Optics

A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects light back to its source with a minimum of scattering.

Distortion is the alteration of the original shape (or other characteristic) of something, such as an object, image, sound or waveform.

In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle θ between the direction of the incident light and the surface normal.

In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength.

An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination.

In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye.

In optics, the refractive index or index of refraction n of a material is a dimensionless number that describes how light propagates through that medium.

Total internal reflection is the phenomenon which occurs when a propagated wave strikes a medium boundary at an angle larger than a particular with respect to the normal to the surface.

In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions.

In physics, optical depth or optical thickness, is the natural logarithm of the ratio of incident to transmitted radiant power through a material, and spectral optical depth or spectral optical thickness is the natural logarithm of the ratio of incident to transmitted spectral radiant power through a material.

Atmospheric optics deals with how the unique optical properties of the Earth's atmosphere cause a wide range of spectacular optical phenomena.

A magnetic lens is a device for the focusing or deflection of moving charged particles, such as electrons or ions, by use of the magnetic Lorentz force.

Ophthalmoscopy, also called funduscopy, is a test that allows a health professional to see inside the fundus of the eye and other structures using an ophthalmoscope (or funduscope).

The Max Born Award is given by the Optical Society (formerly the Optical Society of America) for "outstanding contributions to physical optics", and is named after Max Born.

Binoculars or field glasses are binocular telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects.

The group velocity of a wave is the velocity with which the overall shape of the waves' amplitudes—known as the modulation or envelope of the wave—propagates through space.

An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal.

Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation.

In physics and electrical engineering the reflection coefficient is a parameter that describes how much of an electromagnetic wave is reflected by an impedance discontinuity in the transmission medium.

Spherical aberration is an optical effect observed in an optical device (lens, mirror, etc.) that occurs due to the increased refraction of light rays when they strike a lens or a reflection of light rays when they strike a mirror near its edge, in comparison with those that strike nearer the centre.

In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without being scattered.

In physical and analytical chemistry, colorimetry or colourimetry is a technique "used to determine the concentration of colored compounds in solution.

Photoelasticity is a method to determine the stress distribution in a material experimentally.

A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat surfaces, which reflects waves back directly towards the source, but translated.

In optics, a dichroic material is either one which causes visible light to be split up into distinct beams of different wavelengths (colours) (not to be confused with dispersion), or one in which light rays having different polarizations are absorbed by different amounts.

Asterism (from Ancient Greek: ἀστήρ star), or star stone, is a name applied to the phenomenon of gemstones exhibiting a luminous star-like shape when cut en cabochon (shaped and polished rather than faceted).

In Gaussian optics, the cardinal points consist of three pairs of points located on the optical axis of a rotationally symmetric, focal, optical system.

In describing reflection and refraction in optics, the plane of incidence (also called the meridional plane) is the plane which contains the surface normal and the propagation vector of the incoming radiation.

A frequency-selective surface (FSS) is any thin, repetitive surface (such as the screen on a microwave oven) designed to reflect, transmit or absorb electromagnetic fields based on frequency.

Photoelectrochemical processes are processes in photoelectrochemistry; they usually involve transforming light into other forms of energy.

The signal-to-noise ratio (SNR) is used in imaging as a physical measure of the sensitivity of a (digital or film) imaging system.

Bloch wave – MoM is a first principles technique for determining the photonic band structure of triply periodic electromagnetic media such as photonic crystals.

Cauchy's equation is an empirical relationship between the refractive index and wavelength of light for a particular transparent material.

Opticks is a book by English natural philosopher Isaac Newton that was published in English in 1704.

Nonimaging optics (also called anidolic optics) is the branch of optics concerned with the optimal transfer of light radiation between a source and a target.

Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, followed by theories on light and vision developed by ancient Greek philosophers, and the development of geometrical optics in the Greco-Roman world.

In optics, an index-matching material is a substance, usually a liquid, cement (adhesive), or gel, which has an index of refraction that closely approximates that of another object (such as a lens, material, fiber-optic, etc.).

Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light.

Fourier optics is the study of classical optics using Fourier transforms, (FT) in which the wave is regarded as a superposition of plane waves that are not related to any identifiable sources; instead they are the natural modes of the propagation medium itself.