Photonics Dictionary

Also referred to as a bulb. The glass housing that encloses an incandescent source, or the glass or metal housing that encloses an electron tube.

Envelopes for cathode-ray tubes are made by blowing glass in the same manner as light bulbs. They have a fairly flat end face to carry the phosphor material applied internally.

A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a tungsten filament surrounded by a small amount of halogen gas, such as...

An infrared light source is a device that emits light in the infrared spectrum, which lies beyond the visible spectrum of light. Infrared light has longer wavelengths than visible light and is...

LiFi, short for light fidelity, is a wireless communication technology that utilizes visible light or infrared light to transmit data. Developed as an alternative or complementary technology to...

An LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs are widely used in various applications due to their energy efficiency,...

A lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In other words, the lumen measures the total amount of visible light emitted by a...

A gauge designed to measure high degrees of vacuum. It consists of a glass bulb attached to the vacuum vessel, the measurement being made by filling the bulb with mercury and observing the volume of...

A lamp that has mercury in a tube or bulb that has first been evacuated. The electricity travels through the vapor between the electrodes and produces a blue-green light that is rich in ultraviolet...

A light source, such as the sun or an incandescent lamp, that freely penetrates ordinary glass bulbs and emits in the near-ultraviolet (wavelengths ranging from about 300 to 400 nm). A mercury vapor...

A tungsten filament lamp that uses an opal glass bulb to diffuse light.

Also known as a white-light interferometer. Measures surface texture and shape from nanometer-scale roughness to millimeter-scale step heights. A standard arrangement includes an illumination source,...

An otoscope is a medical device used by healthcare professionals, particularly ear, nose, and throat (ENT) specialists, primary care physicians, and pediatricians, to examine the ear canal and...

Polarization refers to the orientation of oscillations in a transverse wave, such as light waves, radio waves, or other electromagnetic waves. In simpler terms, it describes the direction in which...

A lamp used in projection that is made with a reflector built into the bulb, normally by coating a portion of its interior with a reflective material to ensure the reflector's optimum position in...

An evacuated bulb containing a tungsten filament that is heated by passing an electric current through it. In domestic light bulbs the inside of the bulb is frosted to soften shadows. In projection...

A type of lamp that emits a high quantity of ultraviolet radiation. This may be an arc lamp encased in a bulb of a glass that is transparent to ultraviolet rays.

A small bulb containing a conducting gas, an arc being formed between a metal ring and a tiny zirconium electrode near the center of the ring. The heated zirconium emits light, and constitutes a...