ORCID Profile
0000-0002-5324-6405
Current Organisation
Friedrich-Schiller-Universität Jena
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Optical Physics | Nonlinear Optics and Spectroscopy | Lasers and Quantum Electronics
Industrial Instruments | Medical Instruments | Expanding Knowledge in the Physical Sciences |
Publisher: The Optical Society
Date: 27-07-2016
DOI: 10.1364/OE.24.017860
Publisher: The Optical Society
Date: 27-04-2017
DOI: 10.1364/OL.42.001812
Publisher: AIP Publishing
Date: 15-09-2008
DOI: 10.1063/1.2982083
Abstract: We present experimental results on coupling to surface plasmon modes on gold nanowires selectively introduced into polarization-maintaining photonic crystal fibers. Highly polarization- and wavelength-dependent transmission is observed. In one s le 24.5 mm long, the transmission on and off resonance differs by as much as 45 dB. Near-field optical images of the light emerging from such a gold-filled fiber show light guided on the wire at surface plasmon resonances. Finite element simulations are in good agreement with the experimental results. These gold-filled fibers can be potentially used as in-fiber wavelength-dependent filters and polarizers and as near-field tips for sub-wavelength-scale imaging.
Publisher: The Optical Society
Date: 29-08-2016
DOI: 10.1364/OE.24.020515
Publisher: IEEE
Date: 06-2019
Publisher: Springer Science and Business Media LLC
Date: 09-10-2012
DOI: 10.1038/NCOMMS2109
Publisher: American Chemical Society (ACS)
Date: 19-10-2022
DOI: 10.1021/ACSSENSORS.2C00988
Abstract: Nanoparticle tracking analysis (NTA) is a widely used methodology to investigate nanoscale systems at the single species level. Here, we introduce the locally structured on-chip optofluidic hollow-core light cage, as a novel platform for waveguide-assisted NTA. This hollow waveguide guides light by the antiresonant effect in a sparse array of dielectric strands and includes a local modification to realize aberration-free tracking of in idual nano-objects, defining a novel on-chip solution with properties specifically tailored for NTA. The key features of our system are (i) well-controlled nano-object illumination through the waveguide mode, (ii) diffraction-limited and aberration-free imaging at the observation site, and (iii) a high level of integration, achieved by on-chip interfacing to fibers. The present study covers all aspects relevant for NTA including design, simulation, implementation via 3D nanoprinting, and optical characterization. The capabilities of the approach to precisely characterize practically relevant nanosystems have been demonstrated by measuring the solvency-induced collapse of a nanoparticle system which includes polymer brush-based shells that react to changes in the liquid environment. Our study unlocks the advantages of the light cage approach in the context of NTA, suggesting its application in various areas such as bioanalytics, life science, environmental science, or nanoscale material science in general.
Publisher: AIP Publishing
Date: 06-2021
DOI: 10.1063/5.0048501
Abstract: Interfacing integrated on-chip waveguides with spectroscopic approaches represents one research direction within current photonics aiming at reducing geometric footprints and increasing device densities. Particularly relevant is to connect chip-integrated waveguides with established fiber-based circuitry, opening up the possibility for a new class of devices within the field of integrated photonics. Here, one attractive waveguide is the on-chip light cage, confining and guiding light in a low-index core through the anti-resonance effect. This waveguide, implemented via 3D nanoprinting and reaching nearly 100% overlap of mode and material of interest, uniquely provides side-wise access to the core region through the open spaces between the cage strands, drastically reducing gas diffusion times. Here, we extend the capabilities of the light cage concept by interfacing light cages and optical fibers, reaching a fully fiber-integrated on-chip waveguide arrangement with its spectroscopic capabilities demonstrated here on the ex le of tunable diode laser absorption spectroscopy of ammonia. Controlling and optimizing the fiber circuitry integration have been achieved via automatic alignment in etched v-grooves on silicon chips. This successful device integration via 3D nanoprinting highlights the fiber-interfaced light cage to be an attractive waveguide platform for a multitude of spectroscopy-related fields, including bio-analytics, lab-on-chip photonic sensing, chemistry, and quantum metrology.
