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Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation which means waves can only travel in a direct visual path from the source to the receiver without obstacles. [ 1] Electromagnetic transmission includes light emissions traveling in a straight line. The rays or waves may be diffracted ...
Rayleigh scattering ( / ˈreɪli / RAY-lee ), named after the 19th-century British physicist Lord Rayleigh (John William Strutt), [1] is the predominantly elastic scattering of light, or other electromagnetic radiation, by particles with a size much smaller than the wavelength of the radiation. For light frequencies well below the resonance ...
At 2 inches (5.1 cm) in diameter and 0.5 inches (13 mm) thick, both surfaces are flat to within 1/10 of the wavelength of the light (58.9 nm), as indicated by the perfectly straight fringes. An optical flat is an optical -grade piece of glass lapped and polished to be extremely flat on one or both sides, usually within a few tens of nanometres ...
A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones ...
In physics, Raman scattering or the Raman effect ( / ˈrɑːmən /) is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrational energy being gained by a molecule as incident photons from a visible laser are shifted to lower ...
Band theory derives these bands and band gaps by examining the allowed quantum mechanical wave functions for an electron in a large, periodic lattice of atoms or molecules. Band theory has been successfully used to explain many physical properties of solids, such as electrical resistivity and optical absorption , and forms the foundation of the ...
The group is designated by a group number (-2, -1, 0, 1, 2, etc.) which is the power to which 2 should be raised to obtain the spatial frequency of the first element (e.g., group -2 is 0.25 line pairs per millimeter). Each element is the 6th root of 2 smaller than the preceding element in the group (e.g. element 1 is 2^0, element 2 is 2^(-1/6 ...
The zero-phonon line is located at a frequency ω’ determined by the intrinsic difference in energy levels between ground and excited state as well as by the local environment. The phonon sideband is shifted to a higher frequency in absorption and to a lower frequency in fluorescence. The frequency gap Δ between the zero-phonon line and the ...