Paper
2 February 2009 The ultrafast photoconductive characteristics of GaAs bulk investigated by optical-pump terahertz probe spectroscopy
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Abstract
The ultrafast photoconductive characteristics of GaAs bulk were investigated by the optical-pump terahertz-probe spectroscopy (OPTP) at room temperature. In our experiment, a significant decrease of the terahertz transmittance has been observed when the time delay between the optical pump pulse and the terahertz probe pulse was adjusted. It can be concluded that the electronic states of the GaAs became metallic, when the optical excitation occurred on the surface of the GaAs material. Since we expect only the free carrier response in the terahertz range, the decrease of the transmittance is obviously assigned to the appearance of the high electronic conductivity due to the increasing free carriers. Furthermore, it was found that transmittance of the terahertz radiation decreased with the increase of the optical pump power due to the more optical generated carriers under the higher power. We can also find that the carrier recombination time of the GaAs became shorter while the power of the optical pump was lowered.
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Bin Jin, Qing-li Zhou, and Cunlin Zhang "The ultrafast photoconductive characteristics of GaAs bulk investigated by optical-pump terahertz probe spectroscopy", Proc. SPIE 7157, 2008 International Conference on Optical Instruments and Technology: Advanced Sensor Technologies and Applications, 71570Q (2 February 2009); https://doi.org/10.1117/12.807030
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KEYWORDS
Gallium arsenide

Terahertz radiation

Spectroscopy

Ultrafast laser spectroscopy

Terahertz spectroscopy

Transmittance

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