Picosecond nonlinearity of GeO2–Bi2O3–PbO–TiO2 glasses at 532 and 1,064 nm

The third-order optical properties of GeO2–Bi2O3–PbO–TiO2 glasses at 532 nm and 1,064 nm were studied to evaluate their potential for optical limiting and all-optical switching. The Z-scan technique was used to determine the nonlinear (NL) refractive index, n2, and the NL absorption coefficient, α2, of samples with different amounts of the constituent oxides. Values of n2 ≈ + 0.7 × 10−14 cm2/W at 1,064 nm and ≈+1.5 × 10−14 cm2/W at 532 nm were measured. The NL absorption coefficient, α2, was smaller than the minimum that our apparatus can measure (α2 < 0.01 cm/GW) in the near-infrared (1,064 nm); in the visible region (532 nm), we obtained α2 ≈ 4.4 cm/GW. The set of NL parameters measured indicates the potential usefulness of the GeO2–Bi2O3–PbO–TiO2 glasses for all-optical switching at 1,064 nm and for optical limiting at 532 nm.