Meta-fibres: Optical fibres with meta-surfaces for advanced optical biopsy through needles

Cancers that occur deep within the body are difficult to detect and treat due to their inaccessibility via natural orifices. For example, ovarian cancer has a 50% 5-year survival rate while for pancreatic cancer this is just 1%.

Early detection of these cancers could allow surgeons to treat or remove them before they spread, dramatically improving survival.

However, early cancer is only subtly different to healthy tissue so accurate detection requires very high resolution imaging to reveal these subtle differences, much higher than MRI or X-rays.

Imaging using light can achieve the necessary resolution but requires the camera to be very close to the tissue being examined, which is difficult for internal organs like the pancreas.

I propose to overcome this limitation by developing a new generation of endoscopes that take images through optical fibres: hair-thin pieces of glass that fit inside tiny needles, which can be harmlessly inserted deep into the body.

Imaging through optical fibres requires using holography, which provides a further advantage over conventional endoscopy: holography enables state-of-the-art optical microscopy techniques to be performed at the tip of the fibre.

These techniques not only provide unprecedented resolution (100nm) but also measure additional optical information that dramatically improves their ability to see subtle changes in tissue microstructure and chemical composition indicating early cancer.

However, this additional functionality has not been fully exploited because optical fibres bend during use, distorting images.

I propose to overcome this limitation by using nanotechnology to fabricate a special type of optical element, called a 'meta-surfaces', on the tips of fibres. Meta-surfaces are made from tiny metal structures, smaller than the wavelength of light (