Abstract The rapid developments in optical and electronic technologies have accelerated developments of solid state laser technology. The diode-pumped solid state laser has the merits of the diode laser, such as compactness, low cost, and the merits of the solid state laser, such as high laser quality, high conversion efficiency, long lifetime, and simple structure. So, it has been applied in electronics, communication and medicine widely. In this work, the crystal fiber was used as the laser gain medium, and coated with optical thin film at its end facets as the laser cavity to be able to reduce largely the volume of solid-state laser, and improve the heat dissipation. We used laser heated pedestal growth (LHPG) method to grow crystal fiber, which can grow with small diameters at very fast rate and accurate control. High quality Nd:YAG crystal fibers with diameter of 23~285 mm were grown. After cladding, grinding, polishing, and coating, we successfully fabricated the Nd:YAG crystal fiber laser. We discovered that the gradient concentration of Nd ions distributed over the cross section of crystal fiber is helpful in focusing lights. We have successfully implemented diode-laser pumped Nd:YAG crystal fiber laser with a slope efficiency of 28.9%. It is the best result up to this time as we know. The maximum output power is 80 mW. In the future, we shall improve the cooling system, the cladding, and coating to further increase the conversion efficiency and output power.

Solid-state lasers are capable of providing versatile output characteristics with greater flexibility compared to other popular laser systems. Lasing action has been achieved in many hundreds of solid-state media, but Nd-ion doped gain media are widely used to reach high power levels with short pulses. In this work, commercially available Nd:KGW crystal served as a gain medium to achieve pulsed operation at 1067 nm. This laser crystal offers large stimulated emission crosssection and gain bandwidth which facilitates generation of high peak power pulses in the picosecond regime. The KGW crystal is monoclinic and biaxial in structure, and anisotropic in its optical and thermal properties. Due to poor thermal conductivity, this crystal can be operated within a limited power range before crystal fracture takes place. To reduce the amount of heat deposited in the gain media, we introduced a new pumping wavelength of 910 nm which reduces the quantum defect by more than 45%. Continuous-wave laser operation was optimized to operate in mode-locked regime. In order to achieve short light pulses from the continuous-wave laser, one of the end mirrors was replaced by a semiconductor saturable absorber mirror (SESAM) to generate 2.4 ps pulses at a repetition rate of 83.8 MHz. An average output power of 87 mW was obtained at lasing wavelength of 1067 nm and the beam was nearly diffraction limited with M^2 < 1.18. The peak power of the generated pulses was 427 W and energy of each pulse was >1 nJ. Pumping the crystal at longer wavelength (910 nm) reduced the thermal lensing of the crystal by half when compared to conventional pumping at shorter wavelength (808 nm). To the best of our knowledge, this is the first time passive mode-locking of a Nd:KGW laser was explored using the pump wavelength at 910 nm. / February 2017

Wasserdampf in der Stratosphäre und Troposphäre ist eines der wichtigsten atmosphärischen Treibhausgase. Neben seiner Bedeutung für das Klima hat es großen Einfluss auf die Bildung von polaren stratosphärischen Wolken sowie auf die atmosphärische Chemie. Weltweit erstmalig soll innerhalb eines Forscherverbundes in Deutschland ein leistungsstarkes, mobiles, abtastendes Wasserdampf-DIAL zur dreidimensional hochaufgelösten Messung des atmosphärischen Wasserdampfs entwickelt werden. Mit dem Wasserdampf-DIAL können Wasserdampfkonzentrationen in der Atmosphäre mit hoher zeitlicher und räumlicher Auflösung gemessen werden. Das DIAL basiert auf einem Titan-Saphir-Laser oder einem dazu alternativen OPO-Laser (optisch parametrischer Oszillator). Der für das optische Pumpen dieser Laser nötige Pumplaser wurde im Rahmen dieser Arbeit in der Arbeitsgruppe Nichtlineare Optik des Instituts für Physik der Universität Potsdam entwickelt. Ein hochauflösendes, mobiles