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.

Preavalanche instabilities in a granular pile.

Abstract: We investigate numerically the transition between static equilibrium and dynamic surface flow of a 2D cohesionless granular system driven by a continuous gravity loading. This transition is characterized by intermittent local dynamic rearrangements and can be described by an order parameter defined as the density of critical contacts, i.e., contacts where the friction is fully mobilized. Analysis of the spatial correlations of critical contacts shows the occurrence of "fluidized" clusters which exhibit a power-law divergence in size at the approach of the stability limit. The results are compatible with recent models that describe the granular system during the static/dynamic transition as a multiphase system.

415W Single-Mode CW Thulium Fiber Laser in all-fiber format

Abstract: High power Tm lasers at 2um region is a great source of interest for many application including optical pumping of hybrid (fiber-solid state) lasers, bio-medical, remote sensing and plastic welding. Cladding-pumped single-mode Tm-doped fiber lasers demonstrate significant advantages over solid state Tm lasers. Over last several years multiple groups [1,2] using different techniques demonstrated power scaling of fiber bas ed Tm laser to above 100W level. In this paper, we report a development of a single mode all-fiber format Tm fiber laser with M -value of < =1.1, emission linewidth of <1 nm at 1940nm and output power exceeding 400W CW. This is a highest CW output power for a single-mode Tm fiber laser reported up to date.

Rediscovering ancient glass technologies through the examination of opacifier crystals

Abstract: The aim of the study is to understand how antimonate opacifying crystals were obtained throughout history. Two archaeological glass productions opacified with calcium and lead antimonates are studied in this paper, in order to rediscover ancient opaque glass technologies: Roman mosaic tesserae (1st cent. B.C.–4th cent. A.D.) and Nevers lampworking glass (18th cent. A.D.). The fine examination of crystalline phases and of the vitreous matrix is undertaken using various and complementary techniques. Results are compared with a modern reference production, for which the technological process is well known. We demonstrate that Ca-antimonate opacifiers in Roman mosaic tesserae, as well as in Nevers lampworking glass, were obtained by in situ crystallization. Nevertheless, Roman and Nevers glass would have undergone different firing processes. We propose that the addition of previously synthesized crystals or the use of “anime” could be the process used to obtain Pb-antimonate opacified glass, for both productions studied. We demonstrate that CaO, PbO and Sb2O3 concentrations in the bulk compositions and in the matrices, and their evolution with the crystallinity ratio, offer robust criteria for the distinction of the opacification process used. Also, the different crystalline structures help to provide information on the experimental conditions.