laser diode, whereas the noise characteristics of the pump source have no such discontinuities. The highest noise level has been observed at pump currents corresponding to concurrent generation of two longitudinal modes. (lasers)

  17. Diode-pumped laser operation of Pr3+:Ba(Ysub>0.8sub>Lusub>0.2sub>)sub>2sub>Fsub>8sub> in the visible region.

    Sottile, Alberto; Damiano, Eugenio; Tonelli, Mauro


    We report on, to the best of our knowledge, the first growth, spectroscopy, and laser operation of monocrystalline Ba(Ysub>0.8sub>Lusub>0.2sub>)sub>2sub>Fsub>8sub> doped with 1.25 at.% of Pr3+ ions (Pr:BYLF). We studied the spectroscopic properties of this material, particularly in comparison with its isomorph Pr3+: BaYsub>2sub>Fsub>8sub> (Pr:BYF). Under diode-pumped excitation, we achieved continuous-wave laser operation in the orange, red, and deep red regions in the three possible crystal orientations. We obtained considerably improved laser performances and remarkably low passive losses, in comparison with Pr:BYF crystals and other fluorides, indicating that Pr:BYLF is an excellent host material in the visible region.

  18. April 25, 2003, FY2003 Progress Summary and FY2002 Program Plan, Statement of Work and Deliverables for Development of High Average Power Diode-Pumped Solid State Lasers,and Complementary Technologies, for Applications in Energy and Defense

    Meier, W; Bibeau, C


    The High Average Power Laser Program (HAPL) is a multi-institutional, synergistic effort to develop inertial fusion energy (IFE). This program is building a physics and technology base to complement the laser-fusion science being pursued by DOE Defense programs in support of Stockpile Stewardship. The primary institutions responsible for overseeing and coordinating the research activities are the Naval Research Laboratory (NRL) and Lawrence Livermore National Laboratory (LLNL). The current LLNL proposal is a companion document to the one submitted by NRL, for which the driver development element is focused on the krypton fluoride excimer laser option. The NRL and LLNL proposals also jointly pursue complementary activities with the associated rep-rated laser technologies relating to target fabrication, target injection, final optics, fusion chamber, target physics, materials and power plant economics. This proposal requests continued funding in FY03 to support LLNL in its program to build a 1 kW, 100 J, diode-pumped, crystalline laser, as well as research into high gain fusion target design, fusion chamber issues, and survivability of the final optic element. These technologies are crucial to the feasibility of inertial fusion energy power plants and also have relevance in rep-rated stewardship experiments. The HAPL Program pursues technologies needed for laser-driven IFE. System level considerations indicate that a rep-rated laser technology will be needed, operating at 5-10 Hz. Since a total energy of {approx}2 MJ will ultimately be required to achieve suitable target gain with direct drive targets, the architecture must be scaleable. The Mercury Laser is intended to offer such an architecture. Mercury is a solid state laser that incorporates diodes, crystals and gas cooling technologies.

  19. FY2002 Progress Summary Program Plan, Statement of Work and Deliverables for Development of High Average Power Diode-Pumped Solid State Lasers, and Complementary Technologies, for Applications in Energy and Defense

    Bayramian, A; Bibeau, C; Beach, R; Behrendt, B; Ebbers, C; Latkowski, J; Meier, W; Payne, S; Perkins, J; Schaffers, K; Skulina, K; Ditmire, T; Kelly, J; Waxer, L; Rudi, P; Randles, M; Witter, D; Meissner, H; Merissner, O


    The High Average Power Laser Program (HAPL) is a multi-institutional, coordinated effort to develop a high-energy, repetitively pulsed laser system for Inertial Fusion Energy and other DOE and DOD applications. This program is building a laser-fusion energy base to complement the laser-fusion science developed by DOE Defense programs over the past 25 years. The primary institutions responsible for overseeing and coordinating the research activities are the Naval Research Laboratory (NRL) and LLNL. The current LLNL proposal is a companion proposal to that submitted by NRL, for which the driver development element is focused on the krypton fluoride excimer laser option. Aside from the driver development aspect, the NRL and LLNL companion proposals pursue complementary activities with the associated rep-rated laser technologies relating to target fabrication, target injection, final optics, fusion chamber, materials and power plant economics. This report requests continued funding in FY02 to support LLNL in its program to build a 1kW, 100J, diode-pumped, crystalline laser. In addition, research in high gain laser target design, fusion chamber issues and survivability of the final optic element will be pursued. These technologies are crucial to the feasibility of inertial fusion energy power plants and also have relevance in rep-rated stewardship experiments.

  20. Partially end-pumped Nd:YAG slab laser with a hybrid resonator.

    Du, K; Wu, N; Xu, J; Giesekus, J; Loosen, P; Poprawe, R


    A Nd:YAG slab is partially end pumped by a diode laser stack with three diode laser bars. The pumped volume has a rectangular cross section. A hybrid resonator, which is stable in the plane of small dimension and is off-axis unstable in the plane of large dimension of the gain cross section, was used to yield highly efficient laser operation at diffraction-limited beam quality. The laser design and experimental results are reported.

  1. Laser diode stacks:pulsed light power for nuclear fusion

    Martin Wlz; Agnieszka Pietrzak; Alex Kindsvater; Jens Meusel; Klaus Stolberg; Ralf Hlsewede; Jrgen Sebastian; Valentin Loyo-Maldonado


    Laser drivers are an enabling factor to inertial confinement fusion, because laser diodes must be used instead of flash lamps. We discuss the limitations of laser diode arrays and show what steps the industry is taking. The pump power requirements of large-scale projects such as LIFE or Hi PER are within reach of semiconductor laser diode assemblies.Pulsed light output powers per laser bars have been around 300 W per bar, as in the Jenoptik 940 nm bars previously used for pumping the Yb:YAG slabs in the Di POLE project. By redesigning the semiconductor laser structures 500 W per bar is now commercially available for 808, 880 and 940 nm pump wavelengths. The construction of one inertial fusion power plant will require an amount of semiconductor laser chips in excess of the current annual production by two orders of magnitude. This adds to the engineering task of improving the device characteristics a challenge to production capacity.While the industry benefits from the recent boost in solid-state lighting that acts as a technology driver, cooperation between manufacturers will be imperative, and to this end we propose standardization efforts.

  2. Compact diode stack end pumped Nd:YAG amplifier using core doped ceramics.

    Denis, Thomas; Hahn, Sven; Mebben, Sandra; Wilhelm, Ralf; Kolleck, Christian; Neumann, Jörg; Kracht, Dietmar


    We report on a compact Nd:YAG amplifier emitting a maximum pulse energy of 14 mJ. By amplifying a passively Q-switched oscillator (M(2)diode pumped by an 8 bar diode stack of 800 W power and a nonimaging optic. This optic homogenizes the pump light and transfers it into a 5 mm diameter core doped rod with a centrally neodymium doped region of 3 mm and a samarium doped YAG cladding. We show that this cladding reduces parasitic effects in the laser rod compared to an undoped YAG cladding. Finally, we compare the compact amplifier with an amplifier, which is mode selectively pumped by a fiber coupled pump diode.

  3. Tandem-pumped 1120-nm actively Q-switched fiber laser

    王建华; 胡金萌; 张世强; 陈露璐; 房勇; 冯衍


    We report on a tandem-pumped actively Q-switched fiber laser system emitting at 1120 nm. Parasitic oscillation is challenging in Yb-doped Q-switched 1120-nm fiber laser, which is suppressed by pumping with a fiber laser at 1018 nm. At least 4 times improvement in output peak power is demonstrated in a single laser setup with 1018-nm fiber laser pumping instead of 976-nm laser diode pumping. This is, to the best of our knowledge, the first demonstration of a tandem-pumped Q-switched fiber laser.

  4. Transverse Pumping with Diode Lasers


    little different. Previously, given a , we 3 imagine a horizontal line at height a on Figure 4 intersecting the curve a(0) to identify . The algebraic ...coprocessor. The geometrical optics programs used for comparison were written by another programer, in a different version of BASIC (interpreted BASICA

  5. Portable Diode Pumped Femtosecond Lasers


    Michelson interferometer in an autocorrelator. [3] . . . . . . 75 x Figure Page 4.7. Example of pulse comparison in an intensity autocorrelator. The...line milled in it for placement. The design for the 3-mm crystal is just a small 3-mm notch cut in a piece of aluminum. 3.3 Cavity Design An example of...dt (4.1) Most often for pulses shorter than 1 ps, the reference pulse is the pulse itself. [14, p.459] This is accomplished normally by a Michelson

  6. Physics and Applications of Laser Diode Chaos

    Sciamanna, Marc


    An overview of chaos in laser diodes is provided which surveys experimental achievements in the area and explains the theory behind the phenomenon. The fundamental physics underpinning this behaviour and also the opportunities for harnessing laser diode chaos for potential applications are discussed. The availability and ease of operation of laser diodes, in a wide range of configurations, make them a convenient test-bed for exploring basic aspects of nonlinear and chaotic dynamics. It also makes them attractive for practical tasks, such as chaos-based secure communications and random number generation. Avenues for future research and development of chaotic laser diodes are also identified.

  7. Effects of radiation on laser diodes.

    Phifer, Carol Celeste


    The effects of ionizing and neutron radiation on the characteristics and performance of laser diodes are reviewed, and the formation mechanisms for nonradiative recombination centers, the primary type of radiation damage in laser diodes, are discussed. Additional topics include the detrimental effects of aluminum in the active (lasing) volume, the transient effects of high-dose-rate pulses of ionizing radiation, and a summary of ways to improve the radiation hardness of laser diodes. Radiation effects on laser diodes emitting in the wavelength region around 808 nm are emphasized.

  8. Advances in high power semiconductor diode lasers

    Ma, Xiaoyu; Zhong, Li


    High power semiconductor lasers have broad applications in the fields of military and industry. Recent advances in high power semiconductor lasers are reviewed mainly in two aspects: improvements of diode lasers performance and optimization of packaging architectures of diode laser bars. Factors which determine the performance of diode lasers, such as power conversion efficiency, temperature of operation, reliability, wavelength stabilization etc., result from a combination of new semiconductor materials, new diode structures, careful material processing of bars. The latest progress of today's high-power diode lasers at home and abroad is briefly discussed and typical data are presented. The packaging process is of decisive importance for the applicability of high-power diode laser bars, not only technically but also economically. The packaging techniques include the material choosing and the structure optimizing of heat-sinks, the bonding between the array and the heat-sink, the cooling and the fiber coupling, etc. The status of packaging techniques is stressed. There are basically three different diode package architectural options according to the integration grade. Since the package design is dominated by the cooling aspect, different effective cooling techniques are promoted by different package architectures and specific demands. The benefit and utility of each package are strongly dependent upon the fundamental optoelectronic properties of the individual diode laser bars. Factors which influence these properties are outlined and comparisons of packaging approaches for these materials are made. Modularity of package for special application requirements is an important developing tendency for high power diode lasers.

  9. Reliability of high power laser diodes with external optical feedback

    Bonsendorf, Dennis; Schneider, Stephan; Meinschien, Jens; Tomm, Jens W.


    Direct diode laser systems gain importance in the fields of material processing and solid-state laser pumping. With increased output power, also the influence of strong optical feedback has to be considered. Uncontrolled optical feedback is known for its spectral and power fluctuation effects, as well as potential emitter damage. We found that even intended feedback by use of volume Bragg gratings (VBG) for spectral stabilization may result in emitter lifetime reduction. To provide stable and reliable laser systems design, guidelines and maximum feedback ratings have to be found. We present a model to estimate the optical feedback power coupled back into the laser diode waveguide. It includes several origins of optical feedback and wide range of optical elements. The failure thresholds of InGaAs and AlGaAs bars have been determined not only at standard operation mode but at various working points. The influence of several feedback levels to laser diode lifetime is investigated up to 4000h. The analysis of the semiconductor itself leads to a better understanding of the degradation process by defect spread. Facet microscopy, LBIC- and electroluminescence measurements deliver detailed information about semiconductor defects before and after aging tests. Laser diode protection systems can monitor optical feedback. With this improved understanding, the emergency shutdown threshold can be set low enough to ensure laser diode reliability but also high enough to provide better machine usability avoiding false alarms.

  10. Photonic crystal fibers for supercontinuum generation pumped by a gain-switched CW fiber laser

    Larsen, Casper; Noordegraaf, Danny; Hansen, Kim P.


    Supercontinuum generation in photonics crystal fibers (PCFs) pumped by CW lasers yields high spectral power density and average power. However, such systems require very high pump power and long nonlinear fibers. By on/off modulating the pump diodes of the fiber laser, the relaxation oscillations...

