Efficiency of single-pulse laser fragmentation of organic nutraceutical dispersions in a circular jet flow-through reactor

• Tina Friedenauer,
• Maximilian Spellauge,
• Alexander Sommereyns,
• Verena Labenski,
• Tuba Esatbeyoglu,
• Christoph Rehbock,
• Heinz P. Huber and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2025, 16, 711–727, doi:10.3762/bjnano.16.55

• used an ultrashort-pulsed laser. We choose picosecond pulse duration to avoid the risk of optical breakdown in the liquid at shorter pulse durations [48]. In addition to the comminution efficiency, the formation of degradation products was quantitatively evaluated as a high degree of product purity is

• small peaks at higher retention times in the HPL chromatograms. The photochemical degradation could occur via two partially interacting pathways, namely, (I) direct damage by the particle fragmentation process or (II) indirect damage by ROS resulting either from the optical breakdown of the solvent or

• degradation when the concentration is reduced by a factor of ten (0.1 wt % versus 0.01 wt %) warrants further explanations. One main contribution in this context is optical shielding following the Beer–Lambert (or Bouguer–Lambert) law. Furthermore, laser-induced optical breakdown effects causing the

Laser synthesis of nanoparticles in organic solvents – products, reactions, and perspectives

• Theo Fromme,
• Sven Reichenberger,
• Katharine M. Tibbetts and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2024, 15, 638–663, doi:10.3762/bjnano.15.54

• physical synthesis method. Moreover, the irradiation of pure organic solvents with femtosecond or picosecond radiation led to the formation of numerous products induced by the intense conditions, which can be attributed to laser-induced optical breakdown and/or shockwaves. The optical breakdown of the

• oxygen species (ROS), for example, hydrogen peroxide, hydroxyl radicals, or dissolved oxygen, react with the particles leading to their surface oxidation. During irradiation of water with intense laser pulses, a weakly ionized plasma forms because of optical breakdown, supercontinuum emission, or both

• . Optical breakdown occurs when the free-electron density surpasses a critical value, resulting in a high-density plasma, and the optical breakdown threshold is significantly reduced in the presence of metal nanoparticles [49][81][82]. Supercontinuum emission can occur at low fluences, when pulses shorter

The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

• Yevgeniy R. Davletshin and
• J. Carl Kumaradas

Beilstein J. Nanotechnol. 2016, 7, 869–880, doi:10.3762/bjnano.7.79

• -dimensional assembly of particles affects the optical breakdown threshold of its surroundings. For this purpose we used a fully coupled electromagnetic, thermodynamic and plasma dynamics model for a laser pulse interaction with gold nanospheres, nanorods and assemblies, which was solved using the finite

• element method. The thresholds of optical breakdown for off- and on-resonance irradiated gold nanosphere monomers were compared against nanosphere dimers, trimers, and gold nanorods with the same overall size and aspect ratio. The optical breakdown thresholds had a stronger dependence on the optical near

• -field enhancement than on the mass or absorption cross-section of the nanostructure. These findings can be used to advance the nanoparticle-based nanoscale manipulation of matter. Keywords: electron plasma; finite element method; optical breakdown; plasmon coupling; plasmonic nanoparticles