Optical beam scanning using potassium tantalate niobate

Date of Award


Degree Name

M.S. in Electro-Optics


Department of Electro-Optics and Photonics


Advisor: Qiwen Zhan


This thesis aims to study the characteristics of the one-dimensional optical scanner made of Potassium Tantalate Niobate [KTa₁₋xNbxO₃] (KTN) based on electro-optic (EO) effect and space-charge-controlled electrical condition. A large deflection angle of 11.28° full range is achieved by applying a relatively low voltage ±250V to a 1.0-mm-thick KTN crystal with a short interaction length of 3.2mm. In theory, the electrical conduction is carried by the electrons injected from the Ohmic contact of the electrodes. The injected electrons induce the space-charge effect and the electrical field becomes non-uniform while the electrical field has a square root dependence on the distance from the cathode. Consequently, a linearly graded refractive index is induced and the optical beam is cumulatively deflected as it propagates through the crystal. Deflection angle, deflection efficiency, resolution and frequency response are characterized. A thermistor is also utilized because that the temperature of KTN crystal has to be controlled around 44.2°C.


Light deflectors, Electron beams, Optoelectronic devices, Optical scanners, Electrical Engineering, Optics

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