Quantum aid for microscopy

In light microscopes, increasing the intensity of the illumination light helps to reach higher sensitivity or resolution. But this is not always possible when analysing living samples, as light that is too bright may cause damage. One theoretical possibility to increase the performance of a microscope without increasing the photon number is to use light prepared in a quantum state. Catxere Casacio et al. experimentally show that a coherent Raman microscope obtains a 35% better signal-to-noise ratio at equal beam brightness when using squeezed light, revealing biological structures within cells that would not otherwise be resolved at the photodamage limit.