Related Experiment Video
Updated: Jul 20, 2026

Clarifying and Imaging Candida albicans Biofilms
Published on: March 6, 2020
Resolution of 90 nm (lambda/5) in an optical transmission microscope with an annular condenser
Arnold Vainrub1, Oleg Pustovyy, Vitaly Vodyanoy
1Department of Anatomy, Physiology and Pharmacology, College of Vetirenary Medicine, Auburn University, Auburn, Alabama 36849, USA.
Abstract:
Resolution of 90 nm was achieved with a research microscope simply by replacing the standard bright-field condenser with a homebuilt illumination system with a cardioid annular condenser. Diffraction gratings with 100 nm width lines as well as less than 100 nm size features of different-shaped objects were clearly visible on a calibrated microscope test slide. The resolution increase results from a known narrower diffraction pattern in coherent illumination for the annular aperture compared with the circular aperture. This explanation is supported by an excellent accord of calculated and measured diffraction patterns for a 50 nm radius disk.
Related Concept Videos
Imaging Biological Samples with Optical Microscopy
In optical microscopy, the specimen to be viewed is placed on a glass slide and clipped on the stage...
Super-resolution Fluorescence Microscopy
Overview of Electron Microscopy
Confocal Fluorescence Microscopy

