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Laurent's half-shade polarimeter [ edit ] When plane-polarised light passes through some crystals, the velocity of left-polarized light is different from that of the right-polarized light, thus the crystals are said to have two refractive indices, i.e. double refracting.
Two common types of waveplates are the half-wave plate, which rotates the polarization direction of linearly polarized light, and the quarter-wave plate, which converts between different elliptical polarizations (such as the special case of converting from linearly polarized light to circularly polarized light and vice versa.) [1]
Recording optical rotation with a polarimeter: The plane of polarisation of plane polarised light (4) rotates (6) as it passes through an optically active sample (5). This angle is determined with a rotatable polarizing filter (7). In chemistry, specific rotation ([α]) is a property of a chiral chemical compound.
A simple polarimeter to measure this rotation consists of a long tube with flat glass ends, into which the sample is placed. At each end of the tube is a Nicol prism or other polarizer. Light is shone through the tube, and the prism at the other end, attached to an eye-piece, is rotated to arrive at the region of complete brightness or that of ...
Classical interference microscopy, also called quantitative interference microscopy, uses two separate light beams with much greater lateral separation than that used in phase contrast microscopy or in differential interference microscopy (DIC).
Half-harmonic generation (also called wavelength doubling or frequency halving) is a nonlinear optical process in which photons "split" to generate pairs of new photons with half the energy, therefore half the frequency and twice the wavelength of the initial photons.
In one study, only 23.8 percent of patients with transient monocular vision loss experienced the classic "curtain" or "shade" descending over their vision. [4] Other descriptions of this experience include a monocular blindness, dimming, fogging, or blurring. [ 5 ]
In 1997 two French astronomers, André Baranne and Françoise Launay, after a long and meticulous investigation including a search for unpublished manuscripts and the analysis of parish registers in the places where Cassegrain lived (Chartres first and then Chaudon, near Nogent-le-Roi), identified Laurent Cassegrain as the most likely candidate ...