Dual-Comb Spectroscopy of Laser-Produced Plasmas

Dual-comb spectroscopy (DCS) represents a novel method of using absorption spectroscopy as a diagnostic tool for time-resolved multispecies analysis of excitation temperatures and column densities in laser-produced plasmas (LPPs). DCS utilizes two stabilized modelocked lasers to generate a pair of mutually-coherent frequency combs and enables broadband spectroscopic measurements with high spectral and temporal resolution that are well-suited for studying the quickly evolving conditions of LPPs. The ablation plume of an LPP evolves both spatially and temporally and, when combined with optical diagnostics, has proved useful both as a means for preparing high-temperature gas-phase atomic/molecular species and for non-contact elemental analysis of solid materials. Temperature and number density studies involving ionic, atomic, and molecular species present in the LPP are applicable to quantitative analysis of sample composition as well as plasma diagnostic research focused on plume formation and expansion, molecular formation, diffusion rates, and condensation processes, both spatially and temporally. LPPs can be studied by DCS with both the necessary time and spectral resolutions required to probe many absorption transitions within the timescales of late-time LPP evolution. Recent work has shown that the technique’s high spectral resolutions enable measurements of congested optical spectra, such as those from heavy elements and molecules, to be resolved and more accurately analyzed. Broadband detection of multiple transitions, combined with Boltzmann-plot style analysis commonly used in laser-induced breakdown spectroscopy (LIBS), provides the ability to determine time-resolved excitation temperatures and total column densities of atomic species. Using efficient harmonic conversion in nonlinear crystals (e.g., second harmonic generation), DCS can easily access multiple wavelength regions. The ability to measure spectrally and temporally resolved broadband spectra within many wavelength regions makes DCS an effective optical technique for studying LPPs as well as additional spectroscopic applications

Time-Resolved Dual Frequency Comb Phase Spectroscopy of Laser-Induced Plasmas

We present the first results using time-resolved dual-comb phase spectroscopy in a laser-induced plasma. It can allow for simultaneous plasma characterization as well as multi-species detection and plasma characterization. (c) 2019 The Author(s)Air Force Office of Scientific Research [FA9550-15-1-0091]; Defense Threat Reduction Agency [HDTRA11710030]; U.S. Department of Energy (DOE) [DE-AC05-76RL01830]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Time-Resolved Dual Frequency Comb Spectroscopy for Broadband Multi-Species Detection in Laser-Induced Plasmas

We present the first results using time-resolved broadband dual-comb spectroscopy in a laser-induced plasma. Preliminary results identifying multiple species in a Nd magnet will be shown. (c) 2019 The Author(s)Air Force Office of Scientific Research [FA9550-15-1-0091]; Defense Threat Reduction Agency [HDTRA 11710030]; U.S. Department of Energy (DOE) by the Battelle Memorial Institute [DE-AC05-76RL01830]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Time-resolved dual-comb measurement of number density and temperature in a laser-induced plasma

We utilize time-resolved dual-comb spectroscopy to measure the temporal evolution of the population number densities and absorption excitation temperature of Fe in a laser-induced plasma. The spectra of three excited-state transitions of Fe around 533 nm are simultaneously measured at different time delays following laser ablation of a stainless steel sample. This Letter probes late-time behaviors of laser-induced ablation plumes during plasma cooling. The high spectral resolution and broad spectral coverage of the dual-comb technique, combined with the time-resolved measurement capability shown here, will aid in the characterization of laser induced plasmas, including species identification and molecule and particle formation that can occur at later times in the plasma evolution. (C) 2019 Optical Society of AmericaAir Force Office of Scientific Research (AFOSR) [FA9550-15-1-0091]; Defense Threat Reduction Agency (DTRA) [11710030]; National Science Foundation (NSF) [1206555]; Office of Defense Nuclear Nonproliferation (DNN); National Nuclear Security Administration (NNSA); U.S. Department of Energy (DOE) [DE-AC05-76RL01830]12 month embargo; published online: 10 July 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Characterization of a Laser-Induced Plasma Using Time-Resolved Dual-Frequency-Comb Spectroscopy

We characterize the dynamics of laser-induced plasmas using time-resolved dual-frequency-comb spectroscopy. The temporal evolution of plasma's temperature, population number density are estimated for multiple Fe transitions. (C) 2019 The Author(s)Air Force Office of Scientific Research [FA9550-15-1-0091]; Defense Threat Reduction Agency [HDTRA 11710030]; U.S. Department of Energy (DOE) [DE-AC05-76RL01830]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Dual-comb absorption spectroscopy of molecular CeO in a laser-produced plasma

Broadband and high-resolution absorption spectra of molecular cerium oxide (CeO) are obtained in a laser-produced plasma using dual-comb spectroscopy. Simultaneous measurements of Ce and CeO are used to probe time-resolved dynamics of the system. A spectral resolution of 1.24 GHz (2.4 pm) over a bandwidth of 378.7–383.7 THz (781.1–791.5 nm) allows simultaneous detection of hundreds of closely spaced rotational transitions in complex CeO bands.Defense Threat Reduction Agency (HDTRA1-20-2-0001); Air Force Office of Scientific Research (FA9550-20- 294 261 1-0273).12 month embargo; published: 05 May 2022This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]