A dimensionless number that describes how fast light travels in a medium compared to its speed in a vacuum, influencing the bending of light as it passes from one medium to another.

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Fresnel lenses consist of a flat surface with interspaced, concentric steps whereby each step corresponds to the surface of a conventional lens. Each step thereby acts as a refractive surface, much like a prism. This gives the Fresnel lens a common focal length equivalent to a traditional lens, but with a fraction of the thickness. Additionally, because the lens is so thin little light is lost by absorption. Fresnel Lenses can be desirable for use in condenser and lighting systems to collimate and collect light. Fresnel lenses can be used as magnifiers, but this is not recommended unless the thin profile and light weight is absolutely necessary.

The phenomenon that occurs when two or more waves superpose to form a resultant wave, often leading to patterns of constructive and destructive interference.

Fringe Pattern: The pattern created on a screen or detector as a result of the interference of light waves, characterized by alternating bright and dark bands.

Opticalpathlength

Optical path length (OPL) is defined as the product of the physical length of a light path and the refractive index of the medium through which the light travels. This concept is crucial in understanding how light behaves in different materials and how it affects interference patterns in devices like interferometers, where the phase difference between two beams of light can be related directly to their optical path lengths.

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Opticalpathlengthdifference

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Home / Stock / Lenses / Fresnel Lenses

Knight Optical offers a range of stock Fresnel Lenses made from PMMA Acrylic. Our stock range of PMMA Fresnel Lenses comes in two grades. Our “standard range” start from 5mm f.l x 5mm diameter aperture up to 254mm f.l x 152mm dia aperture.