IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

InSAR monitoring using RADARSAT-2 data at Piton de la Fournaise (La Reunion) and Karthala (Grande Comore) volcanoes

Abstract: Piton de la Fournaise (La Reunion) and Karthala (Grande Comore) are the two active volcanoes of the Southwestern Indian Ocean. A 14 month (April 2013 to June 2014) monitoring period was carried out at both volcanoes using synthetic aperture RADAR interferometry (InSAR) techniques on RADARSAT-2 data. Thanks to the SEAS-OI (Survey of Environment Assisted by Satellite in the Indian Ocean) station, 21 SAR scenes were acquired over this period and InSAR results revealed the slow subsidence of the Dolomieu caldera floor at Piton de la Fournaise, following the 2009 and 2010 eruptions, and the subsidence of the whole cone between April and July 2013. At Karthala no evidence of any volcanic activity was found for the period April 2013 to June 2014. The use of systematic InSAR for volcano monitoring is an efficient tool to study effusive eruptions. We showed that, during periods of unrest, InSAR is able to pick up early signs of a future eruption and monitor secondary phenomena that require no real-time data. During an effusive crisis, it is still difficult to carry out fully operational InSAR monitoring, but using the example of the June 2014 eruption at Piton de la Fournaise, we show that SAR data can help with the detection and tracking of lava flows and active flow paths during effusive eruptions, based on SAR coherence and SAR amplitude. These preliminary results are very promising for the future of InSAR monitoring of active volcanoes and highlight the need for near-real-time access to SAR data in the mapping of active lava flows during effusive eruptions. This study also revealed the major role of ground stations like SEAS-OI in the efficiency of this monitoring, supplying free, near-real-time remote sensing data to the scientific and institutional communities.

Ultra-short pulse mid-ir mode-locked laser

Abstract: A short-pulse mode-locked laser is configured with at least two reflective elements defining a resonant cavity therebetween, a laser gain element ("GE") placed inside the resonant cavity at normal incidence and selected from transition metal doped II- VI materials; and an optical pump emitting pulsed output to synchronously or quasi- synchronously pump the GE at a pulse repetition rate frequency f pUmp , the pump being configured so that the f pump substantially matches an inversed round trip time in the resonant cavity f laSer - f pump ~f laSer = c / 2L , where c is the speed of light, L is the length of the resonant cavity. The synchronous or quasi-synchronous pumping triggers and sustains a short-pulse emission of the laser with picosecond or femtosecond pulse durations.

3He/4He Ratio in Olivines from Linosa, Ustica, and Pantelleria Islands (Southern Italy)

Abstract: We report helium isotope data for 0.03–1 Ma olivine-bearing basaltic hawaiites from three volcanoes of the southern Italy magmatic province (Ustica, Pantelleria, and Linosa Islands). Homogenous 3He/4He ratios (range: 7.3–7.6 Ra) for the three islands, and their similarity with the ratio of modern volcanic gases on Pantelleria, indicate a common magmatic end-member. In particular, Ustica (7.6±0.2 Ra) clearly differs from the nearby Aeolian Islands Arc volcanism, despite its location on the Tyrrhenian side of the plate boundary. Although limited in size, our data set complements the large existing database for helium isotope in southern Italy and adds further constraints upon the spatial extent of intraplate alkaline volcanism in southern Mediterranea. As already discussed by others, the He-Pb isotopic signature of this magmatic province indicates a derivation from a mantle diapir of a OIB-type that is partially diluted by the depleted upper mantle (MORB mantle) at its periphery.