Femtosecond Laser-Induced Breakdown Spectroscopy: Physics, Applications, and Perspectives

Electron-ion relaxation time dependent signal enhancement in ultrafast double-pulse laser-induced breakdown spectroscopy

“…Approximate time scales of ns and fs laser energy absorption and ablation, along with various processes occurring during and after the laser pulse, are given in detail elsewhere. 1,4 On the other hand, ionization, sample heating, and vaporization all occur during the laser pulse in ns LA, fs laser pulses are sufficiently short that these phenomena do occur at a later time compared to the excitation pulse duration. Because of this time difference in the ablation processes, fs laser excitation results in smaller heat affected zone (HAZ), more reproducible material ablation, ablation products resembling bulk stoichiometry, and minimal elemental fractionation and matrix effects.…”

“…Because of this time difference in the ablation processes, fs laser excitation results in smaller heat affected zone (HAZ), more reproducible material ablation, ablation products resembling bulk stoichiometry, and minimal elemental fractionation and matrix effects. 4 In fs LA, the electron impact ionization and strong electric field ionization (photoionization) are the major processes for free electron generation, while the Coulomb explosion (gentle ablation) and thermal vaporization (strong ablation) are the two competing mechanisms resulting in material removal and ablation. 5 Limited HAZ in ULIBS also prevents uncontrollable and undesirable material modification and removal as seen with longer pulse laser ablation.…”

Plasma temperature clamping in filamentation laser induced breakdown spectroscopy

“…1 and are mainly contributed by Cu and Zn neutral lines. It has been reported previously that fs LIBS predominantly provides neutral atomic plumes in contrast to the strong ion emission seen in nanosecond LIBS [18,19]. We evaluated the changes in plasma emission intensity along the filament channel and results are given in Fig.…”

Laser‐induced Breakdown Spectroscopy

“…(10,11) Fs lasers typically generate pulses of 20-200 fs duration with energies of a few millijoules and focused power densities on the order of 100 TW cm −2 . The center wavelength of the pulse is around 800 nm and due to the narrow pulsewidth, the spectral content of the pulse is relatively broad.…”