Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

Abstract

Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS), coherent Raman spectroscopy, and terahertz (THz) spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications.

Adaptive femtosecond laser-induced breakdown spectroscopy of uranium

“…6 Ultrafast lasers (10 −12 -10 −14 s) are frequently used for applications in spectroscopy and sensing, particularly when studying the dynamics of atomic and molecular processes. 7,8 Significant advances in the science and technology of laser ablation resulted from the advent of ultrafast lasers. Compared to nanosecond pulses, femtosecond pulses nearly fully ionize the target (at typical intensities of 10 13 -10 14 W/cm 2 ), leading to improved ablation precision and lower background from continuum emission.…”

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

“…The recent advancements in fs laser technology stimulated the development of a new field called ultrafast laserinduced breakdown spectroscopy (ULIBS), or fs LIBS. [1][2][3] Even though the only difference between the conventional ns laser based LIBS and ULIBS is the difference in laser system, the mechanisms leading to energy absorption and subsequent target ablation are entirely different for both cases due to significant higher rate of energy deposition in fs laser ablation (LA). 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.…”

Advances in explosives analysis—part II: photon and neutron methods

“…Emission from a mixture of molecules, atoms, and ions in a variety of rapidly evolving excited states is collected, and chemometrics/analysis of the C, H, O, N, Cl, and CN components is performed. Reviews within the past five years cover the different techniques [101,[165][166][167][168][169][170]. Recent work has revealed the effects of substrate and interferent dependence [171] on analyte classification and how selective sampling can enable surface sensitivity [172][173][174][175][176].…”