2017

show Content B. Doherty, A. Csáki, M. Thiele, M. Zeisberger, A. Schwuchow, J. Kobelke, W. Fritzsche, and M. Schmidt, "Nanoparticle functionalised small-core suspended-core fibre – a novel platform for efficient sensing," Biomed. Opt. Express 8, 790-799 (2017).

Abstract

Detecting small quantities of specific target molecules is of major importance within bioanalytics for efficient disease diagnostics. One promising sensing approach relies on combining plasmonically-active waveguides with microfluidics yielding an easy-to-use sensing platform. Here we introduce suspended-core fibres containing immobilised plasmonic nanoparticles surrounding the guiding core as a concept for an entirely integrated optofluidic platform for efficient refractive index sensing. Due to the extremely small optical core and the large adjacent microfluidic channels, over two orders of magnitude of nanoparticle coverage densities have been accessed with millimetre-long sample lengths showing refractive index sensitivities of 170 nm/RIU for aqueous analytes where the fibre interior is functionalised by gold nanospheres. Our concept represents a fully integrated optofluidic sensing system demanding small sample volumes and allowing for real-time analyte monitoring, both of which are highly relevant within invasive bioanalytics, particularly within molecular disease diagnostics and environmental science.

doi:10.1364/BOE.8.000790

show Content B. Doherty, M. Thiele, S. Warren-Smith, E. Schartner, H. Ebendorff-Heide, W. Fritzsche, M. A. Schmidt, "Plasmonic nanoparticle-functionalized exposed-core fiber—an optofluidic refractive index sensing platform," Opt. Lett.42, 4395-4398 (2017)

Abstract

Here, we show that immobilizing ensembles of gold nanospheres within tailored areas on the open side of an exposed-core microstructured fiber yields a monolithic, highly sensitive plasmon-based refractive index sensor. The nanoparticle densities (average nanoparticle diameter: 45 nm) on the small-core fiber (core diameter: 2.5 μm) are controlled electrostatically, yielding densities of 4  nanoparticles/μm2. Refractive index sensitivities of 200 nm/RIU for aqueous analytes at high fringe contrast levels (−20  dB) have been observed. Our concept presents an easy-to-use, efficient, and multiplex-compatible sensing platform for rapid small-volume detection with the capacity for integration into a bioanalytic, optofluidic, or microfluidic system.

doi:10.1364/OL.42.004395

show Content M. Falge, F.G. Fröbel, V. Engel, and S. Gräfe, "Time-resolved photoelectron spectroscopy of IR-driven electron dynamics in a charge transfer model system," Phys. Chem. Chem. Phys. 19, 19683 (2017).

Abstract

If the adiabatic approximation is valid, electrons smoothly adapt to molecular geometry changes. In contrast, as a characteristic of diabatic dynamics, the electron density does not follow the nuclear motion. Recently, we have shown that the asymmetry in time-resolved photoelectron spectra serves as a tool to distinguish between these dynamics [Falge et al., J. Phys. Chem. Lett., 2012, 3, 2617]. Here, we investigate the influence of an additional, moderately intense infrared (IR) laser field, as often applied in attosecond time-resolved experiments, on such asymmetries. This is done using a simple model for coupled electronic-nuclear motion. We calculate time-resolved photoelectron spectra and their asymmetries and demonstrate that the spectra directly map the bound electron–nuclear dynamics. From the asymmetries, we can trace the IR field-induced population transfer and both the field-driven and intrinsic (non-)adiabatic dynamics. This holds true when considering superposition states accompanied by electronic coherences. The latter are observable in the asymmetries for sufficiently short XUV pulses to coherently probe the coupled states. It is thus documented that the asymmetry is a measure for phases in bound electron wave packets and non-adiabatic dynamics.

doi:10.1039/c7cp01832k

show Content M. Gebhardt, C. Gaida, F. Stutzki, S. Hädrich, C. Jauregui, J. Limpert, and A. Tünnermann, "High average power nonlinear compression to 4  GW, sub-50  fs pulses at 2  μm wavelength," Opt. Lett. 42, 747-750 (2017).

Abstract

The combination of high-repetition-rate ultrafast thulium-doped fiber laser systems and gas-based nonlinear pulse compression in waveguides offers promising opportunities for the development of high-performance few-cycle laser sources at 2 μm wavelength. In this Letter, we report on a nonlinear pulse compression stage delivering 252 μJ, sub-50 fs-pulses at 15.4 W of average power. This performance level was enabled by actively mitigating ultrashort pulse propagation effects induced by the presence of water vapor absorptions.

doi:10.1364/OL.42.000747

show Content M. Gebhardt et al , "Nonlinear pulse compression to 43  W GW-class few-cycle pulses at 2  μm wavelength," Opt. Lett. 42, 4179-4182 (2017).

