Precise knowledge of the group velocity dispersion in gas-filled hollow-core photonic crystal fiber is essential for accurate modeling of ultrafast nonlinear dynamics. Here we study the validity of the capillary approximation commonly used to calculate the modal refractive index in kagome-style photonic crystal fibers. For area-preserving core radius alpha(AP) and core wall thickness t, measurements and finite element simulations show that the approximation has an error greater than 15% for wavelengths longer than 0.56 root(alpha(AP)t), independently of the gas-filling pressure. By introducing an empirical wavelength-dependent core radius, the range of validity of the capillary approximation is extended out to a wavelength of at least 0.98 root(alpha(AP)t). (C) 2014 Optical Society of America
Rydberg atoms in hollow-core photonic crystal fibres
G. Epple,
K. S. Kleinbach,
T. G. Euser,
N. Y. Joly,
T. Pfau,
P. St J. Russell,
R. Loew
The exceptionally large polarizability of highly excited Rydberg atoms-six orders of magnitude higher than ground-state atoms-makes them of great interest in fields such as quantum optics, quantum computing, quantum simulation and metrology. However, if they are to be used routinely in applications, a major requirement is their integration into technically feasible, miniaturized devices. Here we show that a Rydberg medium based on room temperature caesium vapour can be confined in broadband-guiding kagome-style hollow-core photonic crystal fibres. Three-photon spectroscopy performed on a caesium-filled fibre detects Rydberg states up to a principal quantum number of n = 40. Besides small energy-level shifts we observe narrow lines confirming the coherence of the Rydberg excitation. Using different Rydberg states and core diameters we study the influence of confinement within the fibre core after different exposure times. Understanding these effects is essential for the successful future development of novel applications based on integrated room temperature Rydberg systems.
Atomic mercury vapor inside a hollow-core photonic crystal fiber
Ulrich Vogl,
Christian Peuntinger,
Nicolas Y. Joly,
Philip St. J. Russell,
Christoph Marquardt,
Gerd Leuchs
We demonstrate high atomic mercury vapor pressure in a kagome-style hollow-core photonic crystal fiber at room temperature. After a few days of exposure to mercury vapor the fiber is homogeneously filled and the optical depth achieved remains constant. With incoherent optical pumping from the ground state we achieve an optical depth of 114 at the 6(3)P(2) - 6(3)D(3) transition, corresponding to an atomic mercury number density of 6 x 10(10) cm(-3). The use of mercury vapor in quasi one-dimensional confinement may be advantageous compared to chemically more active alkali vapor, while offering strong optical nonlinearities in the ultraviolet region of the optical spectrum. (C) 2014 Optical Society of America
Multistability and spontaneous breaking in pulse-shape symmetry in fiber
ring cavities
M. J. Schmidberger,
D. Novoa,
F. Biancalana,
P. St J. Russell,
N. Y. Joly
We describe the spatio-temporal evolution of ultrashort pulses propagating in a fiber ring cavity using an extension of the Lugiato-Lefever model. The model predicts the appearance of multistability and spontaneous symmetry breaking in temporal pulse shape. We also use a hydrodynamical approach to explain the stability of the observed regimes of asymmetry. (C) 2014 Optical Society of America
Damage-free single-mode transmission of deep-UV light in hollow-core PCF
F. Gebert,
M. H. Frosz,
T. Weiss,
Y. Wan,
A. Ermolov,
N. Y. Joly,
P. O. Schmidt,
P. St. J. Russell
Transmission of UV light with high beam quality and pointing stability is desirable for many experiments in atomic, molecular and optical physics. In particular, laser cooling and coherent manipulation of trapped ions with transitions in the UV require stable, single-mode light delivery. Transmitting even similar to 2 mW CW light at 280 nm through silica solid-core fibers has previously been found to cause transmission degradation after just a few hours due to optical damage. We show that photonic crystal fiber of the kagome type can be used for effectively single-mode transmission with acceptable loss and bending sensitivity. No transmission degradation was observed even after >100 hours of operation with 15 mW CW input power. In addition it is shown that implementation of the fiber in a trapped ion experiment increases the coherence time of the internal state transfer due to an increase in beam pointing stability. (C) 2014 Optical Society of America
Scientific career
Since 2021: Head of the microstructured optical fibres independent research group at the Max-Planck Institute for the Science of Light in Erlangen, Germany
Since 2009: Associate professor at the Univ. of Erlangen-Nuremberg in Germany
2005 – 2008: Maître de conférences at the Univ. of Lille in France
Education background
2012: Habilitation at the Ecole Normale Supérieure of Cachan (France) Title: Supercontinuum generation using pulses propagating in photonic crystal fibres, Defended in July. 10th 2012. Thesis adviser: Prof. Dr. Joseph Zyss.
