We combine soliton dynamics in gas-filled hollow-core photonic crystal fibers with a state-of-the-art fiber laser to realize a turnkey system producing few-femtosecond pulses at 8-MHz repetition rate at pump energies as low as 220 nJ. Furthermore, by exploiting the soliton self-frequency shift in a second hydrogen-filled hollow-core fiber, we efficiently generate pulses as short as 22 fs, continuously tunable from 1100 to 1474 nm.
Nonreciprocal vortex isolator via topology-selective stimulated Brillouin scattering
Xinglin Zeng,
Philip Russell,
Christian Wolff ,
Michael Frosz,
Gordon Wong,
Birgit Stiller
Science Advances
8
(42)
eabq6064
(2022)
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Optical nonreciprocity, which breaks the symmetry between forward and backward propagating optical waves, has become vital in photonic systems and enables many key applications. So far, all the existing nonreciprocal systems are implemented for linearly or randomly polarized fundamental modes. Optical vortex modes, with wavefronts that spiral around the central axis of propagation, have been extensively studied over the past decades and offer an additional degree of freedom useful in many applications. Here, we report a light-driven nonreciprocal isolation system for optical vortex modes based on topology-selective stimulated Brillouin scattering (SBS) in chiral photonic crystal fiber. The device can be reconfigured as an amplifier or an isolator by adjusting the frequency of the control signal. The experimental results show vortex isolation of 22 decibels (dB), which is at the state of the art in fundamental mode isolators using SBS. This device may find applications in optical communications, fiber lasers, quantum information processing, and optical tweezers.
Label-free monitoring of proteins in optofluidic hollow-core photonic crystal fibres
Jan R. Heck ,
Ermanno Miele,
Ralf Mouthaan,
Michael Frosz,
Tuomas P J Knowles,
Tijmen G Euser
Methods and Applications in Fluorescence
10
045008
(2022)
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The fluorescent detection of proteins without labels or stains, which affect their behaviour and require additional genetic or chemical preparation, has broad applications to biological research. However, standard approaches require large sample volumes or analyse only a small fraction of the sample. Here we use optofluidic hollow-core photonic crystal fibres to detect and quantify sub-microlitre volumes of unmodified bovine serum albumin (BSA) protein down to 100 nM concentrations. The optofluidic fibre's waveguiding properties are optimised for guidance at the (auto)fluorescence emission wavelength, enabling fluorescence collection from a 10 cm long excitation region, increasing sensitivity. The observed spectra agree with spectra taken from a conventional cuvette-based fluorimeter, corrected for the guidance properties of the fibre. The BSA fluorescence depended linearly on BSA concentration, while only a small hysteresis effect was observed, suggesting limited biofouling of the fibre sensor. Finally, we briefly discuss how this method could be used to study aggregation kinetics. With small sample volumes, the ability to use unlabelled proteins, and continuous flow, the method will be of interest to a broad range of protein-related research.
Strong circular dichroism for the HE11 mode in
twisted single-ring hollow-core photonic crystal
fiber: erratum
Paul Roth,
Yang Chen,
Mehmet Can Günendi,
Ramin Beravat,
Nitin Edavalath,
Michael Frosz,
Goran Ahmed,
Gordon Wong,
Philip Russell
Recent work has revealed that the dispersion relation, given inOptica 5, 1315 (2018), for helicalBloch modes in a ring of capillaries surrounding a central hollowcore, is incorrect.Herewe correct this error and provide a revised version of Fig. 2. The overall conclusions of the original paper are unaffected.
Erratum to “Bragg Reflection and Conversion Between Helical Bloch Modes in Chiral Three-Core Photonic Crystal Fiber”
Sébastien Loranger,
Yang Chen,
Paul Roth,
Michael Frosz,
Gordon Wong,
Philip Russell
Journal of Lightwave Technology
40
(22)
7479-7479
(2022)
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The dispersion relation for the helical Bloch modes in this paper contains an error, which affects Equation (3) in the original manuscript, as well as Fig. 2. Otherwise the conclusions of the paper are unaffected.
