We numerically investigate the effect of ionization on ultrashort high-energy pulses propagating in gas-filled kagome-lattice hollow-core photonic crystal fibers by solving an established uni-directional field equation. We consider the dynamics of two distinct regimes: ionization induced blue-shift and resonant dispersive wave emission in the deep-UV. We illustrate how the system evolves between these regimes and the changing influence of ionization. Finally, we consider the effect of higher ionization stages. (C) 2011 Optical Society of America
Optofluidic refractive-index sensor in step-index fiber with parallel
hollow micro-channel
H. W. Lee,
M. A. Schmidt,
P. Uebel,
H. Tyagi,
N. Y. Joly,
M. Scharrer,
P. St. J. Russell
We present a simple refractive index sensor based on a step-index fiber with a hollow micro-channel running parallel to its core. This channel becomes waveguiding when filled with a liquid of index greater than silica, causing sharp dips to appear in the transmission spectrum at wavelengths where the glass-core mode phase-matches to a mode of the liquid-core. The sensitivity of the dip-wavelengths to changes in liquid refractive index is quantified and the results used to study the dynamic flow characteristics of fluids in narrow channels. Potential applications of this fiber microstructure include measuring the optical properties of liquids, refractive index sensing, biophotonics and studies of fluid dynamics on the nanoscale. (C) 2011 Optical Society of America
Bright Spatially Coherent Wavelength-Tunable Deep-UV Laser Source Using
an Ar-Filled Photonic Crystal Fiber
N.Y. Joly,
J. Nold,
W. Chang,
P. Hoelzer,
A. Nazarkin,
G. K. L. Wong,
F. Biancalana,
P. St. J. Russell
We report on the spectral broadening of similar to 1 mu J 30 fs pulses propagating in an Ar-filled hollow-core photonic crystal fiber. In contrast with supercontinuum generation in a solid-core photonic crystal fiber, the absence of Raman and unique pressure-controlled dispersion results in efficient emission of dispersive waves in the deep-UV region. The UV light emerges in the single-lobed fundamental mode and is tunable from 200 to 320 nm by varying the pulse energy and gas pressure. The setup is extremely simple, involving <1 m of a gas-filled photonic crystal fiber, and the UV signal is stable and bright, with experimental IR to deep-UV conversion efficiencies as high as 8 %. The source is of immediate interest in applications demanding high spatial coherence, such as laser lithography or confocal microscopy.
Entangling Different Degrees of Freedom by Quadrature Squeezing
Cylindrically Polarized Modes
C. Gabriel,
A. Aiello,
W. Zhong,
T. G. Euser,
N. Y. Joly,
P. Banzer,
M. Foertsch,
D. Elser,
U. L. Andersen, et al.
Quantum systems such as, for example, photons, atoms, or Bose-Einstein condensates, prepared in complex states where entanglement between distinct degrees of freedom is present, may display several intriguing features. In this Letter we introduce the concept of such complex quantum states for intense beams of light by exploiting the properties of cylindrically polarized modes. We show that already in a classical picture the spatial and polarization field variables of these modes cannot be factorized. Theoretically it is proven that by quadrature squeezing cylindrically polarized modes one generates entanglement between these two different degrees of freedom. Experimentally we demonstrate amplitude squeezing of an azimuthally polarized mode by exploiting the nonlinear Kerr effect in a specially tailored photonic crystal fiber. These results display that such novel continuous-variable entangled systems can, in principle, be realized.
