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An automated test station to measure the laser-induced damage threshold (LIDT) according to ISO 21254-1,2,3,4:2011 standards is presented. The laser is a single longitudinal mode, 500 mJ, 6 ns, Q-switched, 10 Hz, linearly polarized, 1064 nm laser, with 2-nd and 3-rd harmonic capabilities. The machine is able to operate the S-on-1 test (S = 500), or the Type 2 endurance (durability) test. The main blocks of the station are described, emphasizing some original solutions. Preliminary results of LIDT measurements using the S-on-1 test on several coatings and on uncoated fused silica substrates with various degrees of roughness are also presented.

Single pulse laser ablation of glass, Ag, Au, and Co thin films was experimentally investigated with a laser pulse width of 400 ps at a wavelength of 532 nm both in the far and near fields. In the far-field regime, the electromagnetic field results from a focused laser beam, while the near-field regime is realized by a combination of the focused laser beam incident on a spherical colloidal particle. For the near-field experiments we have used polystyrene colloidal particles of 700 nm diameter self-assembled or spin coated on top of the surfaces. Laser fluences applied are in the range of 0.01–10 J/cm2. The diameter and the morphologies of the ablated holes were investigated by optical microscopy, profilometry, scanning electron microscopy, and atomic force microscopy. The dependence of the shape of the holes reflects the fluence regime and the thermophysical properties, i.e., melting temperature and thermal diffusivity of the surfaces involved in the experiments. We give quantitative data about the fluence threshold, diameter, and depth ablation dependence for the far and near fields and discuss their values with respect to the enhancement factor of the intensity of the electromagnetic field due to the use of the colloidal particles. Theoretical estimations of the intensity enhancement were done using the finite-difference time-domain method by using the RSOFT software. The application of near fields allows structuring of the surfaces with structure dimension in the order of 100 nm and even below.

We describe a pulsed doubly resonant LB3O5 (LBO) optical paramethc oscilator (OPO) pumped with a frequency doubled Q-switched Nd:YAG laser amplifier. The threshold power density near degeneracy was found to be 29 MW/cm2. The OPO was continuously tuned from 970 mu to 1175 nm by rotalion ofthe LBO crystal. The linewidth ofthe signal radiatton at 998 nm, and idler radiation at 1136 nm wavelength, were found to be 10 rim, and 13 nm respectively. The OPO output pulse energy ofsignal and idler near degeneracy was 1.51 mJ for 18 mJ pump energy.