Publisher: Springer Science and Business Media LLC
Date: 31-05-2021
DOI: 10.1038/S41377-021-00556-Z
Abstract: Controlling coherent interaction between optical fields and quantum systems in scalable, integrated platforms is essential for quantum technologies. Miniaturised, warm alkali-vapour cells integrated with on-chip photonic devices represent an attractive system, in particular for delay or storage of a single-photon quantum state. Hollow-core fibres or planar waveguides are widely used to confine light over long distances enhancing light-matter interaction in atomic-vapour cells. However, they suffer from inefficient filling times, enhanced dephasing for atoms near the surfaces, and limited light-matter overlap. We report here on the observation of modified electromagnetically induced transparency for a non-diffractive beam of light in an on-chip, laterally-accessible hollow-core light cage. Atomic layer deposition of an alumina nanofilm onto the light-cage structure was utilised to precisely tune the high-transmission spectral region of the light-cage mode to the operation wavelength of the atomic transition, while additionally protecting the polymer against the corrosive alkali vapour. The experiments show strong, coherent light-matter coupling over lengths substantially exceeding the Rayleigh range. Additionally, the stable non-degrading performance and extreme versatility of the light cage provide an excellent basis for a manifold of quantum-storage and quantum-nonlinear applications, highlighting it as a compelling candidate for all-on-chip, integrable, low-cost, vapour-based photon delay.
Publisher: The Optical Society
Date: 18-01-2016
DOI: 10.1364/OL.41.000448
Publisher: The Optical Society
Date: 25-01-2019
DOI: 10.1364/OL.44.000626
Publisher: The Optical Society
Date: 09-05-2016
DOI: 10.1364/OME.6.001790
Publisher: The Optical Society
Date: 24-10-2017
DOI: 10.1364/OL.42.004395
Publisher: AIP Publishing
Date: 10-2022
DOI: 10.1063/5.0102071
Abstract: The on-chip detection of fluorescent light is essential for many bioanalytical and life-science related applications. Here, the optofluidic light cage consisting of a sparse array of micrometer encircling a hollow core represents an innovative concept, particularly for on-chip waveguide-based spectroscopy. In the present work, we demonstrate the potential of the optofluidic light cage concept in the context of integrated on-chip fluorescence spectroscopy. Specifically, we show that fluorescent light from a dye-doped aqueous solution generated in the core of a nanoprinted dual-ring light cage can be efficiently captured and guided to the waveguide ports. Notably, the fluorescence collection occurs predominantly in the fundamental mode, a property that distinguishes it from evanescent field-based waveguide detection schemes that favor collection in higher-order modes. Through exploiting the flexibility of waveguide design and 3D nanoprinting, both excitation and emission have been localized in the high transmission domains of the fundamental core mode. Fast diffusion, detection limits comparable to bulk measurements, and the potential of this approach in terms of device integration were demonstrated. Together with previous results on absorption spectroscopy, the achievements presented here suggest that the optofluidic light cage concept defines a novel photonic platform for integrated on-chip spectroscopic devices and real-time sensors compatible with both the fiber circuitry and microfluidics. Applications in areas such as bioanalytics and environmental sciences are conceivable, while more sophisticated applications such as nanoparticle tracking analysis and integrated Raman spectroscopy could be envisioned.
Publisher: Optica Publishing Group
Date: 24-12-2019
DOI: 10.1364/OL.45.000196
Abstract: Here, we show that the optical properties of direct-laser-written on-chip hollow-core waveguides—so-called light cages—can be controlled to a very high degree by dielectric nanofilms. Using low-temperature atomic layer deposition (ALD), alumina nanofilms are concentrically deposited on the high-aspect strands that surround the central air core and confine the light via the anti-resonant effect. In accordance with modal cutoff simulations without any free parameters, a linear spectral shift of the resonances with increasing film thickness is experimentally observed. The phenomenon is explained by a shift in the dispersions of cladding supermodes. As neither cage geometry nor polymer is affected by the film deposition, our results suggest ALD to be an essential tool for fine-tuning the properties of hollow-core light cages and to protect them from aggressive substances, being relevant for, e.g., bioanalytics or quantum technology.
