Scientists demonstrate label-free super-resolution microscopy

Science and Technology Daily, Beijing, April 24 (Intern Reporter Zhang Jiaxin) Researchers from the University of Graz in Austria have recently developed a new measurement and imaging method that can resolve particles smaller than the diffraction limit of light without the need for any dyes or labels.

The new method, described in Optics, a high-impact journal of the International Optical Publishing Group, is an improvement on laser scanning microscopy, which uses a strongly focused laser beam to illuminate the specimen

"Our method can help expand the microscopy toolbox for studying nanostructures in a variety of samples,

The research shows that the new method can measure the position and size of gold nanoparticles with an accuracy of a few nanometers, even when multiple particles are in contact

In a laser scanning microscope, a beam of light is scanned over a sample, and transmitted, reflected, or scattered light from the sample is measured

The light's phase, polarization and intensity vary spatially in a way that includes details of the sample it interacts with, however, if the overall optical power is measured only after the interaction, most of the information is lost, the researchers said.

The researchers studied simple samples containing metal nanoparticles of different sizes, demonstrating the new method by scanning a region of interest and then recording polarization and angle-resolved images of the transmitted light

Although these particles and their distances are much smaller than the resolution limit of many microscopes, the new method is able to address this, Banzer said