Oscillation effect in frequency domain current from a photoconductive antenna via double-probe-pulse terahertz detection technique

Abstract

Via constructing a special terahertz time domain spectroscopy (THz-TDS) system in which two femtosecond (fs) laser pulses were used as probe pulses to excite a photoconductive (PC) THz detector, the time behavior of the current from the detector was measured. The corresponding theoretical analysis was performed by a well-known equivalent-circuit model. When the time domain current was transformed to frequency domain, an oscillation effect was observed. The oscillation frequency was decided by the time delay between the two probe pulses. The number of the extrema in the frequency domain current curve was proportion to the pulse interval in 0.1-2 THz. A method to measure the interval of fs laser pulses was proposed. It is important for applications of fs laser pulses or train.

Keywords

terahertz (THz) / photoconductivity / frequency oscillation

References

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Acknowledgements

This research wass supported by the Wuhan Applied Basic Research Project (No. 20140101010009), the National Natural Science Foundation of China (Grant Nos. 61177095, 61475054 and 61405063), Hubei Natural Science Foundation (Nos. 2012FFA074 and 2013BAA002), the Fundamental Research Funds for the Central Universities (Nos. 2013KXYQ004, 2014ZZGH021 and 2014QN023), and the Technology Innovation Foundation From Innovation Institute of Huazhong University of Science and Technology (No. CXY13Q015).

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2014 Higher Education Press and Springer-Verlag Berlin Heidelberg