Researchers from the University of Bath are demonstrating the latest developments in photonics and optical fibres at the Summer Science exhibition at the Royal Society in London this week.

The team from the Centre for Photonics and Photonic Materials are showing a new way to trap and channel high-powered lasers using delicate glass bubbles that reach as far as 100m. These hollow fibres are used in healthcare, developing new lasers, manufacturing, and quantum technologies.

The Royal Society Summer Science Exhibition is an annual display of the most exciting cutting-edge science and technology in the UK, visited by over 10,000 members of the public and 2,500 school students.

Why bubbles?

The researchers, led by Dr William Wadsworth, created hollow-core fibres made up of a ring of glass bubbles that are thinner than a strand of hair and more than 100m long. When a powerful laser is sent through the fibre, any light that hits the bubbles’ surface is reflected off, confining it in the hollow core. When you see light reflecting from the surface of a soap bubble, the different colours arise from different thicknesses of the soap film. Similarly, by carefully controlling the wall thickness of the glass bubbles in the fibres they can carry different colour lasers.

100m preform-cut-upTo prevent light escaping from the core of the fibre, the researchers create a structure – called cladding – made from tiny glass tubes with very thin walls that are just a few thousands of a millimetre thick. The optical fibres are made by hand at the centre, built on a bigger scale, called a preform (see left) before being shrunk down by stretching. The cross-section of the preform structure is typically shrunk down by a factor of around ten thousand as it is stretched into fibre.

The lab facilities include a pair of state-of-the-art optical fibre drawing towers that are used to turn glass tubes into preforms and preforms into fibre. Advanced computer software is used to design the fibres, and high-power laser systems and measurement equipment to test their properties.

You can see more of the team’s work at the Bath University Centre for Photonics and Photonic Materials web page and you can hear about the University of Bath’s latest news by following them on Twitter here: @UniOfBath