Abstract
This Letter reports the shape-dependent third-order nonlinear optical properties of anisotropic gold nanoparticles. We characterized the nonlinear absorption coefficients of nanorods, nanostars, and nanoshells using femtosecond Z-scan measurements. By comparing nanoparticle solutions with a similar linear extinction at the laser excitation wavelength, we separated shape effects from that of the localized surface plasmon wavelength. We found that the nonlinear response depended on particle shape. Using pump-probe spectroscopy, we measured the ultrafast transient response of nanoparticles, which supported the strong saturable absorption observed in nanorods and weak nonlinear response in nanoshells. We found that the magnitude of saturable absorption as well as the ultrafast spectral responses of nanoparticles were affected by the linear absorption of the nanoparticles.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4904-4908 |
| Number of pages | 5 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 6 |
| Issue number | 24 |
| DOIs | |
| State | Published - Nov 23 2015 |
Funding
This work was supported by National Science Foundation NSF Grants CHE-1058501 and CHE-1507790 and a National Institutes of Health (NIH) Director’s Pioneer Award (DP1 EB016540). This work made use of the NU Keck Biophysics Facility supported by the Cancer Center Support Grant, the Biological Imaging Facility, and the Center for Nanoscale Materials that was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Keywords
- Z-scan
- anisotropic metal nanoparticles
- gold nanostars
- hot electrons
- nonlinear
- saturable absorption
ASJC Scopus subject areas
- General Materials Science
- Physical and Theoretical Chemistry