  11. Nuclear pumped gas laser research

    Thom, K.


    Nuclear pumping of lasers by fission-fragments from nuclear chain reactions is discussed. Application of the newly developed lasers to spacecraft propulsion or onboard power, to lunar bases for industrial processing, and to earth for utilization of power without pollution and hazards is envisioned. Emphasis is placed on the process by which the fission-fragement kinetic energy is converted into laser light.

  12. Diode-pumped high power 2.7 μm Er:Y2O3 ceramic laser at room temperature

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


    Investigation of room temperature laser performance of the polycrystalline Er:Y2O3 ceramic at 2.7 μm with respect to dopant concentrations was conducted. With 7 at.% Er3+ concentration Er:Y2O3 ceramic as laser gain medium, over 2.05 W of CW output power at 2.7 μm was generated with a slope efficiency of 11.1% with respect to the absorbed LD pump power. The prospects for improvement in lasing efficiency and output power are considered.

  13. Qualification of diode foil materials for excimer lasers

    Anderson, R.G.; Shurter, R.P.; Rose, E.A.


    The Aurora facility at Los Alamos National Laboratory uses KrF excimer lasers to produce 248 nm light for inertial confinement fusion applications. Diodes in each amplifier produce relativistic electron beams to pump a Kr-F-Ar gas mixture. A foil is necessary to separate the vacuum diode from the laser gas. High tensile strength, high electron transmission, low ultraviolet reflectivity, and chemical compatibility with fluorine have been identified as requisite foil properties. Several different materials were acquired and tested for use as diode foils. Transmission and fluorine compatibility tests were performed using the Electron Gun Test Facility (EGTF) at Los Alamos. Off-line tests of tensile strength and reflectivity were performed. Titanium foil, which is commonly used as a diode foil, was found to generate solid and gaseous fluoride compounds, some of which are highly reactive in contact with water vapor. 6 refs., 6 figs., 1 tab.

  14. Qualification of diode foil materials for excimer lasers

    Anderson, R. G.; Shurter, R. P.; Rose, E. A.

    The Aurora facility at Los Alamos National Laboratory uses KrF excimer lasers to produce 248 nm light for inertial confinement fusion applications. Diodes in each amplifier produce relativistic electron beams to pump a Kr-F-Ar gas mixture. A foil is necessary to separate the vacuum diode from the laser gas. High tensile strength, high electron transmission, low ultraviolet reflectivity, and chemical compatibility with fluorine have been identified as requisite foil properties. Several different materials were acquired and tested for use as diode foils. Transmission and fluorine compatibility tests were performed using the Electron Gun Test Facility (EGTF) at Los Alamos. Off-line tests of tensile strength and reflectivity were performed. Titanium foil, which is commonly used as a diode foil, was found to generate solid and gaseous fluoride compounds, some of which are highly reactive in contact with water vapor.

  15. Pumping of titanium sapphire laser

    Jelínková, H.; Vaněk, P.; Valach, P.; Hamal, K.; Kubelka, J.; Škoda, V.; Jelínek, M.


    Two methods of Ti:Sapphire pumping for the generation of tunable laser radiation in the visible region were studied. For coherent pumping, the radiation of the second harmonic of a Nd:YAP laser was used and a maximum output energy of E out=4.5 mJ was reached from the Ti:Sapphire laser. For noncoherent pumping, two different lengths of flashlamp pulses were used and a maximum of E out=300 mJ was obtained. Preliminary estimations of the wavelength range of tunability were made.

  16. Diode-Pumped High Energy and High Average Power All-Solid-State Picosecond Amplifier Systems

    Jiaxing Liu; Wei Wang; Zhaohua Wang; Zhiguo Lv; Zhiyuan Zhang; Zhiyi Wei


    We present our research on the high energy picosecond laser operating at a repetition rate of 1 kHz and the high average power picosecond laser running at 100 kHz based on bulk Nd-doped crystals. With diode-pumped solid state (DPSS) hybrid amplifiers consisting of a picosecond oscillator, a regenerative amplifier, end-pumped single-pass amplifiers, and a side-pumped amplifier, an output energy of 64.8 mJ at a repetition rate of 1 kHz was achieved. An average power of 37.5 W at a repetition ra...

  17. Laser diode package with enhanced cooling

    Deri, Robert J.; Kotovsky, Jack; Spadaccini, Christopher M.


    A laser diode package assembly includes a reservoir filled with a fusible metal in close proximity to a laser diode. The fusible metal absorbs heat from the laser diode and undergoes a phase change from solid to liquid during the operation of the laser. The metal absorbs heat during the phase transition. Once the laser diode is turned off, the liquid metal cools off and resolidifies. The reservoir is designed such that that the liquid metal does not leave the reservoir even when in liquid state. The laser diode assembly further includes a lid with one or more fin structures that extend into the reservoir and are in contact with the metal in the reservoir.

  18. Hermetic diode laser transmitter module

    Ollila, Jyrki; Kautio, Kari; Vahakangas, Jouko; Hannula, Tapio; Kopola, Harri K.; Oikarinen, Jorma; Sivonen, Matti


    In very demanding optoelectronic sensor applications it is necessary to encapsulate semiconductor components hermetically in metal housings to ensure reliable operation of the sensor. In this paper we report on the development work to package a laser diode transmitter module for a time- off-light distance sensor application. The module consists of a lens, laser diode, electronic circuit and optomechanics. Specifications include high acceleration, -40....+75 degree(s)C temperature range, very low gas leakage and mass-production capability. We have applied solder glasses for sealing optical lenses and electrical leads hermetically into a metal case. The lens-metal case sealing has been made by using a special soldering glass preform preserving the optical quality of the lens. The metal housings are finally sealed in an inert atmosphere by welding. The assembly concept to retain excellent optical power and tight optical axis alignment specifications is described. The reliability of the laser modules manufactured has been extensively tested using different aging and environmental test procedures. Sealed packages achieve MIL- 883 standard requirements for gas leakage.

  19. Thermal effect of thin disk laser side-pumped by laser-diode array%激光二极管阵列侧面泵浦薄片激光器的热效应

    刘全喜; 钟鸣


    建立了激光二极管阵列快轴垂直于薄片表面、对快轴压缩、环绕侧面泵浦复合薄片激光器的数值模型.依据激光二极管阵列的输出光束特性,运用有限元法,得出了薄片内的泵浦光、温度和热应力分布.分析了温度和热应力与泵浦功率、换热系数和时间的变化规律.模拟结果表明:热破坏主要为复合面外侧的拉伸破裂;温度和应力的上升时间和恢复时间随泵浦功率的变化不明显,随换热系数的增大而减小,存在一个最佳的换热系数;考虑热力学参数温度相关性的稳态温度和应力要大于不考虑热力学参数温度相关性时的值.%A numerical model of the thin composite disk side-pumped by ring laser-diode array(LDA) is set up. The LDA fast axis is upright to the disk surface and is compressed. The distribution of the pump, temperature and thermal stress in the thin disk is calculated by a finite element method and the influence of pump power, heat transfer coefficient and time on the temperature and thermal stress is analyzed. Results of simulation indicate that thermal extendable destroy appears on the edge of the composite surface. The rise time and recovery time of the temperature and stress show no obvious change as the pump power increases, while they decrease along with the increase of the heat transfer coefficient. The steady temperature and thermal stress of temperature correlation considering the thermodynamic parameters are bigger than those of the constant thermodynamic parameters.The theoretical results accord with related experiment results.

  20. Multi-pass 1.9 um Tm:YLF slab laser pump source

    Strauss, HJ


    Full Text Available A novel multi-pass Tm: YLF laser was demonstrated with an improvement in efficiency, footprint and cost over a two diode stack pumped, single pass system. 100 W of output power from 261 W of incident diode pump power with a slope efficiency of 44...

  1. Recent advances of diode-pumped thin disk laser%半导体泵浦盘片激光器的技术发展

    崔文达; 韩凯; 王红岩; 华卫红; 许晓军


    概述了盘片激光器的技术发展现状,评述了盘片激光器泵浦结构、增益介质的发展过程,并且分析了连续和脉冲盘片激光器的功率定标放大特点,指出了盘片激光器现存的技术瓶颈,展望了下一步的发展方向。%The recent development of thin disk laser was summarized,and its pump structure and gain medium were commented,meanwhile the power-scalable characteristics of continuous and pulse thin disk lasers were also analyzed. Finally,the technology restrictions were pointed out and the development trends of thin disk lasers were presented.

  2. Welding of Vanadium, Tantalum, 304L and 21-6-9 Stainless Steels, and Titanium Alloys at Lawrence Livermore National Laboratory using a Fiber Delivered 2.2 kW Diode Pumped CW Nd:YAG Laser

    Palmer, T; Elmer, J; Pong, R; Gauthier, M


    This report summarizes the results of a series of laser welds made between 2003 and 2005 at Lawrence Livermore National Laboratory (LLNL). The results are a compilation of several, previously unpublished, internal LLNL reports covering the laser welding of vanadium, tantalum, 304L stainless steel, 21-6-9 (Nitronic 40) steel, and Ti-6Al-4V. All the welds were made using a Rofin Sinar DY-022 diode pumped continuous wave Nd:YAG laser. Welds are made at sharp focus on each material at various power levels and travel speeds in order to provide a baseline characterization of the performance of the laser welder. These power levels are based on measurements of the output power of the laser system, as measured by a power meter placed at the end of the optics train. Based on these measurements, it appears that the system displays a loss of approximately 10% as the beam passes through the fiber optic cable and laser optics. Since the beam is delivered to the fixed laser optics through a fiber optic cable, the effects of fiber diameter are also briefly investigated. Because the system utilizes 1:1 focusing optics, the laser spot size at sharp focus generally corresponds to the diameter of the fiber with which the laser is delivered. Differences in the resulting weld penetration in the different materials system are prevalent, with the welds produced on the Nitronic 40 material displaying the highest depths (> 5 mm) and minimal porosity. A Primes focusing diagnostic has also been installed on this laser system and used to characterize the size and power density distribution of the beams as a function of both power and focus position. Further work is planned in which this focusing diagnostic will be used to better understand the effects of changes in beam properties on the resulting weld dimensions in these and other materials systems.

  3. End-Pumped Tm:YAG Ceramic Slab Lasers

    CHENG Xiao-Jin; XU Jian-Qiu; ZHANG Wen-Xin; JIANG Sen-Xue; PAN Yu-Bai


    Lasers from a Tm:YAG ceramic aare reported for the first time to our best knowledge. The Tm:YAG ceramic slab is end-pumped by a laser diode with central wavelength 792nm. At room temperature, the maximum continuous-wave output power is 4.5 W, and the sloping efficiency is obtained to be 20.5%. The laser spectrum of the Tm: YAG ceramic is centered at 2015 nm.

  4. High power collimated diode laser stack

    LIU Yuan-yuan; FANG Gao-zhan; MA Xiao-yu; LIU Su-ping; FENG Xiao-ming


    A high power collimated diode laser stack is carried out based on fast-axis collimation and stack packaging techniques.The module includes ten typical continuous wave (cw) bars and the total output power can be up to 368W at 48.6A.Using a cylindrical lens as the collimation elements,we can make the fast-axis divergence and the slow-axis divergence are 0.926 40 and 8.2060 respectively.The light emitting area is limited in a square area of 18.3 mm×11 mm.The module has the advantage of high power density and offers a wide potential applications in pumping and material processing.

  5. DPSS Laser Beam Quality Optimization Through Pump Current Tuning

    Omohundro, Rob; /Newport Spectra-Physics, Santa Clara; Callen, Alice; /SLAC; Sukuta, Sydney; /San Jose City Coll.


    The goal of this study is to demonstrate how a DPSS laser beam's quality parameters can be simultaneously optimized through pump current tuning. Two DPSS lasers of the same make and model were used where the laser diode pump current was first varied to ascertain the lowest RMS noise region. The lowest noise was found to be 0.13% in this region and the best M{sup 2} value of 1.0 and highest laser output power were simultaneously attained at the same current point. The laser manufacturer reported a M{sup 2} value of 1.3 and RMS noise value of .14% for these lasers. This study therefore demonstrates that pump current tuning a DPSS laser can simultaneously optimize RMS Noise, Power and M{sup 2} values. Future studies will strive to broaden the scope of the beam quality parameters impacted by current tuning.

  6. Continuous-wave operation of a room-temperature Tm: YAP-pumped Ho: YAG laser


    We report a continuous-wave (CW) 2.1-μm Ho:YAG laser operating at room temperature pumped by a diode-pumped 1.94-?m Tm:YAP laser.The maximum output power of 1.5 W is obtained from Ho:YAG laser,corresponding to Tm-to-Ho slope efficiency of 17.9% and diode-to-He conversion efficiency of 5.6%.