DIAL erfordert einen Pumplaser mit großen Pulsenergien, guter Strahlqualität und einer hohen Effizienz. Um diese Ziele zu erreichen, wurde ein MOPA-System (Master Oscillator Power Amplifier) mit Frequenzstabilisierung auf der Basis von doppelbrechungskompensierten, transversal diodengepumpten Laserstäben entwickelt und untersucht. Auf dem Weg dahin wurden unterschiedliche Realisierungsmöglichkeiten des MOPA-Systems geprüft. Im Rahmen dessen wurden die Festkörperlasermaterialien Yb:YAG [1], kerndotierte Nd:YAG-Keramik [2] und herkömmliches Nd:YAG vorgestellt und hinsichtlich ihrer Eignung für dieses MOPA-System untersucht. Nachdem die Entscheidung für Nd:YAG als laseraktives Material gefallen war, konnte darauf aufbauend die Konzeptionierung des Lasersystems auf der Basis von Verstärkungsrechnungen vorgenommen werden. Die entwickelte Verstärkungsrechnung trägt den Tatbeständen von realen Systemen Rechnung, indem radiusabhängige Intensitäten und eine radiale, nicht homogene Inversionsdichte berücksichtigt werden. Die Frequenzstabilisierung des gepulsten Oszillators (Frequenzstabilität von 1 MHz) wurde mittels des Pound-Drever-Hall-Verfahrens vorgenommen. Mit der Heterodynmethode wird die Frequenzstabilität des Oszillators gemessen. Nach Untersuchungen über verschiedene Konfigurationen für lineare und ringförmige Oszillatoren, wurde ein Ringoszillator mit zwei Laserköpfen aufgebaut, in welchen von außen mit einem Laser fester Frequenz eingestrahlt wird. Dieser emittiert bei einer Wiederholrate von 400 Hz eine Pulsenergie von Eout = 21 mJ bei nahezu beugungsbegrenzter Strahlqualität (M2 < 1,2). Die Verstärkung dieser Laserpulse erfolgte zunächst durch eine Vorverstärkerstufe und anschließend durch zwei doppelbrechungskompensierte Hauptverstärker im Doppeldurchgang. Eine gute Strahlqualität (M2 = 1,75) konnte unter anderem erzielt werden, indem der Doppeldurchgang durch die Hauptverstärker mit einem phasenkonjugierenden Spiegel (SF6), auf der Basis der stimulierten Brillouin Streuung, realisiert wurde. Der entwickelte Laser emittiert Pulse mit einer Länge von 25 ns und einer Energie von 250 mJ. Insgesamt wurde ein bisher einmaliges Lasersystem entwickelt. In der Literatur sind die erreichte Frequenzstabilität, Strahlqualität und Leistung in dieser Kombination bisher nicht dokumentiert. In der Zukunft soll durch den Einsatz von kerndotierten, keramischen Lasermaterialien, höheren Pumpleistungen der Hauptverstärker und phasenkonjugierenden Spiegeln aus Quarz die Pulsenergie des Systems weiter erhöht werden. [1] M. Ostermeyer, A. Straesser, “Theoretical investigation of Yb:YAG as laser material for nanosecond pulse emission with large energies in the joule range”, Optics Communications, Vol. 274, pp. 422-428 (2007) [2] A. Sträßer and M. Ostermeyer, “Improving the brightness of side pumped power amplifiers by using core doped ceramic rods”, Optics Express, Vol. 14, pp. 6687- 6693 (2006) / Vapour in the stratosphere and troposphere is one of the most important atmospheric greenhouse gases. Apart from its importance for the climate it has a great influence on the formation of polar stratospheric clouds as well as the atmospheric chemistry. A German research group is currently developing the world’s first powerful, mobile, screening vapour-DIAL, which can measure the atmospheric vapour three-dimensionally and in high resolution. Vapour concentrations in the atmosphere can be measured in high temporal and local resolution with this vapour-DIAL. The DIAL is based on a titan-saphire-laser or an alternative OPO-laser (Optical Parametric Oscillator). The seeding-laser, which is needed in order to seed those lasers, was developed in the course of this work by the research group for nonlinear optics in the institute for physics at the University of Potsdam. A highly-resolutive, mobile DIAL needs a seeding-laser with high pulse energy, excellent beam quality and high efficiency. In order to realise this, a frequency stabilised MOPA-System (Master Oscillator Power Amplifier) was developed, which based on birefringence-compensated, transversally diode-pumped laser rods. During the research process several ways to realise the MOPA-System were investigated. In this process the solid laser materials Yb:YAG [1], core-doped