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Jauregui C.,Friedrich - Schiller University of Jena | Limpert J.,Friedrich - Schiller University of Jena | Limpert J.,Helmholtz Center for Heavy Ion Research | Limpert J.,Fraunhofer Institute for Applied Optics and Precision Engineering | And 3 more authors.
Nature Photonics | Year: 2013

Fibre lasers are now associated with high average powers and very high beam qualities. Both these characteristics are required by many industrial, defence and scientific applications, which explains why fibre lasers have become one of the most popular laser technologies. However, this success, which is largely founded on the outstanding characteristics of fibres as an active medium, has only been achieved through researchers around the world striving to overcome many of the limitations imposed by the fibre architecture. This Review focuses on these limitations, both past and current, and the creative solutions that have been proposed for overcoming them. These solutions have enabled fibre lasers to generate the highest diffraction-limited average power achieved to date by solid-state lasers. © 2013 Macmillan Publishers Limited. All rights reserved.


Jauregui C.,Friedrich - Schiller University of Jena | Eidam T.,Friedrich - Schiller University of Jena | Limpert J.,Friedrich - Schiller University of Jena | Tunnermann A.,Friedrich - Schiller University of Jena | Tunnermann A.,Fraunhofer Institute for Applied Optics and Precision Engineering
Optics Express | Year: 2011

Recent work on high-power fiber amplifiers report on a degradation of the output beam quality or even on the appearance of mode instabilities. By combining the transversally resolved rate equations with a 3D Beam propagation method we have managed to create a model able to provide an explanation of what we believe is at the root of this effect. Even though this beam quality degradation is conventionally linked to transversal hole burning, our simulations show that this alone cannot explain the effect in very large mode area fibers. According to the model presented in this paper, the most likely cause for the beam quality degradation is an inversion-induced grating created by the interplay between modal interference along the fiber and transversal hole burning. © 2011 Optical Society of America.


Duparre A.,Fraunhofer Institute for Applied Optics and Precision Engineering | Ristau D.,Laser Zentrum Hannover e.V.
Applied Optics | Year: 2011

The 2010 Measurement Problem comprised the determination of the reflectance of high-reflective dielectric mirrors at 1064 nm. © 2010 Optical Society of America.


Zwick S.,Fraunhofer Institute for Applied Optics and Precision Engineering | Fessler R.,Fraunhofer Institute for Industrial Mathematics | Jegorov J.,Fraunhofer Institute for Industrial Mathematics | Notni G.,Fraunhofer Institute for Applied Optics and Precision Engineering
Optics Express | Year: 2012

Picture-generating freeform surfaces are able to generate a picture in a defined plane by incoherent beam shaping comparable to illumination purposes. No classical imaging is performed. Therefore the classical Rayleigh criterion of the diffraction limit cannot be applied. In this paper, we investigate the physical light formation of picture-generating freeform surfaces using Fresnel-Huygens-based simulations. A criterion for the diffraction limit was found. The resolution of such surfaces is significantly inferior to the resolution of classical imaging systems. However, in many cases, such systems are limited by the geometrical resolution. The influence of those two limitations were examined and a maximum of resolution, being limited by diffraction and by geometrical parameters can be found. © 2012 Optical Society of America.


Wilbrandt S.,Fraunhofer Institute for Applied Optics and Precision Engineering | Stenzel O.,Fraunhofer Institute for Applied Optics and Precision Engineering | Kaiser N.,Fraunhofer Institute for Applied Optics and Precision Engineering
Optics Express | Year: 2010

A new all-oxide design for broadband antireflection coatings with significantly reduced impact of deposition errors to the final reflectance is presented. Computational manufacturing including reoptimization during deposition has been used in the design work to account for maximum insensibility of the design with respect to deposition errors typical for plasma ion assisted deposition PIAD. Repeated deposition runs with the deducted monitoring and re-optimization strategy verify the validity of the simulations and the stability of the derived design solution. © 2010 Optical Society of America.


Eckstein H.-C.,Fraunhofer Institute for Applied Optics and Precision Engineering | Zeitner U.D.,Fraunhofer Institute for Applied Optics and Precision Engineering
Optics Express | Year: 2013

To increase the brightness of broad area laser diodes, it is necessary to tailor the optical properties of their waveguide region. For this purpose, there is the need for simulation tools which can predict the optical properties of the complete device and thus of the outcoupled light. In the present publication, we show a numerical method to calculate typical intensity distributions of the multimode beam inside a high-power semiconductor laser. The model considers effects of mode competition and the influence of the gain medium on the optical field. Simulation results show a good agreement with near and far field measurements of the analyzed broad area laser diodes. © 2013 Optical Society of America.


