Recent developments in optical techniques for plasma diagnostics are critically reviewed. The primary emphasis is on plasma-induced emission and laser-induced fluorescence probes of radical and ionic concentrations and temperatures in low pressure discharges like those used in microelectronic fabrication. Other techniques such as optogalvanic, infrared, spontaneous and stimulated Raman, and mul...

The Be stars display variable optical emission lines originating in the circumstellar disc. Here we analyse high resolution spectroscopic observations of and distance between peaks H-alpha, H-beta, H-gamma ($\Delta V_\alpha$, $\Delta V_\beta$, V_\gamma$ respectively). Combining published data, spectra from ELODIE archive (obtained period 1998 -- 2003) Rozhen 2015 2023) 93 stars, find a set rela...

Purpose: The primary purpose of this study is to introduce fluorescence spectroscopy technology as a tool for optical biopsy and to evaluate the reliability of this real-time non-invasive technique in assessing tumor therapeutic response in radiotherapy. Methods: Four oral cancer patients with inflammatory conditions of the oral cavity volunteered to participate in the study. Using FastEEM (Exc...

Three-dimensional topological insulators are materials that behave as an insulator in the interior, but as a metal on the surface with Dirac surface states protected by the topological properties of the bulk wavefunctions. The newly discovered second surface state, located about 1.5 eV above the conduction band in Bi2Se3 allows direct photoexcitation of the surface electrons in n-doped samples ...