Publisher: American Chemical Society (ACS)
Date: 09-12-2020
Publisher: Optica Publishing Group
Date: 11-01-2023
DOI: 10.1364/OE.475794
Abstract: Here, we unlock the properties of the recently introduced on-chip hollow-core microgap waveguide in the context of optofluidics which allows for intense light-water interaction over long lengths with fast response times. The nanoprinted waveguide operates by the anti-resonance effect in the visible and near-infrared domain and includes a hollow core with defined gaps every 176 µm. The spectroscopic capabilities are demonstrated by various absorption-related experiments, showing that the Beer-Lambert law can be applied without any modification. In addition to revealing key performance parameters, time-resolved experiments showed a decisive improvement in diffusion times resulting from the lateral access provided by the microgaps. Overall, the microgap waveguide represents a pathway for on-chip spectroscopy in aqueous environments.
Publisher: The Optical Society
Date: 09-08-2019
DOI: 10.1364/OL.44.004016
Publisher: American Physical Society (APS)
Date: 20-11-2019
Publisher: American Chemical Society (ACS)
Date: 31-12-2018
Publisher: The Optical Society
Date: 07-2016
DOI: 10.1364/OE.24.015702
Publisher: The Optical Society
Date: 28-01-2021
DOI: 10.1364/OME.413199
Publisher: American Chemical Society (ACS)
Date: 03-01-2017
DOI: 10.1021/ACS.NANOLETT.6B03373
Abstract: We propose and experimentally demonstrate a monolithic nanowire-enhanced fiber-based nanoprobe for the broadband delivery of light (550-730 nm) to a deep subwavelength scale using short-range surface plasmons. The geometry is formed by a step index fiber with an integrated gold nanowire in its core and a protruding gold nanotip with sub-10 nm apex radius. We present a novel coupling scheme to excite short-range surface plasmons, whereby the radially polarized hybrid mode propagating inside the nanowire section excites the plasmonic mode close to the fiber endface, which is in turn superfocused down to nanoscale dimensions at the tip apex. We show that in this all-integrated fiber-plasmonic coupling scheme the wire length can be orders of magnitude longer than the attenuation length of short-range plasmon polaritons, yielding a broadband plasmon excitation and reducing demands in fabrication. We observe that the scattered light in the far-field from the nanotip is axially polarized and preferentially excited by a radially polarized input, unambiguously revealing that it originates from a short-range plasmon propagating on the nanotip, in agreement with simulations. This novel excitation scheme will have important applications in near-field microscopy and nanophotonics and potentially offers significantly improved resolution compared to current delivery near-field probes.
Publisher: Optica Publishing Group
Date: 22-02-2022
DOI: 10.1364/PRJ.449067
Abstract: We evaluate the sensing properties of plasmonic waveguide sensors by calculating their resonant transmission spectra in different regions of the non-Hermitian eigenmode space. We elucidate the pitfalls of using modal dispersion calculations in isolation to predict plasmonic sensor performance, which we address by using a simple model accounting for eigenmode excitation and propagation. Our transmission calculations show that resonant wavelength and spectral width crucially depend on the length of the sensing region, so that no single criterion obtained from modal dispersion calculations alone can be used as a proxy for sensitivity. Furthermore, we find that the optimal detection limits occur where directional coupling is supported, where the narrowest spectra occur. Such narrow spectral features can only be measured by filtering out all higher-order modes at the output, e.g., via a single-mode waveguide. Our calculations also confirm a characteristic square root dependence of the eigenmode splitting with respect to the permittivity perturbation at the exceptional point, which we show can be identified through the sensor beat length at resonance. This work provides a convenient framework for designing and characterizing plasmonic waveguide sensors when comparing them with experimental measurements.
