Professor Philip St.J. Russell, FRS

Director of the Russell Division – Photonic Crystal Fibres

Professor Philip Russell is a founding Director of the Max-Planck Institute for the Science of Light (MPL), which began operations in January 2009. Since 2005 he has also held the Krupp Chair in Experimental Physics at the University of Erlangen-Nuremberg. He obtained his D.Phil. degree in 1979 at the University of Oxford, spending three years as a Research Fellow at Oriel College, Oxford. In 1982 and 1983 he was a Humboldt Fellow at the Technical University Hamburg-Harburg (Germany), and from 1984 to 1986 he worked at the University of Nice (France) and the IBM TJ Watson Research Center in Yorktown Heights, New York. From 1986 to 1996 he was based mainly at the University of Southampton, first of all in the Optical Fibre Group and then in the Optoelectronics Research Centre. From 1996 to 2005 he was professor in the Department of Physics at the University of Bath, where he established the Centre for Photonics and Photonic Materials. His research interests currently focus on scientific applications of photonic crystal fibres and related structures. He is a Fellow of the Royal Society and The Optical Society (OSA) and has won several international awards for his research including the 2000 OSA Joseph Fraunhofer Award/Robert M. Burley Prize, the 2005 Thomas Young Prize of the Institute for Physics (UK), the 2005 Körber Prize for European Science, the 2013 EPS Prize for Research into the Science of Light, the 2014 Berthold Leibinger Zukunftspreis and the 2015 IEEE Photonics Award. He was OSA's President in 2015, the International Year of Light.

2015

Compressing mu J-level pulses from 250 fs to sub-10 fs at 38-MHz repetition rate using two gas-filled hollow-core photonic crystal fiber stages

K. F. Mak, M. Seidel, O. Pronin, M. H. Frosz, A. Abdolvand, V. Pervak, A. Apolonski, F. Krausz, J. C. Travers, et al.

OPTICS LETTERS 40 (7) 1238-1241 (2015) | Journal

Compression of 250-fs, 1-mu J pulses from a KLM Yb:YAG thin-disk oscillator down to 9.1 fs is demonstrated. A kagome-PCF with a 36-mu m core-diameter is used with a pressure gradient from 0 to 40 bar of krypton. Compression to 22 fs is achieved by 1200 fs(2) group-delay-dispersion provided by chirped mirrors. By coupling the output into a second kagome-PCF with a pressure gradient from 0 to 25 bar of argon, octave spanning spectral broadening via the soliton-effect is observed at 18-W average output power. Self-compression to 9.1 fs is measured, with compressibility to 5 fs predicted. Also observed is strong emission in the visible via dispersive wave generation, amounting to 4% of the total output power. (C) 2015 Optical Society of America

An ion trap built with photonic crystal fibre technology

F. Lindenfelser, B. Keitch, D. Kienzler, D. Bykov, P. Uebel, M. A. Schmidt, P. St. J. Russell, J. P. Home

REVIEW OF SCIENTIFIC INSTRUMENTS 86 (3) 033107 (2015) | Journal

We demonstrate a surface-electrode ion trap fabricated using techniques transferred from the manufacture of photonic-crystal fibres. This provides a relatively straightforward route for realizing traps with an electrode structure on the 100 micron scale with high optical access. We demonstrate the basic functionality of the trap by cooling a single ion to the quantum ground state, allowing us to measure a heating rate from the ground state of 787 +/- 24 quanta/s. Variation of the fabrication procedure used here may provide access to traps in this geometry with trap scales between 100 mu m and 10 mu m. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

Photoionization-Induced Emission of Tunable Few-Cycle Midinfrared Dispersive Waves in Gas-Filled Hollow-Core Photonic Crystal Fibers

