On second harmonic generation and multiphoton-absorption induced luminescence from laser-reshaped silver nanoparticles embedded in glass

摘要

Spherical silver nanoparticles of 30 nm diameter embedded in soda-lime glass were uniformly reshaped (elongated) after irradiation by a linearly polarised 250-fs pulsed laser operating within the nanoparticles’ surface plasmon resonance band. We observed Second Harmonic Generation (SHG) and Multiphoton-Absorption-Induced Luminescence (MAIL) in the embedded laser-reshaped nanoparticles upon picosecond (10 ps) pulsed laser excitation at 1064 nm. A complementary study of SHG and MAIL was conducted in soda-lime glass containing embedded, silver nanoparticles of a similar elongation ratio (aspect ratio) to the nanoparticles. This supports the notion that the observed difference in SHG and MAIL in the studied nanocomposite systems is due to the shape modification mechanism. The discrete dipole approximation (DDA) method was used to assess the absorption and scattering cross-sections of the reshaped nanoparticles with different elongation ratios.