Publisher: Walter de Gruyter GmbH
Date: 06-2018
Abstract: The concentration of light to deep-subwavelength dimensions plays a key role in nanophotonics and has the potential to bring major breakthroughs in fields demanding to understand and initiate interaction on nanoscale dimensions, including molecular disease diagnostics, DNA sequencing, single nanoparticle manipulation and characterization, and semiconductor inspection. Although planar metallic nanostructures provide a pathway to nanoconcentration of electromagnetic fields, the delivery/collection of light to/from such plasmonic nanostructures is often inefficient, narrow-band, and requires complicated excitations schemes, limiting widespread applications. Moreover, planar photonic devices reveal a reduced flexibility in terms of bringing the probe light to the s le. An ideal photonic-plasmonic device should combine (i) a high spatial resolution at the nanometre level beyond to what is state-of-the-art in near-field microscopy with (ii) flexible optical fibers to promote a straightforward integration into current near-field scanning microscopes. Here, we review the recent development and main achievements of nanoconcentrators interfacing optical fibers at their end-faces that reach entirely monolithic designs, including c anile probes, gold-coated fiber-taper nanotips, and fiber-integrated gold nanowires.
Publisher: The Optical Society
Date: 29-03-2016
DOI: 10.1364/OE.24.007507
Publisher: American Chemical Society (ACS)
Date: 19-12-2018
Publisher: Springer Science and Business Media LLC
Date: 20-08-2021
DOI: 10.1038/S41377-021-00491-Z
Abstract: Strong focusing on diffraction-limited spots is essential for many photonic applications and is particularly relevant for optical trapping however, all currently used approaches fail to simultaneously provide flexible transportation of light, straightforward implementation, compatibility with waveguide circuitry, and strong focusing. Here, we demonstrate the design and 3D nanoprinting of an ultrahigh numerical aperture meta-fibre for highly flexible optical trapping. Taking into account the peculiarities of the fibre environment, we implemented an ultrathin meta-lens on the facet of a modified single-mode optical fibre via direct laser writing, leading to a diffraction-limited focal spot with a record-high numerical aperture of up to NA ≈ 0.9. The unique capabilities of this flexible, cost-effective, bio- and fibre-circuitry-compatible meta-fibre device were demonstrated by optically trapping microbeads and bacteria for the first time with only one single-mode fibre in combination with diffractive optics. Our study highlights the relevance of the unexplored but exciting field of meta-fibre optics to a multitude of fields, such as bioanalytics, quantum technology and life sciences.
Publisher: American Chemical Society (ACS)
Date: 02-09-2022
Publisher: American Physical Society (APS)
Date: 09-04-2018
Publisher: Optica Publishing Group
Date: 11-03-2021
DOI: 10.1364/OME.419398
Abstract: Three-dimensional laser nanoprinting represents a unique approach for implementing on-chip hollow-core waveguides. Here we discuss the fabrication characteristics of the light cage geometry arising from the used two-photon polymerization lithography. We reveal the current limits of achievable waveguide length (3 cm), single strand aspect ratio (8200) and modal attenuation. Very high reproducibility for light cages on the same chip is found, while different conditions in fabrication cycles impose chip-to-chip variations. We also highlight the relevance of including reinforcement rings to prevent structural collapse. The results presented uncover key issues that result from nanoprinting light cages and can be transferred to other nanoprinted waveguides.
