Phys.org June 9, 2021
The performance of light microscopes is limited by the stochastic nature of light. Randomness in the times that photons are detected introduces shot noise, which fundamentally constrains sensitivity, resolution, and speed. Although the long-established solution to this problem is to increase the intensity of the illumination light, this is not always possible when investigating living systems, because bright lasers can severely disturb biological processes. An international team of researchers (Australia, Germany) has experimentally shown that quantum correlations allow a signal-to-noise ratio beyond the photodamage limit of conventional microscopy. They developed a coherent Raman microscope that offers subwavelength resolution and incorporates bright quantum correlated illumination. The correlations allow imaging of molecular bonds within a cell with a 35% improved signal-to-noise ratio compared with conventional microscopy, corresponding to a 14% improvement in concentration sensitivity. This enables the observation of biological structures that would not otherwise be resolved. Coherent Raman microscopes allow highly selective biomolecular fingerprinting in unlabeled specimens but photodamage is a major roadblock for many applications. Their work will enable order-of-magnitude improvements in the signal-to-noise ratio and the imaging speed…read more. TECHNICAL ARTICLEÂ
Experimental setup. Credit: Nature volume 594, pages201–206 (2021)Â