  7. Parametric amplification of broadband radiation of a cw superluminescent diode under picosecond pumping

    Vereshchagin, K. A.; Il'chenko, S. N.; Morozov, V. B.; Olenin, A. N.; Tunkin, V. G.; Yakovlev, D. V.; Yakubovich, S. D.


    It is proposed to use cw superluminescent diodes with a spectral width of about 300 cm-1 and high spatial coherence as seed radiation sources in parametric amplifiers with picosecond pumping in order to form broadband picosecond pulses. A two-cascade parametric amplifier based on BaB2O4 (BBO) crystals is pumped by 20-ps pulses of the second harmonic of an Nd : YAG laser. For a superluminescent diode spectral width of 275 cm-1 (centre wavelength 790 nm), the spectral width of picosecond pulses at the parametric amplifier output is 203 cm-1. At a total pump energy of 7.2 mJ for BBO crystals, the energy of the enhanced emission of the superluminescent diode is found to be 0.6 mJ.

  8. Improved Thermoelectrically Cooled Laser-Diode Assemblies

    Glesne, Thomas R.; Schwemmer, Geary K.; Famiglietti, Joe


    Cooling decreases wavelength and increases efficiency and lifetime. Two improved thermoelectrically cooled laser-diode assemblies incorporate commercial laser diodes providing combination of both high wavelength stability and broad wavelength tuning which are broadly tunable, highly stable devices for injection seeding of pulsed, high-power tunable alexandrite lasers used in lidar remote sensing of water vapor at wavelengths in vicinity of 727 nanometers. Provide temperature control needed to take advantage of tunability of commercial AlGaAs laser diodes in present injection-seeding application.

  9. Thermal Lensing, Laser Performance at 1.06 μm and 0.53 μm of a NYAB Laser End-pumped by a Diode-laser-array

    LIU Junhai; WANG Jiyang; SUN Lianke; SHAO Zongshu; JIANG Minhua


    The thermal lensing, output characteristics of an end-pumped NYAB laser with high pump power levels and operated at the fundamental wavelength, and the manner of self-frequency-doubling, have been investigated. The thermal lensing in the NYAB crystal was found to be significantly stronger than that in Nd:YVO4 crystal. A maximum output of 3.2 W at 1.06 μm was achieved with an optical conversion efficiency of 29.1% and an average slope efficiency of 37.5%. These results were found to be slightly inferior to those of Nd:YVO4 crystal. When operated in the fashion of selffrequency-doubling, 23 mW green output was obtained at the incident pump power of 5 W, such inefficient operation was attributed to the large mode size in the NYAB crystal.

  10. Diode laser (980nm) cartilage reshaping

    El Kharbotly, A.; El Tayeb, T.; Mostafa, Y.; Hesham, I.


    Loss of facial or ear cartilage due to trauma or surgery is a major challenge to the otolaryngologists and plastic surgeons as the complicated geometric contours are difficult to be animated. Diode laser (980 nm) has been proven effective in reshaping and maintaining the new geometric shape achieved by laser. This study focused on determining the optimum laser parameters needed for cartilage reshaping with a controlled water cooling system. Harvested animal cartilages were angulated with different degrees and irradiated with different diode laser powers (980nm, 4x8mm spot size). The cartilage specimens were maintained in a deformation angle for two hours after irradiation then released for another two hours. They were serially measured and photographed. High-power Diode laser irradiation with water cooling is a cheep and effective method for reshaping the cartilage needed for reconstruction of difficult situations in otorhinolaryngologic surgery. Key words: cartilage,diode laser (980nm), reshaping.

  11. Progress in the development of active heat sink for high-power laser diodes

    Vetrovec, John; Feeler, Ryan; Bonham, Steve


    We report on the development of a novel active heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink receives diode waste heat at high flux and transfers it at reduced flux to environment, coolant fluid, heat pipe, or structure. Thermal conductance of the heat sink is electronically adjustable, allowing for precise control of diode temperature and the output light wavelength. When pumping solid-state lasers, diode wavelength can be precisely tuned to the absorption features of the laser gain medium. This paper presents the AHS concept, scaling laws, model predictions, and data from initial testing.

  12. Interferometry and Holography With Diode Laser Light

    Lunazzi, Jose Joaquin


    We made an interferometric Michelson type setup and a simple holographic setup to demonstrate the feasibility of interferometric and holographic techniques by means of a diode laser. The laser was made by using a common diode available as a penlight element (less than R$ 15,00 value) and a simple stabilized 110 VCA- 3 VCC power supply. Interference fringes and holograms of small objects where obtained very similar to those of a helium-neon laser based setup.

  13. Intensity scaling of an optically pumped potassium laser

    Hurd, Edward J.; Holtgrave, Jeremy C.; Perram, Glen P.


    A pulsed, optically pumped potassium laser has been demonstrated with output intensity exceeding 7 MW/cm2. By using a surrogate pump, heat pipe gain cell, and helium pressure of 2500 Torr, the intensity of Diode Pumped Alkali Lasers (DPAL) has been increased by a factor of 38. Bottlenecking due to slow fine structure mixing can be avoided without hydrocarbon buffer gases with as many as 375 lasing photons obtained per potassium atom following a 7.4 ns pump pulse. A slope efficiency of 9.4% is achieved and primarily limited by a mismatch between pumped and cavity mode volumes. Laser performance is well described by a three-level, longitudinally averaged model without ionization.

  14. Advanced laser diodes for sensing applications



    The authors have developed diode lasers for short pulse duration and high peak pulse power in the 0.01--100.0 m pulsewidth regime. A primary goal of the program was producing up to 10 W while maintaining good far-field beam quality and ease of manufacturability for low cost. High peak power, 17 W, picosecond pulses have been achieved by gain switching of flared geometry waveguide lasers and amplifiers. Such high powers area world record for this type of diode laser. The light emission pattern from diode lasers is of critical importance for sensing systems such as range finding and chemical detection. They have developed a new integrated optical beam transformer producing rib-waveguide diode lasers with a symmetric, low divergence, output beam and increased upper power limits for irreversible facet damage.

  15. High power coherent polarization locked laser diode.

    Purnawirman; Phua, P B


    We have coherently combined a broad area laser diode array to obtain high power single-lobed output by using coherent polarization locking. The single-lobed coherent beam is achieved by spatially combining four diode emitters using walk-off crystals and waveplates while their phases are passively locked via polarization discrimination. While our previous work focused on coherent polarization locking of diode in Gaussian beams, we demonstrate in this paper, the feasibility of the same polarization discrimination for locking multimode beams from broad area diode lasers. The resonator is designed to mitigate the loss from smile effect by using retro-reflection feedback in the cavity. In a 980 nm diode array, we produced 7.2 W coherent output with M2 of 1.5x11.5. The brightness of the diode is improved by more than an order of magnitude.

  16. Transverse pumped laser amplifier architecture

    Bayramian, Andrew James; Manes, Kenneth; Deri, Robert; Erlandson, Al; Caird, John; Spaeth, Mary


    An optical gain architecture includes a pump source and a pump aperture. The architecture also includes a gain region including a gain element operable to amplify light at a laser wavelength. The gain region is characterized by a first side intersecting an optical path, a second side opposing the first side, a third side adjacent the first and second sides, and a fourth side opposing the third side. The architecture further includes a dichroic section disposed between the pump aperture and the first side of the gain region. The dichroic section is characterized by low reflectance at a pump wavelength and high reflectance at the laser wavelength. The architecture additionally includes a first cladding section proximate to the third side of the gain region and a second cladding section proximate to the fourth side of the gain region.

  17. Semiconductor laser diodes and the design of a D.C. powered laser diode drive unit

    Cappuccio, Joseph C., Jr.


    Approved for public release; distribution is unlimited This thesis addresses the design, development and operational analysis of a D.C. powered semiconductor laser diode drive unit. A laser diode requires an extremely stable power supply since a picosecond spike of current or power supply switching transient could result in permanent damage. The design offers stability and various features for operational protection of the laser diode. The ability to intensity modulate (analog) and pulse m...

  18. Semiconductor laser diodes and the design of a D.C. powered laser diode drive unit

    Cappuccio, Joseph C., Jr.


    Approved for public release; distribution is unlimited This thesis addresses the design, development and operational analysis of a D.C. powered semiconductor laser diode drive unit. A laser diode requires an extremely stable power supply since a picosecond spike of current or power supply switching transient could result in permanent damage. The design offers stability and various features for operational protection of the laser diode. The ability to intensity modulate (analog) and pulse m...

  19. Laser diode initiated detonators for space applications

    Ewick, David W.; Graham, J. A.; Hawley, J. D.


    Ensign Bickford Aerospace Company (EBAC) has over ten years of experience in the design and development of laser ordnance systems. Recent efforts have focused on the development of laser diode ordnance systems for space applications. Because the laser initiated detonators contain only insensitive secondary explosives, a high degree of system safety is achieved. Typical performance characteristics of a laser diode initiated detonator are described in this paper, including all-fire level, function time, and output. A finite difference model used at EBAC to predict detonator performance, is described and calculated results are compared to experimental data. Finally, the use of statistically designed experiments to evaluate performance of laser initiated detonators is discussed.

  20. External cavity diode laser around 657 nm

    Desheng Lǖ (吕德胜); Kaikai Huang (黄凯凯); Fengzhi Wang (王凤芝); DonghaiYang (杨东海)


    Operating a laser diode in an external cavity, which provides frequency-selective feedback, is a very effective method to tune the laser frequency to a range far from its free running frequency. For the Ca atomic Ramsey spectroscopy experiment, we have constructed a 657-nm laser system based on the LittmanMetcalf configuration with a 660-nm commercial laser diode. Continuously 10-GHz tuning range was achieved with about 100-kHz spectral linewidth, measured with beat-note spectrum of two identical laser systems.

  1. Arbitrary waveform generator to improve laser diode driver performance

    Fulkerson, Jr, Edward Steven


    An arbitrary waveform generator modifies the input signal to a laser diode driver circuit in order to reduce the overshoot/undershoot and provide a "flat-top" signal to the laser diode driver circuit. The input signal is modified based on the original received signal and the feedback from the laser diode by measuring the actual current flowing in the laser diode after the original signal is applied to the laser diode.

  2. LED pumped Nd:YAG laser development program

    Farmer, G. I.; Kiang, Y. C.; Lynch, R. J.


    The results of a development program for light emitting diode (LED) pumped Nd:YAG lasers are described. An index matching method to increase the coupling efficiency of the laser is described. A solid glass half-cylinder of 5.0 by 5.6 centimeters was used for index matching and also as a pumping cavity reflector. The laser rods were 1.5 by 56 millimeters with dielectric coatings on both end surfaces. The interfaces between the diode array, glass cylinder, and laser rod were filled with viscous fluid of refractive index n = 1.55. Experiments performed with both the glass cylinder and a gold coated stainless steel reflector of the same dimensions under the same operating conditions indicate that the index matching cylinder gave 159 to 200 percent improvement of coupling efficiency over the metal reflector at various operating temperatures.

  3. Electron beam pumped semiconductor laser

    Hug, William F. (Inventor); Reid, Ray D. (Inventor)


    Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

  4. Beam shaping design for compact and high-brightness fiber-coupled laser-diode system.

    Yu, Junhong; Guo, Linui; Wu, Hualing; Wang, Zhao; Tan, Hao; Gao, Songxin; Wu, Deyong; Zhang, Kai


    Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. A compact and high-brightness fiber-coupled system has been designed based on a significant beam shaping method. The laser-diode stack consists of eight mini-bars and is effectively coupled into a standard 100 μm core diameter and NA=0.22 fiber. The simulative result indicates that the module will have an output power over 440 W. Using this technique, compactness and high-brightness production of a fiber-coupled laser-diode module is possible.

  5. Determining Extinction Ratio Of A Laser Diode

    Unger, Glenn L.


    Improved technique to determine extinction ratio of pulsed laser diode based partly on definition of extinction ratio applicable to nonideal laser pulses. Heretofore, determinations involved assumption of ideal laser pulses, and neglected optical power from background light. Because power fluctuates during real pulse, more realistic to define extinction ratio in terms of energy obtained.

