Could invisible clothes be the answer to shrinkage problems facing winter nudists? Picture: Brad Hunter Source: News Limited

But before you start acting out your Harry Potter fantasies, that’s not a cloak that makes you disappear. It’s one that you can't see.

Alessandro Tuniz, a PhD student at the University of Sydney's Institute of Photonics and Optical Science, is working on creating invisible threads by shrinking metamaterials to a size so small he can make them disappear in certain light wavelengths.

Mr Tuniz told news.com.au his work will prove light "can be manipulated to the point of making objects invisible".

The theory is based around something called the "refractive index", which measures the speed at which light travels through a substance.

"The invisibility is realised by matching the refractive index of the metamaterial fibre with the surroundings," Mr Tuniz said.

Metamaterials absorb light. Metal will reflect it and glass will slow it down — this is what makes the light visible.

The thicker the material, the more light it absorbs.

Using a process called fibre drawing, the physicists shrink fibres to a nanoscale while still retaining their internal structure.

If all that sounds complicated, it's because it is.

Fibre drawing is same process used to make optic fibres, but for invisibility it needs to make them much smaller before the tiny wavelengths of light travelling through them can be controlled.

Mr Tuniz and his colleagues have so far created threads that are 100 microns thick. The invisible fibre needs to be just one micron. Mr Tuniz has planned out the smaller thickness using computer modelling.

He described it as an expensive and technologically challenging process.

"We're trying to create a composite material with structures that are smaller than the wavelength," he said.

The metamaterial can only be made invisible for particular wavelengths.

Mr Tuniz has been working with red wavelengths as this is more commonly found in general items such as lasers.

The thread would not be entirely invisible, but rather would "disappear" in a certain wavelength. In this case, it would disappear in red light, but would be visible in green.

But the big question is — why?

The idea, says Mr Tuniz, is that "if you give me a wavelength I can design something to be invisible at that wavelength".

Made-to-order, wavelength-specific, invisible fibres may only have so many potential uses, but Mr Tuniz said the ultimate goal was about controlling optical properties.

"The invisibility is just one tiny spec of the possibilities."

So maybe you can put the invention down to "just because" — for now at least.

The best applications news.com.au could think of involved pranks or perhaps an elaborate Lady Gaga costume.

But if you have a better idea, post it below.