D. Novoa, M. Cassataro, J. C. Travers, P. St. J. Russell

PHYSICAL REVIEW LETTERS 115 (3) 033901 (2015) | Journal

We propose a scheme for the emission of few-cycle dispersive waves in the midinfrared using hollow-core photonic crystal fibers filled with noble gas. The underlying mechanism is the formation of a plasma cloud by a self-compressed, subcycle pump pulse. The resulting free-electron population modifies the fiber dispersion, allowing phase-matched access to dispersive waves at otherwise inaccessible frequencies, well into the midinfrared. Remarkably, the pulses generated turn out to have durations of the order of two optical cycles. In addition, this ultrafast emission, which occurs even in the absence of a zero dispersion point between pump and midinfrared wavelengths, is tunable over a wide frequency range simply by adjusting the gas pressure. These theoretical results pave the way to a new generation of compact, fiber-based sources of few-cycle midinfrared radiation.

Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

H. Bromberger, A. Ermolov, F. Belli, H. Liu, F. Calegari, M. Chavez-Cervantes, M. T. Li, C. T. Lin, A. Abdolvand, et al.

APPLIED PHYSICS LETTERS 107 (9) 091101 (2015) | Journal

A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gasfilled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few mu J energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials. (C) 2015 AIP Publishing LLC.

Phase-matched electric-field-induced second-harmonic generation in Xe-filled hollow-core photonic crystal fiber

Jean-Michel Menard, Philip St. J. Russell

OPTICS LETTERS 40 (15) 3679-3682 (2015) | Journal

Second-order nonlinearity is induced inside a Xe-filled hollow-core photonic crystal fiber (PCF) by applying an external dc field. The system uniquely allows the linear optical properties to be adjusted by changing the gas pressure, allowing for precise phase matching between the LP01 mode at 1064 nm and the LP02 mode at 532 nm. The dependence of the second-harmonic conversion efficiency on the gas pressure, launched pulse energy, and applied field agrees well with theory. The ultra-broadband guidance offered by anti-resonant reflecting hollow-core PCFs, for example, a kagome PCF, offers many possibilities for generating light in traditionally difficult-to-access regions of the electromagnetic spectrum, such as the ultraviolet or the terahertz windows. The system can also be used for non-invasive measurements of the transmission loss in a hollow-core PCF over a broad spectrum, including the deep and vacuum UV regions. (C) 2015 Optical Society of America

Raman amplification of pure side-seeded higherorder modes in hydrogen-filled hollow-core PCF

Jean-Michel Menard, Barbara M. Trabold, Amir Abdolvand, Philip St J. Russell

OPTICS EXPRESS 23 (2) 895-901 (2015) | Journal

We use Raman amplification in hydrogen-filled hollow-core kagome photonic crystal fiber to generate high energy pulses in pure single higher-order modes. The desired higher-order mode at the Stokes frequency is precisely seeded by injecting a pulse of light from the side, using a prism to select the required modal propagation constant. An intense pump pulse in the fundamental mode transfers its energy to the Stokes seed pulse with measured gains exceeding 60 dB and output pulse energies as high as 8 mu J. A pressure gradient is used to suppress stimulated Raman scattering into the fundamental mode at the Stokes frequency. The growth of the Stokes pulse energy is experimentally and theoretically investigated for six different higher-order modes. The technique has significant advantages over the use of spatial light modulators to synthesize higher-order mode patterns, since it is very difficult to perfectly match the actual eigenmode of the fiber core, especially for higher-order modes with complex multi-lobed transverse field profiles. (C) 2015 Optical Society of America

Supercontinuum generation in the vacuum ultraviolet through dispersive-wave and soliton-plasma interaction in a noble-gas-filled hollow-core photonic crystal fiber

