Nonlinear optical scattering and absorption in bismuth nanorod suspensions

The authors present the results of optical limiting measurements of ∼10nm wide bismuth nanorods suspended in chloroform. Their Z-scan measurements reveal that optical limiting under 532nm excitation stems from a strong nonlinear scattering (NLS) subsequent to nonlinear absorption (NLA) by suspension. On the other hand, the optical limiting is entirely due to NLA when excited with 1064nm excitation in the nanosecond regime. The occurrence of NLS at one wavelength and absence at another is unusual, especially when compared to the behavior of carbon nanotubes under similar conditions, in which NLS is dominant at both wavelengths.