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A polarimeter [1] is a scientific instrument used to measure optical rotation: the angle of rotation caused by passing linearly polarized light through an optically active substance. [ 2 ] Some chemical substances are optically active, and linearly polarized (uni-directional) light will rotate either to the left (counter-clockwise) or right ...
Polarized light microscopy is used extensively in optical mineralogy. Although the invention of the polarizing microscope is typically attributed to David Brewster around 1815, Brewster clearly acknowledges the priority of Henry Fox Talbot , who published his work in 1834.
Optical activity is measured using a polarized source and polarimeter. This is a tool particularly used in the sugar industry to measure the sugar concentration of syrup, and generally in chemistry to measure the concentration or enantiomeric ratio of chiral molecules in solution.
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 ...
The rotation is reported using degrees, and no units of concentration are given (it is assumed to be g/100mL). The sign of the rotation (+ or −) is always given. If the wavelength of the light used is 589 nanometer (the sodium D line), the symbol “D” is used. If the temperature is omitted, it is assumed to be at standard room temperature ...
In order for a molecule (or crystal) to exhibit circular birefringence and circular dichroism, it must be distinguishable from its mirror image. An object that cannot be superimposed on its mirror image is said to be chiral , and optical rotatory dispersion and circular dichroism are known as chiroptical properties.
The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) was a space telescope with a 50cm diameter mirror for spectroscopy and polarimetry in the ultraviolet spectral range. It was used in conjunction with other telescopes on the shuttle missions STS-35 (ASTRO-1 in December 1990) [ 1 ] and STS-67 (ASTRO-2 in March 1995).
The GDx nerve fiber analyzers measure the retinal nerve fiber layer (RNFL) thickness with a scanning laser polarimeter based on the birefringent properties of the RNFL. Measurement is obtained from a band 1.75 disc diameters concentric to the disc. It projects a polarized beam of a light into the eye.