Photonics Dictionary

Light that is directed or focused by means of curved reflective surfaces.

Catoptrics is the field of optics concerned with the reflection of light from reflective surfaces such as mirrors. It encompasses the study and analysis of how light rays interact with these...

Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a lens or optical system, leading to a failure to focus all colors to the same...

The image of a point source that appears as a circle of finite diameter because of defocusing or the aberrations inherent in an optical system.

Best point of focus for an image in a beam of light at the smallest cross section of the beam.

Also known as clear glass or clear filter. The clear glass plate is used to simulate a filter, in converging or diverging light, to maintain focus.

Computational imaging refers to the use of computational techniques, algorithms, and hardware to enhance or enable imaging capabilities beyond what traditional optical systems can achieve. It...

A phase reflection scanner that eliminates the need for a complex translation device while maintaining a high-energy-density level during laser materials processing. These devices direct and focus...

Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In the context of geometry or optics, a concave shape is one that curves or...

Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These mirrors are commonly used in optics for various applications, including...

A reflecting grating ruled on a concave spherical surface that not only disperses the light but focuses the spectrum. The great advantage of this grating lies in the fact that no separate collimating...

A type of laser welding of thin materials using a defocused or low-power carbon dioxide laser beam. The energy is absorbed by the material through conduction and melts the material to produce an edge...

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator configuration used in laser systems. The term confocal in this context refers to the...

The two points on the principal axis of a mirror or lens so positioned that light emitted from either point will be focused at the other, i.e., object and image points.

A type of photoelectric proximity mode sensing incorporating a lens system to focus the light from the emitter in a small, concentrated spot at a specific point in front of the sensor. Also referred...

Also known as convergent lens or convex lens. A lens that converges an incident bundle of rays to a focus.

A semispherical or conical lens created directly on the core of an optical fiber to focus light from a laser into the fiber core.

A rangefinder on a camera that is integrated with the focusing mechanism so that when an object's range is determined, the camera is automatically in focus.

The internal lens of the eye. It is semielastic to permit changes in its power when focusing on objects at near distances.

A cylindrical lens is an optical component that has different curvatures along its two orthogonal axes, resulting in a shape resembling a cylinder. Unlike spherical lenses, which have the same...

Deep multiphoton microscopy is an advanced imaging technique used in biological and biomedical research to visualize structures and processes deep within tissues with high resolution. It combines the...

The distance, on either side of the object plane focused on, through which satisfactory image definition can be obtained. For the special case of an imaging system with lens axis perpindicular to the...

A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film cameras, which use photographic film to capture and store images, digital...

A scale located on the eyepiece focusing screw and used to measure the amount of defocusing of the eyepiece in diopters. The reciprocal of the image distance in meters is a measure of the amount of...

Directed energy refers to a type of energy that is emitted and transferred in a controlled direction. The term is often associated with military and technological applications where energy, typically...

A diverging lens is a type of lens that causes parallel rays of light to spread out or diverge. It is thinner in the center than at the edges and is commonly referred to as a concave lens. The most...

An edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the semiconductor chip rather than from the surface. Edge-emitting LEDs are...

A device that uses four electrodes set in an alternating positive-negative polarity series to focus the beams of charged particles employed in electron microscopes and particle accelerators.

An image intensifier tube that uses a magnetic field for focusing. It yields high-quality images, but its use is limited by its size and weight relative to other image tubes.

A special evacuated camera equipped with means for holding a specimen and bombarding it with a sharply focused beam of electrons. A cylindrical film is placed around the specimen to record the...

An analytical technique used to determine the nature of extremely small samples by forming the x-ray spectrum of the samples through excitation by a finely focused electron beam.

An instrument that serves to produce an enlarged electron image on a fluorescent screen by focusing an infrared image of a distant object upon a photosensitive cathode.

The use of a tightly focused beam of electrons to drill minute holes in substances. The drilling is accomplished by the evaporation of the material in the desired circumference by the intense heat of...

The method by which photographic film is scanned by an electron beam. One technique uses the uniform light of a television screen, focused by a lens onto the processed film, as a means of creating a...

An electron-beam lithography (EBL) system is a sophisticated nanofabrication tool used in the semiconductor industry and research laboratories to pattern extremely fine features with sub-micrometer...