A new class of third-order nonlinear optical materials: laser pulse-duration dependant saturable absorption and nonlinear refraction in platinum(II) diimine-dithiolate complexes.

The third-order nonlinear optical (NLO) properties of a series of platinum diimine-dithiolate complexes [Pt(N^N)(S^S)] were investigated by means of -scan measurements, revealing second hyperpolarizability values up to 10 esu, saturable absorption properties, and nonlinear refractive behaviour, which were rationalized also by means of DFT calculations.

Third-order nonlinear optical response and optical limiting of colloidal carbon dots.

In this work, the nonlinear optical response of some organophilic and hydrophilic carbon dots derived from gallate precursors is studied under 4 ns and 35 ps, visible (532 nm) and infrared (1064 nm) laser excitation conditions by the Z-scan technique. The prepared carbon dots were found to exhibit considerable nonlinear optical response in the visible, the organophilic ones exhibiting stronger response in the infrared and, in general, significantly larger response than their hydrophilic counterparts. In all cases, the corresponding nonlinear optical parameters have been determined.