@article{ZinkWernerJechowetal.2014,
  author    = {Zink, Christof and Werner, Nils and Jechow, Andreas and Heuer, Axel and Menzel, Ralf},
  title     = {Multi-wavelength operation of a single broad area diode laser by spectral beam combining},
  series = {IEEE photonics technology letters},
  volume    = {26},
  journal   = {IEEE photonics technology letters},
  number    = {3},
  publisher = {Inst. of Electr. and Electronics Engineers},
  address   = {Piscataway},
  issn      = {1041-1135},
  doi       = {10.1109/LPT.2013.2291963},
  pages     = {253 -- 256},
  year      = {2014},
  abstract  = {Stabilized multi-wavelength emission from a single emitter broad area diode laser (BAL) is realized by utilizing an external cavity with a spectral beam combining architecture. Self-organized emitters that are equidistantly spaced across the slow axis are enforced by the spatially distributed wavelength selectivity of the external cavity. This resulted in an array like near-field emission although the BAL is physically a single emitter without any epitaxial sub-structuring and only one electrical contact. Each of the self-organized emitters is operated at a different wavelength and the emission is multiplexed into one spatial mode with near-diffraction limited beam quality. With this setup, multi-line emission of 31 individual spectral lines centered around and a total spectral width of 3.6 nm is realized with a 1000 mu m wide BAL just above threshold. To the best of our knowledge, this is the first demonstration of such a self-organization of emitters by optical feedback utilizing a spectral beam combining architecture.},
  language  = {en}
}
@article{ZinkNiebuhrJechowetal.2014,
  author    = {Zink, Christof and Niebuhr, Mario and Jechow, Andreas and Heuer, Axel and Menzel, Ralf},
  title     = {Broad area diode laser with on-chip transverse Bragg grating stabilized in an off-axis external cavity},
  series = {Optics express : the international electronic journal of optics},
  volume    = {22},
  journal   = {Optics express : the international electronic journal of optics},
  number    = {12},
  publisher = {Optical Society of America},
  address   = {Washington},
  issn      = {1094-4087},
  doi       = {10.1364/OE.22.014108},
  pages     = {14108 -- 14113},
  year      = {2014},
  abstract  = {The emission characteristics of a novel, specially designed broad area diode laser (BAL) with on-chip transversal Bragg resonance (TBR) grating in lateral direction were investigated in an off-axis external cavity setup. The internal TBR grating defines a low loss transversal mode at a specific angle of incidence and a certain wavelength. By providing feedback at this specific angle with an external mirror, it is possible to select this low loss transverse mode and stabilize the BAL. Near diffraction limited emission with an almost single lobed far field pattern could be realized, in contrast to the double lobed far field pattern of similar setups using standard BALs or phase-locked diode laser arrays. Furthermore, we could achieve a narrow bandwidth emission with a simplified setup without external frequency selective elements. (C) 2014 Optical Society of America},
  language  = {en}
}
@article{vonSeggernModrakowskiSpitzetal.2004,
  author    = {von Seggern, David and Modrakowski, Claudia and Spitz, Christian and Schl{\"u}ter, A. D. and Menzel, Ralf},
  title     = {Charge transfer initiated by optical excitation in diester substituted biphenylpyrene as a function of the solvent characterized by excited state absorption spectroscopy},
  year      = {2004},
  abstract  = {Cross-sections for ground and excited state absorptions of the charge transfer system 3-(3-tert- butoxycarbonylamino-propyl)-4'-pyren-1-yl-biphenyl-2,5-dicarbo xylicacid dimethyl ester (Py-C) are determined from nonlinear absorption and fluorescence measurements as a function of solvent. While in non-polar solvents no stable charge transfer (CT) state occurs after optical excitation, in polar solvents the CT state is stabilized. (C) 2004 Elsevier B.V. All rights reserved},
  language  = {en}
}
@article{UnterhuberPovazayBizhevaetal.2004,
  author    = {Unterhuber, Angelika and Povazay, B. and Bizheva, K. and Hermann, B. and Sattmann, Harald and Stingl, A. and Le, Trang and Seefeldt, Michael and Menzel, Ralf and Preusser, Matthias and Budka, Herbert and Schubert, Christian and Reitsamer, H. and Ahnelt, Peter Kurt and Morgan, J. E.},
  title     = {Advances in broad bandwidth light sources for ultrahigh resolution optical coherence tomography},
  issn      = {0031-9155},
  year      = {2004},