A. Ermolov, K. F. Mak, M. H. Frosz, J. C. Travers, P. St. J. Russell

PHYSICAL REVIEW A 92 (3) 033821 (2015) | Journal

We report on the generation of a three-octave-wide supercontinuum extending from the vacuum ultraviolet (VUV) to the near infrared, spanning at least 113-1000 nm (i.e., 11-1.2eV), in He-filled hollow-core kagome-style photonic crystal fiber. Numerical simulations confirm that the main mechanism is an interaction between dispersive-wave emission and plasma-induced blue-shifted soliton recompression around the fiber zero dispersion frequency. The VUV part of the supercontinuum, the modeling of which proves to be coherent and possesses a simple phase structure, has sufficient bandwidth to support single-cycle pulses of 500 asec duration. We also demonstrate, in the same system, the generation of narrower-band VUV pulses through dispersive-wave emission, tunable from 120 to 200 nm with efficiencies exceeding 1% and VUV pulse energies in excess of 50 nJ.

Stable subpicosecond soliton fiber laser passively mode-locked by gigahertz acoustic resonance in photonic crystal fiber core

M. Pang, X. Jiang, W. He, G. K. L. Wong, G. Onishchukov, N. Y. Joly, G. Ahmed, C. R. Menyuk, P. St J. Russell

OPTICA 2 (4) 339-342 (2015) | Journal

Ultrafast lasers with high repetition rates are of considerable interest in applications such as optical fiber telecommunications, frequency metrology, high-speed optical sampling, and arbitrary waveform generation. For fiber lasers mode-locked at the cavity round-trip frequency, the pulse repetition rate is limited to tens or hundreds of megahertz by the meter-order cavity lengths. Here we report a soliton fiber laser passively mode-locked at a high harmonic (similar to 2 GHz) of its fundamental frequency by means of optoacoustic interactions in the small solid glass core of a short length ( 60 cm) of photonic crystal fiber. Due to tight confinement of both light and vibrations, the optomechanical interaction is strongly enhanced. The long-lived acoustic vibration provides strong modulation of the refractive index in the photonic crystal fiber core, fixing the soliton spacing in the laser cavity and allowing stable mode-locking, with low pulse timing jitter, at gigahertz repetition rates. (C) 2015 Optical Society of America

Vacuum-ultraviolet to infrared supercontinuum in hydrogen-filled photonic crystal fiber

Federico Belli, Amir Abdolvand, Wonkeun Chang, John C. Travers, Philip St. J. Russell

OPTICA 2 (4) 292-300 (2015) | Journal

Although supercontinuum sources are readily available for the visible and near infrared (IR), and recently also for the mid-IR, many areas of biology, chemistry, and physics would benefit greatly from the availability of compact, stable, and spectrally bright deep-ultraviolet and vacuum-ultraviolet (VUV) supercontinuum sources. Such sources have, however, not yet been developed. Here we report the generation of a bright supercontinuum, spanning more than three octaves from 124 nm to beyond 1200 nm, in hydrogen-filled kagome-style hollow-core photonic crystal fiber (kagome-PCF). Few-microjoule, 30 fs pump pulses at wavelength of 805 nm are launched into the fiber, where they undergo self-compression via the Raman-enhanced Kerr effect. Modeling indicates that before reaching a minimum subcycle pulse duration of similar to 1 fs, much less than one period of molecular vibration (8 fs), nonlinear reshaping of the pulse envelope, accentuated by self-steepening and shock formation, creates an ultrashort feature that causes impulsive excitation of long-lived coherent molecular vibrations. These phase modulate a strong VUV dispersive wave (at 182 nm or 6.8 eV) on the trailing edge of the pulse, further broadening the spectrum into the VUV. The results also show for the first time that kagome-PCF guides well in the VUV. (C) 2015 Optical Society of America

Broadband-tunable LP01 mode frequency shifting by Raman coherence waves in a H-2-filled hollow-core photonic crystal fiber