Nd:YAG-Ceramics [2] und conventional Nd:YAG were introduced and their suitability for the MOPA-System was investigated. After the choice for Nd:YAG as laser-active material was made, the concept of the laser-system could be developed based on amplification-calculations. The amplification-calculation meets the requirements of real systems, because intensities depending on diameter and a radial, non-homogeneous inversion density are being taken into consideration. The frequency of the pulsed oscillator (frequency stabilisation of 1 MHz) was stabilised by means of the Pound-Drever-Hall-Method. The frequency stability of the oscillator is measured using the Heterodyn-Method. After the investigation of different configurations for linear and circular oscillators a circular oscillator with two laser heads was set up, which is injection-seeded by a second laser with a stable frequency. At a repetition rate of 400 Hz the circular oscillator emits a pulse energy of Eout = 21 mJ with almost diffraction-limited beam quality (M2 < 1.2). These laser pulses were first amplified by a pre-amplifier and afterwards by two birefringence compensated main-amplifier in doublepass. Among other factors, an excellent beam quality (M2 = 1.75) could be reached by the doublepass through the main amplifier realised with a phase conjugating mirror (SF6) based on stimulated Brillouin-scattering. The developed laser emits pulses that are of 25 ns length and have an energy of 250 mJ. A currently unique laser system was developed. In the research findings there are no previous documents of the combination of the reached stability of frequency, beam quality and power in one system. In the future the pulse energy of the system is to be further increased through the use of core-doped, ceramic laser material, a higher pump power of the main amplifiers and phase-conjugating mirrors made of quartz. [1] M. Ostermeyer, A. Straesser, “Theoretical investigation of Yb:YAG as laser material for nanosecond pulse emission with large energies in the joule range”, Optics Communications, Vol. 274, pp. 422-428 (2007) [2] A. Sträßer and M. Ostermeyer, “Improving the brightness of side pumped power amplifiers by using core doped ceramic rods”, Optics Express, Vol. 14, pp. 6687- 6693 (2006)

A novel non-planar and multi-reentrant two-spherical-mirror ring cavity is demonstrated. It is compact and free of astigmatism compare to the commercial ring cavity systems. The multi-reentrant condition of the ring cavity is derived and the stability of the laser cavity is analyzed. The study of polarization evolution in this kind of ring cavity is also presented. Unidirectional operation is achieved by use of reciprocal and nonreciprocal polarization rotators to differentiate the round-trip loss. The multi-reentrant ring cavity has been utilized in single frequency laser and passively Q-switched laser. Single frequency laser possesses the advantages of high coherence and low noise, which can be used to the applications such as precision measurement. In the methods of single frequency generation, ring cavity configuration was shown to be the most robust one. Using this ring cavity, an IR and its intra-cavity frequency doubled green laser were demonstrated which the amplitude noise is lower than 0.3%. Passively Q-switched laser is an efficient and compact way to generate high-peak-power laser pulses because high voltages and fast driving electronics are not required. Its high power is useful for diverse applications including nonlinear optical processes, micromachining, material processing and range finders. But the major drawback of a passively Q-switched laser is its inherent large timing jitter, which is mainly originated from the photo dynamics in the cavity, environmental instabilities and spontaneous noise from the gain medium. In our study, we demonstrated the operation of a low-jitter, passively Q-switched laser by using the reentrant two-mirror unidirectional ring cavity, which generates a pulse width of 63ns, peak power of 250 W laser output. Due to the elimination of spontaneous noise and spatial hole burning effects, the timing jitter can be maintained below 3% over a wide range of pump powers with integrations of over 52,000 pulses.

No description available.