  abstract  = {Novel ultra-broad bandwidth light sources enabling unprecedented sub-2 pm axial resolution over the 400 nm-1700 nm wavelength range have been developed and evaluated with respect to their feasibility for clinical ultrahigh resolution optical coherence tomography (UHR OCT) applications. The state-of-the-art light sources described here include a compact Kerr lens mode locked Ti:sapphire laser (lambda(c) = 785 nm, Deltalambda = 260 nm, P-out = 50 mW) and different nonlinear fibre-based light sources with spectral bandwidths (at full width at half maximum) up to 350 nm at lambda(c) = 1130 nm and 470 nm at lambda(c) = 1375 run. In vitro UHR OCT imaging is demonstrated at multiple wavelengths in human cancer cells, animal ganglion cells as well as in neuropathologic and ophthalmic biopsies in order to compare and optimize UHR OCT image contrast, resolution and penetration depth},
  language  = {en}
}
@article{TedeschiLiMoehwaldetal.2004,
  author    = {Tedeschi, Concetta and Li, L. and M{\"o}hwald, Helmuth and Spitz, Christian and von Seggern, David and Menzel, Ralf and Kirstein, Stefan},
  title     = {Engineering of layer-by-layer coated capsules with the prospect of materials for efficient and directed electron transfer},
  year      = {2004},
  abstract  = {We show a Lefschetz fixed point formula for holomorphic functions in a bounded domain D with smooth boundary in the complex plane. To introduce the Lefschetz number for a holomorphic map of D, we make use of the Bergman kernel of this domain. The Lefschetz number is proved to be the sum of the usual contributions of fixed points of the map in D and contributions of boundary fixed points, these latter being different for attracting and repulsing fixed points},
  language  = {en}
}
@article{SpitzvonSeggernGrunwaldtetal.2002,
  author    = {Spitz, Christian and von Seggern, David and Grunwaldt, Gisela and Menzel, Ralf},
  title     = {Biochemical Diagnostics by Excited State Absorption Spectroscopy},
  isbn      = {0-8194-4365-4},
  year      = {2002},
  language  = {en}
}
@article{SkoczowskyJechowStuermeretal.2010,
  author    = {Skoczowsky, Danilo and Jechow, Andreas and St{\"u}rmer, Herbert and Poßner, Torsten and Sacher, Joachim and Menzel, Ralf},
  title     = {Quasi-monolithic ring resonator for efficient frequency doubling of an external cavity diode laser},
  issn      = {0946-2171},
  doi       = {10.1007/s00340-009-3802-7},
  year      = {2010},
  abstract  = {A quasi-monolithic second-harmonic-generation ring resonator assembled with miniaturized components is presented. The ring contains a 10-mm-long bulk periodically poled lithium niobate crystal for second-harmonic generation, four plane mirrors and two gradient-index lenses. All parts are mounted on a glass substrate with an overall size of 19.5 mmx8.5 mmx4 mm. As pump source a broad-area laser diode operated in an external resonator with Littrow arrangement is utilized. This external cavity diode laser provides near diffraction limited, narrow-bandwidth emission with an optical output power of 450 mW at a wavelength of 976 nm. Locking of the diode laser emission to the resonance frequency of the ring cavity was achieved by an optical self-injection locking technique. With this setup more than 126 mW of diffraction-limited blue light at 488 nm could be generated. The opto-optical conversion efficiency was 28\% and a wall plug efficiency better than 5.5\% could be achieved.},
  language  = {en}
}
@article{SkoczowskyJechowMenzeletal.2010,
  author    = {Skoczowsky, Danilo and Jechow, Andreas and Menzel, Ralf and Paschke, Katrin and Erbert, G{\"o}tz},
  title     = {Efficient second-harmonic generation using a semiconductor tapered amplifier in a coupled ring-resonator geometry},
  issn      = {0146-9592},
  doi       = {10.1364/OL.35.000232},
  year      = {2010},
  abstract  = {A new approach for efficient second-harmonic generation using diode lasers is presented. The experimental setup is based on a tapered amplifier operated in a ring resonator that is coupled to a miniaturized enhancement ring resonator containing a periodically poled lithium niobate crystal. Frequency locking of the diode laser emission to the resonance frequency of the enhancement cavity is realized purely optically, resulting in stable, single-frequency operation. Blue light at 488 nm with an output power of 310 mW is generated with an optical-to-optical conversion efficiency of 18\%.},
  language  = {en}
}
@article{SeefeldtHeuerMenzel2003,
  author    = {Seefeldt, Michael and Heuer, Axel and Menzel, Ralf},
  title     = {Compact white-light source with an average output power of 2.4 W and 900 nm spectral bandwidth},
  year      = {2003},
  language  = {en}
}
@article{SchwarzeGarzTeuchneretal.2014,
  author    = {Schwarze, Thomas and Garz, Andreas and Teuchner, Klaus and Menzel, Ralf and Holdt, Hans-J{\"u}rgen},
  title     = {Two-photon probes for metal ions based on phenylaza[18]crown-6 ethers and 1,2,3-triazoles as pi-linkers},
  series = {ChemPhysChem : a European journal of chemical physics and physical chemistry},
  volume    = {15},
  journal   = {ChemPhysChem : a European journal of chemical physics and physical chemistry},
  number    = {12},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1439-4235},
  doi       = {10.1002/cphc.201402232},
  pages     = {2436 -- 2439},
  year      = {2014},
  language  = {en}
}