  6. High Power Diode Lasers Technology and Applications

    Bachmann, Friedrich; Poprawe, Reinhart


    In a very comprehensive way this book covers all aspects of high power diode laser technology for materials processing. Basics as well as new application oriented results obtained in a government funded national German research project are described in detail. Along the technological chain after a short introduction in the second chapter diode laser bar technology is discussed regarding structure, manufacturing technology and metrology. The third chapter illuminates all aspects of mounting and cooling, whereas chapter four gives wide spanning details on beam forming, beam guiding and beam combination, which are essential topics for incoherently coupled multi-emitter based high power diode lasers. Metrology, standards and safety aspects are the theme of chapter five. As an outcome of all the knowledge from chapter two to four various system configurations of high power diode lasers are described in chapter six; not only systems focussed on best available beam quality but especially also so called "modular" set...

  7. A low-threshold efficient KTA OPO by a fiber-coupled diode-end-pumped Nd:YVO4 laser

    ZHONG Kai; YAO Jian-quan; XU De-gang; WANG Yu-ye; WANG Peng


    @@ A low-threshold efficient high-repetition-rate eye-safe optical parametric oscillator (OPO) is presented. The OPO is based on an x-cut non-critically phase-matched (NCPM) KTA intra-cavity pumped by an acousto-optieally (A-O) Q-switched Nd:YVO4 laser. At 10 kHz, the lowest threshold of 0.75 W and the signal power of 0.6 W are got, corresponding to the single pulse energy of 60 μJ and the peak power of 20 kW. Tuning the frequency, the maximum output power at 1536 nm is 1.03 W at 30 kHz with an optical-to-optical conversion efficiency of 12.26%. The fluctuation of the output power is 2.1%during 2 h operation.

  8. Efficient, resonantly pumped, room-temperature Er3+:GdVO4 laser.

    Ter-Gabrielyan, N; Fromzel, V; Ryba-Romanowski, W; Lukasiewicz, T; Dubinskii, M


    We report an efficient room-temperature operation of a resonantly pumped Er3+:GdVO4 laser at 1598.5 nm. The maximum continuous wave (CW) output power of 3.5 W with slope efficiency of 56% was achieved with resonant pumping by an Er-fiber laser at 1538.6 nm. With pumping by a commercial laser diode bar stack, a quasi-CW (QCW) output of 7.7 W and maximum slope efficiency of ~53% versus absorbed pump power were obtained. This is believed to be the first resonantly (in-band) pumped, room-temperature Er3+:GdVO4 laser.

  9. Stable mode-locked operation of a low repetition rate diode-pumped Nd:GdVO4 laser by combining quadratic polarisation switching and a semiconductor saturable absorber mirror.

    Gerhard, Christoph; Druon, Frédéric; Georges, Patrick; Couderc, Vincent; Leproux, Philippe


    In this paper, we present the mode-locked operation of an ultra-robustly stabilised Nd:GdVO(4) laser with low repetition rate by combining quadratic polarisation switching and a semiconductor saturable absorber mirror (SESAM). In addition, similar experiment was also done with Nd:YVO(4). For Nd:GdVO(4), 16-ps pulses at 1063 nm with a repetition rate of 3.95 MHz have been obtained for a laser average output power of 1.4 W. For Nd:YVO(4), the performance was 2.5 W of average power for 15-ps pulses at 1064 nm. Moreover, we demonstrate experimentally the advantage of combining these two passive mode locking techniques in terms of stability ranges. We show how the dual mode-locking technique is crucial to obtain a stable and long-term mode-locked regime in our case of a diode-pumped Nd:GdVO(4) laser operating at low repetition rate and more generally how this dual mode-locking technique improves the stability range of the mode-locked operation giving more flexibility on different parameters.

  10. Diode laser based light sources for biomedical applications

    Müller, André; Marschall, Sebastian; Jensen, Ole Bjarlin;


    Diode lasers are by far the most efficient lasers currently available. With the ever-continuing improvement in diode laser technology, this type of laser has become increasingly attractive for a wide range of biomedical applications. Compared to the characteristics of competing laser systems, diode...... imaging. This review provides an overview of the latest development of diode laser technology and systems and their use within selected biomedical applications....

  11. Simple highly efficient pumping configuration in high-power thin-disk laser

    Seyedzamani, Sasan; Eslami, Esmaeil


    A simple high-power thin-disk pumping configuration using a radiation combination of four commercially available laser-diode stacks is introduced. Two setup modifications are presented to compensate the nonsuitable shape of the pumping spot arising from low beam quality in our combination method. The effects of setup modifications on pumping spot shapes are confirmed by ray tracing simulations using Trace-pro™ software. All setups are arranged in the laboratory, and the experimental measurements show pumping spots improvements on the disk due to modifications in agreement with simulation results. Output power measurements show that by adapting the pumping spot size to the disk cooling capacity the modified setups can deliver higher output powers and efficiencies. Furthermore, the modifications reduce the laser threshold and improve output laser beam quality. Hence, the modifications make the simple four laser-diodes beam combination applicable for thin-disk laser pumping.

  12. Laser cooling of beryllium ions using a frequency-doubled 626 nm diode laser.

    Cozijn, F M J; Biesheuvel, J; Flores, A S; Ubachs, W; Blume, G; Wicht, A; Paschke, K; Erbert, G; Koelemeij, J C J


    We demonstrate laser cooling of trapped beryllium ions at 313 nm using a frequency-doubled extended cavity diode laser operated at 626 nm, obtained by cooling a ridge waveguide diode laser chip to -31°C. Up to 32 mW of narrowband 626 nm laser radiation is obtained. After passage through an optical isolator and beam shaping optics, 14 mW of 626 nm power remains of which 70% is coupled into an external enhancement cavity containing a nonlinear crystal for second-harmonic generation. We produce up to 35 μW of 313 nm radiation, which is subsequently used to laser cool and detect 6×10(2) beryllium ions, stored in a linear Paul trap, to a temperature of about 10 mK, as evidenced by the formation of Coulomb crystals. Our setup offers a simple and affordable alternative for Doppler cooling, optical pumping, and detection to presently used laser systems.

  13. Drivers for High Power Laser Diodes

    Yankov P; Todorov D; Saramov E


    During the last year the high power laser diodes jumped over the 1 kW level of CW power for a stack,and the commercial 1 cm bars reached 100 W output optical power at the standard wavelengths around 800 nm and 980 nm. The prices are reaching the industry acceptable levels. All Nd:YAG and fiber industrial lasers manufacturers have developed kW prototypes. Those achievements have set new requirements for the power supplies manufactuers-high and stable output current, and possibilities for fast control of the driving current, keeping safe the expensive laser diode. The fast switching frequencies also allow long range free space communications and optical range finding. The high frequencies allow the design of a 3D laser radar with high resolution and other military applications. The prospects for direct laser diode micro machining are also attractive.

  14. Deterministic polarization chaos from a laser diode

    Virte, Martin; Thienpont, Hugo; Sciamanna, Marc


    Fifty years after the invention of the laser diode and fourty years after the report of the butterfly effect - i.e. the unpredictability of deterministic chaos, it is said that a laser diode behaves like a damped nonlinear oscillator. Hence no chaos can be generated unless with additional forcing or parameter modulation. Here we report the first counter-example of a free-running laser diode generating chaos. The underlying physics is a nonlinear coupling between two elliptically polarized modes in a vertical-cavity surface-emitting laser. We identify chaos in experimental time-series and show theoretically the bifurcations leading to single- and double-scroll attractors with characteristics similar to Lorenz chaos. The reported polarization chaos resembles at first sight a noise-driven mode hopping but shows opposite statistical properties. Our findings open up new research areas that combine the high speed performances of microcavity lasers with controllable and integrated sources of optical chaos.

  15. Composite resonator vertical cavity laser diode

    Choquette, K.D.; Hou, H.Q.; Chow, W.W.; Geib, K.M.; Hammons, B.E.


    The use of two coupled laser cavities has been employed in edge emitting semiconductor lasers for mode suppression and frequency stabilization. The incorporation of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. Composite resonators can be utilized to control spectral and temporal properties within the laser; previous studies of coupled cavity vertical cavity lasers have employed photopumped structures. The authors report the first composite resonator vertical cavity laser diode consisting of two optical cavities and three monolithic distributed Bragg reflectors. Cavity coupling effects and two techniques for external modulation of the laser are described.

  16. Real-time power measurement and control for high power diode laser

    Qin, Wen-bin; Liu, You-qiang; Cao, Yin-hua; Wang, Zhi-yong


    As the continual improvement of technology and beam quality, diode laser, with poor beam quality, no longer just apply to pump solid-state laser. As a kind of implement of laser materials processing, high-power diode laser has been used in manufacture, as a brand new means of laser processing. Due to the influence of inevitable unstable factors, for example, the temperature of water-cooler, the current of power supply, etc, the output power of diode laser will be unstable. And laser output power, as an important parameter, frequently affects the performance of the laser beam and the experimental results of processing, especially in the laser materials processing. Therefore, researching the real-time power measurement and control of high power diode laser has great significance, and for diode laser, it would improve performance of itself. To achieve the purpose of real-time detection, traditional measuring method, placing a power sensor behind the total-reflection mirror of laser resonant cavity, is mainly applied in the system of gas laser and solid-state laser. However, Owing to the high integration level of diode laser, traditional measuring method can't be adopted. A technique for real-time measure output power of high power diode laser is developed to improve quality of the laser in this paper. A lens placed at an angle of 45° in the system was used to sample output light of laser, and a piece of ground glass was used to uniform the beam power density, then the photoelectric detector received an optic signal and converted it into electric signal. This feeble signal was processed by amplification circuit with a filter. Finally, this detected electric signal was applied to accomplish the closed-loop control of power. The performance of power measurement and control system was tested with the 300W diode laser, and the measuring inaccuracy achieved was less than +/-1%.

  17. Diode-pumped intracavity optical parametric oscillator in pulsed and continuous-wave operation

    Jensen, Ole Bjarlin; Skettrup, Torben; Petersen, O.B.;


    An intracavity optical parametric oscillator is investigated in pulsed and continuous-wave operation. The intracavity optical parametric oscillator is based on Yb:YAG as the laser material and a periodically poled lithium niobate crystal as the nonlinear material. Tuneable idler output powers above...... 200 mW are obtained in both modes of operation with 13.5 W of incident diode pump power. The idler output was tuned in the wavelength range 3820-4570 nm....

  18. Quasi-passive heat sink for high-power laser diodes

    Vetrovec, John


    We report on a novel heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink uses a liquid coolant flowing at high speed in a miniature closed and sealed loop. Diode waste heat is received at high flux and transferred to environment, coolant fluid, heat pipe, or structure at a reduced flux. When pumping solid-state or alkali vapor lasers, diode wavelength can be electronically tuned to the absorption features of the laser gain medium. This paper presents the heat sink physics, engineering design, performance modeling, and configurations.

  19. High slope efficiency and low threshold in a laser-diode-pumped passively Q-switched ion-implanted Nd:YVO4 planar waveguide laser with GaAs saturable absorber

    Du, G. L.; Li, G. Q.; Zhao, S. Z.; Li, T.; Yang, K. J.; Li, X.


    A passively Q-switched waveguide laser, to our knowledge, has been firstly demonstrated in Nd: YVO4 crystal formed by 3 MeV Si+ ion implantation at a dose of 1 × 1015 ions/cm2 at room temperature, in which GaAs was used as saturable absorber. The dependences of the average output power, pulse width, pulse repetition rate on absorbed pump power have been measured at different output plane mirror transmissions. At an absorbed pump power of 78.8 mW and output transmission of 20%, the shortest pulse width of 3.88 ns was obtained, corresponding to the peak power and single pulse energy of 212 W and 0.82 μJ, respectively. The threshold pump power was as low as 40 mW, and the slope efficiency was about 64.5% when the absorbed pump power was lower than 70 mW.

  20. Reliable pump sources for high-energy class lasers

    Wölz, Martin; Pietrzak, Agnieszka; Kindsvater, Alex; Wolf, Jürgen; Meusel, Jens; Hülsewede, Ralf; Sebastian, Jürgen


    High-energy class laser systems operating at high average power are destined to serve fundamental research and commercial applications. System cost is becoming decisive, and JENOPTIK supports future developments with the new range of 500 W quasi-continuous wave (QCW) laser diode bars. In response to different strategies in implementing high-energy class laser systems, pump wavelengths of 880 nm and 940 nm are available. The higher power output per chip increases array irradiance and reduces the size of the optical system, lowering system cost. Reliability testing of the 880 nm laser diode bar has shown 1 Gshots at 500 W and 300 μs pulse duration, with insignificant degradation. Parallel operation in eight-bar diode stacks permits 4 kW pulse power operation. A new high-density QCW package is under development at JENOPTIK. Cost and reliability being the design criteria, the diode stacks are made by simultaneous soldering of submounts and insulating ceramic. The new QCW stack assembly technology permits an array irradiance of 12.5 kW/cm². We present the current state of the development, including laboratory data from prototypes using the new 500 W laser diode in dense packaging.

