Powerful microscopes have made a quantum leap. Using a quantum trick with light has allowed researchers to examine living cells in unprecedented detail without destroying them, a technique that could improve medical diagnoses and microbiology research.
The microscopes that are generally used to examine living biological systems shine one or two bright lights on their targets, and more powerful light sources allow researchers to see the cells in greater detail. But this approach has a fundamental limit to the precision it can achieve: at some point, a bright enough light will destroy a living cell.
“Our understanding of life as it is now has relied almost entirely on the quality of our microscopes,” says Warwick Bowen at the University of Queensland in Australia. “We’re really limited by technology, and it’s not obvious how to break the existing limits because we’ve already pushed the intensity as high as we can without destroying the cell.”
Bowen and his colleagues have found a way to overcome this problem. They used a type of microscope with two laser light sources, but sent one of the beams through a specially designed crystal that “squeezes” the light. It does so by introducing quantum correlations in the photons – the particles of light in the laser beam.