Later this year Dr Tzou hopes to have one that will deliver femtosecond pulses along flexible fibre cables, which can be held like a light-pen.

ECONOMIST: Ultra-fast lasers

Dr Tzou and his colleagues are looking at uses ranging from cutting out burnt skin and melanomas, to dentistry, bonding joint implants to bone, and general surgery.

ECONOMIST: Ultra-fast lasers

The optimal wavelength, pulse and duration can vary, according not just to which part of the body is being operated on but also to the age of a patient, says Dr Tzou.

ECONOMIST: Ultra-fast lasers