Air-clad fibres for astronomical instrumentation: focal-ratio degradation

Åslund, Mattias L.; Canning, John

doi:10.1007/s10686-008-9132-7

Cited by 11 publications

(5 citation statements)

References 13 publications

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“…The self-assembled wires are of sufficient dimension and high index contrast with the surrounding air-cladding to act as highly multimode slab (rectangular) waveguides. When light is launched into several angular rays [ 22 , 23 ], after propagating a few centimeters there is sufficient cross-coupling between all modes, aided by interface scattering, to ensure even coupling into all modes of the waveguide at the point at which optical interrogation is undertaken. A schematic of the experimental setup is shown in Figure 4 .…”

Section: Results and Analysismentioning

confidence: 99%

“…From the slope of this expression, an estimated mass spectrometer intensity based diffusion coefficient is D ~ 4.8 x 10 -4 nm 2 s -1 . Since I C = c.N A where N A is Avogadro's number, the diffusion coefficient for the hydrated Zn 2+ can also be extracted from the slope of lnC vs x 2 by converting to C noting I 0 obtained from extrapolating to x 2 = 0 in Figure 6(b) is assumed to equal 0.1 M x 6.022 x10 23 . From this, the effective molecular diffusion coefficient is estimated to be a little lower: D ~ 3 x 10 -4 nm 2 s -1 .…”

Section: Measuring Diffusion Through Laser Ablation Of Self-assembled...mentioning

confidence: 99%

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Percolation Diffusion into Self-Assembled Mesoporous Silica Microfibres

Canning

Huyang

et al. 2014

Nanomaterials

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Percolation diffusion into long (11.5 cm) self-assembled, ordered mesoporous microfibres is studied using optical transmission and laser ablation inductive coupled mass spectrometry (LA-ICP-MS). Optical transmission based diffusion studies reveal rapid penetration (<5 s, D > 80 μm2∙s−1) of Rhodamine B with very little percolation of larger molecules such as zinc tetraphenylporphyrin (ZnTPP) observed under similar loading conditions. The failure of ZnTPP to enter the microfibre was confirmed, in higher resolution, using LA-ICP-MS. In the latter case, LA-ICP-MS was used to determine the diffusion of zinc acetate dihydrate, D~3 × 10−4 nm2∙s−1. The large differences between the molecules are accounted for by proposing ordered solvent and structure assisted accelerated diffusion of the Rhodamine B based on its hydrophilicity relative to the zinc compounds. The broader implications and applications for filtration, molecular sieves and a range of devices and uses are described.

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Section: Results and Analysismentioning

confidence: 99%

Section: Measuring Diffusion Through Laser Ablation Of Self-assembled...mentioning

confidence: 99%

Percolation Diffusion into Self-Assembled Mesoporous Silica Microfibres

Canning

Huyang

et al. 2014

Nanomaterials

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“…(19) and Eq. (20) can also describe the FRD properties because FRD can broaden the output ring in both inner and outer directions, which makes the ring diffused and widens the FWHM (Murphy et al 2008(Murphy et al , 2013Aslund & Canning 2009). Here we consider it as FWHM model.…”

Section: Frd Dependence On Optical Fibre Lengthmentioning

confidence: 99%

A modified method for determining the focal ratio degradation and length properties of optical fibres in astronomy

Yan

Wang

Sun

et al. 2017

Mon. Not. R. Astron. Soc.

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Focal ratio degradation (FRD) is a major contributor to throughput and light loss in a fibre spectroscopic telescope system. We combine the guided mode theory in geometric optics and a well-known model, power distribution model (PDM), to predict and explain the FRD dependence properties. We present a robust method by modifying the energy distribution method (EDM) with f-intercept to control the input condition. This method provides a way to determine the proper position of the fibre end on the focal plane to improve energy utilization and FRD performance, which lifts the relative throughput up to 95% with variation of output focal ratio less than 2%. And this method can also help to optimize the arrangement of the position of focal-plane plate to enhance the coupling efficiency in a telescope. To investigate length properties, we modified PDM by introducing a new parameter, focal distance f, into the original model to make it available for multi-position measurement system. The results show that the modified model is robust and feasible for measuring the key parameter d 0 to simulate the transmission characteristics. The output focal ratio in the experiment does not follow the prediction trend but shows an interesting phenomenon that the output focal ratio increases at first to the peak, then decreases and remains stable finally with increasing fibre length longer than 15m, which provides a reference for choosing appropriate length of fibre to improve the FRD performance for the design of the fibre system in a telescope.

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“…These particular fibres are especially important for astrophotonics and imaging applications because they can have extraordinarily high numerical apertures as a result of approaching the idealised air ring fibre. Recently, careful consideration to the effect on focal ratio degradation (FRD) was reported [88]-whilst no significant impact from diffractive scattering was noted, scattering generally off the corrugated surface was observed to give rise to degradation in FRD.…”

Section: Refractive Index Measurements Using Photonic Crystal Fibresmentioning

confidence: 99%

Properties of Specialist Fibres and Bragg Gratings for Optical Fiber Sensors

Canning

2009

Journal of Sensors

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The advent of optical fibres based on air holes running along their entirety opens up new directions in addressing various properties relevant to sensing, including the temperature/strain challenge of optical fibre sensors. This paper looks at the measurement challenges associated with temperature and strain, examines the potentially unique functionality structured fibre designs with and without gratings open up, and briefly describes some current research directions within conventional fibre and grating technologies.

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Air-clad fibres for astronomical instrumentation: focal-ratio degradation

Cited by 11 publications

References 13 publications

Percolation Diffusion into Self-Assembled Mesoporous Silica Microfibres

Percolation Diffusion into Self-Assembled Mesoporous Silica Microfibres

A modified method for determining the focal ratio degradation and length properties of optical fibres in astronomy

Properties of Specialist Fibres and Bragg Gratings for Optical Fiber Sensors

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