Photometric error analysis, x: enriched energy (total illuminance) calculations for annular apertures
Applied Optics
|January 23, 2010
Abstract:
Encircled energy calculations show the effects of focus errors, spherical aberration, and a central stop on image contrast. The complementary quantity (excluded energy) gives the illumination at the center of a dark spot on an incoherent background and is useful in some photometric situations. A simple formula is given for the approximate calculation of the excluded energy at large distances from the center of the diffraction pattern.
Related Concept Videos
01:27Polar Coordinates: Problem Solving
Directional radiation patterns are central to antenna analysis, as they illustrate how signal strength varies with direction. These patterns are often modeled using polar plots, where the radial distance from the origin represents signal intensity at a given angle. A commonly used idealized form is the four-lobed rose curve, which captures the concept of directional beams in a simplified mathematical form.The four-lobed rose curve, described by r = cos(2θ), features four symmetric lobes, each...
01:16Flame Photometry: Lab
In a flame photometer, when a solution like potassium chloride is aspirated into the flame, the solvent evaporates, leaving behind dehydrated salt. This salt dissociates into free gaseous atoms in their ground state. Some of these atoms absorb energy from the flame, leading to their excitation. The excited atoms return to the ground state, emitting photons at characteristic wavelengths. Because only electronic transitions are involved, the resulting emission lines are very narrow. The intensity...