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Lecture

Numerical Aperture and Resolution: Understanding Microscope Performance

In course

MICRO-561: Fundamentals of biomicroscopy

Introduction to the basic operational principles of the most commonly used optical microscopes such as widefield and fluorescence.
Introduction to essential microscopy components such as lenses, objectives, filters, cameras and light sources. ...

Description

This lecture covers the relationship between Numerical Aperture (NA) and resolution in optical microscopy. It explains how increasing NA enhances resolution by reducing diffraction-limited spot size. The instructor discusses the impact of NA on capturing diffraction orders and presents examples of resolution improvement with oil immersion objectives. The lecture also delves into the effective NA influenced by condenser aperture, emphasizing its role in system resolution. Historical examples, including the 1888 Zeiss catalog images of diatoms, illustrate the significance of NA in achieving high resolution. Furthermore, the lecture explores super-resolution microscopy advancements, such as STED microscopy, and showcases bio-imaging with STORM for sub-diffraction imaging of microtubules.

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Instructors (2)

Hatice Altug

2020-current Full Professor at the Institute of Bioengineering, EPFL, Switzerland2013-2020 Associate Professor (with tenure) at the Institute of Bioengineering, EPFL, Switzerland 2013 Associate Professor (with tenure) at Electrical and Computer Engineering Department of Boston University, USA 2007-2013 Assistant Professor (tenure-track) at Electrical and Computer Engineering Department of Boston University, USA 2007 Post-doctoral Fellow at Center for Engineering in Medicine of Harvard Medical School, USA 2000-2007 PhD. in Applied Physics at Stanford University, USA 1996-2000 B.S. in Physics at Bilkent University, Turkey

Arne Seitz

04/1996-06/2000 Scientific co-worker at Philipps-University of Marburg, Dep. of Physical Chemistry 07/2000-10/2002 Post Doc at Max-Planck Unit for Structural Molecular Biology in Hamburg 11/2002-11/2005 Post Doc at European Molecular Biolohy Laboratory (EMBL), Cell Biology and Cell Biophysics Programme 11/2005-03/2009 Staff Scientist at Advanced Light Microscopy Facility, EMBL 04/2009- Head of Bioimaging and Optics platforme (BIOP), Ecole Polytechnique Fédérale de Lausanne (EPFL)

Official source

Ontological neighbourhood

Biology

Anatomy: Histology

Related concepts (32)

Optical microscope

The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century. Basic optical microscopes can be very simple, although many complex designs aim to improve resolution and sample contrast. The object is placed on a stage and may be directly viewed through one or two eyepieces on the microscope.

Super-resolution microscopy

Super-resolution microscopy is a series of techniques in optical microscopy that allow such images to have resolutions higher than those imposed by the diffraction limit, which is due to the diffraction of light. Super-resolution imaging techniques rely on the near-field (photon-tunneling microscopy as well as those that use the Pendry Superlens and near field scanning optical microscopy) or on the far-field.

Confocal microscopy

Confocal microscopy, most frequently confocal laser scanning microscopy (CLSM) or laser scanning confocal microscopy (LSCM), is an optical imaging technique for increasing optical resolution and contrast of a micrograph by means of using a spatial pinhole to block out-of-focus light in image formation. Capturing multiple two-dimensional images at different depths in a sample enables the reconstruction of three-dimensional structures (a process known as optical sectioning) within an object.

Diffraction-limited system

In optics, any optical instrument or system a microscope, telescope, or camera has a principal limit to its resolution due to the physics of diffraction. An optical instrument is said to be diffraction-limited if it has reached this limit of resolution performance. Other factors may affect an optical system's performance, such as lens imperfections or aberrations, but these are caused by errors in the manufacture or calculation of a lens, whereas the diffraction limit is the maximum resolution possible for a theoretically perfect, or ideal, optical system.

Oil immersion

In light microscopy, oil immersion is a technique used to increase the resolving power of a microscope. This is achieved by immersing both the objective lens and the specimen in a transparent oil of high refractive index, thereby increasing the numerical aperture of the objective lens. Without oil, light waves reflect off the slide specimen through the glass cover slip, through the air, and into the microscope lens (see the colored figure to the right).

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