Total-internal-reflection fluorescence microscopy with W-shaped axicon mirrors

A scheme based on a W-shaped axicon mirror device for total-internal-reflection fluorescence microscopy (TIRFM) is presented. This approach combines the advantages of higher efficiency compared with traditional TIRFM, ad-justable illumination area, and simple switching between wide-field and TIRF imaging modes. TIRF images ob-tained with this approach are free of shadow artifacts and of interference fringes. Example micrographs of fluorescently labeled polystyrene beads, of Convallaria majalis tissue, and of Propidium-iodide-labeled Chinese hamster ovary cells are shown, and the capabilities of the scheme are discussed. © 2010Optical Society of America OCIS codes: 110.0180, 180.2520, 170.2945. Background reduction is an important issue in fluores-cence microscopy. In many cases, (auto)fluorescence from out-of-focus excited and detected areas is the main source of background. For this reason, a variety of ap-proaches ranging from confocal microscopy to total-internal-reflection fluorescence microscopy (TIRFM) [1] are employed to eliminate background and to improve the signal-to-noise ratio as well as the spatial resolution