title: Differential near-field scanning optical microscopy.
abstract: We theoretically and experimentally illustrate a new apertured near-field scanning optical microscopy (NSOM) technique, termed differential NSOM (DNSOM). It involves scanning a relatively large (e.g., 0.3-2 mum wide) rectangular aperture (or a detector) in the near-field of an object and recording detected power as a function of the scanning position. The image reconstruction is achieved by taking a two-dimensional derivative of the recorded power map. Unlike conventional apertured NSOM, the size of the rectangular aperture/detector does not determine the resolution in DNSOM; instead, the resolution is practically determined by the sharpness of the corners of the rectangular aperture/detector. Principles of DNSOM can also be extended to other aperture/detector geometries such as triangles and parallelograms.
authors.affiliation: Wellman Center for Photomedicine, Harvard Medical School, Boston, Massachusetts 02114, USA. aozcan@mgh.harvard.edu
authors.forename: Aydogan
authors.initials: A
authors.lastname: Ozcan
authors.forename: Ertugrul
authors.initials: E
authors.lastname: Cubukcu
authors.forename: Alberto
authors.initials: A
authors.lastname: Bilenca
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Crozier
authors.forename: Brett E
authors.initials: BE
authors.lastname: Bouma
authors.forename: Federico
authors.initials: F
authors.lastname: Capasso
authors.forename: Guillermo J
authors.initials: GJ
authors.lastname: Tearney
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D020527:Microscopy, Scanning Probe / Q000295:instrumentation / Q000379:methods*; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D010316:Particle Size; D012680:Sensitivity and Specificity; D013499:Surface Properties