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Optical cross section of a flat mirror with a given reflectivity at a particular wavelength () can be expressed by the formula = Where is the cross sectional diameter of the beam. Note that the direction of the light has to be perpendicular to the mirror surface for this formula to be valid, else the return from the mirror would no longer go ...
Subscripts 1 and 2 refer to initial and final optical media respectively. These ratios are sometimes also used, following simply from other definitions of refractive index, wave phase velocity, and the luminal speed equation:
Radar Cross Section, Optical Theorem, Physical Optics Approx, Radiation by Line Sources for detailed lecture on introduction to the Radar Cross-Section (RCS) Hip-pocket formulas for high-frequency RCS backscatter; useful reference sheet (PDF) Method to measure radar cross section parameters of antennas
The index ellipsoid is not to be confused with the index surface, whose radius vector (from the origin) in any direction is indeed the refractive index for propagation in that direction; for a birefringent medium, the index surface is the two-sheeted surface whose two radius vectors in any direction have lengths equal to the major and minor semiaxes of the diametral section of the index ...
Rayleigh–Gans approximation has been applied on the calculation of the optical cross sections of fractal aggregates. [6] The theory was also applied to anisotropic spheres for nanostructured polycrystalline alumina and turbidity calculations on biological structures such as lipid vesicles [7] and bacteria.
where Q is the efficiency factor of scattering, which is defined as the ratio of the scattering cross-section and geometrical cross-section πa 2. The term p = 4πa( n − 1)/λ has as its physical meaning the phase delay of the wave passing through the centre of the sphere, where a is the sphere radius, n is the ratio of refractive indices ...
These formulas [14] [15] [16] are known respectively as Fresnel's sine law and Fresnel's tangent law. [17] Although at normal incidence these expressions reduce to 0/0, one can see that they yield the correct results in the limit as θ i → 0 .
Like every optical grating, a blazed grating has a constant line spacing , determining the magnitude of the wavelength splitting caused by the grating. The grating lines possess a triangular, sawtooth-shaped cross section, forming a step structure.