  1. Theoretical model for frequency locking a diode laser with a Faraday cell

    Wanninger, P.; Shay, T. M.


    A new method was developed for frequency locking a diode lasers, called 'the Faraday anomalous dispersion optical transmitter (FADOT) laser locking', which is much simpler than other known locking schemes. The FADOT laser locking method uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. The FADOT method is vibration insensitive and exhibits minimal thermal expansion effects. The system has a frequency pull in the range of 443.2 GHz (9 A). The method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters.

  2. Qualification and Selection of Flight Diode Lasers for Space Applications

    Liebe, Carl C.; Dillon, Robert P.; Gontijo, Ivair; Forouhar, Siamak; Shapiro, Andrew A.; Cooper, Mark S.; Meras, Patrick L.


    The reliability and lifetime of laser diodes is critical to space missions. The Nuclear Spectroscopic Telescope Array (NuSTAR) mission includes a metrology system that is based upon laser diodes. An operational test facility has been developed to qualify and select, by mission standards, laser diodes that will survive the intended space environment and mission lifetime. The facility is situated in an electrostatic discharge (ESD) certified clean-room and consist of an enclosed temperature-controlled stage that can accommodate up to 20 laser diodes. The facility is designed to characterize a single laser diode, in addition to conducting laser lifetime testing on up to 20 laser diodes simultaneously. A standard laser current driver is used to drive a single laser diode. Laser diode current, voltage, power, and wavelength are measured for each laser diode, and a method of selecting the most adequate laser diodes for space deployment is implemented. The method consists of creating histograms of laser threshold currents, powers at a designated current, and wavelengths at designated power. From these histograms, the laser diodes that illustrate a performance that is outside the normal are rejected and the remaining lasers are considered spaceborne candidates. To perform laser lifetime testing, the facility is equipped with 20 custom laser drivers that were designed and built by California Institute of Technology specifically to drive NuSTAR metrology lasers. The laser drivers can be operated in constant-current mode or alternating-current mode. Situated inside the enclosure, in front of the laser diodes, are 20 power-meter heads to record laser power throughout the duration of lifetime testing. Prior to connecting a laser diode to the current source for characterization and lifetime testing, a background program is initiated to collect current, voltage, and resistance. This backstage data collection enables the operational test facility to have full laser diode

  3. Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

    Tawfieq, Mahmoud; Jensen, Ole Bjarlin; Hansen, Anders Kragh;


    a 1063 nm tapered diode laser, inside a periodically poled MgO doped lithium niobate crystal. This corresponds to an optical to optical conversion ef fi ciency of 12.1%. As an example of potential applica- tions, the generated nearly diffraction-limited green light is used for pumping a Ti:sapphire laser...

  4. Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

    Tawfieq, Mahmoud; Jensen, Ole Bjarlin; Hansen, Anders Kragh


    a 1063 nm tapered diode laser, inside a periodically poled MgO doped lithium niobate crystal. This corresponds to an optical to optical conversion ef fi ciency of 12.1%. As an example of potential applica- tions, the generated nearly diffraction-limited green light is used for pumping a Ti:sapphire laser...... (FWHM), indicating less than 20 fs pulse width...

  5. Laser diode self-mixing technique for liquid velocimetry

    Alexandrova, A.; Welsch, C. P.


    Using the self-mixing technique, or optical feedback interferometry, fluid velocity measurements of water seeded with titanium dioxide have been performed using a laser diode to measure the effect of the seeding particle concentration and also the pump speed of the flow. The velocimeter utilises commercially available laser diodes with a built-in photodiode for detection of the self-mixing effect. The device has demonstrated an accuracy better than 10% for liquid flow velocities up to 1.5 m/s with a concentration of scattering particles in the range of 0.8-0.03%. This is an improvement of one order of magnitude compared to previous experiments. The proposed velocimeter is to be developed further for application in gas-jet measurements.

  6. Laser diode self-mixing technique for liquid velocimetry

    Alexandrova, A., E-mail: [Cockcroft Institute, Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); University of Liverpool, Department of Physics, Liverpool L69 7ZE (United Kingdom); Welsch, C.P. [Cockcroft Institute, Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); University of Liverpool, Department of Physics, Liverpool L69 7ZE (United Kingdom)


    Using the self-mixing technique, or optical feedback interferometry, fluid velocity measurements of water seeded with titanium dioxide have been performed using a laser diode to measure the effect of the seeding particle concentration and also the pump speed of the flow. The velocimeter utilises commercially available laser diodes with a built-in photodiode for detection of the self-mixing effect. The device has demonstrated an accuracy better than 10% for liquid flow velocities up to 1.5 m/s with a concentration of scattering particles in the range of 0.8–0.03%. This is an improvement of one order of magnitude compared to previous experiments. The proposed velocimeter is to be developed further for application in gas-jet measurements.

  7. Rugged, Tunable Extended-Cavity Diode Laser

    Moore, Donald; Brinza, David; Seidel, David; Klipstein, William; Choi, Dong Ho; Le, Lam; Zhang, Guangzhi; Iniguez, Roberto; Tang, Wade


    A rugged, tunable extended-cavity diode laser (ECDL) has been developed to satisfy stringent requirements for frequency stability, notably including low sensitivity to vibration. This laser is designed specifically for use in an atomic-clock experiment to be performed aboard the International Space Station (ISS). Lasers of similar design would be suitable for use in terrestrial laboratories engaged in atomic-clock and atomic-physics research.

  8. Phase Noise Reduction of Laser Diode

    Zhang, T. C.; Poizat, J.-Ph.; Grelu, P.; Roch, J.-F.; Grangier, P.; Marin, F.; Bramati, A.; Jost, V.; Levenson, M. D.; Giacobino, E.


    Phase noise of single mode laser diodes, either free-running or using line narrowing technique at room temperature, namely injection-locking, has been investigated. It is shown that free-running diodes exhibit very large excess phase noise, typically more than 80 dB above shot-noise at 10 MHz, which can be significantly reduced by the above-mentioned technique.

  9. Locking of self-oscillation frequency by pump modulation in an erbium-doped fiber laser

    Pisarchik, A. N.; Barmenkov, Yu. O.


    Frequency locking of self-oscillations in a diode-pumped erbium-doped fiber laser by external modulation of the diode current is studied experimentally. The coexistence of locking and unlocking regimes is detected. The condition for onset of the bistability and dependences of the frequency detuning on the modulation frequency and amplitude are established. Transitions to torus-chaos are also demonstrated.

  10. Stirling-Cycle Cooling For Tunable Diode Laser

    Durso, Santo S.; May, Randy D.; Tuchscherer, Matthew A.; Webster, Christopher R.


    Miniature Stirling-cycle cooler effective in continously cooling PbSnTe tunable diode laser to stable operating temperature near 80 K. Simplifies laboratory diode-laser spectroscopy and instruments for use aboard aircraft and balloons.

  11. Diode lasers and photonic integrated circuits

    Coldren, Larry A; Mashanovitch, Milan L


    Diode Lasers and Photonic Integrated Circuits, Second Edition provides a comprehensive treatment of optical communication technology, its principles and theory, treating students as well as experienced engineers to an in-depth exploration of this field. Diode lasers are still of significant importance in the areas of optical communication, storage, and sensing. Using the the same well received theoretical foundations of the first edition, the Second Edition now introduces timely updates in the technology and in focus of the book. After 15 years of development in the field, this book wil

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

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


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

  13. Lasers from fission. [nuclear pumping feasibility experiments

    Schneider, R. T.; Thom, K.; Helmick, H. H.


    The feasibility of the nuclear pumping of lasers was demonstrated in three experiments conducted independently at three different laboratories. In this context nuclear pumping of lasers is understood to be the excitation of a laser by the kinetic energy of the fission fragments only. A description is given of research concerned with the use of nuclear energy for the excitation of gas lasers. Experimental work was supplemented by theoretical research. Attention is given to a nuclear pumped He-Xe laser, a nuclear pumped CO laser, and a neon-nitrogen laser pumped by alpha particles. Studies involving uranium hexafluoride admixture to laser media are discussed along with research on uranium hexafluoride-fueled reactors.

  14. Nd:GGG disk laser with multipoint spatially periodic optical pumping

    Guryev, D. A.; Nikolaev, D. A.; Tsvetkov, V. B.


    The results of the study of the output laser beam spatial characteristics of the Nd:Gd3Ga5O12 (Nd:GGG) disk laser with multipoint spatially periodic diode-pumping are presented. The presence of the optical coupling between the TEM00 lasing channels is demonstrated. The phase-locking of channels was realized due to partial overlapping of laser beams inside the pumped areas of the active element disk.

  15. Directly diode-pumped high-energy Ho:YAG oscillator.

    Lamrini, Samir; Koopmann, Philipp; Schäfer, Michael; Scholle, Karsten; Fuhrberg, Peter


    We report on the high-energy laser operation of an Ho:YAG oscillator resonantly pumped by a GaSb-based laser diode stack at 1.9 μm. The output energy was extracted from a compact plano-concave acousto-optically Q-switched resonator optimized for low repetition rates. Operating at 100 Hz, pulse energies exceeding 30 mJ at a wavelength of 2.09 μm were obtained. The corresponding pulse duration at the highest pump power was 100 ns, leading to a maximum peak power above 300 kW. Different pulse repetition rates and output coupling transmissions of the Ho:YAG resonator were studied. In addition, intracavity laser-induced damage threshold measurements are discussed.

  16. Tunable diode laser control by a stepping Michelson interferometer

    Valentin, A.; Nicolas, C.; Henry, L.; Mantz, A.W.


    A tunable diode laser beam is sent through a Michelson interferometer and is locked to a fringe of the diode laser interferometer pattern by controlling the diode laser polarization current. The path difference change of the Michelson interferometer is controlled step by step by a stabilized He--Ne red laser. When the interferometer path differences increases or decreases, the polarization current of the diode is forced to change in order to preserve the interference order of the diode beam. At every step the diode frequency is accurately fixed and its phase noise significantly reduced.

  17. [Endonasal and endocanalicular dacryocystorhinostomy by diode laser. Preliminary results].

    Alañón Fernández, M A; Alañón Fernández, F J; Martínez Fernández, A; Cárdenas Lara, M; Rodríguez Domínguez, R; Ballesteros Navarro, J M; Sainz Quevedo, M


    To describe the surgical technique and to evaluate the clinical results after having performed the transcanalicular and endocanalicular dacryocystorhinostomies by diode laser, including the advantages and limits of this technique. 34 were performed by diode laser in patients with clinical history of epiphora, with or without mucopurulent secretion, for nasolacrimal duct obstruction. The study was prospective, interventional, non randomized and non comparative. Diode laser was used to realize vaporization of lacrimal sac, osteotomy and vaporization with coagulation of nasal mucosa. The mean of surgical time was 15 minutes (range 7 to 29 minutes). Bicanalicular intubation was performed with a silicone tube and prolene filament for two months in all cases. Postsurgical follow-up was between 4 and 11 months. The degree of epiphora was evaluated by the Munk scale and lacrimal permeability was evaluated by endoscopic functional staining test in all cases. Out of the 34 DCR-EDN+ENC that were performed, 32 cases (94.11%) remain asymptomatic. Two of them (5.88%) required endonasal dacryocystorhinostomies by drilling, because the bony perforation was impossible to achieve by laser fiber. Two cases (5.88%) presented fibrosis and lacrimal and lower canaliculi obstruction, without epiphora because the superior canaliculi was permeable. Endonasal and endocanalicular dacryocystorhinostomy technique performed by diode laser is a valid method. It does not cause cutaneous scarring, it decreases thermic canalicular damage, it respects the lacrimal pump, it minimizes pain and bleeding, it needs less surgical time and it has turned into an out-patient procedure with a minimal surgical and postsurgical morbility.

  18. Study on the Beam Quality of Uncoupled Laser Diode Arrays

    GAO Chunqing; WEI Guanghui


    The beam quality of uncoupled laser diode array is studied theoretically and experimentally. By calculating the second order moments of the beam emitted from the laser diode array, the dependence of the M2-factor of the laser diode array on the M2-factor of the single emitter, the ratio of the emitting region to the non-emitting space, and the number of emitters, has been deduced. From the measurement of the beam propagation the M2-factor of a laser diode bar is experimentally determined. The measured M2-factor of the laser diode bar agrees with the theoretical prediction.