As directed energy technology continues to evolve and become a viable weapon alternative, a need exists to investigate the impacts of these applications without a "plug-and-check" method, but rather with an analysis governed by fundamental principles. This thesis examines the transient thermal loads that a high-energy weapon system introduces into a high performance aircraft using fundamental thermodynamic and heat transfer analyses. The high-energy weapon system employed in this research contains power storage, power conditioning equipment, optics, and a solid-state laser. The high-energy weapon system is integrated into the aircraft by a dedicated thermal management system connected to the onboard air and fuel fluid networks. The dedicated thermal management system includes heat exchangers, thermal storage, microchannel coolers, valves, and pumps. Governing equations for the electric directed energy weapon subsystem and thermal management system are formulated for each system component and modeled in Mathwork's Simulink™. System models are integrated into a generic, high-performance aircraft model created as part of the Air Force Research Laboratory's Integrated Vehicle Energy Technology Demonstration (INVENT) program. The aircraft model performs a defined mission profile, firing the directed energy weapon during the high-altitude, transonic cruise segment. When firing a 100-kilowatt directed energy weapon system operating at 16.9% efficiency, large thermal transients quickly heat downstream onboard systems. Real-time heat rejection causes temperature spikes in avionic and environment systems that exceed allowable operation constraints. The addition of thermal storage to the thermal management system mitigates thermal impacts downstream of the directed energy weapon by delaying the time thermal loads are rejected to aircraft, thereby reducing peak and average loads. Although thermal storage is shown to mitigate peak loads in downstream onboard systems, thermal closure is yet to be achieved. This research presents a general and fundamental approach to investigating the thermal impacts of a directed energy weapon system on a high-performance aircraft. Although specific cases are analyzed, this general approach to model development and simulation is conducive to component and system customization for many other cases. Additionally, the supplementation of models with analytical, semi-empirical, and empirical data further tailors model development to each user's need while increasing the potential to enhance accuracy and efficacy. Without the material expenses of a "plug-and-check" method, component and system level modeling of the directed energy weapon system and high-performance aircraft provides valuable insight into the thermal responses of highly-coupled systems. / Master of Science

Le développement du laser a ouvert la voix à l'exploration de nouveaux domaines scientifiques et industriels. Les impulsions laser à haute intensité sont un outil unique pour les études d'interaction lumière/matière et leurs applications. Mais elles sont générées par des systèmes laser reposant sur l'utilisation de milieux à gain en verre pompés par des lampes flashes et sont donc intrinsèquement limitées en termes de cadence et d'efficacité. Le développement, au cours de ces dernières années, des lasers semi-conducteurs a attiré l'attention sur une nouvelle classe de lasers, les « laser solides pompés par diodes » (DPSSL). Ils possèdent une grande efficacité et sont des candidats de choix pour les systèmes compacts à haute puissance moyenne requis pour des applications industrielles, mais aussi en tant que sources de pompe à haute puissance pour des lasers ultra-intenses. Les travaux décrits dans cette thèse s'inscrivent dans le cadre du système laser Lucia (1 kilowatt de puissance moyenne), actuellement en construction au «Laboratoire d'Utilisation des Intenses lasers» (LULI) à l'Ecole Polytechnique, France. La génération d'impulsions laser de durée sub-10 nanosecondes avec des énergies allant jusqu'à 100 joules et des taux de répétition de 10 hertz est principalement limitée par l'émission spontanée amplifiée (ASE) et les effets thermiques. L'étude de ces limitations est le thème central de ce travail. Leur impact est discuté dans le cadre d'un premier jalon énergétique fixé vers 10 joules. Le système laser mis au point est présenté en détails depuis l'oscillateur jusqu'à la fin de la chaine d'amplification. Une discussion complète de l'impact de l'ASE et des effets thermiques est complétée par des vérifications expérimentales. Les modèles de simulation informatique développés sont validés puis utilisés pour prédire les performances du système laser qui, lors d'une première activation, à atteint un niveau d'énergie de 7 joules en régime mono-coup et de 6,6 joules pour un taux de répétition de 2 hertz. Les limitations actuelles sont discutées ainsi que les approches envisagées pour des développements futurs.

