Polarization can change the measured transmission or reflection spectrum of an optical interference filter, especially when the filter operates at a non-normal angle of incidence. At oblique incidence, s-polarized and p-polarized light no longer interact with the multilayer coating in exactly the same way. Their…
Optic diameter is the physical outside diameter of a circular optical component. Clear aperture is the region of that optic over which specified optical performance is required. The clear aperture is therefore usually smaller than the physical diameter, because part of the edge may be…
A collimated N-BK7 plano-convex lens with f = 50 mm reaches the 0.07 λ RMS diffraction limit at f/6.4 (computed, 587.6 nm). Face the curved side of a plano-convex lens toward the collimated beam; reversing it quadruples computed longitudinal spherical aberration. An asphere corrects on-axis…
A cone half angle shifts an interference filter’s spectrum toward shorter wavelengths and softens its edges; a pure tilt only shifts it. With the chief ray normal and a uniformly filled pupil, the mean shift equals half the marginal-ray shift. The same cone produces far…
