Time- and space-resolved spectroscopic characterization of laser-induced swine muscle tissue plasma

The spatial-temporal evolution of muscle tissue sample plasma induced by a high-power transversely excited atmospheric (TEA) CO₂ pulsed laser at vacuum conditions (0.1–0.01 Pa) has been investigated using high-resolution optical emission spectroscopy (OES) and imaging methods. The induced plasma shows mainly electronically excited neutral Na, K, C, Mg, H, Ca, N and O atoms, ionized C⁺, C²⁺, C³⁺, Mg⁺, Mg²⁺, N⁺, N²⁺, Ca⁺, O⁺ and O²⁺ species and molecular band systems of CN(B²Σ⁺–X²Σ⁺), C₂(d³Π_g–a³Π_u), CH(B²Σ⁻–X²Π; A²Δ–X²Π), NH(A³Π–X³Σ⁻), OH(A²Σ⁺–X² Σ⁺), and CaOH(B²Σ⁺–X²Σ⁺; A²Π–X²Σ⁺). Time-resolved two-dimensional emission spectroscopy is used to study the expanded distribution of different species ejected during ablation. Spatial and temporal variations of different atoms and ionic excited species are reported. Plasma parameters such as electron density and temperature were measured from the spatio-temporal analysis of different species. Average velocities of some plasma species were estimated. - Highlights: • LIBS of swine muscle tissue sample generated by CO₂ laser pulses has been done for the first time. • Average velocities of some plasma species have been calculated from spatial and temporally resolved 2D OES images. • Electron density (~ 9 × 10¹⁷ cm^-3) has been studied with spatial and temporal resolution. • Temporal evolution of the plasma temperature has been calculated by means of Boltzmann plots