Abbe number

Refra.ctlon, Optical glasses are usually described in terms of their refractive index at the sodium D line (589.3 nm), and their v value (or Abbe number) which is a measure of the dispersion or variation of index with wavelength, ie, v = ), in which is the refractive index at the... 

Figure <8. Optical map designating glass groups (letters) and glass types (numbers) as defined by index of refraction (n ) and Abbe-number (vj...

Observations Resins having a refractive index >1.51 and an Abbe number 57 are... 

The refractive index of experimental agents was measured at 25°C at 589 nm using an Abbe refractometer. The Abbe number was determined by measuring the... 

TABLE 1. Physical Properties of Selected Polymers Prepared According to Current Application Indicating the Favorable Balance between Refractive Index and Abbe Number... 

Entry PolyDTTCMA PolyDTHTMA PolyTHPMBL PMMA Refractive Index (nD) Abbe Number (v0) Water Absorption (%)... 

Polythiocarbonate urethanes, (I), prepared by Watanabe et aL (1) having molecular weights 2500 Da had favorable refractive indexes and Abbe numbers and were used in plastic lenses. 

Bojkova et al. (4) prepared high-impact poly(urethane-urea) polysulfides having a refractive index of at least 1.57, an Abbe number of at least 32, and a density >1.3g/cm2 3, which consisted of the reaction product of... 

Research Focus Synthesis of poly(thiocarbonate-cothiourethane) derivatives having a high refractive index and Abbe number. 

Amorphous polymers characteristically possess excellent optical properties. Unlike all the other commercially available fluoropolymers, which are semicrystalline, Teflon AF is quite clear and has optical transmission greater than 90% throughout most of the UV, visible, and near-IR spectrum. A spectrum of a 2.77-mm-thick slab of AF-1600 is shown in Figure 2.5. Note the absence of any absorption peak. Thin films of Teflon AF have UV transmission greater Ilian 95% at 200 mm and are unaffected by radiation from UV lasers. The refractive indexes of Teflon AF copolymers are shown in Figure 2.6 and decrease with increasing FDD content. These are the lowest refractive indexes of any polymer family. It should be noted that the abscissa could also be labeled as glass transition temperature, Tg, since Tg is a function of the FDD content of the AF copolymer. Abbe numbers are low 92 and 113 for AF-1600 and AF-2400. 

Abbe number. (1) The reciprocal of dispersive power. (2) The measure of optical dispersion of a glass the measure of two planes not displacing the axis. 

In the visible region, the dispersion of refractive index is often described by the Abbe number, vj is given by... 

The value of n also depends on the wavelength of measurement. It decreases very slowly with increasing wavelength. This dependence is usually characterized by the Abbe number A, defined by Equation 8.9, where the refractive indices measured at three standard wavelengths are denoted by nF (measured at 6563A), nF (measured at 4861A), and up (measured at 5890A). 

While the Abbe number is important in certain specialized applications such as the design of achromatic lenses which focus a range of wavelengths to the same spot, the variation of n with the wavelength of visible light is normally quite small, and will not be discussed further. 

Several useful empirical relationships which involve dispersion are in the literature. The Abbe number , given by (14)... 

For comparative purposes methyl methacrylate polymerized with the same initiator under the same conditions gave a resin with a refractive index of 1.491 and an Abbe number of 57.8. 

Use the data given below to calculate the Abbe number and the molar refractivity of the following sodium borate glasses. Plot the Abbe number, n, and the molar refractivity versus soda content. Offer an explanation for the behavior of each curve. 

The refractive index varies with the wavelength of the incident light. The Abbe number p is given as a measure of this dispersion. p is obtained from three refractive index measurements at the wavelengths 656.3,589.3, and 486.1 nm ... 

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