At the core of the device is a photonic crystal slide which basically turns the iPhone into a high-resolution spectrometer.

ENGADGET

One example the company has developed is a crystal fibre that squeezes light into such a narrow core that the intensity of the light modifies the optical properties of the glass itself.

ECONOMIST: A new approach to making optical fibres

In the same way, the pattern of holes in a crystal fibre can create the equivalent for light of a graphite core and a diamond cladding.

ECONOMIST: A new approach to making optical fibres