title: Resolution of 90 nm (lambda/5) in an optical transmission microscope with an annular condenser.
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.
authors.affiliation: Department of Anatomy, Physiology and Pharmacology, College of Vetirenary Medicine, Auburn University, Auburn, Alabama 36849, USA.
authors.forename: Arnold
authors.initials: A
authors.lastname: Vainrub
authors.forename: Oleg
authors.initials: O
authors.lastname: Pustovyy
authors.forename: Vitaly
authors.initials: V
authors.lastname: Vodyanoy
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007909:Lenses; D008029:Lighting / Q000295:instrumentation* / Q000379:methods; D008853:Microscopy / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity