Patent ID: 7710563

Claim:
A method of imaging with an optical system characterized by a diffraction-limited resolution volume, the method comprising: in a sample comprising a plurality of phototransformable optical labels (“PTOLs”) distributed in the sample with a density greater than an inverse of the diffraction-limited resolution volume of the optical system, activating a first subset of the PTOLs in the sample, wherein the density of the activated PTOLs in the first subset is less than the inverse of the diffraction-limited resolution volume; exciting a first portion of the PTOLs in the first subset of PTOLs; detecting radiation emitted from the activated and excited PTOLs in the first portion of PTOLs with the imaging optics; and determining locations of activated and excited PTOLs in the first portion of PTOLs with a sub-diffraction-limited accuracy based on the detected radiation emitted from the activated and excited PTOLs.