Two-photon absorption based optical limiting and stabilization by using a CdTe quantum dot solution excited at optical communication wavelength of ∼1300 nm

This letter presents the results of two-photon study of CdTe quantum dots (QDs) in chloroform. The measured two-photon absorption (2PA) spectrum shows that 2PA coefficient at similar to 1300 nm is similar to 0.02 cm/GW. Based on a 1 cm path-length CdTe QD solution sample of 8 mg/ml concentration, irradiated by a focused similar to 1300 nm laser beam of similar to 160 fs duration, the nonlinear transmission could be changed from similar to 100% to similar to 20% when the input pulse energy was varied from similar to 50 nJ to similar to 10 mu J, demonstrating a superior optical limiting performance. The input laser fluctuation was significantly reduced after passing through the sample, indicating a remarkable optical stabilization behavior. (c) 2007 American Institute of Physics.