Abstract

High-average power laser sources delivering intense few-cycle pulses in wavelength regions beyond the near infrared are promising tools for driving the next generation of high-flux strong-field experiments. In this work, we report on nonlinear pulse compression to 34.4 μJ-, 2.1-cycle pulses with 1.4 GW peak power at a central wavelength of 1.82 μm and an average power of 43 W. This performance level was enabled by the combination of a high-repetition-rate ultrafast thulium-doped fiber laser system and a gas-filled antiresonant hollow-core fiber.

doi:10.1364/OL.42.004179

show Content L. Maczewsky, J. M.Zeuner, S. Nolte, A. Szameit, "Observation of photonic anomalous Floquet topological insulators," Nat. Commun. 8, 13756 (2017).

Abstract

Topological insulators are a new class of materials that exhibit robust and scatter-free transport along their edges — independently of the fine details of the system and of the edge — due to topological protection. To classify the topological character of two-dimensional systems without additional symmetries, one commonly uses Chern numbers, as their sum computed from all bands below a specific bandgap is equal to the net number of chiral edge modes traversing this gap. However, this is strictly valid only in settings with static Hamiltonians. The Chern numbers do not give a full characterization of the topological properties of periodically driven systems. In our work, we implement a system where chiral edge modes exist although the Chern numbers of all bands are zero. We employ periodically driven photonic waveguide lattices and demonstrate topologically protected scatter-free edge transport in such anomalous Floquet topological insulators.

doi:10.1038/ncomms13756

show Content R. Sollapur et al., "Resonance-enhanced multi-octave supercontinuum generation in antiresonant hollow-core fibers," Light: Science & Applications (2017)

Abstract

Ultrafast supercontinuum generation in gas-filled waveguides is an enabling technology for many intriguing applications ranging from attosecond metrology towards biophotonics, with the amount of spectral broadening crucially depending on the pulse dispersion of the propagating mode. In this study, we show that structural resonances in a gas-filled antiresonant hollow core optical fiber provide an additional degree of freedom in dispersion engineering, which enables the generation of more than three octaves of broadband light that ranges from deep UV wavelengths to near infrared. Our observation relies on the introduction of a geometric-induced resonance in the spectral vicinity of the ultrafast pump laser, outperforming gas dispersion and yielding a unique dispersion profile independent of core size, which is highly relevant for scaling input powers. Using a krypton-filled fiber, we observe spectral broadening from 200 nm to 1.7 μm at an output energy of approximately 23 μJ within a single optical mode across the entire spectral bandwidth. Simulations show that the frequency generation results from an accelerated fission process of soliton-like waveforms in a non-adiabatic dispersion regime associated with the emission of multiple phase-matched Cherenkov radiations on both sides of the resonance. This effect, along with the dispersion tuning and scaling capabilities of the fiber geometry, enables coherent ultra-broadband and high-energy sources, which range from the UV to the mid‐infrared spectral range.

doi: 10.1038/lsa.2017.124

show Content D. Richter et al., "Minimizing residual spectral drift in laser diode bars using femtosecond-written volume Bragg gratings in fused silica," Opt. Lett. 42, 623 (2017).

Abstract

Ultrashort laser pulses are used to inscribe volume Bragg gratings (VBGs) into fused silica. These VBGs demonstrate excellent performance for the external stabilization of laser diode bars. The stabilized system emits at a wavelength of 969 nm with a signal width (FWHM) of 100 pm and shows a spectral drift as low as 24 pm for a change in output power of 45 W for a grating surface area of 10  mm2 .

doi:10.1364/OL.42.000623

show Content T. A. Goebel et al., "Flexible femtosecond inscription of fiber Bragg gratings by an optimized deformable mirror," Opt.Lett. 42, 4215 (2017)

Abstract

The period of fiber Bragg gratings is adapted by shaping the wavefronts of ultrashort laser pulses applied in a phase mask inscription technique. A specially designed deformable mirror, based on a dielectric substrate to withstand high peak powers, is utilized to deform the wavefront. A shift of about 11 nm is demonstrated for a Bragg wavelength around 1550 nm.

doi:10.1364/OL.42.004215

show Content M. Chemnitz, M. Gebhardt, C. Gaida, F. Stutzki, J. Kobelke, J. Limpert, A. Tünnermann, and M. A. Schmidt, "Hybrid soliton dynamics in liquid-core fibres," Nat. Commun. 8, 42 (2017).

