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Novel active fibres with broad-band emission

English title Novel active fibres with broad-band emission
Applicant Lüthy Willy
Number 113269
Funding scheme Project funding (Div. I-III)
Research institution Institut für angewandte Physik Universität Bern
Institution of higher education University of Berne - BE
Main discipline Technical Physics
Start/End 01.10.2006 - 30.09.2008
Approved amount 100'581.00
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Keywords (7)

active fibres; broad-band emission; rare earth doping; transition metal doping; optical fibres; transition metals; rare earths

Lay Summary (English)

Lead
Lay summary
Optical fibres in general and micro-structured optical fibres in particular have opened up fascinating perspectives in exploiting the interaction effects between luminescent materials and light. This is particularly due to the high intensities which can be achieved in the core of an optical fibre over long distances. Even more, in micro-structured optical fibres light guiding can be achieved in fibres with core diameters in the range of the wavelength of the used light allowing to reach highest intensities at moderate average powers and a correspondingly strong interaction with the core materials.
In this project we address the possibility of exploiting the strong interaction between guided light and material in the fibre core to obtain broadband emission from transition metal elements and from rare earths with intensities in the range of 1kW/cm2.
Although the investigation of transition metals in crystals is well established, there has been up to now only limited interest in studying transition metals in glass hosts while rare earths have been mainly investigated in view of being used as laser materials or amplifiers for telecommunication.
The broadband emitters which could result from our study would have a low temporal but highest spatial coherence and be ideally suited for low-coherence interferometry applications such as confocal microscopy or optical coherence tomography.
In this project we produce preforms doped with those transition metals, which have shown laser action in crystals (such as Cr3+, Ti3+, V2+, Co2+ and Ni2+) and draw them to standard or micro-structured fibres in the drawing tower of our institute. Although for these elements in fused silica we know of a high non-radiative relaxation rate by the strong electron phonon coupling between chromophore and silica host and thus expect low luminescence efficiency, this can be compensated by the strong interaction of the luminescents with the pump over long distances (some meters to several tens of meters).
In a following step single rare earths or combinations thereof will be used as dopants. Of special interest will be Cerium which in several glass hosts behaves like a transition metal with broad absorption and emission bands. Of even higher interest will be fibres with multiple doping such asTm3+ and Ho3+ or Nd3+ and Yb3+ which will lead to strong broadbandemission at 2um and 1um respectively.
We will produce the preforms with our dry powder technique which is suited for both, standard fibres with a core whose index is raised by co-doping with aluminum or by using micro-structured fibres that allow tailoring the guiding properties without adding any dopant to the core.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
121663 Metal-doped fibre laser 01.10.2008 Project funding (Div. I-III)
105154 Nanoparticle laser materials embedded in Sol-Gel layers 01.10.2004 Project funding (Div. I-III)

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