Acoustically induced light gyration in nickel nanoparticles

Circularly polarized acoustically induced light gyration (AILG) in nickel nanoparticles (NiNPs) attached to indium tin oxide (ITO) substrates was observed to be enhanced by nanosecond UV laser excitation at a wavelength in the surface plasmon resonance region. The AILG was observed during exposure to two acoustical waves with frequencies of 2 and 4 MHz and power densities of up to 5 W/cm2. The maximum value of the AILG observed for NiNPs of average size ca. 8.7 nm, attached to an ITO substrate was about 2.8°/mm without UV-light illumination. Additional irradiation by 5 ns pulse UV laser light (λ: 337 nm) at the surface plasmon resonance region was found to favour the additional enhancement of the AILG up to 11°/mm. The effect was optimized at a temperature of 120 K. This increase was not observed when the size of NiNPs was 16.8 nm.