Ultrafast nonlinear optics in gas-filled hollow-core photonic crystal
fibers [Invited]
John C. Travers,
Wonkeun Chang,
Johannes Nold,
Nicolas Y. Joly,
Philip St. J. Russell
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
28
(12)
A11-A26
(2011)
We review the use of hollow-core photonic crystal fibers (PCFs) in the field of ultrafast gas-based nonlinear optics, including recent experiments, numerical modeling, and a discussion of future prospects. Concentrating on broadband guiding kagome-style hollow-core PCF, we describe its potential for moving conventional nonlinear fiber optics both into extreme regimes-such as few-cycle pulse compression and efficient deep ultraviolet wavelength generation-and into regimes hitherto inaccessible, such as single-mode guidance in a photoionized plasma and high-harmonic generation in fiber. (C) 2011 Optical Society of America
Birefringence and dispersion of cylindrically polarized modes in
nanobore photonic crystal fiber
T. G. Euser,
M. A. Schmidt,
N. Y. Joly,
C. Gabriel,
C. Marquardt,
L. Y. Zang,
M. Foertsch,
P. Banzer,
A. Brenn, et al.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
28
(1)
193-198
(2011)
| Journal
We demonstrate experimentally and theoretically that a nanoscale hollow channel placed centrally in the solid-glass core of a photonic crystal fiber strongly enhances the cylindrical birefringence (the modal index difference between radially and azimuthally polarized modes). Furthermore, it causes a large split in group velocity and group velocity dispersion. We show analytically that all three parameters can be varied over a wide range by tuning the diameters of the nanobore and the core. (C) 2010 Optical Society of America
Theory of Photoionization-Induced Blueshift of Ultrashort Solitons in
Gas-Filled Hollow-Core Photonic Crystal Fibers
Mohammed F. Saleh,
Wonkeun Chang,
Philipp Hoelzer,
Alexander Nazarkin,
John C. Travers,
Nicolas Y. Joly,
Philip St. J. Russell,
Fabio Biancalana
We show theoretically that the photoionization process in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas leads to a constant acceleration of solitons in the time domain with a continuous shift to higher frequencies, limited only by ionization loss. This phenomenon is opposite to the well-known Raman self-frequency redshift of solitons in solid-core glass fibers. We also predict the existence of unconventional long-range nonlocal soliton interactions leading to spectral and temporal soliton clustering. Furthermore, if the core is filled with a Raman-active molecular gas, spectral transformations between redshifted, blueshifted, and stabilized solitons can take place in the same fiber.
Pressure-assisted melt-filling and optical characterization of Au
nano-wires in microstructured fibers
H. W. Lee,
M. A. Schmidt,
R. F. Russell,
N. Y. Joly,
H. K. Tyagi,
P. Uebel,
P. St. J. Russell
We report a novel splicing-based pressure-assisted melt-filling technique for creating metallic nanowires in hollow channels in microstructured silica fibers. Wires with diameters as small as 120 nm (typical aspect ration 50:1) could be realized at a filling pressure of 300 bar. As an example we investigate a conventional single-mode step-index fiber with a parallel gold nanowire (wire diameter 510 nm) running next to the core. Optical transmission spectra show dips at wavelengths where guided surface plasmon modes on the nanowire phase match to the glass core mode. By monitoring the side-scattered light at narrow breaks in the nanowire, the loss could be estimated. Values as low as 0.7 dB/mm were measured at resonance, corresponding to those of an ultra-long-range eigenmode of the glass-core/nanowire system. By thermal treatment the hollow channel could be collapsed controllably, permitting creation of a conical gold nanowire, the optical properties of which could be monitored by side-scattering. The reproducibility of the technique and the high optical quality of the wires suggest applications in fields such as nonlinear plasmonics, near-field scanning optical microscope tips, cylindrical polarizers, optical sensing and telecommunications. (C) 2011 Optical Society of America
Femtosecond Nonlinear Fiber Optics in the Ionization Regime
P. Hoelzer,
W. Chang,
J. C. Travers,
A. Nazarkin,
J. Nold,
N. Y. Joly,
M. F. Saleh,
F. Biancalana,
P. St. J. Russell
By using a gas-filled kagome-style photonic crystal fiber, nonlinear fiber optics is studied in the regime of optically induced ionization. The fiber offers low anomalous dispersion over a broad bandwidth and low loss. Sequences of blueshifted pulses are emitted when 65 fs, few-microjoule pulses, corresponding to high-order solitons, are launched into the fiber and undergo self-compression. The experimental results are confirmed by numerical simulations which suggest that free-electron densities of similar to 10(17) cm(-3) are achieved at peak intensities of 10(14) W/cm(2) over length scales of several centimeters.
Single-mode hollow-core photonic crystal fiber made from soft glass
X. Jiang,
T. G. Euser,
A. Abdolvand,
F. Babic,
F. Tani,
N. Y. Joly,
J. C. Travers,
P. St J. Russell
We demonstrate the first soft-glass hollow core photonic crystal fiber. The fiber is made from a high-index lead-silicate glass (Schott SF6, refractive index 1.82 at 500 nm). Fabricated by the stack-and-draw technique, the fiber incorporates a 7-cell hollow core embedded in a highly uniform 6-layer cladding structure that resembles a kagome-like lattice. Effective single mode guidance of light is observed from 750 to 1050 nm in a large mode area (core diameter similar to 30 mu m) with a low loss of 0.74 dB/m. The underlying guidance mechanism of the fiber is investigated using finite element modeling. The fiber is promising for applications requiring single mode guidance in a large mode area, such as particle guidance, fluid and gas filled devices. (C) 2011 Optical Society of America
Contact
Research Group Nicolas Joly
Professor for Photonics Friedrich-Alexander-Universität Erlangen-Nürnberg
and
Max Planck Institute for the Science of Light Staudtstr. 2 91058 Erlangen, Germany
