Leica Science Lab - Tag : Diffraction https://www.leica-microsystems.com//science-lab/tag/tags/diffraction/show/Tag/ Article tagged with Diffraction en-US https://www.leica-microsystems.com/19605 Basics in Microscopy Collecting Light: The Importance of Numerical Aperture in Microscopy Numerical aperture (abbreviated as ‘NA’) is an important consideration when trying to distinguish detail in a specimen viewed down the microscope. NA is a number without units and is related to the angles of light which are collected by a lens. In calculating NA (see below), the refractive index of a medium is also taken into account and by matching the refractive index of a slide or cell culture container with an immersion medium, then more of the detail of a specimen will be resolved. The way in which light behaves when travelling from one medium to another is also related to NA (and termed ‘refraction’). This article also covers a brief history of refraction and how this concept is a limiting factor in achieving high NA. https://www.leica-microsystems.com//science-lab/collecting-light-the-importance-of-numerical-aperture-in-microscopy/ Wed, 12 Jul 2017 07:46:00 +0000 PhD Martin Wilson https://www.leica-microsystems.com/18991 Basics in Microscopy Microscope Resolution: Concepts, Factors and Calculation In microscopy, the term ‘resolution’ is used to describe the ability of a microscope to distinguish detail. In other words, this is the minimum distance at which two distinct points of a specimen can still be seen - either by the observer or the microscope camera - as separate entities. The resolution of a microscope is intrinsically linked to the numerical aperture (NA) of the optical components as well as the wavelength of light which is used to examine a specimen. In addition, we have to consider the limit of diffraction which was first described in 1873 by Ernst Abbe. This article covers some of the history behind these concepts as well as explaining each using relatively simple terminology. https://www.leica-microsystems.com//science-lab/microscope-resolution-concepts-factors-and-calculation/ Fri, 02 Dec 2016 14:09:00 +0000 PhD Martin Wilson https://www.leica-microsystems.com/13927 Basics in Microscopy Video Talk by Jeff Lichtman: Point Spread Function An infinitesimally small point appears in the microscope as a spot with a certain size, blurred in the z-direction and with concentric rings around it. This "point spread function" reveals many of the optical properties of your microscope. This lecture explains why and how the microscope images a point as a point spread function. https://www.leica-microsystems.com//science-lab/video-talk-by-jeff-lichtman-point-spread-function/ Thu, 08 Jan 2015 13:23:00 +0000 Dr. Jeff Lichtman https://www.leica-microsystems.com/9680 Confocal Microscopy Pinhole Geometry: Four Corners are Perfect Square and hexagonal pinholes provide identical image signal levels, if the geometries are compared in a sensible manner. The amount of light passing the pinhole depends on the area of that aperture, consequently the area is the parameter that must be compared when discussing brightness of focus images. The use of incommensurable edge lengths is meant to confuse the reader and thus dishonest and reprehensible. In this article, the signal level as a function of geometry and size in confocal microscopes is described. https://www.leica-microsystems.com//science-lab/pinhole-geometry-four-corners-are-perfect/ Thu, 23 May 2013 12:59:00 +0000 Dr. Rolf T. Borlinghaus