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.

Highly efficient, narrow-linewidth, and single-frequency actively and passively Q-switched fiber-bulk hybrid Er:YAG lasers operating at 1645 nm.

Abstract: High power, highly efficient single frequency oscillation of Er:YAG fiber-bulk hybrid laser at 1645 nm is demonstrated in actively and passively Q-switched operation modes. The slope efficiencies in the active and passive Q-switched operation reached 75% and 20%, respectively, with the record output powers in the narrow-linewidth and single longitudinal mode regimes of operation.

Method and device for controlling optical output of laser diode

Abstract: A method of controlling an optical output of a laser diode includes applying a bipolar current pulse to the laser diode, thereby substantially suppressing the emission tail of the optical output of the laser diode. A device for generating sub-nanosecond intense optical pulses includes a driver unit operative to generate a plurality of bipolar current pulses, and a semiconductor laser diode driven by the bipolar current pulses and operative to emit the intense optical pulses each of which has a substantially suppressed or completely eliminated emission tail.

Implementation of sub-nanoseconds TDC in FPGA: applications to time-of-flight analysis in muon radiography

Abstract: Time-of-flight (tof) techniques are standard techniques in high energy physics to determine particles propagation directions. Since particles velocities are generally close to c, the speed of light, and detectors typical dimensions at the meter level, the state-of-the-art tof techniques should reach sub-nanosecond timing resolution. Among the various techniques already available, the recently developed ring oscillator TDC ones, implemented in low cost FPGA, feature a very interesting figure of merit since a very good timing performance may be achieved with limited processing ressources. This issue is relevant for applications where unmanned sensors should have the lowest possible power consumption. Actually this article describes in details the application of this kind of tof technique to muon tomography of geological bodies. Muon tomography aims at measuring density variations and absolute densities through the detection of atmospheric muons flux's attenuation, due to the presence of matter. When the measured fluxes become very low, an identified source of noise comes from backwards propagating particles hitting the detector in a direction pointing to the geological body. The separation between through-going and backward-going particles, on the basis of the tof information is therefore a key parameter for the tomography analysis and subsequent previsions.

New K-Ar ages from La Montagne massif, Réunion Island (Indian Ocean), supporting two geomagnetic events in the time period 2.2–2.0 Ma

Abstract: We present new radiometric ages obtained at the type locality in La Reunion Island where palaeomagnetic records of the Reunion events have first been identified. Seven dated lava flows from the Riviere Saint Denis section, which recorded a reverse-to-normal transition, display ages from 2.12 ± 0.03 to 2.17 ± 0.03 Ma, with a mean age of 2.15 ± 0.02 Ma. Two significantly younger flows from this section, interpreted here as valley fill flows from trace elements compositions and Pb isotopic data, have been dated at 2.06 ± 0.03 and 2.08 ± 0.03 Ma. Within the Grande Chaloupe section, where a normal-to-reverse transition is recorded, two coherent ages of 2.05 ± 0.03 and 2.03 ± 0.03 Ma have been obtained. When a direct comparison was possible, our new K-Ar ages performed on separated groundmass show a rather good coherence with previous ages from La Reunion Island. When considered with continuous palaeomagnetic sedimentary records in the 2.2-2.0 Ma interval, these new results suggest that two distinct events are recorded in La Montagne lava flows at La Reunion Island, with ages of 2.15 ± 0.02 and 2.04 ± 0.02 Ma. Following recent nomenclature, the former is the Reunion event s.s., while the latter can be related to the Huckleberry Ridge event. Globally distributed volcanic and sedimentary records show that the first (Reunion s.s.; RU-1) is associated with a large dipole intensity decrease at 2.15 ± 0.02 Ma, and hence is recorded in many sequences. On the other hand, the dipole intensity decrease was not as pronounced at 2.04 ± 0.02 Ma, when the Huckleberry Ridge (RU-2) palaeomagnetic event occurred. Consequently, it is not present as a full directional change in many sections worldwide, but rather appears as a geomagnetic excursion during an episode of increased secular variation. Finally, the use of the Reunion event for magnetostratigraphic studies is recommended, while the clear identification of the Huckleberry Ridge excursion might often be difficult, preventing its use as a reliable time marker.