Photo-induced absorption in the pump probe spectroscopy of single-walled carbon nanotubes

• Published in: Chinese physics B Vol. 22; no. 7; pp. 542 - 546
• Main Author: 朱子鹏
• Format: Journal Article
• Language: English
• Published: 01.07.2013
• Subjects: Enrichment; Femtosecond; Ground state; Nanostructure; Pumps; Sheds; Single wall carbon nanotubes; Spectroscopy; Tuning; 光致吸收; 光诱导吸收; 光谱; 单壁碳纳米管; 吸收功能; 呼吸模式; 探测; 泵浦波长
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/22/7/077803

Femtosecond pump probe spectroscopy is employed to study the photo-induced absorption feature in the single-walled carbon nanotube transient spectrum. The two advantages of the experiment, a chirality enriched sample and tuning the pump wavelength to the resonance of a specific nanotube species, greatly facilitate the identification of the photo-induced absorption signal of one tube species. It is found that a photo-induced absorption feature is located at one radial breathing mode to the blue side of the E11 state. This finding prompts a new explanation for the origin of the photo-induced absorption： the transition from the ground state to a phonon coupled state near the E ii state. The explanation suggests a superposition mechanism of the photo-bleach and photo-induced absorption signals, which may serve as a key to the interpretation of the complex pump probe transient spectrum of carbon nanotubes. The finding sheds some light on the understanding of the complex non-radiative relaxation process and the electronic structure of single-walled carbon nanotubes.