Tunable photoluminescence emission and third order optical nonlinearity in Sm2/3Cu3Ti4O12 ceramics for optical limiting applications

A combined investigation of the photoluminescence and third order optical nonlinearity of polycrystalline samarium copper titanate, Sm2/3Cu3Ti4O12 (SmCTO), is presented in the current work. SmCTO ceramic has been synthesized using a cost-effective solid state reaction method and investigated by means of spectral absorbance (UV-Vis), photoluminescence (PL), X-ray diffraction (XRD), Field Emission Secondary Emission Microscopy (FESEM), energy dispersive X-ray Analysis (EDAX) and X-ray Photoelectron Spectroscopy (XPS). From the PL spectra, it is clear that the blue band is due to the TiO6 cluster with oxygen vacancy of the Cu+ type and is assigned to the shallow defects. The green band obtained is due to the reduction in the density of trapped charges as well as particle size. The orange to red emission band corresponds to the charge transfer to the TiO6 cluster with oxygen vacancy of doubly ionized ions. Thus, we can infer the presence of defects like oxygen vacancies (Vxo, V & BULL;o, and V & BULL;& BULL; o ) in SmCTO. The third order nonlinear absorption coefficient measured by employing the open aperture Z-scan technique shows high values of the order of 10-8 cm/W and 10-4 cm/W, for pulsed and continuous wave lasers, respectively. This is primarily due to the effect of strong excited state absorption, which leads to excellent optical limiting behaviour. Therefore, these materials can be used to make optical limiting devices which can protect human eyes and sensitive optical detectors from dangerous laser beams. The PL and nonlinear optical studies reveals that SmCTO ceramics are practically useful for photonic applications.

Automated summary

A combined investigation of the photoluminescence and nonlinear optical properties of SmCTO ceramics has been carried out. The presence of defects such as oxygen vacancies in SmCTO has been confirmed through photoluminescence spectra. The high third order nonlinear absorption coefficient of SmCTO ceramics makes them suitable for the development of optical limiting devices.