title: Optical-limiting properties of oleylamine-capped gold nanoparticles for both femtosecond and nanosecond laser pulses.
abstract: We report strong broad-band optical-limiting properties of oleylamine-capped gold nanoparticles in solution for both femtosecond and nanosecond laser pulses. The nanosecond optical-limiting effects were characterized by using fluence-dependent transmittance measurements with 7 ns laser pulses at 532 and 1064 nm, and the femtosecond optical-limiting effects were characterized with a z-scan technique using 300 fs laser pulses at 780 nm. The oleylamine-capped gold nanoparticles were found to show strong broad-band optical-limiting effects for nanosecond laser pulses at 532 and 1064 nm and femtosecond laser pulses at 780 nm. These oleylamine-capped gold nanoparticles displayed exceptional optical-limiting effects with thresholds lower than that of carbon nanotube suspension, a benchmark optical limiter. Input-fluence- and angle-dependent scattering measurements suggested that nonlinear scattering played an important role in the observed optical-limiting behavior at 532 and 1064 nm.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Lakshminarayana
authors.initials: L
authors.lastname: Polavarapu
authors.forename: N
authors.initials: N
authors.lastname: Venkatram
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Xu