  19. High-power green diode laser systems for biomedical applications

    Müller, André

    Due to their unique characteristics, diode lasers are increasingly attractive for numerous applications. For example, in the biomedical field the provided output power, spatial quality, and wavelength coverage of diode lasers has enabled their applications in, e.g., dermatology, diffuse spectrosc......Due to their unique characteristics, diode lasers are increasingly attractive for numerous applications. For example, in the biomedical field the provided output power, spatial quality, and wavelength coverage of diode lasers has enabled their applications in, e.g., dermatology, diffuse......, the obtained results clearly strengthen the application potential of diode lasers, including the biomedical field....

  20. Monolithic resonant optical reflector laser diodes

    Hirata, T.; Suehiro, M.; Maeda, M.; Hihara, M.; Hosomatsu, H.


    The first monolithic resonant optical reflector laser diode that has a waveguide directional coupler and two DBR reflectors integrated by compositional disordering of quantum-well heterostructures is described. A linewidth of 440 kHz was obtained, and this value is expected to be greatly decreased by reducing the propagation loss in the integrated waveguide.

  1. Microring Diode Laser for THz Generation

    Mariani, S.; Andronico, A.; Favero, I.;


    We report on the modeling and optical characterization of AlGaAs/InAs quantum-dot microring diode lasers designed for terahertz (THz) difference frequency generation (DFG) between two whispering gallery modes (WGMs) around 1.3 $\\mu$m. In order to investigate the spectral features of this active...

  2. A Bidirectional, Diode-Pumped, Passively Mode-Locked Nd:YVO4 Ring Laser with a Low-Temperature-Grown Semiconductor Saturable Absorber Mirror

    CAI Zhi-Qiang; YAO Jian-Quan; WANG Peng; WANG Yong-Gang; ZHANG Zhi-Gang


    We report the operation of a bidirectional picosecond pulsed ring Nd:YVO4 laser based on a low-temperaturegrown semiconductor saturable absorber mirror. Except for the laser crystal, the six-mirror ring laser cavity has no intra-cavity elements such as focusing lens or mirror. The bidirectional mode locked pluses are obtained at the repetition rate of 117.5MHz, pulse duration of Sips, power of 2×200 mW.

  3. Pulsed pumping of semiconductor disk lasers.

    Hempler, Nils; Hopkins, John-Mark; Kemp, Alan J; Schulz, Nico; Rattunde, Marcel; Wagner, Joachim; Dawson, Martin D; Burns, David


    Efficient operation of semiconductor disk lasers is demonstrated using uncooled and inexpensive 905nm high-power pulsed semiconductor pump lasers. Laser emission, with a peak power of 1.7W, is obtained from a 2.3mum semiconductor disk laser. This is seven times the power achieved under continuous pumping. Analysis of the time-dependent spectral characteristics of the laser demonstrate that significant device heating occurs over the 100-200ns duration of the pumping pulse - finite element modelling of the thermal processes is undertaken in support of these data. Spectral narrowing to below 0.8nm is obtained by using an intra-cavity birefringent filter.

  4. Polarization chaos in an optically pumped laser.

    Serrat, C; Kul'minskii, A; Vilaseca, R; Corbalán, R


    We study the steady-state and dynamic behavior of an optically pumped J = 0 ? J = 1 ? J = 0 laser operating with an isotropic ring cavity and an axial magnetic field. The gain anisotropy induced by a linearly polarized pump-laser f ield leads, in the steady state, to locking of the two circularly polarized components of the laser field, which acquires a linear polarization parallel to that of the pump field. In the presence of laser intensity instabilities, however, locking does not occur, and polarization instabilities appear. For the f irst time to our knowledge, polarization chaos has been found in a laser system.

  5. Demonstration of a diode pumped Nd,Y co-doped SrF2 crystal based, high energy chirped pulse amplification laser system

    Chen, Junchi; Peng, Yujie; Zhang, Zongxin; Su, Hongpeng; Leng, Yuxin; Jiang, Dapeng; Ma, Fengkai; Qian, Xiaobo; Tang, Fei; Su, Liangbi


    We report, to the best of our knowledge, a chirped pulse amplification laser system based on the Nd,Y:SrF2 crystal for the first time. The incorporation of Y3+ nonactive ions can significantly improve laser properties of Nd:SrF2 crystal, including broader emission linewidth, larger cross-section as well as longer fluorescence lifetime. Pulse laser with 5.1 mJ (uncompressed), 3.7 mJ (compressed) energy, 1.6 ps duration at 5 Hz repetition rate is demonstrated. The results indicate that the Nd,Y:SrF2 crystal is a potential candidate with excellent laser and thermal performance for developing ultra-intense laser with high repetition rate.

  6. Multipass diode-pumped solid-state optical amplifier

    Plaessmann, Henry; Re, Sean A.; Alonis, Joseph J.; Vecht, David L.; Grossman, William M.


    A new diode-pumped solid-state multipass amplifier produced 38-dB small-signal gain at 1.047 micron in Nd:YLF with 1.6-W pump power and 37 percent extraction efficiency near saturation. The amplifier had a 1:1 confocally reimaging multipass design that generated both high gain and high efficiency. The same amplifier design with 13 W of pump power was tested with Nd:YAG at 1.064 micron, which gave 38-dB small-signal gain and 3.2 W of output power, and with Nd:YVO4, also at 1.064 micron, which gave greater than 50-dB small-signal gain and 4.3 W of output power.

  7. Novel Design of Type I High Power Mid-IR Diode Lasers for Spectral Region 3 - 4.2 Microns


    active regions, metamorphic virtual substrate and cascade pumping scheme. Cascade pumping of type-I quantum well gain section opened the whole new...lasers were studied including those based on triple layer quantum well active regions, metamorphic virtual substrate and cascade pumping scheme...SECURITY CLASSIFICATION OF: Novel designs of the mid-infrared GaSb-based diode lasers were studied including those based on triple layer quantum well

  8. Tunable high-power narrow-spectrum external-cavity diode laser at 675 nm as a pump source for UV generation

    Chi, Mingjun; Jensen, Ole Bjarlin; Erbert, Gotz;


    of 1.0 W. The laser system B based on device B is tunable from 666 to 685 nm. As high as 1.05 W output power is obtained around 675.67 nm. The emission spectral bandwidth is less than 0.07 nm throughout the tuning range, and the beam quality factor M2 is 1.13 at an output power of 0.93 W. The laser...

  9. Experimental study of 880 nm laser-diode end-pumped Nd:GdVO4 laser with hybrid resonator at 1.34 μm%880 nm LD 泵浦 Nd:GdVO4混合腔激光器1.34μm 实验研究

    崔丽; 胡文华; 张恒利; 王燕辛; 张亦卓; 李忠建


    将880 nm 上能级直接泵浦与部分端面泵浦混合腔结构结合,对 Nd:GdVO4晶体的1342 nm激光输出特性进行了实验研究。采用正支离轴混合谐振腔,4-bar 中心波长为880 nm 的激光二极管列阵作为泵浦源,在泵浦功率为178 W 时,激光输出功率为26.3 W,斜效率和光-光转换效率分别为27%和14.8%。在20 W 输出功率时非稳腔和稳腔方向的 M2因子均为1.3。结果表明:由于采用了上能级直接泵浦与部分端面泵浦混合腔结构,相对于目前同等输出功率级别的端面泵浦 Nd:GdVO4激光器,光束质量得到很大提高。%The 880 nm LD directly pumping into the emitting level with LD partially end-pumped structure was combined, some experiment was done to study the output characteristic of Nd:GdVO4 laser at 1 342 nm. An off-axis positive confocal unstable resonator was built up, and a 4-bar laser diode stack which central wavelength was 880 nm as pump source was used. 26.3 W continuous-wave laser power output was gotten under the pump power of 178 W, and the slope efficiency and optical-to-optical efficiency were 27% and nearly 14.8% , respectively. At the output power of 20 W, beam quality M2 factors were both 1.3 in the unstable direction and stable direction. The result showed that by combining 880 nm LD directly pumping into the emitting level with LD partially end-pumped structure, beam quality has been greatly improved compared with the same output power level end-pumped Nd: GdVO4 laser.

  10. Visible fiber lasers excited by GaN laser diodes

    Fujimoto, Yasushi; Nakanishi, Jun; Yamada, Tsuyoshi; Ishii, Osamu; Yamazaki, Masaaki


    This paper describes and discusses visible fiber lasers that are excited by GaN laser diodes. One of the attractive points of visible light is that the human eye is sensitive to it between 400 and 700 nm, and therefore we can see applications in display technology. Of course, many other applications exist. First, we briefly review previously developed visible lasers in the gas, liquid, and solid-state phases and describe the history of primary solid-state visible laser research by focusing on rare-earth doped fluoride media, including glasses and crystals, to clarify the differences and the merits of primary solid-state visible lasers. We also demonstrate over 1 W operation of a Pr:WPFG fiber laser due to high-power GaN laser diodes and low-loss optical fibers (0.1 dB/m) made by waterproof fluoride glasses. This new optical fiber glass is based on an AlF3 system fluoride glass, and its waterproof property is much better than the well known fluoride glass of ZBLAN. The configuration of primary visible fiber lasers promises highly efficient, cost-effective, and simple laser systems and will realize visible lasers with photon beam quality and quantity, such as high-power CW or tunable laser systems, compact ultraviolet lasers, and low-cost ultra-short pulse laser systems. We believe that primary visible fiber lasers, especially those excited by GaN laser diodes, will be effective tools for creating the next generation of research and light sources.

  11. Wavelength diversity in optically pumped alkali vapor lasers

    Perram, Glen P.


    Alternative wavelengths for optically pumped alkali vapor lasers have been developed using single photon excitation of higher lying P-states, stimulated Raman processes, two-photon excitation of S and D states, and electric quadruple excitation on S-D transitions. Two photon excitation of Cs 72D leads to competing and cascade lasing producing red and infrared lasers operating on the D-P transitions, followed by ultraviolet, blue, the standard near infrared DPAL transitions operating on P-S transitions. The S-D pump transitions are fully bleached at pump intensities exceeding 1 MW/cm2, allowing for lasing transitions that terminate on the ground state. The kinetics of these systems are complex due to competition for population inversion among the many optical transitions. An optically pumped mid-infrared rubidium pulsed, mirrorless laser has also been demonstrated in a heat pipe along both the 62P3/2 - 62S1/2 transition at 2.73 μm and the 62P1/2 - 62S1/2 transition at 2.79 μm with a maximum energy of 100 nJ. Performance improves dramatically as the rubidium vapor density is increased, in direct contradiction with the prior work. No scaling limitations associated with energy pooling or ionization kinetics have been observed. Practical application for infrared counter measures depends on the further development of blue diode pump sources. Finally, stimulated electronic Raman scattering and hyper-Raman processes in potassium vapor near the D1 and D2 lines have been observed using a stable resonator and pulsed laser excitation. First and second order Stokes and anti-Stokes lines were observed simultaneously and independently for a pump laser tuning range exceeding 70 cm-1. When the pump is tuned between the K D1 and D2 lines, an efficient hyper-Raman process dominates with a slope efficiency that exceeds 10%. Raman shifted laser may be useful as a target illuminator or atmospheric compensation beacon for a high power diode pumped alkali laser.

  12. Integrated software package for laser diodes characterization

    Sporea, Dan G.; Sporea, Radu A.


    The characteristics of laser diodes (wavelength of the emitted radiation, output optical power, embedded photodiode photocurrent, threshold current, serial resistance, external quantum efficiency) are strongly influenced by their driving circumstances (forward current, case temperature). In order to handle such a complex investigation in an efficient and objective manner, the operation of several instruments (a laser diode driver, a temperature controller, a wavelength meter, a power meter, and a laser beam analyzer) is synchronously controlled by a PC, through serial and GPIB communication. For each equipment, instruments drivers were designed using the industry standards graphical programming environment - LabVIEW from National Instruments. All the developed virtual instruments operate under the supervision of a managing virtual instrument, which sets the driving parameters for each unit under test. The manager virtual instrument scans as appropriate the driving current and case temperature values for the selected laser diode. The software enables data saving in Excel compatible files. In this way, sets of curves can be produced according to the testing cycle needs.

