Nonlinear optical transmission of nanocrystalline Cu2Se in the ultrafast excitation regime

Nanocrystalline copper selenide (Cu2Se) has been synthesized by the hydrothermal co-reduction method. X-ray diffraction studies reveal the crystalline nature of its single phase. TEM images of the as-prepared sample show the formation of nanoparticles of diameter 10–35 nm. Open aperture z-scan measurements carried out using ultrafast (100 fs) laser pulses at 800 nm show that the sample exhibits saturable absorption at relatively lower input fluences and reverse saturable absorption at relatively high input fluences, indicating its versatile use as a photonic material.