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Electrically Controllable Terahertz Second‐Harmonic Generation in GaAs
Author(s) -
Lee Kanghee,
Park Jagang,
Kang Bong Joo,
Kim Won Tae,
Kim HyeonDon,
Baek Soojeong,
Ahn Kwang Jun,
Min Bumki,
Rotermund Fabian
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202000359
Subject(s) - terahertz radiation , terahertz gap , second harmonic generation , photomixing , terahertz spectroscopy and technology , optoelectronics , electric field , materials science , high harmonic generation , gallium arsenide , nonlinear optics , terahertz time domain spectroscopy , semiconductor , far infrared laser , graphene , optics , physics , laser , nanotechnology , terahertz metamaterials , quantum mechanics
Terahertz radiation and its nonlinear optical manipulation may possess potential for a variety of applications in next‐generation electronics and optics. Pioneering studies have shown that the nonlinearity of carrier drift in semiconductors and graphene can be utilized for nonlinear optical processes at terahertz frequencies. However, because of the symmetric response of carriers to the terahertz field direction, most experiments have confirmed only the presence of odd‐order nonlinear processes. In this study, electric‐field‐induced terahertz second‐harmonic generation (SHG) in photoexcited gallium arsenide is demonstrated, where an applied bias field breaks the directional symmetry of the drift transport of electrons. The amplitudes of odd‐ and even‐harmonic waves are found to be highly controllable using the bias field. The measured conversion efficiency of SHG reaches beyond 10 −5 , substantially higher than the value previously reported. This terahertz harmonic generation platform with electrical controllability may be useful for future nonlinear applications at terahertz frequencies.