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We present a thorough investigation of surface deformation and thermal properties of high-damage threshold large-area semiconductor saturable absorber mirrors (SESAMs) designed for kilowatt average power laser oscillators. We compare temperature rise, thermal lensing, and surface deformation of standard SESAM samples and substrate-removed SESAMs contacted using different techniques. We demonstrate that for all cases the thermal effects scale linearly with the absorbed power, but the contacting technique critically affects the strength of the temperature rise and the thermal lens of the SESAMs (i.e. the slope of the linear change). Our best SESAMs are fabricated using a novel substrate-transfer direct bonding technique and show excellent surface flatness (with non-measureable radii of curvature (ROC), compared to astigmatic ROCs of up to 10 m for standard SESAMs), order-of-magnitude improved heat removal, and negligible deformation with absorbed power. This is achieved without altering the saturation behavior or the recovery parameters of the samples. These SESAMs will be a key enabling component for the next generation of kilowatt-level ultrafast oscillators.

The definition of "ecosystem engineers" has deeply influenced our assessment of the role of organisms in ecosystem functioning (Jones et al. 1994). Ecosystem engineers are organisms that directly or indirectly modulate the availability of resources to other species, by causing physical state changes in biotic or abiotic materials (Jones et al., 1994, 1997). They are primarily physical engineers, building resistant soil aggregates and pores. In that way, ecosystem engineers plays a key role in the formation of soil structure, providing an important contribution to the soil physical quality. In fact soil structure affects the soil ability to sustain animal and plant life necessary to maintaining agricultural productivity and environmental quality. Lavelle (2002) deduced that in soil the relative importance of regulation imposed by ecosystem engineering is likely to be greater than regulation by trophic relationships, because of the specific ecological constraints observed in this environment when compared to above-ground conditions. Some organisms are no longer considered to play a role only as elements of a food web, but they are studied from the viewpoint of being responsible for altering ecosystem dynamics through the modification, maintenance and/or creation of habitats for other organisms in the ecosystem. Earthworms are well known ecosystem engineers, however other species of macrofauna contribute to change the soil pore system by means of their burrowing activities. The X-ray tomography is a technique increasingly used to obtain non-destructive analysis of the pore netwoks produced by earthworms (Pagenkemper et al., 2015; Whalen et al., 2015; Capowiez et al., 2014, 2015; Auclerc et al., 2013). In this work it was developed an experimental approach based on the use of repacked soil mesocosms prepared in order to identify and quantify the contribution of different taxa of macrofauna to soil structure changes. At the end of the incubation period in the field or in the laboratory mesocosms were subjected to X-ray tomography. The resulting images were processed in order to obtain three-dimensional reconstructions and analysis of the identified biopores. Here are shown preliminary results about 5 mesocosms regarding 6 different species, both adult and larvae individuals.