Enhanced All-Optical Modulation of Terahertz Waves on the Basis of Manganese Ferrite Nanoparticles

We present an all-optical modulator based on manganese ferrite nanoparticles (MnFe₂O₄ NPs), which provides an enhanced attenuation of broad-band terahertz waves. A wide-band modulation of THz transmission was observed in a frequency range from 0.15 to 1.2 THz. The experimental results were assessed by simulations in the context of a band structure model of semiconductors. Our work demonstrated that coatings of MnFe₂O₄ NPs can be efficiently used to improve the performance of THz modulators based on optical modulation. This paper describes a new route to increase the surface photoconductivity of semiconductors by coating of MnFe₂O₄ NPs. This work demonstrates that the THz modulator based on MnFe₂O₄ NPs can significantly boost the overall performance of THz communication systems, and MnFe₂O₄ NPs may offer some useful solutions for future THz devices

Investigation of the Viability of Cells upon Co-Exposure to Gold and Iron Oxide Nanoparticles

Cell lines were exposed either to mixtures of gold and iron oxide nanoparticles, or to a hybrid nanoparticle with gold and iron oxide domain. In the case of simultaneous exposure to gold and iron oxide nanoparticles, enhanced toxicity as compared to the exposure to only one type of nanoparticles was observed. An indication was found that, at equivalent concentrations, the hybrid nanoparticles may slightly reduce cell viability more strongly than mixtures of both nanoparticle types. The results suggest that composite nanomaterials, in which different materials are present in particle form, need to be analyzed carefully, as not only the concentration of the respective materials but also their arrangement may influence their toxicity