Large saturation of absorption of CdSSeTe nanocrystallites in glass measured by femtosecond Z-scan technique

The optical non‐linearity of CdSSeTe nanocrystallite‐doped glasses has been studied using a single‐beam, femtosecond Z‐scan technique. We have observed very large absorption saturation in a composite of CdSSeTe nanocrystals in a glass host compared with CdS or CdSe, although we have not reached the saturation limit. The wavelength and power dependence of absorption saturation in these composites are reported. The experimental data are interpreted by two‐level model system. A comparison is also made with other nanocrystallite composites with different stoichiometric compositions. Copyright © 2000 John Wiley & Sons, Ltd.