Phased array optics
Encyclopedia
Phased array optics is the technology of controlling the phase of light waves transmitting or reflecting from a two-dimensional surface by means of adjustable surface elements. It is the optical analog of phased array
radar. By dynamically controlling the optical properties of a surface on a microscopic scale, it is possible to steer the direction of light beams, or the view direction of sensors, without any moving parts. Hardware associated with beam steering applications is commonly called an optical phased array (OPA). Phased array beam steering is used for optical switching and multiplexing in optoelectronic devices, and for aiming laser
beams on a macroscopic scale.
Complicated patterns of phase variation can be used to produce diffractive optical elements, such as dynamic virtual lenses, for beam focusing or splitting in addition to aiming. Dynamic phase variation can also produce real-time holograms. Devices permitting detailed addressable phase control over two dimensions are a type of spatial light modulator
(SLM).
In nanotechnology
, phased array optics refers to arrays of lasers or SLMs with addressable phase and amplitude elements smaller than a wavelength of light. While still theoretical, such high resolution arrays would permit extremely realistic three dimensional image display by dynamic holography
with no unwanted orders of diffraction. Applications for weapons, space communications, and invisibility
by optical camouflage have also been suggested.
Phased array
In wave theory, a phased array is an array of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions.An antenna array...
radar. By dynamically controlling the optical properties of a surface on a microscopic scale, it is possible to steer the direction of light beams, or the view direction of sensors, without any moving parts. Hardware associated with beam steering applications is commonly called an optical phased array (OPA). Phased array beam steering is used for optical switching and multiplexing in optoelectronic devices, and for aiming laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
beams on a macroscopic scale.
Complicated patterns of phase variation can be used to produce diffractive optical elements, such as dynamic virtual lenses, for beam focusing or splitting in addition to aiming. Dynamic phase variation can also produce real-time holograms. Devices permitting detailed addressable phase control over two dimensions are a type of spatial light modulator
Spatial light modulator
A spatial light modulator is an object that imposes some form of spatially-varying modulation on a beam of light. A simple example is an overhead projector transparency. Usually when the phrase SLM is used, it means that the transparency can be controlled by a computer. In the 1980s, large SLMs...
(SLM).
In nanotechnology
Molecular nanotechnology
Molecular nanotechnology is a technology based on the ability to build structures to complex, atomic specifications by means of mechanosynthesis. This is distinct from nanoscale materials...
, phased array optics refers to arrays of lasers or SLMs with addressable phase and amplitude elements smaller than a wavelength of light. While still theoretical, such high resolution arrays would permit extremely realistic three dimensional image display by dynamic holography
Holography
Holography is a technique that allows the light scattered from an object to be recorded and later reconstructed so that when an imaging system is placed in the reconstructed beam, an image of the object will be seen even when the object is no longer present...
with no unwanted orders of diffraction. Applications for weapons, space communications, and invisibility
Invisibility
Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible . The term is usually used as a fantasy/science fiction term, where objects are literally made unseeable by magical or technological means; however, its effects can also be seen in the real...
by optical camouflage have also been suggested.