Von Finck A.,Fraunhofer Institute for Applied Optics and Precision Engineering | Hauptvogel M.,Fraunhofer Institute for Applied Optics and Precision Engineering | Duparre A.,Fraunhofer Institute for Applied Optics and Precision Engineering
Applied Optics | Year: 2011

Scatter analysis is an effective method for the characterization of thin film components. The new highly sensitive table top system ALBATROSS-TT (3D-Arrangement for Laser Based Transmittance, Reflectance and Optical Scatter Measurement-Table Top) has been developed at the Fraunhofer Institute in Jena to meet the specific requirements for close-to-process applications. Extremely high sensitivity with a noise equivalent angle resolved scatter level of 2 × 10-8 sr-1, full three-dimensional spherical measurement capability, and an instrument size as small as 0:8m × 0:8m × 0:8m have been achieved. Details of specifications, optical components, and software are presented, including a comparison to our laboratory system. Anisotropy analysis of diamond-turned aluminum substrates as well as substrate and coating characterization are demonstrated as examples of application. © 2011 Optical Society of America.


Michaelis D.,Fraunhofer Institute for Applied Optics and Precision Engineering | Schreiber P.,Fraunhofer Institute for Applied Optics and Precision Engineering | Brauer A.,Fraunhofer Institute for Applied Optics and Precision Engineering
Optics Letters | Year: 2011

The geometrical method for constructing optical surfaces for illumination purpose developed by Oliker and co-workers [Trends in Nonlinear Analysis (Springer, 2003)] is generalized in order to obtain freeform designs in arbitrary optical systems. The freeform is created by a set of primitive surface elements, which are generalized Cartesian ovals adapted to the given optical system. Those primitives are determined by Hamiltonian theory of ray optics. The potential of this approach is demonstrated by some examples, e.g., freeform lenses with collimating front elements. © 2011 Optical Society of America.


Gather M.C.,University of Iceland | Gather M.C.,Harvard University | Meerholz K.,University of Cologne | Danz N.,Fraunhofer Institute for Applied Optics and Precision Engineering | Leosson K.,University of Iceland
Nature Photonics | Year: 2010

Plasmonicsthe study of the interaction between electromagnetic waves and electron plasmas on metal surfaces and in metallic nanostructureshas received much attention in recent years, with potential new applications ranging from subwavelength photonic circuits to photothermal cancer therapy. In many cases, however, the substantial attenuation of the electromagnetic wave due to absorption (ohmic loss) in the metal is of serious concern. Introduction of optical gain into the dielectric material adjacent to the metal surface has been identified as a means of compensating for the absorption loss, but the experimental realization of lossless propagation or optical gain in plasmonic waveguides has proven elusive. Here, we demonstrate direct proof of plasmonic propagation with net positive gain over macroscopic distances. The gain is provided by an optically pumped layer of fluorescent conjugated polymer adjacent to the metal surface in a dielectric-metal-dielectric plasmonic waveguide. © 2010 Macmillan Publishers Limited. All rights reserved.


Flammich M.,Fraunhofer Institute for Applied Optics and Precision Engineering | Michaelis D.,Fraunhofer Institute for Applied Optics and Precision Engineering | Danz N.,Fraunhofer Institute for Applied Optics and Precision Engineering
Organic Electronics: physics, materials, applications | Year: 2011

The optical features of the internal dipole radiation have major impact on the emission pattern and overall device efficiency of organic light-emitting diodes (OLEDs). We provide some general directives on how the OLED layered stack should be designed in order to enable precise measurements of the active optical properties of the emissive material (namely internal electroluminescence spectrum, profile of the emission zone and dipole moment orientation) by radiation pattern analyses. We discuss a model layered system and deduce universal emitter positions most suitable for the determination of the particular OLED internal features of interest. Furthermore, we evaluate the real benefit of conducting radiation pattern analyses utilizing a substrate index-matched glass-hemisphere. © 2010 Elsevier B.V. All rights reserved.

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