Microscope

Carl Zeiss binocular compound microscope, 1914

Electron microscope constructed by Ernst Ruska in 1933

Fluorescence microscope with the filter cube turret above the objective lenses, coupled with a camera.

Types of microscopes illustrated by the principles of their beam paths

Evolution of spatial resolution achieved with optical, transmission (TEM) and aberration-corrected electron microscopes (ACTEM).

Unstained cells viewed by typical brightfield (left) compared to phase-contrast microscopy (right).

Transmission electron micrograph of a dividing cell undergoing cytokinesis

Leaf surface viewed by a scanning electron microscope.

Laboratory instrument used to examine objects that are too small to be seen by the naked eye.

- Microscope

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Lens

Transmissive optical device which focuses or disperses a light beam by means of refraction.

$Light being refracted by a spherical glass container full of water. Roger Bacon, 13th century$

Lens for LSST, a planned sky surveying telescope

The position of the focus of a spherical lens depends on the radii of curvature of the two facets.

A camera lens forms a real image of a distant object.

Virtual image formation using a positive lens as a magnifying glass.

Images of black letters in a thin convex lens of focal length f are shown in red. Selected rays are shown for letters E, I and K in blue, green and orange, respectively. Note that E (at 2f) has an equal-size, real and inverted image; I (at f) has its image at infinity; and K (at f/2) has a double-size, virtual and upright image.

Other uses are in imaging systems such as monoculars, binoculars, telescopes, microscopes, cameras and projectors.

Optical microscope

The oldest published image known to have been made with a microscope: bees by Francesco Stelluti, 1630

Basic optical transmission microscope elements (1990s)

Two Leica oil immersion microscope objective lenses: 100× (left) and 40× (right)

U.S. CBP Office of Field Operations agent checking the authenticity of a travel document at an international airport using a stereo microscope

A 40x magnification image of cells in a medical smear test taken through an optical microscope using a wet mount technique, placing the specimen on a glass slide and mixing with a salt solution

$The diffraction limit set in stone on a monument for Ernst Abbe.$

3D dual color super resolution microscopy with Her2 and Her3 in breast cells, standard dyes: Alexa 488, Alexa 568 LIMON

Stimulated emission depletion (STED) microscopy image of actin filaments within a cell.

Bright field illumination, sample contrast comes from absorbance of light in the sample.

Cross-polarized light illumination, sample contrast comes from rotation of polarized light through the sample.

Dark field illumination, sample contrast comes from light scattered by the sample.

Phase contrast illumination, sample contrast comes from interference of different path lengths of light through the sample.

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.

Optics

Branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it.

Alhazen (Ibn al-Haytham), "the father of Optics"

$Reproduction of a page of Ibn Sahl's manuscript showing his knowledge of the law of refraction.$

The first treatise about optics by Johannes Kepler, Ad Vitellionem paralipomena quibus astronomiae pars optica traditur (1604)

Cover of the first edition of Newton's Opticks (1704)

$Geometry of reflection and refraction of light rays$

Illustration of Snell's Law for the case n1 < n2, such as air/water interface

A ray tracing diagram for a converging lens.

When oil or fuel is spilled, colourful patterns are formed by thin-film interference.

Conceptual animation of light dispersion through a prism. High frequency (blue) light is deflected the most, and low frequency (red) the least.

Dispersion: two sinusoids propagating at different speeds make a moving interference pattern. The red dot moves with the phase velocity, and the green dots propagate with the group velocity. In this case, the phase velocity is twice the group velocity. The red dot overtakes two green dots, when moving from the left to the right of the figure. In effect, the individual waves (which travel with the phase velocity) escape from the wave packet (which travels with the group velocity).

A polariser changing the orientation of linearly polarised light. In this picture, θ1 – θ0 = θi.

The effects of a polarising filter on the sky in a photograph. Left picture is taken without polariser. For the right picture, filter was adjusted to eliminate certain polarizations of the scattered blue light from the sky.

Experiments such as this one with high-power lasers are part of the modern optics research.