Laseres de estado sólido que operan en la región espectral de seguridad ocular alrededor de los 2 micrómetros (2µm) son de elevado interés en la actualidad debido a su potencial aplicación en los campos de la medicina, teledetección remota y como fuentes de bombeo en osciladores ópticos paramétricos (OPOs) para conversión en el infrarrojo medio. La transición láser en las 2 µm es posible en los iones de tulio (Tm) ligeramente por debajo de las 2 µm y en iones de holmio (Ho) ligeramente por encima de las 2 µm. La generación láser en iones de Tm es relativamente simple con la utilización de láseres de diodo como fuentes de bombeo, sin embargo, los láseres basados en Ho se han conseguido tradicionalmente en el pasado mediante el codopaje con Tm o mediante bombeo directo del nivel emisor del Ho. Recientemente, diodos láser que operan a 1.9 µm han aparecido en el mercado con buena eficiencia y con alto potencial para el escalado en potencia de los láseres de Ho. Los láseres de Ho son más apropiados que los láseres de Tm especialmente para aplicaciones médicas por dos razones: La longitud de onda láser ligeramente por encima de las 2 µm, donde el agua (mayor componente del cuerpo humano) presenta una ligera menor absorción que la típica longitud de onda láser del Tm, hace que el láser penetre más en el tejido humano. La segunda razón es que los láseres de Ho pueden operar en régimen pulsado generando mayores energías por pulso que los láseres de Tm debido al mayor tiempo de vida del nivel emisor 5I7 y las aplicaciones médicas requieren por lo general régimen pulsado para evitar daño térmico del tejido. Numerosos óxidos y fluoruros cristalinos han demostrado ser adecuadas matrices para Ho, sin embargo, poca atención se ha puesto en los dobles tungstatos cristalinos de fase monoclínica, de fórmula química KRE(WO4)2, brevemente KREW, donde RE = Y, Gd y Lu conocidos por ser matrices láser muy eficientes para la generación láser a potencias intermedias. Estos cristales anisotrópicos presentan una elevada sección eficaz de absorción y emisión cuando son dopados con iones lantánidos y especialmente para ciertas polarizaciones. Considerando el potencial del Ho y las buenas propiedades de KREW, nuestro trabajo se centra en la investigación de las prestaciones láser en cristales de KREW dopados con Ho utilitzando tanto Tm o Yb como iones sensibilizadores y utilizando fuentes de bombeo emitiendo a 1.9 µm que permiten la excitación directa del nivel emisor. En esta tesis, presentamos los resultados basados en el crecimiento cristalino de monocristales de Ho:KREW, codopajes (Ho,Tm) y (Ho,Yb):KLuW a diferentes concentraciones de Ho, su caracterización en términos de estructura, composición y espectroscopia y finalmente la generación láser alrededor de 2.1 µm. / Eye-safe solid-state lasers that operate in the 2µm spectral range are the subject of interest in the present years because of their potential applications in the field of remote sensing, medicine and as a pump source for Optical Parametric Oscillators (OPOs). Laser transitions around 2 µm are possible in the trivalent lanthanide ions Tm3+ (Tm) (slightly below 2 µm) and Ho3+ (Ho) (slightly above 2 µm). Laser generation in Tm ions is easily achieved with comfortable diode pump sources, however, Ho lasers have usually been achieved in the past either by co-doping the active medium with Tm or by direct pumping of the Ho ions with Tm lasers. Recently, relatively cheap diodes emitting around 1.9 µm are in the market to realize Ho lasers with great potential for power scaling. Ho lasers are more suitable than Tm lasers especially for medical applications because of two reasons: The laser wavelength is slightly above 2µm, where water (main component of human tissue) shows slightly less absorption than the typical wavelength of Tm leading to a deeper penetration in human tissue. The second reason is that Ho lasers can operate in pulsed regime delivering higher energies than Tm lasers due to the longer lifetime of the emitting level 5I7 and medical applications are required to be generally in pulsed regime to avoid thermal damage of human tissue. Many oxide and fluoride crystals were shown to be suitable host for Ho, however little attention was paid to the monoclinic potassium rare earth double tungstate crystal, shortly KRE(WO4)2 or KREW, where RE= Y, Gd, Lu known to be very efficient rare earth solid state hosts for generating intermediate power levels. These anisotropic crystals exhibit very high absorption and emission cross sections when doped with lanthanide ions and especially for selected polarizations. Considering the potentialities of Ho and good properties of KREW, our work focuses in the investigation of the laser performances of a Ho doped KREW either by using Tm or Yb as sensitizers and by using in-band pump sources emitting around 1.9 µm, where the development of compact solid state infrared laser emitting at 2.1 µm for intermediate power levels is followed. Here, in this thesis, we present the results based on growth of single doped Ho:KREW, co-doped (Ho,Tm) and (Ho,Yb):KLuW crystals of several doping concentrations, their characterisation in terms of structure, composition and spectroscopy and finally dedicated for the laser generation around 2.1 µm from these materials, which was highly successful.

