Imaging breakthrough could aid development of quantum microscopes

A breakthrough in quantum imaging could lead to the development of advanced forms of microscopy for use in medical research and diagnostics. A team of physicists from the University of Glasgow and Heriot-Watt University have found a new way to create detailed microscopic images under conditions which would cause conventional optical microscopes to fail. In a new paper published today , the team describe how they have generated images by finding a new way to harness a quantum phenomenon known as Hong-Ou-Mandel (HOM) interference. Named after the three researchers who first demonstrated it in 1987, HOM interference occurs when quantum-entangled photons are passed through a beam splitter - a glass prism which can turn a single beam of light into two separate beams as it passes through. Inside the prism, the photons can either be reflected internally or transmitted outwards. When the photons are identical, they will always exit the splitter in the same direction, a process known as 'bunching'. When the entangled photons are measured using photodetectors at the end of the path of the split beam of light, a characteristic 'dip' in the output probability graph of the light shows that the bunched photons are reaching only one detector and not the other.