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.

System and method for cutting using a variable astigmatic focal beam spot

Abstract: A variable astigmatic focal beam spot is formed using lasers with an anamorphic beam delivery system. The variable astigmatic focal beam spot can be used for cutting applications, for example, to scribe semiconductor wafers such as light emitting diode (LED) wafers. The exemplary anamorphic beam delivery system comprises a series of optical components, which deliberately introduce astigmatism to produce focal points separated into two principal meridians, i.e. vertical and horizontal. The astigmatic focal points result in an asymmetric, yet sharply focused, beam spot that consists of sharpened leading and trailing edges. Adjusting the astigmatic focal points changes the aspect ratio of the compressed focal beam spot, allowing adjustment of energy density at the target without affecting laser output power. Scribing wafers with properly optimized energy and power density increases scribing speeds while minimizing excessive heating and collateral material damage.

Structure of the intermediate phase of PbTe at high pressure.

Abstract: The evolution of PbTe with pressure has been reexamined using synchrotron x-ray diffraction. The phase transition at 6 GPa is not to the GeS (B16) or TlI (B33) type structures, as previously reported, but to an orthorhombic Pnma structure, with cell parameters a=8.157(1), b=4.492(1), and c=6.294(1)A at 6.7 GPa. This structure corresponds to a distortion of the low-pressure NaCl structure with a coordination intermediate between the sixfold B1 (NaCl) and the eightfold B2 (CsCl) structure. We discuss the stability of this new structure with respect to other proposed phases using numerical methods. These results may modify the admitted paths of phase transitions between the B1 and B2 structures.

Progress in mid-IR Cr 2+ and Fe 2+ doped II-VI materials and lasers [Invited]

Abstract: Recent progress in fabrication and mid-IR lasing of transition metal doped II-VI single crystal and thermo-diffusion doped polycrystalline and hot-pressed ceramic gain media as well as nano and micro-crystalline laser active powders, powders in the liquid suspension, polymer-film, thin film waveguides and chalcogenides glass composites is reported.