1,720,999 research outputs found
Nonlinearity in holey optical fibers: measurement and future opportunities - errata
No full textErrata to Nonlinearity in holey optical fibers: measurement and future opportunities. (1999) Optics Letters, 24 (20), 1395-1397. (doi:10.1364/OL.24.001395).Broderick, N.G.R., Monro, T.M., Bennett, P.J. and Richardson, D.J. <br/
Developing holey fibers for evanescent field devices
No full textThe overlap of the optical mode in a HF with the air holes is calculated for the first time. This is done using a vector modal decomposition approach. We show that a significant fraction of the modal power can be made to overlap with the holes, which suggests that these unusual fibres may be useful as evanescent field devices
A robust large air fill fraction holey fibre
No full textHoley fibres have an array of holes around the core which run along the entire length of the fibre. This reduces the effective index of the cladding and provides the light guiding mechanism. This new type of fibre offers a wide range of unique optical properties which make them of great interest for a wide range of applications including telecommunications and sensing. Holey fibres are produced by stacking pure silica capillaries in a hexagonal pattern, with a solid silica rod as the core, as shown in figure 1, step 1. This stack is then drawn down to fibre in a single, or two stage, process. Around 300 capillaries are required to produce an appropriately microstructured fibre of 30 - 40 µm diameter. Whilst high quality fibres of such dimensions can be made they are extremely fragile and difficult to handle in appreciable lengths, severely compromising their practicality. Therefore means for scaling the fibre to practical dimensions and protecting the fragile mechanical structure are required. Both theory and experiment show that the guidance properties of the fibre are defined predominantly by the inner-most rings of capillaries. This gives considerable scope for simplification and improvements in fibre design
Towards practical holey fibre technology: fabrication splicing and characterisation
No full textWe report the fabrication of long lengths of mechanically-robust holey fibre and the first demonstration of their splicing. These practical advances have permitted the first detailed characterization of a holey fibre around 1.5µm
Towards practical holey fibre technology: fabrication splicing modeling and characterization
No full textWe report the fabrication of long lengths of mechanically robust holey fiber and what is believed to be the first demonstration of their splicing. These practical advances have permitted what is to our knowledge the first detailed characterization of a holey fiber near 1.5µm. We compare dispersion measurements with our numerical predictions and confirm that our model can be used to predict accurately holey fiber properties
Holey fibers for evanescent field devices
No full textIn a holey fiber (HF), the cladding is formed by an array of holes which run along its length, and the core is simply the absence of a hole. HFs guide light because of the effective volume average index difference between the core and the cladding. The holes provide new opportunities for exploiting the interaction of light with gases and liquids through evanescent field effects. For example, the concentration of pollutants in a gas can be determined using the absorption which occurs as light propagates through the gas for a range of wavelengths, and HFs offer an alternative which naturally provide the possibility of extremely long optical path lengths
Ultrafast Cubic Optical nonlinearity in semitransparent films: bulk versus surface contributions
No full textSummary form only given. We report the results of a study of semitransparent films of nickel of varying thickness using femtosecond time-resolved polarimetry. For the first time we have combined transmission and reflection measurements, and have studied glass and air interfaces of nickel films of different thicknesses. We have identified importance of the surface contribution to the film nonlinearity, and have also observed that not only the magnitude of the cubic nonlinearity in nickel, but even its sign could be different depending on the nature of the interface. We also saw that both bulk and surface components of the cubic optical nonlinearity in nickel films are exceptionally fast with relaxation times shorter than ~40 fs
Nonlinearity of liquefying gallium: controlling light with light at milliwatt power levels
No full textLiquefying gallium shows a new type of huge reversible nonlinearity which is compatible with waveguide technology and offers a breakthrough in broadband, high-contrast light by light modulation at milliwatt power levels with sub-microsecond response times
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