electrooptical

Electro-optical refers to the interaction between electric fields and the optical properties of materials, or to devices whose function derives from that interaction. In an electro-optic material, an applied electric field changes refractive index, absorption, or birefringence, enabling control of light without mechanical parts. The most important effects are the linear (Pockels) effect and the quadratic (Kerr) effect. The Pockels effect occurs in non-centrosymmetric crystals such as lithium niobate, lithium tantalate, potassium titanyl phosphate, and certain gallium arsenide structures, allowing rapid, voltage-controlled phase or amplitude modulation. The Kerr effect is weaker but present in many materials and requires higher fields. Other related phenomena include electroabsorption and the Franz-Keldysh or quantum-confined Stark effect used in certain modulators.

Devices based on electro-optical effects include electro-optic modulators and switches. EO modulators change the phase or intensity of light in response to an electrical signal and are essential in high-speed fiber-optic communications. Integrated versions use lithium niobate, lithium tantalate, or EO polymers, and newer platforms explore silicon-based approaches that rely on external drive or hybrid materials. Electro-optic deflectors and scanners use refractive index changes to steer beams.

Applications span telecommunications, laser systems, imaging, adaptive optics, and display technologies. Key advantages include very fast response times and the potential for low insertion loss and high modulation depth, though practical performance depends on material choice and device design.