Photonics Dictionary

An isotope of cesium that emits negative beta particles and has a half-life of 2.19 years; its applications include photoelectric cells and developmental ion propulsion systems.

Colorless crystals used in photoelectric cells and for photosensitive material in cathodes.

A photoemissive detector sensitive to wavelengths up to 1 µm. It has one sharp maximum of sensitivity at 350 nm and a broad maximum at 800 nm.

A phototube having a cesium-coated cathode that has its greatest sensitivity in the infrared region.

A lamp that emits light as the result of the passage of an electrical current through ionized cesium vapor.

A photocathode that exhibits maximum sensitivity in the blue and ultraviolet regions of the spectrum. The sensitivity is obtained by the exposure of a thin layer of antimony to cesium vapor at an...

Any system of time measurement that is based on atomic resonances. The transition times between the hyperfine levels of cesium-133 have been accepted as the international standard.

An atomic clock is a highly precise timekeeping device that uses the vibrations or oscillations of atoms as a reference for measuring time. The most common type of atomic clock uses the vibrations of...

A solid with a structure that exhibits a basically symmetrical and geometrical arrangement. A crystal may already possess this structure, or it may acquire it through mechanical means. More than 50...

An image intensifier, also known as an image intensification tube or image intensification device, is a specialized electronic device used to amplify low-light-level images to make them visible to...

The range of materials that, unlike glass, may be used in the infrared. Water-soluble salts, such as cesium iodide, and other substances such as arsenic sulfide, selenium, thallium bromide-iodide and...

An optical clock is a highly precise and advanced timekeeping device that relies on the oscillations of electromagnetic radiation in the optical or ultraviolet part of the electromagnetic spectrum....

The fundamental wavelength standard of time or frequency. An atomic standard, it is properly expressed as 9,192,631,770 times the frequency of the transition between the hyperfine structure levels of...

A scintillation crystal, also known simply as a scintillator, is a material that emits light when it interacts with ionizing radiation such as gamma rays, x-rays, or charged particles. The emitted...