Measurement of the 4Pi-confocal point spread function proves 75 nm axial resolution
Abstract
In a 4Pi-confocal microscope the specimen is illuminated and observed coherently from above and below such that the numerical aperture is increased [S. W. Hell, European Patent Application 91121368.4 (filed 1990, published 1992), S. W. Hell and E. H. K. Stelzer, J. Opt. Soc. Am. A 9, 2159 (1992)]. The point spread functions of 4Pi-confocal and confocal microscopes were measured. Our measurements prove a three- to seven-fold increase of axial resolution, thus opening the prospect for a powerful three-dimensional imaging technique with an axial resolution down to 75 nm.
- Publication:
-
Applied Physics Letters
- Pub Date:
- March 1994
- DOI:
- 10.1063/1.111926
- Bibcode:
- 1994ApPhL..64.1335H
- Keywords:
-
- Illuminating;
- Imaging Techniques;
- Microscopes;
- Optical Measurement;
- Resolution;
- Wave Fronts;
- Detectors;
- Helium-Neon Lasers;
- Lenses;
- Light Scattering;
- Polarization (Waves);
- Optics