Nonlinear optical properties of CuxS and CuInS2 nanoparticles in sol–gel glasses

Silica glasses with ultrafine CuxS and CuInS2 particles (average radius of 5±3 nm) were fabricated by means of a sol–gel technique. Linear and differential absorption spectra were studied. The glasses reveal absorption peaks in the 600–700 nm range associated with the first excitonic resonance in the quantum confined particles. Laser excitation by 540 nm pulses leads to the induced absorption effect in the 480–980 nm spectral range. The relaxation of the induced absorption has a time constant equal to about 500 ps for CuS-doped glasses and a biexponential type (with τ1≈30 ps and τ2>1 ns) for CuInS2-doped ones.