Fabrice Leardini

With the purpose of obtaining synthetic materials from other natural sources for industrial and technological applications, a thermal alteration study was carried out with commercial vermiculites of different purity and origin. For this objective, samples were subjected to 1000 °C in a furnace both at ambient and reduced (N2/Ar) atmospheres. The thermal behavior and physicochemical properties of the different vermiculites were investigated by X-ray diffraction (XRD), thermal analysis (TG and DTG), and scanning electron microscopy (SEM), and their textural parameters were analyzed by BET treatment. The transformations undergone by the investigated commercial vermiculites subjected to heating treatments caused textural and structural changes in them. There was a decrease in the specific surface area, adsorption capacity, and pore volume values for the samples treated with in situ heating at 1000 °C, both at ambient and reduced atmospheres, and the samples were treated with ex situ abrupt heating at 1000 °C at ambient conditions. There was a decrease in the specific surface area, adsorption capacity, and pore volume values for the samples treated with in situ heating at 1000 °C, both in ambient and reduced atmospheres, which was not observed in the samples treated with an ex situ abrupt heating at 1000 °C at ambient conditions. This corroborated with our findings that the expansion in the first type of thermal treatment produced less separation of the exfoliation sheets than the expansion in the second type of thermal treatment. These textural changes, together with the structural ones, could play a fundamental role in the choice of industrial and technological applications for which these materials could be used.

The current need for coherent light sources for integrated (nano)photonics motivates the search for novel laser designs emitting at technologically relevant wavelengths with high‐frequency stability and low power consumption. Here, a new monolithic architecture that integrates monolayer MoS 2 and chains of silver nanoparticles on a rare‐earth (Nd 3+ ) doped LiNbO 3 platform is developed to demonstrate Q‐switched lasing operation at the nanoscale. The localized surface plasmons provided by the nanoparticle chains spatially confine the gain generated by Nd 3+ ions at subwavelength scales, and large‐area monolayer MoS 2 acts as saturable absorber. As a result, an ultra‐compact coherent pulsed light source delivering stable train pulses with repetition rates of hundreds of kHz and pulse duration of 1 µs is demonstrated without the need of any voltage‐driven optical modulation. Moreover, the monolithic integration of the different elements is achieved without sophisticated processing, and it is compatible with LiNbO 3 ‐based photonics. The results highlight the robustness of the approach, which can be extended to other 2D materials and solid‐state gain media. Potential applications in communications, quantum computing, or ultra‐sensitive sensing can benefit from the synergy of the materials involved in this approach, which provides a wealth of opportunities for light control at reduced scales.