Stern–Volmer analysis of photocatalyst fluorescence quenching within hollow-core photonic crystal fibre microreactors
Alexander S. Gentleman,
Takashi Lawson,
Matthew G. Ellis,
Molly Davis,
Jacob Turner-Dore,
Alison S. H. Ryder,
Michael Frosz,
Maria Ciaccia,
Erwin Reisner, et al.
Chemical Communications
58
10548
(2022)
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We report the use of optofluidic hollow-core photonic crystal fibres as microreactors for Stern–Volmer (SV) luminescence quenching analysis of visible-light photocatalytic reactions. This technology enables measurements on nanolitre volumes and paves the way for automated SV analyses in continuous flow that minimise catalyst and reagent usage. The method is showcased using a recently developed photoredox-catalysed α-C–H alkylation reaction of unprotected primary alkylamines.
Hollow-core optical fibre sensors for operando Raman spectroscopy investigation of Li-ion battery liquid electrolytes
Ermanno Miele,
Wesley M. Dose,
Ilya Manyakin,
Michael Frosz,
Zachary Ruff,
Michael F. L. De Volder,
Clare P. Grey,
Jeremy J. Baumberg,
Tijmen G. Euser
Nature Communications
13
1651
(2022)
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Improved analytical tools are urgently required to identify degradation and failure mechanisms in Li-ion batteries. However, understanding and ultimately avoiding these detrimental mechanisms requires continuous tracking of complex electrochemical processes in different battery components. Here, we report an operando spectroscopy method that enables monitoring the chemistry of a carbonate-based liquid electrolyte during electrochemical cycling in Li-ion batteries with a graphite anode and a LiNi0.8Mn0.1Co0.1O2 cathode. By embedding a hollow-core optical fibre probe inside a lab-scale pouch cell, we demonstrate the effective evolution of the liquid electrolyte species by background-free Raman spectroscopy. The analysis of the spectroscopy measurements reveals changes in the ratio of carbonate solvents and electrolyte additives as a function of the cell voltage and show the potential to track the lithium-ion solvation dynamics. The proposed operando methodology contributes to understanding better the current Li-ion battery limitations and paves the way for studies of the degradation mechanisms in different electrochemical energy storage systems.
Stimulated Brillouin scattering in chiral photonic crystal fiber
Xinglin Zeng,
Wenbin He,
Michael Frosz,
Andreas Geilen,
Paul Roth,
Gordon Wong,
Philip Russell,
Birgit Stiller
Photonics Research
10
(3)
711-718
(2022)
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Stimulated Brillouin scattering (SBS) has many applications; for example, in sensing, microwave photonics, and signal processing. Here, we report the first experimental study of SBS in chiral photonic crystal fiber (PCF), which displays optical activity and robustly maintains circular polarization states against external perturbations. As a result, circularly polarized pump light is cleanly backscattered into a Stokes signal with the orthogonal circular polarization state, as is required by angular momentum conservation. By comparison, untwisted PCF generates a Stokes signal with an unpredictable polarization state, owing to its high sensitivity to external perturbations. We use chiral PCF to realize a circularly polarized continuous-wave Brillouin laser. The results pave the way for a new generation of stable circularly polarized SBS systems with applications in quantum manipulation, optical tweezers, optical gyroscopes, and fiber sensors.
Efficient Excitation of High-Purity Modes in Arbitrary Waveguide Geometries
Ralf Mouthaan,
Peter J. Christopher,
Jonathan Pinnell,
Michael Frosz,
George Gordon,
Timothy D. Wilkinson,
Tijmen G. Euser
Journal of Lightwave Technology
40
(4)
1150-1160
(2022)
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A general method is presented for exciting discrete modes in waveguides of arbitrary geometry. Guided modes supported by the waveguide are first calculated using a finite difference frequency domain model. High efficiency holograms to excite these discrete modes are then generated using the Direct Search hologram generation algorithm. The Direct Search algorithm is optimised such that the inherent properties of waveguide modes are exploited to give faster execution times. A nodeless antiresonant photonic crystal fibre is considered as a test geometry, in which high-purity modes are experimentally excited and in-coupling efficiencies of up to 32.8% are obtained.
Contact
TDSU Fibre Fabrication & Glass Studio Michael Frosz
Max Planck Institute for the Science of Light Staudtstr. 2 91058 Erlangen, Germany
