Potential hazards and mitigation of X-ray radiation generated by laser-induced plasma from research-grade laser systems.

A large range of laser-matter applications employ ultrashort pulses and high laser intensity. Such processes can lead to unrequired X-ray generation, which represents a hazardous radiation factor even for common laboratory research-grade laser systems. We present here an analysis of the radiation dose rate and X-ray spectrum emitted during ablation of a rotating copper cylinder with respect to several laser parameters.

X-ray Dose Rate and Spectral Measurements during Ultrafast Laser Machining Using a Calibrated (High-Sensitivity) Novel X-ray Detector.

Ultrashort pulse laser machining is subject to increase the processing speeds by scaling average power and pulse repetition rate, accompanied with higher dose rates of X-ray emission generated during laser-matter interaction. In particular, the X-ray energy range below 10 keV is rarely studied in a quantitative approach. We present measurements with a novel calibrated X-ray detector in the detection range of 2-20 keV and show the dependence of X-ray radiation dose rates and the spectral emissions for different laser parameters from frequently used metals, alloys, and ceramics for ultrafast laser machining.

Electronic and Nonlinear Optical Properties of l-Histidine on Silver: A Theoretical and Experimental Approach.

An investigation of the electrostatic interactions between histidine and silver have been analyzed using density functional theory (DFT). Variations in the structural parameters were identified to be significant at those atoms of histidine near the silver cluster. The shifting of frontier molecular orbitals, reduction in bandgap, molecular electrostatic potential (MEP), and overlap of natural bond orbitals (NBO) between silver and histidine have been theoretically calculated.

Optical nonlinearity and charge transfer analysis of pyrene adsorbed on silver: Computational and experimental investigations.

The interaction of pyrene on silver has been investigated using both experimental and computational methods. Hyperpolarizabilities computed theoretically together with experimental nonlinear absorption from open aperture Z-scan measurements, point towards a possible use of pyrene adsorbed on silver in the rational design of NLO devices. Presence of a red shift in both simulated and experimental UV-Vis spectra confirms the adsorption on silver, which is due to the electrostatic interaction between silver and pyrene, inducing variations in the structural parameters of pyrene.