Abstract

Liquid-core fibers offer local external control over pulse dispersion due to their strong thermodynamic response, offering a new degree of freedom in accurate soliton steering for reconfigurable nonlinear light generation. Here, we show how to accurately control soliton dynamics and supercontinuum generation in carbon disulfide/silica fibers by temperature and pressure tuning, monitored via the spectral location and the onset energy of non-solitonic radiation. Simulations and phase-matching calculations based on an extended thermodynamic dispersion model of carbon disulfide confirm the experimental results, which allows us to demonstrate the potential of temperature detuning of liquid-core fibers for octave spanning recompressible supercontinuum generation in the near-infrared.

doi:10.1364/OPTICA.5.000695

show Content J. Buldt, M. Müller, R. Klas, T. Eidam, J. Limpert, A. Tünnermann, "Temporal contrast enhancement of energetic laser pulses by filtered self-phase-modulation-broadened spectra," Opt. Lett. 42, 3761 (2017).

Abstract

We present a novel approach for temporal contrast enhancement of energetic laser pulses by filtered self-phase-modulation-broadened spectra. A measured temporal contrast enhancement by at least seven orders of magnitude in a simple setup has been achieved. This technique is applicable to a wide range of laser parameters and poses a highly efficient alternative to existing contrast-enhancement methods.

doi:10.1364/OL.42.003761

show Content M. Müller, A. Klenke, T. Gottschall, R. Klas, C. Rothhardt, S. Demmler, J. Rothhardt, J. Limpert, and A. Tünnermann, "High-average-power femtosecond laser at 258 nm," Opt. Lett. 42, 2826 (2017).

Abstract

We present an ultrafast fiber laser system delivering 4.6 W average power at 258 nm based on two-stage fourth-harmonic generation in beta barium borate (BBO). The beam quality is close to being diffraction limited with an M2 value of 1.3×1.6 . The pulse duration is 150 fs, which, potentially, is compressible down to 40 fs. A plain BBO and a sapphire-BBO compound are compared with respect to the achievable beam quality in the conversion process. This laser is applicable in scientific and industrial fields. Further scaling to higher average power is discussed.

doi:10.1364/OL.42.002826

show Content M. Wimmer, H. M. Price, I. Carusotto and U. Peschel, "Experimental measurement of the Berry curvature from anomalous transport," Nature Phys. 13, 545 (2017).

Abstract

The geometric properties of energy bands underlie fascinating phenomena in many systems, including solid-state, ultracold gases and photonics. The local geometric characteristics such as the Berry curvature can be related to global topological invariants such as those classifying the quantum Hall states or topological insulators. Regardless of the band topology, however, any non-zero Berry curvature can have important consequences, such as in the semi-classical evolution of a coherent wavepacket. Here, we experimentally demonstrate that the wavepacket dynamics can be used to directly map out the Berry curvature. To this end, we use optical pulses in two coupled fibre loops to study the discrete time evolution of a wavepacket in a one-dimensional geometric ‘charge’ pump, where the Berry curvature leads to an anomalous displacement of the wavepacket. This is both the first direct observation of Berry curvature effects in an optical system, and a proof-of-principle demonstration that wavepacket dynamics can serve as a high-resolution tool for mapping out geometric properties.

doi:10.1038/nphys4050

show Content Presentations at conferences

Poster

  • B. Doherty, "Plasmonic Nanoparticles in Microstructured Fibres as Detection Platforms". NanoBioSensors conference, TU Dresden.

  • F. G. Fröbel, "Analysis of avoided crossings in molecular model systems," DPG Spring Meeting, Mainz Germany (Mar 2017).

  • M. Gebhardt, "Multi-GW, 100 fs thulium-doped fiber laser system for high-harmonic generation at high repetition rates". CLEO EU 2017 (CJ-11.1 THU).

  • M. Gebhardt, C. Gaida, F. Stutzki, S. Hädrich, C. Jauregui, J. Limpert, A. Tünnermann, "High-average power 4 GW pulses with sub-8 optical cycles from a Tm-doped fiber laser driven nonlinear pulse compression stage", Proc. SPIE 10083, Fiber Lasers XIV: Technology and Systems, 100830B (22 February 2017).