2002-2005: Post-doctoral fellow at the University of Bath (UK) in the group of Prof. Philip Russell
1999-2002: PhD with honors (“Félicitations du jury”) at the laboratory of Physics of Lasers, Atoms, and Molecules (PhLAM) at the University of Lille (France) Title: Instabilities in pulsed mode-locked lasers: techniques for observation and control Defended on Sept. 23rd 2002. Thesis adviser: Prof. Dr. Serge Bielawski.
Awards & appointments
Since 2023: Advisor of the Erlangen Optica Student Chapter
Since 2021: Scientific coordinator of the Internation Max Planck School for the Physics of Light (IMPRS-PL)
Since 2020: Senior member of Optical Society of America (OSA)
Since 2019: Fellow of the Max Planck School of Photonics (MPSP) and member of the selection committee
Since 2016: Fellow of the Max Planck Center for Extreme and Quantum Photonics, Ottawa, Canada
1999: MENRT scholarship from the French ministry of Research to perform his doctoral degree at the University of Lille from 1999 to 2002
1998: Awarded a CIME scholarship from AUF (Agence universitaire de la Francophonie) to perform his Master study at Laval University (Québec) in 1998
Professional activities
2024: Member of the Technical Program Committee for the SPIE Photonics Europe in Strasbourg
Since 2022: Associate Editor of Opt. Express
2017: General chair of the 1st Sino-German symposium on fiber photonics for light-matter interaction in Shanghai, China
2017 – 2018: Member of the Technical Program Committee for SPIE UV and higher energy photonic
2013 – 2017: Member of Technical Program Committee for CLEO US (OSA)
2015: co-Chair of the 2nd Siegman International School of Laser (OSA)
Since 2015: Member of the Technical Program Committee for WSOF (OSA) in Hong-Kong (2015), Limasol in Cypris (2017), Adelaide in Australia (2022), and in Prague in Czech Republic (2025)
Since 20214: Member of the Student Commission of the internation Master of Advanced Optics and Technologies (MAOT)
2013: Topical session at PIERS (Progress in Electromagnetics Research Symposium) in Stockholm
2011: International conference on Nonlinear optics and complexity in photonic crystal fibers and nanostructures in Erice, in Sicily
2011: 14th International SAOT workshop on Fiber laser, sensors and materials at Reicheschwand, Germany
Since 2009: External expert for the evaluation of proposals from ANR (National agency of research in France), the Polish Society of Science, DFG (National agency of research in Germany) and ERC (European Research Council)
Since 2009: Supervisor of 13 PhD students, 2 post-docs, 14 MSc students
Ongoing projects
DFG project JO 1090/8-3 – OrbitFlySens [FAU] Orbiting flying particle sensor (with Bernhard Schmauß, FAU) – 2025-2028
BayFrance FK-34-2024 [FAU] Real-time detection of Terahertz signals using ultrashort lasers Mobility allowance – collaboration with University of Lille - 2025
BayFrance FK-35-2024 [FAU] Exploring chiral fibers for new-type of polarization-resolved endoscopy Mobility allowance – collaboration with University of Marseille – 2025
DFG project JO 1090/3-2 – Photon Triplets [FAU] Generation of photon triplets via three-photon parametric down-conversion (with Maria Chekhova) – 2024-2027
QuNet beta [MPL] 2021-2026
Max-Planck-School of Photonics (MPSP) [FAU] 2019-2025
DFG project JO 1090/6-1 -Twin Beams [FAU] Fiber source of entangled photons with giant tunable frequency separation (with Maria Chekhova) - 2021-2024
DFG project JO 1090/4-1 – Rydbergatoms in photonic crystal fibres [FAU] (with Robert Löw, University of Stuttgart) - 2019-2023
BayFrance FK-29-2018 [FAU] Frequency conversion of single-photon quantum sources using gas-filled hollow-core photonic crystal fibres Mobility allowance – collaboration with LKB, Ens Paris, France - 2018
DFG project JO 1090/3-1 – Photon Triplets [FAU] Generation of photon triplets via three-photon parametric down-conversion (with Maria Chekhova) – 2017-2020
BayFrance FK-38-2013 [FAU] Dynamical instabilities in photonic crystal fiber ring cavities synchronously pumped by femtosecond pulses Mobility allowance – collaboration with University of Lille, France - 2013-2014
