Abstract-Voltage-controllable terahertz radiation from coherent longitudinal optical phonons in a p-i-n diode structure of GaAs

Masaaki Nakayama¹, Souta Asai¹, Hideo Takeuchi¹,Osamu Ichikawa², and Masahiko Hata^{3
http://apl.aip.org/resource/1/applab/v103/i14/p141109_s1?isAuthorized=no}

We propose and demonstrate the voltage-controllable terahertz radiation from coherent longitudinal optical (LO) phonons in a p-i-ndiode of GaAs at room temperature under illumination of a femtosecond pulse laser. It was found that the intensity of the terahertz radiation is continuously and drastically enhanced by an increase in reverse bias voltage (electric field strength) from 0 (22) to 8.0 V (140 kV/cm). The analysis of the electric-field-strength dependence of the intensity indicates that the initial polarization of the LO phonon induced by the electric field dominates the enhancement and that the second-order electric susceptibility is considerable.

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