Effect of Femtosecond Ultraviolet and Infrared Laser Wavelength on Plasma Characteristics of Metals, Ceramics and Glass Samples Using Femtosecond Laser-Induced Breakdown Spectroscopy.

In this work, we present studies on the effect of laser wavelengths on the laser-induced plasma characterization using a femtosecond (fs) ytterbium-doped potassium-gadolinium tungstate (Yb:KGW) laser. Plasma plumes of copper, steel, ceramics, and glass samples were induced using a multiple shot of 200 fs laser pulses with 1030 nm and 343 nm wavelengths at fixed laser fluence () and analyzed using the laser-induced breakdown spectroscopy (LIBS) technique. Time-resolved fs-LIBS measurements were performed on the same set of samples and under the same experimental conditions.

Direct time-resolved plasma characterization with broadband terahertz light pulses.

We report here the results of comprehensive plasma characterization and diagnostics by analyzing time-resolved absorption spectra of short ultrabroadband (0.1-50 THz) pulses propagated through the test plasma. Spectral analysis of plasma-induced absorption of such THz pulses provides very direct, in situ, high dynamical range, potentially single-shot access to the plasma density, plasma decay time, electron temperature, and ballistic dynamics of the plasma expansion.

Performance investigation of high-efficiency widely tunable subnanosecond optical parametric generator and amplifier based on MgO:PPLN.

We report on experimental and theoretical studies of widely tunable high-efficiency subnanosecond optical parametric generator (OPG) and amplifier (OPA) based on a 2 cm long multigrating MgO-doped periodically-poled lithium niobate (MgO:PPLN) crystal pumped by a passively Q-switched Nd:YAG micro-laser. Our OPG can be continuously tuned from 1442 nm to 4040 nm with signal wave energies ranging from 33 J to 265 J and total OPG conversion efficiency up to 46 % that depended on the pump focusing conditions. Characterization of spatial properties of the OPG determine Lorentzian spatial profile of the signal beam with ≈2 that was also dependent on the pump focusing conditions.

Femtosecond Laser Micromachining of Soda-Lime Glass in Ambient Air and under Various Aqueous Solutions.

We have studied femtosecond ablation of soda-lime glass sample under thin water film, under KOH and NaCl aqueous solutions films and their influence and benefits compared with ablation in the air atmosphere. These have been studied in case of the groove ablation using the infrared (IR) femtosecond laser. KOH aqueous solution film above the glass sample improved the ablation efficiency and led to the formation of the grooves with a higher aspect ratio when multi-scan glass cutting conditions were applied.