Optical limiting properties of Te and Ag₂Te nanowires

We have prepared tellurium (Te) and silver telluride (Ag₂Te) nanowires in solution and investigated their nonlinear optical transmission by the open-aperture z-scan technique, using nanosecond laser pulses, at the excitation wavelengths of 532 and 1064 nm. The nonlinearity has contributions from absorption saturation, excited state absorption and nonlinear scattering processes. The saturation intensity and nonlinear absorption coefficient are calculated numerically. Nonlinear absorption in Ag₂Te nanowires is found to be one order of magnitude higher than that in Te nanowires. Observation of optical limiting at both excitation wavelengths indicates the potential of these materials to be used as broadband optical limiters.