Recently, nonspherical nanoparticles took attention due to advanced properties of these structures. We report the study of the nonlinear optical properties of copper oxide nanoellipsoids using 800 nm and 400 nm, 60 fs pulses. The optical limiting effect of copper oxide nanoellipsoids is analyzed. The influence of band gap of copper nanoparticles and copper oxide nanoellipsoids on their nonlinear optical response was studied. For the first time, the low- and high-order nonlinear optical responses of copper nanoellipsoids were studied. The magnitudes of nonlinear optical parameters of the suspension of copper oxide nanoellipsoids were measured to be γ = 1.23 × 10⁻¹⁵ cm² W⁻¹, and β = 1.0 × 10⁻¹¹ cm W⁻¹ respectively. We observed the four-fold enhancement of the nonlinear optical refraction of copper oxide nanoellipsoids at the wavelength of 400 nm, 60 fs probe pulses compared to 800 nm radiation. We also analyzed the high-order nonlinear response of CuO nanoellipsoids through generation of high-order harmonics of 800 nm, 60 fs pulses in the plasmas produced during laser ablation of the nanoellipsoid-contained targets. We demonstrated the harmonics up to the 35th order (E = 50 eV) in case of single-color pump and 24th (30 eV) in case of two-color pump.

Gold films are widely used for different applications. We present the results of third- and high-order nonlinear optical studies of the thin films fabricated from Au nanoparticle solutions by spin-coating methods. These nanoparticles were synthesized by laser ablation of bulk gold in pure water using 200 ps, 800 nm pulses. The highest values of the nonlinear absorption coefficient (9 × 10⁻⁶ cm W⁻¹), nonlinear refractive index (3 × 10⁻¹¹ cm² W⁻¹), and saturation intensity (1.3 × 10¹⁰ W cm⁻²) were achieved using 35 fs, 400 nm pulses. We also determined the relaxation time constants for transient absorption (220 fs and 1.6 ps) at 400 nm. The high-order harmonic generation was studied during propagation of 35 fs, 800 nm pulses through the plasma during the ablation of gold nanoparticle film and bulk gold. The highest harmonic cutoff (29th order) was observed in the plasma containing gold nanoparticles.