We present a novel scanning fluorescence microscopy technique, nonconfocal theta microscopy (NCTM), that provides almost isotropic resolution. In NCTM, multiphoton absorption from two orthogonal illumination directions is used to induce fluorescence emission. Therefore the point-spread function of the microscope is described by the product of illumination point-spread functions with reduced spatial overlap, which provides the resolution improvement and the more isotropic observation volume. We discuss the technical details of this new method.
© 1999 Optical Society of America
(170.2520) Medical optics and biotechnology : Fluorescence microscopy
(180.2520) Microscopy : Fluorescence microscopy
(180.5810) Microscopy : Scanning microscopy
(180.6900) Microscopy : Three-dimensional microscopy
(190.4180) Nonlinear optics : Multiphoton processes
S. Lindek and E. H. K. Stelzer, "Resolution improvement by nonconfocal theta microscopy," Opt. Lett. 24, 1505-1507 (1999)