Recently Professor John Love from the Australian National University in Canberra visited the centre and presented a seminar on optical fibres containing metal (podcast,PDF).
Prof Love has researched various theoretical aspects of guided wave phenomena in fibres, waveguides and a range of light processing devices at ANU over the last 35 years. He is also Convener for optics and photonics courses in the recently established Centre for Teaching and Learning in the College of Physical Sciences. He is famous for his book ‘Optical Waveguide Theory’ written in conjunction with Allan Snyder and published worldwide.
The abstract of the talk is given below.
Metal-clad optical fibres
In the optical frequency domain, metals can be regarded as dielectric materials, albeit with a relatively large imaginary part to the refractive index that represents the opacity and is normally much larger than the real part. The guidance provided by a metal-clad, dielectric-core fibre is more easily understood in terms of the respective dielectric constants.
Because of the large variation between dielectric constants, Maxwell’s equations are employed to determine modal propagation characteristics and their solution is generally numerically intensive. An exact, explicit analytical solution is available for a surface plasmons propagating along a
planar dielectric-metal interface.
Simple perturbation solutions are possible when only a small fraction of modal power propagates within the metal. Examples will be presented for the cases of (i) a tapered, metal-clad, single-mode fibre for scanning near-field optical microscopy application, and (ii) multimode propagation
inside a hollow, multimode silver capillary for laser light delivery in surgery.