Photoconductive antenna
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A photoconductive antenna is used for generating a terahertz wave or detecting a terahertz wave. A photoconductive antenna is same meaning of a photoconductive switch. In this site, a photoconductive antenna is used for describing the device.
The structure of the photoconductive antenna is outlined below. Electrodes is formed on a photoconductive film having semiconducting behavior. The photoconductive film generates electrons and holes on absorbing light. The electrodes make a small gap between them. The width of the gap is usually 5μm. The electrodes have a function of antennas and electrodes. A laser light is emitted to focus on the gap.
The current flows in the photoconductive film on absorbing light and applying a 10-40 voltage to the electrodes. A oscillating electric field is proportional to a temporal differentiation of current. A oscillating electric field emit a terahertz wave from the antenna.
