Single-image far-field subdiffraction limit imaging with axicon

This Letter presents a technique for subdiffraction limit imaging termed Bessel beam microscopy (BBM). By placing a lens in series with an axicon in the optical path of a microscope, the diffraction-limited resolution of the base microscope is improved by one third. This improvement is demonstrated experimentally by resolving individual subdiffraction limit fluorescent beads in a close-pack arrangement. The behavior of the BBM system is explored using angular diffraction simulations, demonstrating the possibility of resolving features spaced as little as 110 nm apart when viewed with a 100 × 1.4 NA objective. Unique among super-resolution techniques, BBM acquires subdiffraction limit information in a single image with broadband unstructured illumination using only static geometric optics placed between the microscope and camera.