中国物理B ›› 2012, Vol. 21 ›› Issue (4): 47804-047804.doi: 10.1088/1674-1056/21/4/047804

• • 上一篇    下一篇

范光华1,曲士良1,郭忠义1,王强1 2,李中国3   

  • 收稿日期:2011-08-19 修回日期:2011-11-03 出版日期:2012-02-29 发布日期:2012-02-29
  • 通讯作者: 曲士良,slqu1@yahoo.com.cn E-mail:slqu1@yahoo.com.cn

Size-dependent nonlinear absorption and refraction of Ag nanoparticles excited by femtosecond lasers

Fan Guang-Hua(范光华)a), Qu Shi-Liang(曲士良)a)†, Guo Zhong-Yi(郭忠义)a)b), Wang Qiang(王强)a), and Li Zhong-Guo(李中国)c)   

  1. a. Department of Optoelectronics Science, Harbin Institute of Technology at Weihai, Weihai 264209, China;
    b. Department of Physics, Harbin Institute of Technology, Harbin 150001, China;
    c. School of Physical Science and Technology, Suzhou University, Suzhou 215006, China
  • Received:2011-08-19 Revised:2011-11-03 Online:2012-02-29 Published:2012-02-29
  • Contact: Qu Shi-Liang,slqu1@yahoo.com.cn E-mail:slqu1@yahoo.com.cn
  • Supported by:
    Project supported by the Natural Science Foundation of Heilongjiang Province, China (Grant No. A200912), and the Program of Excellent Team in the Harbin Institute of Technology, China, and the National Natural Science Foundation of China (Grant Nos. 60907023 and 10904027).

Abstract: Silver (Ag) nanoparticles with different average sizes are prepared, and the nonlinear absorption and refraction of these nanoparticles are investigated with femtosecond laser pulses at 800 nm. The smallest Ag nanoparticles show insignificant nonlinear absorption, whereas the larger ones show saturable absorption. By considering the previously reported positive nonlinear absorption of 9 nm Ag nanoparticles, the nonlinear absorptions of Ag nanoparticles are found to be size-dependent. All these nonlinear absorptions can be compatibly explained from the viewpoints of electronic transitions, energy bands and electronic structures in the conduction band of Ag nanoparticles. The nonlinear refraction is attributed to the effect of hot electrons arising from the intraband transition in the s-p conduction band of Ag nanoparticles.

Key words: nonlinear absorption, nonlinear refraction, silver nanoparticles, electronic structures

中图分类号:  (Nanocrystals, nanoparticles, and nanoclusters)

  • 78.67.Bf
73.22.Dj (Single particle states) 42.65.Re (Ultrafast processes; optical pulse generation and pulse compression) 42.70.Nq (Other nonlinear optical materials; photorefractive and semiconductor materials)