Showing papers by "Philip St. J. Russell published in 2005"
TL;DR: In this paper, the nonlinear behavior of high air-filling fraction solid-core photonic crystal fibers pumped with ultrashort pulses in the vicinity of a negative-slope zero-crossing of the group velocity dispersion was investigated.
26 citations
TL;DR: In this article, a dual-closet photonic-crystal-fiber (DCPCF) based multiphoton scanning microscope is proposed to achieve beam-scanning by directly scanning an optical fiber.
Abstract: Despite the fact that laser scanning confocal microscopy (LSCM) has become an important tool in modern biological laboratories, it is bulky, inflexible and has limited field of view, thus limiting its applications. To overcome these drawbacks, we report the development of a compact dual-clad photonic-crystal-fiber (DCPCF) based multiphoton scanning microscope. In this novel microscope, beam-scanning is achieved by directly scanning an optical fiber, in contrast to conventional beam scanning achieved by varying the incident angle of a laser beam at an objective entrance pupil. The fiber delivers femtosecond laser pulses for two-photon excitation and collects fluorescence back through the same fiber. Conventional fibers, either single-mode fiber (SMF) or multimode fiber (MMF), are not suitable for this detection configuration because of the low collection efficiency for a SMF and low excitation rate for a MMF. Our newly invented DCPCF allows one to optimize collection and excitation efficiency at the same time. In addition, when a gradient-index (GRIN) lens is used to focus the fiber output to a tight spot, the fluorescence signal collected back through the GRIN lens forms a large spot at the fiber tip because of the chromatic aberrations of the GRIN lens. This problem prevents a standard fiber from being applicable, but is completely overcome by the DCPCF. We demonstrate that this next generation scanning confocal microscope has an extremely simple structure and a number of unique features owing to its fundamentally different scanning mechanism: high flexibility, arbitrarily large scan range, aberration-free imaging, and low cost.
18 citations
TL;DR: The fabrication and characterization of a free-standing silica glass membrane waveguide formed using fiber fabrication processes that outperforms that of conventional planar waveguides by several orders of magnitude is described.
Abstract: We describe the fabrication and characterization of a free-standing silica glass membrane waveguide formed using fiber fabrication processes. The membrane has a thickness of 0.6??m and a width of 60??m and is many meters long. The optical attenuation is measured as 0.4?dB?m. Such attenuation outperforms that of conventional planar waveguides by several orders of magnitude.
17 citations
TL;DR: It is found that the process of pulse collapse enhances the emission of so-called resonant radiation, providing an efficient mechanism of energy transfer from solitonic to dispersive waves and leading to suppression of the collapse.
Abstract: We study the spatiotemporal dynamics of ultrashort pulses close to a point of zero group-velocity dispersion in planar waveguides with focusing nonlinearities. We find that the process of pulse collapse enhances the emission of so-called resonant radiation, providing an efficient mechanism of energy transfer from solitonic to dispersive waves and leading to suppression of the collapse.
12 citations
13 Apr 2005
TL;DR: In this article, the progress made on the fabrication and applications of hollow-core photonic crystal fibres is described along with their dispersion properties, and different results achieved in the fields of laser-induced particle guidance, low-threshold stimulated Raman scattering in hydrogen (vibrational and rotational) and in laser frequency metrology.
Abstract: We review the progress made on the fabrication and applications of hollow-core photonic crystal fibres. The mechanism of the light guidance in these fibers is described along with their dispersion properties. We review the HC-PCF fabrication, the different results achieved in the fields of laser-induced particle guidance, low-threshold stimulated Raman scattering in hydrogen (vibrational and rotational) and in laser frequency metrology. Finally, we show the different new prospects opened up by these fibres.
11 citations
01 Jan 2005
Abstract: We report on the development of all-fiber devices based on a hermetically sealed hollow-core-PCF filled with acetylene at sub-millibar pressure and designed for the generation of electromagnetically-induced transparency and for saturable absorption.
7 citations
23 May 2005
TL;DR: In this article, a low-coherence interferometric scheme for the measurement of the strain and temperature dependences of group delay and dispersion in short, index-guiding, 'endlessly-single-mode', photonic crystal fibre elements in the 840 nm and 1550 nm regions is presented.
Abstract: We report on a low-coherence interferometric scheme for the measurement of the strain and temperature dependences of group delay and dispersion in short, index-guiding, 'endlessly-single-mode', photonic crystal fibre elements in the 840 nm and 1550 nm regions. Based on the measurements, we propose two schemes for simultaneous strain and temperature measurement using a single unmodified PCF element, without a requirement for any compensating components, and we project the measurement accuracies of these schemes.
3 citations
Proceedings Article•
22 May 2005
TL;DR: In this article, a double-clad photonic-crystal-fiber based multiphoton scanning microscope has been developed, which has a number of advantages over conventional scanning microscopes.
Abstract: We report the development of a novel double-clad photonic-crystal-fiber based multiphoton scanning microscope, which has a number of advantages over conventional scanning microscopes.
1 citations
TL;DR: In this article, the authors visualize the dynamics of solitons and continua in several such structures using cross-correlation frequency-resolved optical gating, the technique which provides experimentally the most complete information about an optical pulse.
Abstract: Optical waveguides provide rich environment for various nonlinear
processes thanks to the long interaction lengths, sustained high
intensities and diverse dispersion regimes. Nonlinear and dispersion
properties of fibers and waveguides can be widely controlled through
microstructuring resulting in a broad family of photonic crystal and
bandgap waveguides. This flexibility can be used to realize
previously impossible nonlinear interaction regimes for solitons and
quasi-continuous waves. The dynamics of femtosecond optical pulses
in such dispersive and nonlinear materials provide a truly
challenging measurement task, but reward us with most spectacular
images of nonlinear wave interactions. We visualized the dynamics of
solitons and continua in several such structures using cross- correlation frequency-resolved optical gating, the technique which provides experimentally the most complete information about an optical pulse. These detailed time and frequency-resolved measurements infinitely surpass the simple spectral measurements or
even the time axis-symmetric FROG spectrograms. Soliton dynamics in
the vicinity of the second zero-dispersion point of a silica PC
fiber, Cherenkov continuum generation, stabilization against the
Raman self-frequency shift and other resonant interactions as well
as the supercontinuum generation in soft-glass fibers were characterized. Recent theoretical studies were brought about to
develop a fundamental understanding of these resonant interactions
and excellent agreement was found.
1 citations
22 May 2005
TL;DR: In this article, the dynamics of photonic crystal waveguides pumped from the top was studied using a coupled mode approximation, and the stability of the spatially uniform state and the formation of dissipative solitons were investigated.
Abstract: The dynamics of electromagnetic fields in photonic crystal waveguides pumped from the top is studied using a coupled mode approximation. The stability of the spatially uniform state and the formation of dissipative solitons are investigated.