Terahertz generation and detection of LT-GaAs thin film photoconductive antennas excited by lasers of different wavelengths |
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Institution: | Beijing Advanced Innovation Center for Imaging Theory and Technology, Beijing Key Laboratory for Terahertz Spectroscopy and Imaging;Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048, China |
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Abstract: | A new method of generating and detecting terahertz waves is proposed. Low-temperature-grown gallium arsenide (LT-GaAs) thin films are prepared by etching a sacrificial layer (AlAs) in a four-layer epitaxial structure constituted with LT-GaAs, AlAs, GaAs, and semi-insulating gallium arsenide (SI-GaAs). The thin films are then transferred to clean silicon for fabricating the LT-GaAs thin film antennas. The quality and transmission characteristics of the films are analyzed by an 800-nm asynchronous ultrafast time domain spectroscopy system, and the degree of bonding between the film and silicon wafer is determined. Two LT-GaAs thin film antennas for generating and detecting the terahertz waves are tested with a 1550-nm femtosecond laser. The terahertz signal is successfully detected, proving the feasibility of this home-made LT-GaAs photoconductive antennas. This work lays a foundation for studying the mechanism of terahertz wave generation in GaAs photoconductive antennas below the semiconductor band gap. |
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Keywords: | terahertz low-temperature-grown GaAs photoconductive antenna 1550-nm laser |
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