Transparent curved surfaces {lens, physics}| can refract parallel light rays to point.
convex
For convex lenses, if object is inside focal point, image is virtual, erect, and smaller. For convex lenses, if object is outside focal point, image is real and inverted.
concave
For concave lenses, image is virtual and erect. For concave lenses, if object is inside focal point, image is bigger. For concave lenses, if object is outside focal point, image is smaller.
focus
Focal length F depends on lens refractive index n and radii R of sides: 1/F = (n - 1) * ((1 / Ri) - (1 / Ro)).
curvature radius
Curvature radius is positive if curve is convex. Curvature radius is negative if curve is concave.
size
Ratio of image size I to object size O equals ratio of distance q of image from lens to distance p of object from lens. I/O = q/p.
wavelets
Lenses perform spatial Fourier transforms.
Mirror or lens angular size {aperture}| is angle at focal point between two radii from ends of a spherical-mirror or spherical-lens diameter.
Spherical mirrors or lenses with large aperture deviate from parabolic reflection {spherical aberration}| at edges. Edges do not refract to focal point.
Units {diopter} can measure how much lenses converge or diverge light {dioptric power}. Zero diopters converges light from object at one meter to focus at one meter. Three diopters converges light from object at one meter to focus at one-third meter. Minus three diopters diverges light from object at one meter to focus at three meters.
Parallel light rays from one lens side go through lens to a point {focus, lens} {focal point}| on other lens side.
Images {real image} {image, object}| can form from actual light rays. Images {virtual image} can appear to be in locations where light rays cannot go. Images {erect image} can have same orientation as objects. Images {inverted image} can have opposite orientation as objects. Images can magnify or reduce objects.
Image distance I and object distance O relate to focal point distance F {lens equation, lens}: 1/F = 1/I + 1/O.
Lens surface can curve in {concave lens}.
Lens surface can curve out {convex lens}.
Lens combinations {achromatic lens} can eliminate chromatic aberration.
Lenses {aplanatic lens} can correct spherical aberration.
Microscopes {microscope}| have large lens that collects light to focal point, and second small, high-curvature lens that focuses small but near image. Microscopes {phase contrast microscope} can look for different light phases.
5-Physics-Wave-Superposition-Refraction
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Date Modified: 2022.0225