Electrooptics


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Electrooptics

The branch of physics which deals with the influence of an electric field on the optical properties of matter, especially in its crystalline form. These properties include transmission, emission, and absorption of light.

An electric field applied to a transparent crystal can change its refractive indexes and, therefore, alter the state of polarization of light propagating through it. When the refractive-index changes are directly proportional to the applied field, the phenomenon is termed the Pockels effect. When they are proportional to the square of the applied field, it is called the Kerr effect. See Kerr effect, Polarized light, Refraction of waves

The Pockels effect is used in a light modulator called the Pockels cell. This device (see illustration) consists of a crystal C (usually potassium dihydrogen phosphate, or KDP) placed between two polarizers P1 and P2 whose axes are crossed. Ring electrodes bonded to two crystal faces allow an electronic driver V to apply an electric field parallel to the axis OZ along which a light beam (for example, a laser beam) is made to propagate. Pockels cells can be switched on and off in well under 1 nanosecond. See Laser, Optical modulators

Pockels cell light modulatorenlarge picture
Pockels cell light modulator

The linearity and high-speed response of the Pockels effect within an electrooptic crystal make possible a unique optical technique for measuring the amplitude of repetitive high-frequency (greater than 1 GHz) electric signals that cannot be measured by conventional means. The technique, known as electrooptic sampling, employs a special traveling-wave Pockels cell between crossed polarizers. It is used to analyze ultrafast electric signals such as those generated by high-speed transistors and optical detectors.

A self-electrooptic-effect device (SEED) is a combination of a quantum-well electrooptic modulator with a photodetector which, when light shines on it, changes the voltage on the modulator. Although the device relies internally on an electrooptic effect, the output from the modulator is controlled by the light shining on the photodetector, giving an optically controlled device with an optical output. Most of these devices rely on the quantum-confined Stark effect in semiconductor quantum-well heterostructures as the electrooptic mechanism and utilize the changes in optical absorption resulting from this mechanism. See Semiconductor heterostructures, Stark effect

Electrooptics

 

the branch of physics that deals with changes in the optical properties of media under the influence of an electric field and with the consequent characteristics of the interaction between optical radiation (light) and a medium in an electric field. Electrooptics is usually concerned with effects associated with the dependence of the refractive index n of a medium on the electric field strength E (seePOCKELS EFFECT, KERR EFFECT, and STARK EFFECT).

electrooptics

[i‚lek·trō′äp·tiks]
(optics)
The study of the influence of an electric field on optical phenomena, as in the electrooptical Kerr effect and the Stark effect. Also known as optoelectronics.
References in periodicals archive ?
Mackenzie, "Electrooptic effect in a nano-crystals doped glass," Ferroelectrics, vol.
Bruker Corporation (Nasdaq:BRKR) has signed an agreement with simultaneous closing for the acquisition of Sigma ElectroOptics GmbH (Sigma), a provider of remote gas sensing systems based in Hamburg, Germany.
of Louisville, Ky., headed by Robert Cohn, director of the university's ElectroOptics Research Institute and Nanotechnology Center, have fabricated freestanding micron-diameter wires and bridges in minutes using an atomic force microscope (AFM) to pull poly-methyl methacrylate (PMMA) and other polymer materials into fibers.
The Midlands Photonics Cluster, based at Aston Science Park, Birmingham, has joined forces with the UK Laser and ElectroOptics Association (UKLEO) to consolidate the UK's position as a leading global player in opto-electronics.
However, initial discussions revealed that, in order to achieve useful range for the light source, the electrooptics would become rather complex and uncertain in design.
In spite of recent improvements in Web authoring software, conversion of equations, halftone images, and line drawing from diverse word processor files is still cumbersome," said Henry Paris, editor of the new journal and associate director of GTRI's ElectroOptics, Environment and Materials Lab.
Lasers were developed that could produce a pulse of light that lasted only 0.00000000000001 seconds are emitted at a rate of 76 million times per second.[1] These incredibly short, incredibly fast pulse lengths were important advances in the field of electrooptics.
Hartman is principal research engineer at Electrooptics, Environment and Material Laboratory, Georgia Tech Research Institute, 925 Dalney St., Atlanta, GA 30332-0825, USA; 404-894-3628; 404-894-3503, fax 404-894-6199, nile.hartman@gtri .gatech.edu.
Ouside of Europe, ElectroOptics Industries (EIOp) (Rehovot, Israel) a subsidiary of Elbit Systems (Haifa, Israel) has developed the ElectroOptic Long Range Oblique Photography (EO/IR LOROP) system for high-altitude stand-off missions.