S. T. Bauerschmidt, D. Novoa, A. Abdolvand, P. St. J. Russell

OPTICA 2 (6) 536-539 (2015) | Journal

When a laser pump beam of sufficient intensity is incident on a Raman-active medium such as hydrogen gas, a strong Stokes signal, redshifted by the Raman transition frequency Omega(R), is generated. This is accompanied by the creation of a "coherence wave" of synchronized molecular oscillations with wave vector Delta beta determined by the optical dispersion. Within its lifetime, this coherence wave can be used to shift by Omega(R) the frequency of a third "mixing" signal, provided phase matching is satisfied, i.e., Delta beta is matched. Conventionally, this can be arranged using noncollinear beams or higher-order waveguide modes. Here we report the collinear phase-matched frequency shifting of an arbitrary mixing signal using only the fundamental LP01 modes of a hydrogen-filled hollow-core photonic crystal fiber. This is made possible by the S-shaped dispersion curve that occurs around the pressure-tunable zero dispersion point. Phase-matched frequency shifting by 125 THz is possible from the UV to the near IR. Long interaction lengths and tight modal confinement reduce the peak intensities required, allowing conversion efficiencies in excess of 70%. The system is of great interest in coherent anti-Stokes Raman spectroscopy and for wavelength conversion of broadband laser sources. (C) 2015 Optical Society of America

Generation of three-octave-spanning transient Raman comb in hydrogen-filled hollow-core PCF

F. Tani, F. Belli, A. Abdolvand, J. C. Travers, P. St. J. Russell

OPTICS LETTERS 40 (6) 1026-1029 (2015) | Journal

A noise-seeded transient comb of Raman sidebands spanning three octaves from 180 to 2400 nm, is generated by pumping a hydrogen-filled hollow-core photonic crystal fiber with 26-mu J, 300-fs pulses at 800 nm. The pump pulses are spectrally broadened by both Kerr and Raman-related self-phase modulation (SPM), and the broadening is then transferred to the Raman lines. In spite of the high intensity, and in contrast to bulk gas-cell based experiments, neither SPM broadening nor ionization are detrimental to comb formation. (C) 2015 Optical Society of America

Wideband-tunable soliton fiber laser mode-locked at 1.88 GHz by optoacoustic interactions in solid-core PCF

Wenbin He, Meng Pang, Philip St J. Russell

OPTICS EXPRESS 23 (19) 24945-24954 (2015) | Journal

We report a wavelength-tunable soliton fiber laser stably mode-locked at 1.88 GHz (the 389th harmonic of the cavity round-trip frequency) by a light-driven acoustic resonance in the core of a photonic crystal fiber. Stable high-harmonic mode-locking could be maintained when the lasing wavelength was continuously tuned from 1532 to 1566 nm by means of an optical filter placed inside the laser cavity. We report on the experimental performance of the laser, including its power scalability, super-mode noise suppression ratio, long-term repetition rate stability, short-term pulse amplitude noise and timing jitter, optical comb structure and pulse-to-pulse phase fluctuations. (C) 2015 Optical Society of America

Dramatic Raman Gain Suppression in the Vicinity of the Zero Dispersion Point in a Gas-Filled Hollow-Core Photonic Crystal Fiber

S. T. Bauerschmidt, D. Novoa, P. St J. Russell

PHYSICAL REVIEW LETTERS 115 (24) 243901 (2015) | Journal

In 1964 Bloembergen and Shen predicted that Raman gain could be suppressed if the rates of phonon creation and annihilation (by inelastic scattering) exactly balance. This is only possible if the momentum required for each process is identical, i.e., phonon coherence waves created by pump-to-Stokes scattering are identical to those annihilated in pump-to-anti-Stokes scattering. In bulk gas cells, this can only be achieved over limited interaction lengths at an oblique angle to the pump axis. Here we report a simple system that provides dramatic Raman gain suppression over long collinear path lengths in hydrogen. It consists of a gas-filled hollow-core photonic crystal fiber whose zero dispersion point is pressure adjusted to lie close to the pump laser wavelength. At a certain precise pressure, stimulated generation of Stokes light in the fundamental mode is completely suppressed, allowing other much weaker phenomena such as spontaneous Raman scattering to be explored at high pump powers.