  13. High-power, high-efficiency, high-brightness long-wavelength laser diodes

    Patterson, Steve; Crump, Paul; Wang, Jun; Dong, Weimin; Grimshaw, Mike; Zhang, Shiguo; Elim, Sandrio; Das, Suhit; Bougher, Mike; Patterson, Jason; Kuang, Guokui; Bell, Jake; Farmer, Jason; DeVito, Mark


    Interest is rapidly growing in solid-state lasers emitting from 1500-nm to 2100-nm with applications in eye-safe range finding, LIDAR, infrared countermeasures, medicine, dentistry, and others. Traditionally, these solid-state lasers have been pumped by flash lamps or more recently, by semiconductor diode lasers. In the case of the latter, the diodes of choice have been those emitting below 1-μm. The sub-micron class of semiconductor diode lasers is highly mature and has enjoyed recent rapid advances in power and efficiency. Unfortunately, the quantum defect generated when converting to the desired wavelengths results in large amounts of excess heat generation leading to costly and heavy, expensive cooling systems and performance problems related to thermal lensing. System complexity adds further cost and weight when intermediaries, such as optical parametric oscillators, are required to reach the desired longer wavelengths. Recent advances in laser diodes emitting from 1400-nm to over 1900-nm now enable the near resonant pumping of such solid state media as Er:YAG, Ho:YAG and Cr:ZnSe. Record results in the peak output power and electrical-to-optical conversion efficiency of diode lasers emitting around 1470-nm, 1700-nm and 1900-nm are presented here.

  14. Coherent optical pumping of semiconductor lasers

    Pfister, M.; Dupertuis, M.A. [Inst. de Micro- et Optoelectronique, Lausanne (Switzerland). Dept. de Physique


    The influence of coherent optical pumping in semiconductor lasers is investigated theoretically. In particular the mathematical conditions under which an optically pumped system behaves like an electrically (incoherently) pumped system are derived. The authors show that it is practically impossible to reach the interesting regime where coherent effects are important because of the inherent constraints to absorb photons at the pump frequency and to reach threshold gain at the lasing frequency. The effects of changing the temperature and of reduced dimensionality are discussed.

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

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


    . 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.

  16. A new diode laser acupuncture therapy apparatus

    Li, Chengwei; Huang, Zhen; Li, Dongyu; Zhang, Xiaoyuan


    Since the first laser-needles acupuncture apparatus was introduced in therapy, this kind of apparatus has been well used in laser biomedicine as its non-invasive, pain- free, non-bacterium, and safetool. The laser acupuncture apparatus in this paper is based on single-chip microcomputer and associated by semiconductor laser technology. The function like traditional moxibustion including reinforcing and reducing is implemented by applying chaos method to control the duty cycle of moxibustion signal, and the traditional lifting and thrusting of acupuncture is implemented by changing power output of the diode laser. The radiator element of diode laser is made and the drive circuit is designed. And chaos mathematic model is used to produce deterministic class stochastic signal to avoid the body adaptability. This function covers the shortages of continuous irradiation or that of simple disciplinary stimulate signal, which is controlled by some simple electronic circuit and become easily adjusted by human body. The realization of reinforcing and reducing of moxibustion is technological innovation in traditional acupuncture coming true in engineering.

  17. High-average power THG of a diode-pumped Nd:YAG laser at 355 nm generated by LiB3O5 crystal

    Yong Bi(毕勇); Yan Feng(冯衍); Huarong Gong(巩华荣); Hongbo Zhang(张鸿博); Zuyan Xu(许祖彦)


    More than 6 W average power ultraviolet radiation at 355 nm was generated in LiB3O5 (LBO) crystalthrough the frequency mixing of the fundamental and second harmonic radiation of a Nd:YAG laser. Thisperformance was achieved with 38% optical-to-optical conversion efficiency (532 nm to 355 nm).

  18. Combustion control using an IR diode laser

    Niska, J.; Rensgard, A.; Malmberg, D. [MEFOS, Lulea (Sweden)


    Tunable diode laser absorption spectroscopy (TDLAS) is a recent development in process instrumentation. This paper describes the testing of a commercial TDLAS instrument for continuous oxygen analysis of the furnace combustion gases in an industrial reheating furnace and in a pilot furnace at MEFOS. A time-averaged oxygen concentration signal with a TDC2000 furnace controller at MEFOS was used to prove automatic control of the air-to-fuel ratio. The local measurements of the oxygen concentration using a zirconia probe in both furnaces compared well with the oxygen concentrations measured by the TDLAS instrument. The advantage of the diode laser is its high reliability for average gas concentration measurements in the path of the beam, when compared to point gas analysis with conventional zirconia instrumentation. Improved process control is derived from reliable gas analysis, which translates into energy savings, reduced emissions and improved productivity for steel reheating furnaces. 7 refs., 8 figs.

  19. Dynamics of an erbium-doped fiber laser with pump modulation: theory and experiment

    Pisarchik, Alexander N.; Kir'yanov, Alexander V.; Barmenkov, Yuri O.; Jaimes-Reátegui, Rider


    We study in detail the complex dynamics of an erbium-doped fiber laser that has been subjected to harmonic modulation of a diode pump laser. We introduce a novel laser model that describes perfectly all experimentally observed features. The model is generalized to a nonlinear oscillator. The coexistence of different periodic and chaotic regimes and their relation to subharmonics and higher harmonics of the relaxation oscillation frequency of the laser are demonstrated with codimensional-one and codimensional-two bifurcation diagrams in parameter space of the modulation frequency and amplitude. The phase difference between the laser response and the pump modulation is also investigated.

  20. Diode Laser Sensor for Scramjet Inlet


    Conference’. 1.2 O’Byrne, S., Huynh, L., Wittig, S. M. and Smith, N. S. A. (2009), Non- intrusive water vapour absorp- tion measurements in a simulated...O’Byrne, L. Huynh, S. M. Wittig and N. S. A. Smith, “Non- intrusive Water Vapour Absorp- tion Measurements in a Simulated Helicopter Exhaust”, Proceedings...rather than at a surface. The measurement techniques used at these hypersonic flow conditions should also be non- intrusive . Tuneable diode laser

  1. Beam shaping for kilowatt fiber-coupled diode lasers by using one-step beam cutting-rotating of prisms.

    Wu, Yulong; Dong, Zhiyong; Chen, Yongqi; Qi, Yaoyao; Yuan, Xiandan; Qi, Yunfei; Xu, Li; Lin, Xuechun; Zou, Yonggang; Zhao, Pengfei


    The beam quality mismatch of laser diode stacks in both axes limits many direct applications for fiber or solid laser pumping and material processing. In this paper, a one-step cutting-rotating beam shaping system has been designed to homogenize the beam quality of two polarization-multiplexing laser diode stacks. Coupling laser diode stacks consisting of eight bars into a standard fiber with a core diameter of 600 μm and an NA of 0.22 is achieved. The simulative result shows that the system will have an output power over 1056 W. By using the technique, the production of compact and high brightness fiber-coupling diode lasers can be directly used for laser cladding and laser surface hardening processes.

  2. Laser welding of polymers using high-power diode lasers

    Bachmann, Friedrich G.; Russek, Ulrich A.


    Laser welding of polymers using high power diode lasers offers specific process advantages over conventional technologies, such as short process times while providing optically and qualitatively valuable weld seams, contactless yielding of the joining energy, absence of process induced vibrations, imposing minimal thermal stress and avoiding particle generation. Furthermore this method exhibits high integration capabilities and automatization potential. Moreover, because of the current favorable cost development within the high power diode laser market laser welding of polymers has become more and more an industrially accepted joining method. This novel technology permits both, reliable high quality joining of mechanically and electronically highly sensitive micro components and hermetic sealing of macro components. There are different welding strategies available, which are adaptable to the current application. Within the frame of this discourse scientific and also application oriented results concerning laser transmission welding of polymers using preferably diode lasers are presented. Besides the used laser systems the fundamental process strategies as well as decisive process parameters are illustrated. The importance of optical, thermal and mechanical properties is discussed. Applications at real technical components will be presented, demonstrating the industrial implementation capability and the advantages of a novel technology.

  3. Optical components for tailoring beam properties of multi-kW diode lasers

    Könning, Tobias; Köhler, Bernd; Wolf, Paul; Bayer, Andreas; Hubrich, Ralf; Bodem, Christian; Plappert, Nora; Kindervater, Tobias; Faßbender, Wilhelm; Dürsch, Sascha; Küster, Matthias; Biesenbach, Jens


    One important aspect for the increasing use of diode lasers in industrial applications is the flexibility of diode lasers to tailor the beam properties to the specific needs demanded from the application. For fiber coupled solutions beam shaping with appropriate micro-optical elements is used for efficient fiber coupling of the highly asymmetric diode laser beam, whereas for direct applications optical elements are used to generate specific intensity distributions, like homogenized lines, areas and rings. Applications with diode lasers like solid state laser pump sources often require tailored spectral characteristics with narrow bandwidth, which is realized by using volume Bragg gratings for wavelength stabilization. In this paper we will summarize several concepts for adapting beam properties of diode lasers by using specific optical components. For building very compact laser modules of up to 2 kW we already presented a concept based on beam shaping of high fill factor bars. In this paper we will focus on further tailoring the beam properties of these very compact laser modules in the wavelength range from 808 nm up to 1020 nm. Fiber coupling of such modules into an 800 μm NA0.22 fiber yielded 1.6 kW without using polarization coupling. Another example is the generation of a 2.5 kW homogenized line with 40 mm length and a width of 4 mm.

  4. Promoting Robust Design of Diode Lasers for Space: A National Initiative

    Tratt, David M.; Amzajerdian, Farzin; Kashem, Nasir B.; Shapiro, Andrew A.; Mense, Allan T.


    The Diode-laser Array Working Group (DAWG) is a national-level consumer/provider forum for discussion of engineering and manufacturing issues which influence the reliability and survivability of high-power broad-area laser diode devices in space, with an emphasis on laser diode arrays (LDAs) for optical pumping of solid-state laser media. The goals of the group are to formulate and validate standardized test and qualification protocols, operational control recommendations, and consensus manufacturing and certification standards. The group is using reliability and lifetime data collected by laser diode manufacturers and the user community to develop a set of standardized guidelines for specifying and qualifying laser diodes for long-duration operation in space, the ultimate goal being to promote an informed U.S. Government investment and procurement strategy for assuring the availability and durability of space-qualified LDAs. The group is also working to establish effective implementation of statistical design techniques at the supplier design, development, and manufacturing levels to help reduce product performance variability and improve product reliability for diodes employed in space applications

  5. Comparison of Diode and Argon Laser Lesions in Rabbit Retina

    Hui Zhang; Xiaoxin Li; Bin Li; Jiping Da


    Purpose: To compare the histological alteration of retina with various spot intensities between diode and argon lasers in order to instruct the clinical use of 810 nm diode laser.Methods: Transpupillary retinal photocoagulations were performed on 42 eyes of 27pigmented rabbits. Histopathologic alteration of lesions in different intensities and different time intervals after irradiation produced by diode and argon laser was observed and compared using light microscopy. Areas of various lesions measured by image analysis system (CMIAS) were compared quantitatively.Results: Histopathologically, two-week-old grade 2 lesions produced by diode laser induced the disappearance of outer nuclear cells. More than a half of all showed reduction in number of outer nuclear layer cells in argon. Fibroblasts appeared in the diode grade 3lesions 5 days after irradiation. CMIAS data showed that all the areas of diode lesions immediately after photocoagulation were to be larger than those of argon laser lesions in the same spot intensity (P < 0.05). However, twenty-four hours after photocoagulation, the area of the diode lesions increased less than that of the argon laser lesions (8%vs.23%).Conclusion: The acute histological effect caused by 810 nm diode laser and argon green laser is similar,while the expansion of lesion area 24 hours after photocoagulation was less with the diode laser compared to the argon. This may be the first report in the literature regarding quantitative analysis of the delayed reaction of argon green lasers.

  6. Superluminescent diode and single mode laser

    Kwong, S.K.; Lau, K.Y.; BarChim, N.; Ury, I.


    A buried heterostructure superluminescent diode is described comprising: an elongated active gain layer having an output end and a non-output end; a first n-type cladding layer on one face of the gain layer and a second p-type cladding layer on the other face of the gain layer for pumping the active gain layer, the cladding layer having a lower index of refraction than the active gain layer; a blocking layer having a lower index of refraction than the active gain layer along each longitudinal edge of the active gain layer; and a light absorbing medium at the non-output end of the active gain layer.

  7. Generation of 2.1 W Continuous Wave Blue Light by Intracavity Doubling of a Diode-End-Pumped Nd:YAG Laser in a 30 mm LBO

    CHEN Ya-Hui; HOU Wei; PENG Hai-Bo; GENG Ai-Cong; ZHOU Yong; GUI Da-Fu; XU Zu-Yan


    A folded four-mirror cavity with a composite Nd:YAG rod is optimized to obtain high efficient cw 473nm blue output. The laser could operate stably in the region of the thermal-lens focal length from 20mm to 70 ram. LBO is used for intracavity frequency doubling of the 946nm transition of Nd:YAG and the optimum LBO length is investigated. A maximum output power of 2.1 W in the blue spectral range at 473 nm is achieved with 30-mm-long LBO, corresponding to an optical conversion efficiency of 9.1%.

