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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.
When light waves travel through a medium other than a vacuum, interaction with the medium causes the wave amplitude and phase to change in a manner dependent on properties of the medium. Changes in amplitude (brightness) arise from the scattering and absorption of light, which is often wavelength-dependent and may give rise to colors.
The changes in the light passage result in waves being 'out of phase' with others. This effect can be transformed by phase contrast microscopes into amplitude differences that are observable in the eyepieces and are depicted effectively as darker or brighter areas of the resultant image. [citation needed]
The light path of a bright-field microscope is extremely simple; no additional components are required beyond the normal light-microscope setup. The light path begins at the illuminator or the light source on the base of the microscope. Often a halogen lamp is used. The light travels through the objective lens into the ocular lens, through ...
The pupil function or aperture function describes how a light wave is affected upon transmission through an optical imaging system such as a camera, microscope, or the human eye. More specifically, it is a complex function of the position in the pupil [ 1 ] or aperture (often an iris ) that indicates the relative change in amplitude and phase ...
As the combined image keeps both amplitude and phase information, the interferometric microscopy can be especially efficient for the phase objects, [3] allowing detection of light variations of index of refraction, which cause the phase shift or the light passing through for a small fraction of a radian.
The effect of the contrast transfer function can be seen in the alternating light and dark rings (Thon rings), which show the relation between contrast and spatial frequency. The contrast transfer function ( CTF ) mathematically describes how aberrations in a transmission electron microscope (TEM) modify the image of a sample.
Antonie van Leeuwenhoek (1632–1723). The field of microscopy (optical microscopy) dates back to at least the 17th-century.Earlier microscopes, single lens magnifying glasses with limited magnification, date at least as far back as the wide spread use of lenses in eyeglasses in the 13th century [2] but more advanced compound microscopes first appeared in Europe around 1620 [3] [4] The ...