Le laser Mégajoule, dédié à l’interaction laser-matière pour la physique des hautes énergies est composé de modules pré-amplificateurs (MPA) devant respecter une qualité de faisceau exigeante. Les MPA actuels utilisent des matériaux verre phosphate dopé au Néodyme pour un fonctionnement à 1053 nm. Leur cadence de tir est cependant limitée à 1 tir / 5 min à cause de leur faible conductivité thermique. Il serait intéressant d’augmenter cette cadence pour optimiser le temps alignement des optiques ou réaliser des diagnostics sur l’installation laser. Pour augmenter la cadence de tir des MPA, nous proposons de changer le matériau actuel par du Nd :Lu :CaF2 de conductivité thermique dix fois plus élevée en vue d’atteindre une cadence de répétition de 10 Hz. Dans ce travail de thèse, nous présentons une étude des effets thermomécaniques induits par un pompage diode inhomogène et transverse, de fluence 13 J/cm2. Nous présentons les mesures de biréfringence résolues spatialement avec un montage en polariseur-analyseur croisés. La distribution des contraintes thermomécaniques associées est reconstruite par un modèle de simulation avec le logiciel COMSOL®. Enfin, une étude de l’influence de l’orientation cristalline du Nd :Lu :CaF2 est développée afin d’expliquer la disparité de biréfringence induite mesurée entre les échantillon de Nd :Lu :CaF2. / Laser facility such as the Megajoule Laser dedicated to laser-matter interaction including inertial fusion need pre-amplifier modules (PAM) which must respect a high beam quality. The current PAM use Phosphate glass doped with Neodymium material to work at 1053 nm with a repetition rate of 1 shot / 5 min limited by a low thermal diffusion. However, it would be interesting to increase the shot rate for alignment or diagnostic purposes. Therefore, we propose to change this amplification material by crystal Nd :Lu :CaF2 with a thermal diffusion ten times higher in view of achieving a repetition rate of 10 Hz. In this PhD work, we report a characterization of the thermal induced effects under a diode inhomogeneous and transverse pump with an energy density of 13 J/cm2. We begin by studying the spatially resolved induced birefringence with a cross polarizer-analyzer setup. We reconstruct the stress pattern of our samples by simulating the global setup with COMSOL® software which includes the thermal and mechanic Multiphysics interaction. This model allows us first to compare with experimental results and then to entirely simulate the mechanical behavior of this new material. A detailed study of the influence of the crystal orientation on the induced birefringence is presented to explain the disparity observed on the different samples Nd :Lu :CaF2 measurements

O trabalho experimental aqui apresentado tem como foco o desenvolvimento de um laser de estado sólido cujo desempenho foi otimizado de tal forma que contemple alta potência, alta qualidade de feixe e estabilidade, levando-se em conta os efeitos térmicos sofridos pelo meio ativo em regime de alta potência de bombeamento. Foram testadas cavidades para operação contínua em multimodo com alta potência de saída e cavidades operando em modo único TEM00. Para cavidades operando no modo fundamental, os ressonadores testados serão divididos em grupos de acordo com o seu comportamento no diagrama de estabilidade. A otimização de tais ressonadores foi realizada apenas alterando-se o raio de curvatura dos espelhos de entrada e saída e suas respectivas distâncias ao plano principal do bastão de Nd:YAG. Como resultado foi alcançada a maior eficiência de extração reportada na literatura para um ou dois módulos de Nd:YAG intracavidade. Os resultados dão uma visão geral sobre possíveis projetos de ressonadores para operação dinamicamente estável, com alta potência de saída e qualidade de feixe. Os dados obtidos servem como base para o desenvolvimento de novos lasers de alta potência e eficiência baseados em módulos DPSSL (Diode-Pumped Solid-State Lasers- Lasers de Estado Sólido Bombeados por Diodo) de baixo custo. / The experimental work presented here focuses on the development of a solid-state laser whose performance has been optimized for high power output, high beam quality, and high stability, taking into account the thermal effects experienced by the gain medium under high pumping power. Cavities for continuous wave (CW) operation in multimode with high output power and cavities operating in single mode TEM00 were tested. The resonators will be divided in groups according to their stability diagram. The optimization of such resonators was performed only by changing the curvature radius of the mirrors and their distances to the principal plane of the Nd:YAG rod. As a result was achieved the highest extraction efficiency reported in the literature for one or two intra cavity Nd:YAG modules. The results give an overview of possible designs of resonators for dynamically stable operation with high output power and beam quality. The data serve as basis for the development of new high-power lasers based on low cost DPSSL modules.