  8. FY2005 Progress Summary and FY2006 Program Plan Statement of Work and Deliverables for Development of High Average Power Diode-Pumped Solid State Lasers, and Complementary Technologies, for Applications in Energy and Defense

    Ebbers, C


    The primary focus this year was to operate the system with two amplifiers populated with and pumped by eight high power diode arrays. The system was operated for extended run periods which enabled average power testing of components, diagnostics, and controls. These tests were highly successful, with a demonstrated energy level of over 55 joules for 4 cumulative hours at a repetition rate of 10 Hz (average power 0.55 kW). In addition, high average power second harmonic generation was demonstrated, achieving 227 W of 523.5 nm light (22.7 J, 10 Hz, 15 ns, 30 minutes) Plans to achieve higher energy levels and average powers are in progress. The dual amplifier system utilizes a 4-pass optical arrangement. The Yb:S-FAP slabs were mounted in aerodynamic aluminum vane structures to allow turbulent helium gas flow across the faces. Diagnostic packages that monitored beam performance were deployed during operation. The laser experiments involved injecting a seed beam from the front end into the system and making four passes through both amplifiers. Beam performance diagnostics monitored the beam on each pass to assess system parameters such as gain and nearfield intensity profiles. This year, an active mirror and wavefront sensor were procured and demonstrated in an off-line facility. The active mirror technology can correct for low order phase distortions at user specified operating conditions (such as repetition rates different than 10 Hz) and is a complementary technology to the static phase plates used in the system for higher order distortions. A picture of the laser system with amplifier No.2 (foreground) and amplifier No.1 (background) is shown in Fig. The control system and diagnostics were recently enhanced for faster processing and allow remote operation of the system. The growth and fabrication of the Yb:S-FAP slabs constituted another major element of our program objectives. Our goal was to produce at least fourteen 4x6 cm2 crystalline slabs. These

  9. 5.5 W of Diffraction-Limited Green Light Generated by SFG of Tapered Diode Lasers in a Cascade of Nonlinear Crystals

    Hansen, Anders Kragh; Jensen, Ole Bjarlin; Andersen, Peter Eskil


    Diode-based high power visible lasers are perfect pump sources for, e.g., titaniumsapphire lasers. The combination of favorable scaling laws in both SFG and cascading of nonlinear crystals allows access to unprecedented powers in diode-based systems....

  10. Analysis of Thermal Characteristics in Laser Diode Pump Solid-State Laser with Variable Doping Amplifying Medium%基于非均匀掺杂的激光二极管抽运固体激光系统放大介质热特性分析

    单小童; 严雄伟; 张雄军; 郑建刚; 王明哲; 张永亮; 於海武; 李明中


    利用非均匀掺杂的设计思想,针对正面抽运、背面冷却的有源反射镜放大器结构中不同激活离子掺杂分布的介质进行了模拟计算,分析并比较了传统均匀掺杂介质与非均匀掺杂放大介质中的温度、温度梯度、应力、应变以及波前畸变的分布.结果表明,与传统均匀掺杂介质相比,非均匀掺杂放大介质内的温度、温度梯度、应力、应变与波前畸变均有明显的降低.模拟结果证明,非均匀掺杂可以改善有源反射镜放大器构型冷却与产热异面的问题,可以有效地提高放大器增益介质热管理性能,为进一步讨论基于非均匀掺杂的放大介质的热管理优化提供了基础.%A simulation of performance of thermal management with variable doping gain medium in active mirror configuration of laser diode pump solid-state laser is reported. The parameters of temperature, temperature gradient,stress, strain and optical distortion for a conventional amplifying medium and several variable doping media for different doping distributions, in active mirror configuration amplifier with pumping in the front surface and cooling in the hack are simulated and compared. The calculation indicates a positive result that the variable doping media can ameliorate the problem of heating and cooling in different surfaces in active mirror configuration, and can elevate the thermal, optical and mechanical performances for laser diode pump selid-state laser (DPSSL) system. The simulation results prove the feasibility for ameliorating thermal management performances in DPSSL by variable doping media.

  11. 885-nm Pumped Ceramic Nd:YAG Master Oscillator Power Amplifier Laser System

    Yu, Anthony


    The performance of a traditional diode pumped solid-state laser that is typically pumped with 808-nm laser diode array (LDA) and crystalline Nd:YAG was improved by using 885-nm LDAs and ceramic Nd:YAG. The advantage is lower quantum defect, which will improve the thermal loading on laser gain medium, resulting in a higher-performance laser. The use of ceramic Nd:YAG allows a higher Nd dopant level that will make up the lower absorption at the 885-nm wavelength on Nd:YAG. When compared to traditional 808-nm pump, 885-nm diodes will have 30% less thermal load (or wasted heat) and will thus see a similar percentage improvement in the overall laser efficiency. In order to provide a more efficient laser system for future flight missions that require the use of low-repetition- rate (systems are numerous. The epitaxial structures of these 885-nm diodes are aluminum-free. There is a significant reduction in the thermal load generated from the Stokes shift or quantum defects. A Stokes shift is the energetic difference between the pump and laser photons. Pumping at a wavelength band closer to the lasing wavelength can reduce the thermal load by .30% compared to traditional pumping at 808 nm, and increase the optical- to-optical efficiency by the same factor. The slope efficiency is expected to increase with a reduction in the thermal load. The typical crystalline Nd:YAG can be difficult to produce with doping level >1% Nd. To make certain that the absorption at 885 nm is on the same par as the 808-nm diode, the Nd:YAG material needs to be doped with higher concentration of Nd. Ceramic Nd:YAG is the only material that can be tailored to specific needs.

  12. Laboratory diode laser spectroscopy in molecular planetary astronomy

    Jennings, D. E.


    Infrared spectroscopy of planetary atmospheres is performed at high spectral resolution comparable to that in the laboratory. This requires that laboratory spectroscopy use the highest resolution and the most accurate techniques. Tunable diode laser spectroscopy can supply many of the spectroscopic parameters needed by astronomers. In particular, line positions, line strengths, and collisional line widths are measured with diode lasers, and these are often among the best values available. Diode laser spectra are complimentary to lower resolution, broader-coverage Fourier transform spectra. Certain procedures must be adopted, however, when using diode lasers, for determining their output characteristics and for calibrating each spectrum against quality references.

  13. A novel diode laser system for photodynamic therapy

    Samsøe, E.; Andersen, P. E.; Petersen, P.;


    In this paper a novel diode laser system for photodynamic therapy is demonstrated. The system is based on linear spatial filtering and optical phase conjugate feedback from a photorefractive BaTiO3 crystal. The spatial coherence properties of the diode laser are significantly improved. The system...... is extracted in a high-quality beam and 80 percent of the output power is extracted through the fiber. The power transmitted through tile fiber scales linearly with the power of the laser diode. which means that a laser diode emitting 1.7 W multi-mode radiation would provide 1 W of optical power through a 50...

  14. High stable power control of a laser diode

    YANG Jiu-ru; LI Cheng; YE Hong-an; L(U) Guo-hui; JIA Shi-lou


    In this paper,the low and the high frequency noises of a laser diode have been analyzed. Based on the analysis a novel scheme that adapts analog and digital hybrid techniques is proposed to stabilize the output power of a laser diode. With the hybrid controller,the low and the high frequency noises of a laser diode are conspicuously reduced.By accurate calculation,the short-term stability of the output power of laser diode reaches ±0.55‰, and the long-term stability is ±0.7‰.

  15. 20.6 W Nd∶YVO4 Thin Disk Laser with Laser-Diode Direct Upper-State Pumping%20.6W激光二极管直接上能级抽运Nd∶YVO4薄片激光器

    吴兴盛; 高健存; 唐新春; 王坤; 方茗; 王豫明; 曹有旺


    A 880 nm laser diode direct upper-state pumped Nd: YVO4 thin disk laser is demonstrated. With a 0. 3 mm thick Nd-doping concentration of 0. 5% Nd:YVO4 disk and pump power of 39. 3 W, 20. 6 W output power at 1064 nm is obtained and the optical-optical efficiency exceeds 50% .%使用自行搭建的24通抽运系统,实现了880 nm激光器二极管直接上能级抽运的Nd∶YVO4薄片激光器.采用厚度为0.3 mm、掺杂原子数分数为0.5%的Nd∶YVO4薄片晶体,在39.3W的抽运功率下获得了20.6W的1064 nm连续激光输出,光-光转换效率超过50%.

  16. Selection of the lasing frequency and heating the quantum-well heterostructure laser diodes

    Kononenko, V.K.; Kuntsevich, B. F.


    Numerical simulation of controlling the lasing frequency for the 1.5 μm-range quantum-well heterostructure laser diodes is developed with taking into account increasing the active region temperature under pump current modulation. Peculiarities of the amplitude-frequency characteristics are analyzed at selection of the lasing frequency. General description of the heating of the laser active region during the current modulation is given and selection conditions of the lasing frequency tha...

  17. High-performance 980-nm emission wavelength InGaAs/AlGaAs/GaAs laser diodes

    Suruceanu, Grigore I.; Caliman, Andrei N.; Vieru, Stanislav T.; Iakovlev, V. P.; Sarbu, A. V.; Mereuta, Alexandru Z.


    This paper present the fabrication and mirrors passivation process of InGaAs/AlGaAs/GaAs narrow stripe 980 nm emission wavelength laser diodes. After mesa-stripe definition and Au-contact deposition procedures, a procedure of in-vacuum cleaving and in-situ passivation with (lambda) /2-thick ZnSe layers was performed. 960 micrometers and 500 micrometers length laser diodes bars was fabricated as a result. Antireflection-high reflectivity coating were formed on the bars facets. Laser diodes were soldered p-junction-side down on copper submounts. The room temperature CW threshold current value of 20 mA and CW maximum output power of 440 mW at 760 mA pumping current were obtained. The far-field emission pattern of laser diodes is lateral single mode in large range of output powers. These laser diodes were used for laser diode module fabrication. In this module the laser diodes was coupled with tapered single mode 9 micrometers /125 micrometers optical fiber with a fused microlens at the end. CW output optical power of 40 mW from the fiber was obtained at 240 mA operating current of the laser diode module.

  18. The Adjunctive Soft-Tissue Diode Laser in Orthodontics.

    Borzabadi-Farahani, Ali


    Lasers are a relatively new addition to the orthodontist's armamentarium. This article reviews the fundamental basic science of available soft-tissue lasers, with an emphasis on diode lasers, and discusses various adjunct applications of the diode laser for soft-tissue orthodontic procedures. Diode lasers function by cutting with an initiated hot tip and produce minimal to no interaction with healthy dental hard tissue, making them suitable for soft-tissue procedures. The contact cutting mode provides enhanced bloodless site visibility and facility to perform delicate soft tissue procedures, which is important in areas with difficult access. Such adjunctive uses include laser gingivectomy to improve oral hygiene or bracket positioning, esthetic laser gingival recontouring, and laser exposure of superficially impacted teeth. Selected cases treated with a 940-nm indium-gallium-arsenide-phosphide (InGaAsP) diode laser will be presented.

  19. Mode-locking external-cavity laser-diode sensor for displacement measurements of technical surfaces

    Czarske, Jürgen; Möbius, Jasper; Moldenhauer, Karsten


    A novel laser sensor for position measurements of technical solid-state surfaces is proposed. An external Fabry-Perot laser cavity is assembled by use of an antireflection-coated laser diode together with the technical surface. Mode locking results from pumping the laser diode synchronously to the mode spacing of the cavity. The laser cavity length, i.e., the distance to the measurement object, is determined by evaluation of the modulation transfer function of the cavity by means of a phase-locked loop. The mode-locking external-cavity laser sensor incorporates a resonance effect that results in highly resolving position and displacement measurements. More than a factor-of-10 higher resolution than with conventional nonresonant sensing principles is achieved. Results of the displacement measurements of various technical surfaces are reported. Experimental and theoretical investigations are in good agreement.

  20. Measurement of thermal lensing in end-pumped Yb-doped yttrium vanadate crystal and sesquioxide laser ceramics

    Pestryakov, E. V.; Petrov, V. V.; Trunov, V. I.; Kirpichnikov, A. V.; Merzliakov, M. A.; Laptev, A. V.; Polyakov, K. V.


    The results of theoretical and experimental study of thermal lensing in diode-pumped Yb:YVO4 laser crystal, Yb:Y2O3 and Yb:Sc2O3 laser ceramics are presented. Shown, that influence of thermo-lensing effect is necessary to consider for creation of effective high-intensity femtosecond Yb-doped laser systems.