TY - CONF A1 - Blume, Simon T1 - Femtosecond vs. Nanosecond Laser-induced XUV Spectroscopy (LIXS) N2 - In contrast to laser-induced breakdown spectroscopy (LIBS), measuring after a delay as long as a few microseconds, laser-induced XUV spectroscopy (LIXS) takes advantage of emissions from the very first instant of the pristine plasma. This process exhibits stable and intense line and recombination emissions in the XUV-range. Therefore, common challenges for precise measurements (e.g. quantification efforts) in LIBS caused by signal intensity fluctuations due to matrix effects and plasma-flicker noise are improved, as shown for ns-pulses. A femtosecond laser (pulse length ~100 fs) interacts fundamentally different with matter than a nanosecond laser. Of the many photons needed for ionization of the sample, less are absorbed via inverse Bremsstrahlung and more in a Franck-Condon multiphoton absorption (MPA) process. In combination with the higher peak power, and therefore higher initial plasma temperature (> 10 eV), atoms are selectively ionized to a higher degree while at the same time thermal dissipation and equilibration is reduced. This specificity in excitation leads to a reduced background and the highly ionized atoms overwhelmingly emit the desired XUV-radiation. Thus, fs-LIXS promises to lead to “cleaner” spectra with sharper separation of the emission lines. The capabilities of a fs-LIXS setup in comparison to ns-LIXS will be discussed. Samples of pure elements (Al, Si, Ni, Fe, Mg), as well as composite samples (CaF, LiF, PTFE, polypropylene) serve as model systems to demonstrate these capabilities. T2 - EMSLIBS 2025 CY - Senlis, France DA - 26.01.2026 KW - Femtosecond KW - LIXS KW - XUV KW - Elemental analysis PY - 2026 AN - OPUS4-65470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blume, Simon T1 - Exploiting Lithium Self-Absorption in a Laser-Induced Breakdown Plasma for Isotopic Analysis via Spatial Heterodyne Spectroscopy N2 - Lithium-ion batteries are ubiquitous in modern life. From powering consumer electronics to enabling electric mobility and energy storage, they are a key building block of a sustainable future. Determination of the ratio of the two naturally abundant stable isotopes, 7Li and 6Li, provides access to a wide variety of information, such as studying the aging processes of lithium-ion batteries or elucidating the isotopic fingerprinting of natural or recycled sources of lithium. However, accurately measuring the lithium isotope ratio in complex samples remains challenging, often requiring either extensive sample pretreatment or specialized equipment, thus impeding in-situ and high-throughput demands of global industries. Recognition and determination of the individual lithium isotopes with conventional laser-induced breakdown spectroscopy (LIBS) setups is nearly impossible. While LIBS offers several advantages, such as obviating time- and resource-intensive sample preparation and enabling rapid measurements, the high temperature (~20,000 K) of the plasma, as well as the Stark-broadening caused by the nascent free electrons spectrally broaden the atomic emission lines to such an extent that the isotopic shift of the lithium doublet at 670 nm cannot be resolved. Since, the excited state energy for this transition amounts to only 14,900 cm-1, lithium exhibits a pronounced self-absorption dip in the emission signal. This self-absorption dip is significantly less affected by the broadening effects, therefore, allowing for the resolution of the isotopic shift from its line shape. Spatial heterodyne spectroscopy (SHS) offers the superior resolution capabilities necessary to differentiate the individual isotopic contributions. To address the generally limited sensitivity of SHS, a high-repetition-rate (>10 kHz) laser allows the accumulation of more than 10,000 lasing events per spectral recording for a sufficient signal-to-noise ratio and gain statistical validity. Optical lithium fluoride serves as a model sample to showcase the analytical performance. Additionally, the impact of the laser parameters on the self-absorption will also be discussed. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Isotopic Analysis KW - Spatial Heterodyne Spectroscopy PY - 2025 AN - OPUS4-63559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blume, Simon T1 - Femtosecond Laser-induced XUV Spectroscopy (LIXS) for Elemental Analysis N2 - In a typical laser-induced breakdown spectroscopy (LIBS) setup, emissions from collisional excitation of the atoms in the later stages of the plasma are detected and provide information about the elemental fingerprint of the sample. However, precise measurements, in particular quantification efforts, suffer from fluctuations of the intensity of the detected emission lines due to matrix effects and plasma-flicker noise, as well as significant background noise. In contrast, the early stages of the plasma are dominated by electron-ion recombination and Bremsstrahlung, which lead to sharp and intense x-ray emissions with consistent intensity profiles between laser pulses and suppressed background noise, therefore improving the limit of detection, especially for lighter elements. These emissions are detected in laser-induced XUV spectroscopy (LIXS).[1] Introduction of a femtosecond laser (pulse length ~100 fs) to the LIXS setup fundamentally changes the laser energy absorption and ablation process. The laser pulse energy is absorbed and redistributed by multiphoton absorption and inverse Bremsstrahlung and operates on a time frame faster than the plasma formation. Additionally, the plasma formation itself is accelerated leading to signal generation in the XUV-range before generation of the undesired background emissions. Thus, utilization of a femtosecond laser allows for further suppression of broadband emissions from the plasma allowing for sharper separation of the emission lines and improved limit of detection. This work presents the results of the combination of a LIXS setup with a femtosecond laser and assess the capabilities of this system with a model sample of cathode material from a spent lithium-ion battery. T2 - AMACEE 2025 CY - Brno, Czech Republic DA - 26.8.2025 KW - LIXS KW - Femtosecond laser KW - Instrumentation PY - 2025 AN - OPUS4-64118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blume, Simon T1 - Isotopic analysis of lithium via acousto-optically gated high-repetition laser-induced breakdown spectroscopy and spatial heterodyne spectroscopy N2 - Acousto-optically gating the emission signal from a laser-induced breakdown spectroscopy (LIBS) plasma negates some of the line-broadening effects, therefore, improving the signal line shape. However, the remaining influences disallow the differentiation of the contributions of the individual lithium isotopes, even when utilizing a high-resolution spatial heterodyne spectrometer (SHS). Nevertheless, isotopic analysis of lithium with LIBS is still feasible, because lithium exhibits a strong self-absorption dip in the emission signal, which is likewise characterized by the isotopic shift and even benefits from the broad emission lines typically observed in LIBS. The isotopic ration can be resolved from the absorption dip via high-resolution SHS. T2 - SciX 2024 CY - Raleigh, NC, USA DA - 20.10.2024 KW - LIBS KW - SHS KW - Isotopic analysis KW - Lithium PY - 2024 AN - OPUS4-62012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -