Spectrally Wide-Band Terahertz Wave Modulator Based on Optically Tuned Graphene
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- 作者：Peter Weis ; Juan L. Garcia-Pomar ; Michael H枚h ; Benjamin Reinhard ; Alexander Brodyanski ; Marco Rahm
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：October 23, 2012
- 年：2012
- 卷：6
- 期：10
- 页码：9118-9124
- 全文大小：389K
- 年卷期：v.6,no.10(October 23, 2012)
- ISSN：1936-086X
文摘
New applications in the realms of terahertz (THz) technology require versatile adaptive optics and powerful modulation techniques. Semiconductors have proven to provide fast all-optical terahertz wave modulation over a wide frequency band. We show that the attenuation and modulation depth in optically driven silicon modulators can be significantly enhanced by deposition of graphene on silicon (GOS). We observed a wide-band tunability of the THz transmission in a frequency range from 0.2 to 2 THz and a maximum modulation depth of 99%. The maximum difference between the transmission through silicon and GOS is 螖t = 0.18 at a low photodoping power of 40 mW. At higher modulation power, the enhancement decreased due to charge carrier saturation. We developed a semianalytical band structure model of the graphene鈥搒ilicon interface to describe the observed attenuation and modulation depth in GOS.