Nonlinear structured-illumination microscopy: Wide-field fluorescence imaging with theoretically unlimited resolution

Contrary to the well known diffraction limit, the fluorescence microscope is in principle capable of unlimited resolution. The necessary elements are spatially structured illumination light and a nonlinear dependence of the fluorescence emission rate on the illumination intensity. As an example of this concept, this article experimentally demonstrates saturated structured-illumination microscopy, a recently proposed method in which the nonlinearity arises from saturation of the excited state. This method can be used in a simple, wide-field (nonscanning) microscope, uses only a single, inexpensive laser, and requires no unusual photophysical properties of the fluorophore. The practical resolving power is…

• NS
  National Science Foundation

  Awards: GM31627, GM25101
• WF
  Wenner-Gren Foundation
• KT
  Kungliga Tekniska Högskolan
• NI
  National Institutes of Health

  Awards: GM25101, GM31627
• UO
  University of California, San Francisco