Toward On-Line Slag Composition Analysis: Optical Emissions from Laboratory Electric Arc

Electric arc furnaces and ladle furnaces have an important role in the future of steelmaking where $$\hbox {CO}_2$$ CO 2 emissions have to be mitigated to an acceptable level. One way to address this goal is to optimize and improve the current practices by adjusting the chemistry and reactions with material additions or gas injections. These procedures would greatly benefit from on-line slag composition analysis. Since the electric arcs radiate throughout the melting, optical emission spectroscopy is a potential method for such analysis. In this study, optical emissions from the electric arc are measured in a laboratory environment. Dozens of atomic emission lines were correlated with $$\hbox {Cr}_2\hbox {O}_3$$ Cr 2 O 3 , $$\hbox {Fe}_2\hbox {O}_3$$ Fe 2 O 3 , $$\hbox {Al}_2\hbox {O}_3$$ Al 2 O 3 , $$\hbox {SiO}_2$$ SiO 2 , MnO, MgO, CaO, $$\hbox {CaF}_2$$ CaF 2 , $$\hbox {V}_2\hbox {O}_5$$ V 2 O 5 , and Ni content of the slag together with correlation between $$\hbox {CaF}_2$$ CaF 2 and molecular optical emission bands of CaF. Optimal spectral resolution for industrial applications was deducted to be between 0.022 and 0.179 nm.

Fluorescence blinking in MoS2 atomic layers by single photon energy transfer

The quantum optical phenomena, such as single photon emission, in two-dimensional (2D) transition metal dichalcogenides (TMDCs) have triggered extensive researches on 2D material-based quantum optics and devices. By far, most reported quantum optical emissions in TMDCs are based on atomic defects in the material or the local confinement of excitons by introducing local stain or potential. In contrast, energy transfer between two materials could also manipulate the photon emission behaviors in materials, even at the single photon level. Along with the single-photon emission nature of zero-dimensional (0D) quantum dots (QDs) at room temperature, constructing a 0D-2D hybrid heterostructure may provide an effective way to regulate the quantum states related optical emissions of TMDCs. Here, we report on fluorescence blinking, a quantum phenomenon, from MoS2 atomic layers in QD/ MoS2 heterostructure at room temperature. We demonstrate the single-photon nature of the QDs in heterostructures by second-order photon correlation measurements. Based on the transient PL spectroscopy and PL time trajectories, we attribute the fluorescence blinking behavior in MoS2 to the single photon energy transfer from QD to MoS2. Our work opens the possibility to achieve correlated quantum emitters in TMDCs at room temperature by controlling the energy transfer between QD and TMDCs.