The size of the smallest detail visible in conventional microscopy is determined by the wavelength of the light used to image a specimen. For state-of-the-art optical imaging, this diffraction limit is 200-300 nm, leaving a considerable ‘blind spot’ between the angstrom-scale molecular details visible by X-ray crystallography and the those accessible by visible light microscopy. Recently, a number of developments have been reported that allow fluorescence imaging of samples with resolutions of an order of magnitude below the diffraction limit.One such method makes use of the stochastic fluorescence emission of individual molecules. Massive oversampling of the fluorescence emission of these particles allows the determination of their positions with high accuracy and, thus, the construction the image of a fluorescently labeled, biological sample with a resolution below the diffraction limit. This and related techniques, however, are limited to the imaging of fixed samples and require many minutes or hours to construct a single image. Another approach is making use of certain photophysical properties of fluorophores and a combination of illumination lasers to decrease the size of the excitation focus in confocal microscopy. Disadvantages of this method include the need for sophisticated laser equipment, very specific requirements for the fluorescent labels, and long times to obtain images. In general, live cell imaging at the timescales required to study the dynamics of intracellular processes is impractical with these newly developed super-resolution techniques.Here, we present a drastically different approach to sub-diffraction-limited imaging that utilizes a propagating, nanoscopic beam of visible light with a diameter of a few 10s of nm. This phenomenon relies on the resonance of surface plasmons with the photons at the dielectric/metal interface. The width of the transmitted photon beam is independent of wavelength remains constant over length scales of 100s of nm.