  • M. Gebhardt, C. Gaida, F. Stutzki, C. Jauregui, J. Antonio-Lopez, A. Schulzgen, R. Amezcua-Correa, J. Limpert, and A. Tünnermann, "High average power nonlinear self-compression to few-cycle pulses at 2 µm wavelength in antiresonant hollow-core fiber," in Laser Congress 2017 (ASSL, LAC), OSA Technical Digest (online) (Optical Society of America, 2017), paper ATh3A.6.

  • K. Lammers, "Manipulating Polarization States in Waveguides Using Femtosecond Laser Direct Written.

  • F. J. F. Löchner et al.,  "Polarization dependence of second-harmonic generation in GaAs.

  • Tobias Bucher, Franz J. F. Lochner et al., "Integration of MoS2 Monolayers with Dielectric Nanoantennas".  PIERS St. Petersburg 2017, St. Petersburg, Russia.

  • Aleksandr Vaskin , F. J. F. Lochner et al., "Tailoring Light Emission with Monolithic Nanoantenna Arrays Based on III-V Semiconductors". PIERS St. Petersburg 2017, St. Petersburg, Russia.

  • R. Sollapur, D. Kartashov, M. Zürch, A. Hoffmann, T. Grigorova, A. Hartung, A. Schwuchow, J. Bierlich, J. Kobelke, M. A. Schmidt, C. Spielmann, “Dispersion-Designed Antiresonant Hollow-Core Fibers for Supercontinuum Generation by Soliton Explosion”, Conference on Lasers and Electro-Optics/Europe and the European Quantum Electronics, 2017.

  • Ni. Jayakumar, R. Sollapur, A. Hoffmann, T. Grigorova, A. Hartung, A. Schwuchow, J. Bierlich, J. Kobelke, M. A. Schmidt, C. Spielmann, “Polarization Evolution in  Antiresonant Hollow-Core Fibers, DoKDoK – Doctoral Student Conference on Optics, Suhl, Germany, 2017.

  • M. Mircovich, R. Sollapur, A. Hoffmann,  A. Hartung, A. Schwuchow, J. Bierlich, J. Kobelke, M. A. Schmidt, C. Spielmann, “Ultraviolet pulse generation and characterization for supercontinuum experiments”, OSAPS Fall Meeting and SOS-AAPT at Miami University, Oxford, USA, 2017.

  • E. Shestaev, “CEP stability of high-power few-cycle fiber lasers”. Ultrafast Optics XI in Jackson Hole, Wyoming, USA (2017).

  • C. Stihler, "Controlling mode instabilities at 628 W average output power in an Yb-doped rodtype fiber amplifier by active modulation of the pump power". Photonics West Conference 2017, San Francisco.

  • C. Stihler, "Mitigation of Mode Instabilities in High-Power Fiber Laser Systems by Active Modulation of the Pump Power". CLEO Europe 2017, München.

Talks

  • Brenda Doherty, "Plasmonic Microstructured Fibres for Biosensing". “20 Years Nano-Optics” international symposium, MPI Erlangen.

  • F. G. Fröbel, "Where the BO-Approximation fails: Analysis of avoided crossings in molecular model systems - An Introduction,"  Institute for Physical Chemistry, Jena (Jan 2017).

  • T. Grigorova, R. Sollapur, N. Jayakumar, A. Hoffmann,  A. Hartung, A. Schwuchow, J. Bierlich, J. Kobelke, M. A. Schmidt, C. Spielmann, “Dispersion Measurement of Engineered Antiresonant Hollow‐Core Fibers with Spectral Interferometry”, presented at CLEUO Europe 2017 Munich, Germany.

  • R. Sollapur, D. Kartashov, M. Zürch, A. Hoffmann, T. Grigorova, G. Sauer, A. Hartung, A. Schwuchow, J. Bierlich, J. Kobelke, M. Chemnitz, M. A. Schmidt C. Spielmann, “Multi-octave supercontinuum in dispersion tuned antiresonant hollow-core fibers”, DoKDoK – Doctoral Student Conference on Optics, Suhl, Germany, 2017.

  • M. Zürch, R. Sollapur, D. Kartashov, A. Hoffmann, T. Grigorova, G. Sauer, A. Hartung, A. Schwuchow, J. Bierlich, J. Kobelke, M. A. Schmidt C. Spielmann, “Multi-octave supercontinuum driven by soliton explosion in dispersion-designed antiresonant hollow-core fibers”, Conference on Lasers and Electro-Optics, 2017.

 

 

 

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