Model of a human eye. Features mentioned in this article are 1. vitreous humour 3. ciliary muscle, 6. pupil, 7. anterior chamber, 8. cornea, 10. lens cortex, 22. optic nerve, 26. fovea, 30. retina

The Ponzo Illusion relies on the fact that parallel lines appear to converge as they approach infinity.

Illustrations of various optical instruments from the 1728 Cyclopaedia

A colourful sky is often due to scattering of light off particulates and pollution, as in this photograph of a sunset during the October 2007 California wildfires.

Practical applications of optics are found in a variety of technologies and everyday objects, including mirrors, lenses, telescopes, microscopes, lasers, and fibre optics.

Electron microscope

Diagram illustrating the phenomena resulting from the interaction of highly energetic electrons with matter

Image of Bacillus subtilis taken with a 1960s electron microscope

An image of an ant in a scanning electron microscope

An insect coated in gold for viewing with a scanning electron microscope

JEOL transmission and scanning electron microscope made in the mid-1970s

An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination.

Light

Electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

The electromagnetic spectrum, with the visible portion highlighted

Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily

$Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.$

Hong Kong illuminated by colourful artificial lighting.

$Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.$

Magnifying glasses, spectacles, contact lenses, microscopes and refracting telescopes are all examples of this manipulation.

$A ray of light being refracted in a plastic block.$

Refraction

Redirection of a wave as it passes from one medium to another.

$A ray of light being refracted in a plastic block.$

$Refraction of light at the interface between two media of different refractive indices, with n2 > n1. Since the phase velocity is lower in the second medium (v2 < v1), the angle of refraction θ2 is less than the angle of incidence θ1; that is, the ray in the higher-index medium is closer to the normal.$

$A pen partially submerged in a bowl of water appears bent due to refraction at the water surface.$

When a wave moves into a slower medium the wavefronts get compressed. For the wavefronts to stay connected at the boundary the wave must change direction.

$A pencil part immersed in water looks bent due to refraction: the light waves from X change direction and so seem to originate at Y.$

$An image of the Golden Gate Bridge is refracted and bent by many differing three-dimensional drops of water.$

$The sun appears slightly flattened when close to the horizon due to refraction in the atmosphere.$

Heat haze in the engine exhaust above a diesel locomotive.

$Water waves are almost parallel to the beach when they hit it because they gradually refract towards land as the water gets shallower.$

It is what optical lenses are based on, allowing for instruments such as glasses, cameras, binoculars, microscopes, and the human eye.

c. 1680 Portrait of a Mathematician by Mary Beale, conjectured to be of Hooke but also conjectured to be of Isaac Barrow.

Robert Hooke

English polymath active as a scientist and architect, who, using a microscope, was the first to visualize a micro-organism.

Hooke's microscope, from an engraving in Micrographia

Robert Boyle by Johann Kerseboom, at Gawthorpe Hall, Lancashire

Illustration from The posthumous works of Robert Hooke... published in Acta Eruditorum, 1707

Engraving of a louse from Hooke's Micrographia

Drawings of the Moon and the Pleiades from Hooke's Micrographia

Hooke noted the shadows (a and b) cast by both the globe and the rings on each other in this drawing of Saturn.

Church of St Mary Magdalene at Willen, Milton Keynes

Portrait thought for a time to be Hooke, but almost certainly Jan Baptist van Helmont

Hooke memorial plaque in Westminster Abbey

Hooke's 1665 book Micrographia, describing observations with microscopes and telescopes, as well as original work in biology, contains the earliest of an observed microorganism, a microfungus Mucor.

3D dual colour super resolution microscopy with Her2 and Her3 in breast cancer cells, standard dyes: Alexa 488, Alexa 568 - LIMON (SPDM +SMI

Vertico spatially modulated illumination

Fastest light microscope for the 3D analysis of complete cells in the nanometer range.

SMI + TIRF of human eye tissue affected by macular degeneration

Single YFP molecule super resolution microscopy / SPDMphymod

Dual color localization microscopy SPDMphymod/super resolution microscopy with GFP & RFP fusion proteins

These are processes which modify the point spread function (PSF) of a microscope in a suitable manner to either increase the optical resolution, to maximize the precision of distance measurements of fluorescent objects that are small relative to the wavelength of the illuminating light, or to extract other structural parameters in the nanometer range.