Alessandro Tuniz and colleagues at the University of Sydney have designed a fibre that would be invisible over a range of colours. And because of recent developments in ways to draw hybrid materials into fibres, their proposal may be relatively straightforward to put into practice.
Such fibres could lead to interesting effects in art, architecture and fashion. They are also being studied in the broader context of building cheap, next-generation devices with special optical properties, such as fibre-based super-lensing which improves the resolution limit of microscopes. And the fibres could also provide support for optical elements but without optical distortion.