Publisher: Wiley
Date: 19-05-2020
Publisher: The Optical Society
Date: 07-12-2012
DOI: 10.1364/OE.20.028409
Publisher: IEEE
Date: 07-2017
Publisher: The Optical Society
Date: 08-06-2011
DOI: 10.1364/OE.19.012180
Publisher: The Optical Society
Date: 14-04-2011
DOI: 10.1364/OE.19.008200
Publisher: OSA
Date: 2013
Publisher: OSA
Date: 2016
Publisher: The Optical Society
Date: 05-04-2017
DOI: 10.1364/OME.7.001486
Publisher: Wiley
Date: 06-10-2020
Publisher: Springer Science and Business Media LLC
Date: 07-2021
Publisher: Wiley
Date: 12-04-2011
Abstract: Magneto‐optical glasses are of considerable current interest, primarily for applications in fiber circuitry, optical isolation, all‐optical diodes, optical switching and modulation. While the benchmark materials are still crystalline, glasses offer a variety of unique advantages, such as very high rare‐earth and heavy‐metal solubility and, in principle, the possibility of being produced in fiber form. In comparison to conventional fiber‐drawing processes, pressure‐assisted melt‐filling of microcapillaries or photonic crystal fibers with magneto‐optical glasses offers an alternative route to creating complex waveguide architectures from unusual combinations of glasses. For instance, strongly diamagnetic tellurite or chalcogenide glasses with high refractive index can be combined with silica in an all‐solid, microstructured waveguide. This promises the implementation of as‐yet‐unsuitable but strongly active glass candidates as fiber waveguides, for ex le in photonic crystal fibers.
Publisher: IOP Publishing
Date: 16-01-2013
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C2H_3
Abstract: We experimentally demonstrate a hybrid plasmonic fiber with tuneable Eigenmode interactions near the exceptional point, via near-infrared transmission experiments. We present a design at visible wavelengths, extending design opportunities for tuneable non-Hermitian waveguide systems.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2015
DOI: 10.1038/SREP17060
Abstract: Due to the ongoing improvement in nanostructuring technology, ultrathin metallic nanofilms have recently gained substantial attention in plasmonics, e.g. as building blocks of metasurfaces. Typically, noble metals such as silver or gold are the materials of choice, due to their excellent optical properties, however they also possess some intrinsic disadvantages. Here, we introduce niobium nanofilms (~10 nm thickness) as an alternate plasmonic platform. We demonstrate functionality by depositing a niobium nanofilm on a plasmonic fiber taper and observe a dielectric-loaded niobium surface-plasmon excitation for the first time, with a modal attenuation of only 3–4 dB/mm in aqueous environment and a refractive index sensitivity up to 15 μm/RIU if the analyte index exceeds 1.42. We show that the niobium nanofilm possesses bulk optical properties, is continuous, homogenous and inert against any environmental influence, thus possessing several superior properties compared to noble metal nanofilms. These results demonstrate that ultrathin niobium nanofilms can serve as a new platform for biomedical diagnostics, superconducting photonics, ultrathin metasurfaces or new types of optoelectronic devices.
Publisher: Wiley
Date: 17-01-2022
Abstract: Widely wavelength‐tunable femtosecond light sources in a compact, robust footprint play a central role in many prolific research fields and technologies, including medical diagnostics, biophotonics, and metrology. Fiber lasers are on the verge in the development of such sources, yet widespan spectral tunability of femtosecond pulses remains a pivotal challenge. Dispersive wave generation, also known as Cherenkov radiation, offers untapped potentials to serve these demands. In this work, the concept of quasi‐phase matching for multi‐order dispersive wave formation with record‐high spectral fidelity and femtosecond durations is exploited in selected, partially conventionally unreachable spectral regions. Versatile patterned sputtering is utilized to realize height‐modulated high‐index nano‐films on exposed fiber cores to alter fiber dispersion to an unprecedented degree through spatially localized, induced resonances. Nonlinear optical experiments and simulations, as well as phase‐mismatching considerations based on an effective dispersion, confirm the conversion process and reveal unique emission features, such as almost power‐independent wavelength stability and femtosecond duration. This resonance‐empowered approach is applicable to both fiber and on‐chip photonic systems and paves the way to instrumentalize dispersive wave generation as a unique tool for efficient, coherent femtosecond multi‐frequency conversion for applications in areas such as bioanalytics, life science, quantum technology, or metrology.
Location: Germany
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2018
End Date: 11-2021
Amount: $420,473.00
Funder: Australian Research Council
View Funded Activity