Theory of controlling band-width broadening in terahertz sideband generation in semiconductors by a direct current electric field

详细信息    查看全文

• 作者：Houquan Liu^a ; ^b ; ^{liuhouq@mail2.sysu.edu.cn} ; Xingchu Zhang^c
• 关键词：THz sideband generation ; DC electric field ; Band-width broadening
• 刊名：Optics Communications
• 出版年：2017
• 出版时间：15 March 2017
• 年：2017
• 卷：387
• 期：Complete
• 页码：37-42
• 全文大小：823 K
• 卷排序：387

文摘

When a near-infrared (NIR) laser irradiates a semiconductors in the presence of an intense THz field, the NIR laser excites electron-hole pairs that are then accelerated by the THz field, acquiring kinetic energy. They then recombine to create THz sidebands in the optical spectrum. This phenomenon is the so called high order THz sideband generation (HSG). The generated sideband spectrum in HSG is a frequency comb. Here , we report that the bandwith of this comb spectrum can be markedly broadened by applying an additional direct-current (DC) electric field that is much weaker than the THz field. Our result, on one hand, provides a method to broaden the bandwith; on the other hand, puts forward that the bandwith can be controlled flexibly by changing the DC field, thus facilitating the applications of HSG in wavelength division multiplexing optical communication. In addition, the HSG is a method for ultrafast electro-optical modulation. In our study, the effects of an additional DC field are well investigated. So the result provides a multidimensional modulation method, i.e., one can perform the modulation by controlling not only the THz field but also the DC field. This results in much more flexible control of electro-optical modulation in semiconductors.