We report on atmospheric pressure argon plasma-based surface treatment and hybrid laser-plasma ablation of barite crown glass N-BaK4 and heavy flint glass SF5. By pure plasma treatment, a significant surface smoothing, as well as an increase in both the surface energy and the strength of the investigated glass surfaces, was achieved. It was shown that for both glasses, hybrid laser plasma ablation allows an increase in the ablation depth by a factor of 2.1 with respect to pure laser ablation. The ablated volume was increased by an averaged factor of 1.5 for N-BaK4 and 3.7 for SF5.

In this paper, we present a hybrid laser-plasma ablation method for material processing applications. For this purpose, a coaxial configuration consisting of a low-temperature atmospheric pressure argon plasma beam and a Nd:YAG-laser at a wavelength of 355 nm was used. Both pure laser ablation and hybrid laser-plasma ablation experiments were performed on aluminum at different laser energies and numbers of laser pulses. In the case of hybrid ablation, both the depth and volume ablation rates were increased significantly in comparison to pure laser ablation. This effect is described by a linear interrelationship of both the ablation rate and the particularly applied laser energy and is thus due to energetic synergies. Such behavior can be explained by the de-excitation of argon plasma species and an accompanying energy deposition at the generated debris and the sample surface. The energetic effect was found to abate with increasing ablation depth. However, considerable improvements in terms of ablation rate are achieved in the near-surface depth range of approx. 500 microns

We report on the first microsecond doubly resonant optical parametric oscillator (OPO). It is based on a nested cavity OPO architecture allowing single longitudinal mode operation and low oscillation threshold (few microjoule). The combination with a master oscillator-power amplifier fiber pump laser provides a versatile optical source widely tunable in the 3.3-3.5 μm range with an adjustable pulse repetition rate (from 40 to 100 kHz), high duty cycle (~10(-2)) and mean power (up to 25 mW in the idler beam). The potential for trace gas sensing applications is demonstrated through photoacoustic detection of atmospheric methane.

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We report experimental results on M-lines characterization of GaSb refractive index as a function of doping level and lattice mismatch in the range of 2.15–7.35 μm with an accuracy of 10−3. We apply the same procedure to quaternary AlxGa1−xAsSb alloys lattice-matched to GaSb to study the refractive index evolution with aluminum fraction and with wavelength. We compare our measurements to theory, and we establish new parameter values for the dispersion law of GaSb. These parameters are confirmed by the excellent agreement between the calculated curves and experimental measurements performed on quaternary alloys. Using these values of optical indices, we design a GaSb/AlGaAsSb ridge waveguide and characterize the losses using the Fabry-Perot method at 2 μm. Very low losses are demonstrated in the range of 1 dB/cm and below in a single mode waveguide structure.

This paper reports the main achievements in the development of photonic RF payload solutions for telecommunication satellites based on a multiple-frequency conversion scheme. Representative models of photonic payload equipment, including photonic frequency generation assembly and frequency-converters, have been integrated and proven in a system environment. The end-to-end RF performance for various configurations and frequency plans were tested at ambient temperature. The test plan includes forward and return repeater configurations, with photonic frequency down-conversion from 30 to 20 GHz with up to 6-local oscillators in the case of a Ka-band multi-beam broadband mission. In addition, thermal tests were run over the [-5°C, +65°C] temperature range. The end-to-end RF performances of the photonic repeater demonstrator were assessed in detail experimentally and compared to theoretical predictions. These results are a major step towards new payload solution with enhanced capacity and in-orbit re-configurability.

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