Photo-induced terahertz near-field dynamics of graphene/InAs heterostructures
| Autor: | Mengkun Liu, Seth R. Bank, Xu Du, Ziheng Yao, Xin Zhang, Scott Mills, Xiaoguang Zhao, Qing Dai, Thomas Ciavatti, Xinzhong Chen, Tiger H. Tao, Vasili Perebeinos, Hai Hu, Stephen D. March, Ryan Mescall, Vyacheslav Semenenko, Jiawei Zhang |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Graphene business.industry Terahertz radiation Heterojunction 02 engineering and technology Substrate (electronics) 021001 nanoscience & nanotechnology 01 natural sciences Atomic and Molecular Physics and Optics Terahertz spectroscopy and technology law.invention 010309 optics Optical pumping Optics law 0103 physical sciences Near-field scanning optical microscope 0210 nano-technology business Ultrashort pulse |
| Zdroj: | Optics express. 27(10) |
| ISSN: | 1094-4087 |
| Popis: | In this letter, we report optical pump terahertz (THz) near-field probe (n-OPTP) and optical pump THz near-field emission (n-OPTE) experiments of graphene/InAs heterostructures. Near-field imaging contrasts between graphene and InAs using these newly developed techniques as well as spectrally integrated THz nano-imaging (THz s-SNOM) are systematically studied. We demonstrate that in the near-field regime (λ/6000), a single layer of graphene is transparent to near-IR (800 nm) optical excitation and completely "screens" the photo-induced far-infrared (THz) dynamics in its substrate (InAs). Our work reveals unique frequency-selective ultrafast dynamics probed at the near field. It also provides strong evidence that n-OPTE nanoscopy yields contrast that distinguishes single-layer graphene from its substrate. |
| Databáze: | OpenAIRE |
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