Researchers from the University of Science and Technology of China (USTC) have unveiled a planar optical device that significantly enhances the capabilities of dark-field microscopy, achieving super-resolution imaging beyond the diffraction limit. The work was led by Prof. Zhang Douguo and has been published in the Proceedings of the National Academy of Sciences.

Dark-field microscopy is a powerful technique used to visualize unstained samples by illuminating them with light at oblique angles, resulting in high-contrast images of weakly scattering objects. However, traditional dark-field microscopy is limited by the diffraction barrier and often requires complex, bulky setups with precise alignment. Super-resolution imaging techniques, which can overcome this barrier, are typically expensive and difficult to operate. The need for a simpler, more accessible solution has long been a challenge in the field.

The study introduces a planar photonic device that integrates a scattering layer, a one-dimensional photonic crystal (1DPC), and a metallic film to generate dark-field speckle patterns. This compact device can be easily integrated into conventional microscopes, eliminating the need for complex optical systems or precise alignment.