Showing papers by "Philip St. J. Russell published in 2004"
TL;DR: Nonlinear dynamics of ultrashort optical pulses in the vicinity of the second zero-dispersion point of a small-core photonic crystal fiber is visualized and studied using cross-correlation frequency-resolved optical gating to show strong interaction between solitons and dispersive waves.
Abstract: Nonlinear dynamics of ultrashort optical pulses in the vicinity of the second zero-dispersion point of a small-core photonic crystal fiber is visualized and studied using cross-correlation frequency-resolved optical gating. New spectral features observed in the experiments match well with recent theoretical predictions of the generation of new frequencies via mixing of solitons and dispersive waves. Power- as well as length-dependent dynamics is obtained showing strong interaction between solitons and dispersive waves, soliton-soliton interaction, soliton stabilization against Raman self-frequency shift and Cherenkov continuum generation.
85 citations
08 Sep 2004
TL;DR: In this article, a square lattice photonic crystal fiber is described and the polarization properties of the fiber are investigated, and it is shown that these structures have considerable potential for high birefringence.
Abstract: A square lattice photonic crystal fiber is described. The square lattice structures were fabricated, characterized and their polarization properties were investigated. The polarization properties of the fibers were not as strong as those reported previously in highly birefringent PCF, but these structures have considerable potential for high birefringence.
2 citations
28 Mar 2004
TL;DR: In this paper, scaling modulation instability has been demonstrated in the normal dispersion regime using a PCF leading to efficient upconversion of a red pump to wavelengths throughout the visible.
Abstract: Scalar modulation instability has been demonstrated in the normal dispersion regime using a PCF leading to efficient upconversion of a red pump to wavelengths throughout the visible.
1 citations
28 Mar 2004
TL;DR: In this article, the parametric instabilities in ultra-small core fibers in the two cases of scalar and polarized waves were studied and new unstable regions and new physical behaviour in the far-detuned spectral regions were found.
Abstract: We have studied analytically and numerically the parametric instabilities in ultra-small core fibers in the two cases of scalar and polarized waves, finding new unstable regions and new physical behaviour in the far-detuned spectral regions.
02 Aug 2004
TL;DR: In this article, a cross-correlation frequency-resolved optical gating is used to probe the dynamics of a femtosecond pulse in a double-zero dispersion point photonic crystal fiber.
Abstract: Cross-correlation frequency-resolved optical gating is used to probe the dynamics of a femtosecond pulse in a double-zero dispersion point photonic crystal fiber. Soliton attraction to the second zero-dispersion point and multiple-soliton interaction are observed.
28 Mar 2004
TL;DR: In this article, it was shown that matter-wave solitary pulses formed from Bose condensed atoms in optical lattices continuously radiate dispersive matter waves, and that this radiation exists universally for solitons moving through the lattice with arbitrary small but non-zero velocities.
Abstract: We demonstrate that matter-wave solitary pulses formed from Bose condensed atoms in optical lattices continuously radiate dispersive matter waves. This radiation exists universally for solitons moving through the lattice with arbitrary small but non-zero velocities.
TL;DR: The TPOFF technique is highly promising for real-time, in vivo, quantitative fluorescence measurements and showed results quantitatively in agreement with those from flow cytometry and confocal microscopy.
Abstract: Fluorescence is a powerful tool for biosensing, but conventional fluorescence measurements are limited because solid tumors are highly scattering media. To obtain quantitative in vivo fluorescence information from tumors, we have developed a two-photon optical fiber fluorescence (TPOFF) probe where excitation light is delivered and the two-photon fluorescence (TPF) excited at the tip of the fiber is collected back through the same fiber. In order to determine whether this system can provide quantitative information, we measured the fluorescence from a variety of systems including mouse tumors (both ex vivo and in vivo ) which were transfected with the gene to express varying amounts of green fluorescence protein (GFP), and tumors which were labeled with targeted dendrimer-based drug delivery agents. The TPOFF technique showed results quantitatively in agreement with those from flow cytometry and confocal microscopy. In order to improve the sensitivity of our fiber probe, we developed a dual-clad photonic-crystal fiber which allowed single-mode excitation and multimode (high numerical aperture) collection of TPF. These experiments indicate that the TPOFF technique is highly promising for real-time, in vivo , quantitative fluorescence measurements.