Raman-Free, Noble-Gas-Filled Photonic-Crystal Fiber Source for Ultrafast, Very Bright Twin-Beam Squeezed Vacuum

Martin A. Finger, Timur Sh. Iskhakov, Nicolas Y. Joly, Maria V. Chekhova, Philip St. J. Russell

PHYSICAL REVIEW LETTERS 115 (14) 143602 (2015) | Journal

We report a novel source of twin beams based on modulational instability in high-pressure argon-filled hollow-core kagome-style photonic-crystal fiber. The source is Raman-free and manifests strong photonnumber correlations for femtosecond pulses of squeezed vacuum with a record brightness of similar to 2500 photons per mode. The ultra-broadband (similar to 50 THz) twin beams are frequency tunable and contain one spatial and less than 5 frequency modes. The presented source outperforms all previously reported squeezed-vacuum twin-beam sources in terms of brightness and low mode content.

Deep-ultraviolet to mid-infrared supercontinuum generated in solid-core ZBLAN photonic crystal fibre

Xin Jiang, Nicolas Y. Joly, Martin A. Finger, Fehim Babic, Gordon K. L. Wong, John C. Travers, Philip St J. Russell

NATURE PHOTONICS 9 (2) 133-139 (2015) | Journal

Silica-based photonic crystal fibre has proven highly successful for supercontinuum generation, with smooth and flat spectral power densities. However, fused silica glass suffers from strong material absorption in the mid-infrared (>2,500 nm), as well as ultraviolet-related optical damage (solarization), which limits performance and lifetime in the ultraviolet (<380 nm). Supercontinuum generation in silica photonic crystal fibre is therefore only possible between these limits. A number of alternative glasses have been used to extend the mid-infrared performance, including chalcogenides, fluorides and heavy-metal oxides, but none has extended the ultraviolet performance. Here, we describe the successful fabrication (using the stack-and-draw technique) of a ZBLAN photonic crystal fibre with a high air-filling fraction, a small solid core, nanoscale features and near-perfect structure. We also report its use in the generation of ultrabroadband, long-term stable, supercontinua spanning more than three octaves in the spectral range 200-2,500 nm.

Enhanced optical activity and circular dichroism in twisted photonic crystal fiber

G. K. L. Wong, X. M. Xi, M. H. Frosz, P. St. J. Russell

OPTICS LETTERS 40 (20) 4639-4642 (2015) | Journal

We demonstrate experimentally and theoretically that the core-guided mode in helically twisted photonic crystal fiber exhibits resonantly enhanced optical activity and circular dichroism in the vicinity of anti-crossings with leaky orbital angular momentum (OAM) modes in the cladding. This arises because the anti-crossings for left and right circularly polarized core modes occur at slightly different wavelengths. (C) 2015 Optical Society of America

Flying particle sensors in hollow-core photonic crystal fibre

D. S. Bykov, O. A. Schmidt, T. G. Euser, P. St. J. Russell

NATURE PHOTONICS 9 (7) 461-U63 (2015) | Journal

Optical fibre sensors make use of diverse physical effects to measure parameters such as strain, temperature and electric field. Here we introduce a new class of reconfigurable fibre sensor, based on a 'flying-particle' optically trapped inside a hollow-core photonic crystal fibre and illustrate its use in electric field and temperature sensing with high spatial resolution. The electric field distribution near the surface of a multi-element electrode is measured with a resolution of similar to 100 mu m by monitoring changes in the transmitted light signal due to the transverse displacement of a charged silica microparticle trapped within the hollow core. Doppler-based velocity measurements are used to map the gas viscosity, and thus the temperature, along a hollow-core photonic crystal fibre. The flying-particle approach represents a new paradigm in fibre sensors, potentially allowing multiple physical quantities to be mapped with high positional accuracy over kilometre-scale distances.

MPL Research Centers and Schools