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.

High-volume manufacturing of 8XXnm-10XXnm single emitter pumps by MBE growth technique

Abstract: We report on GaAlInAs/GaAs lasers manufactured by the industry’s biggest production MBE tool. This MBE reactor allows for growth on 23 three-inch diameter wafers at a time, at a cost that compares favorably with the MOCVD method. Data on chip-on-submount performance and uniformity across the entire MBE-growth area are presented and compared to the quality of material produced by smaller size production MBE tools. We also present data on performance characteristics of spatially combined fiber coupled passively cooled single emitter-based pumps. The data include performance characteristics of devices operating at ~805nm and ~975nm wavelengths when driven in CW, QCW and pulsed modes; both pumps use ~105μm core diameter fiber to launch power confined within NA<0.15.

Laser welding tool with a fibre laser

Abstract: The laser welding tool comprises a linear drive (12) by which laser radiation is movable along a welding seam, where the laser is a fiber laser that comprises a fiber (8) for lighting wire, an optics for coupling the laser beam, a radiation source in the fiber, and a collimator (9) connected with the fiber for focusing the progression of the laser radiation. The collimator is arranged on the linear drive that enables a movement of the collimator along a predetermined movement line (13). The linear drive is arranged with the collimator in a housing having an outlet slit (17). The laser welding tool comprises a linear drive (12) by which laser radiation is movable along a welding seam, where the laser is a fiber laser that comprises a fiber (8) for lighting wire, an optics for coupling the laser beam, a radiation source in the fiber, and a collimator (9) connected with the fiber for focusing the progression of the laser radiation. The collimator is arranged on the linear drive that enables a movement of the collimator along a predetermined movement line (13). The linear drive is arranged with the collimator in a housing having an outlet slit (17) for the laser radiation. The movement line of the collimator passes parallel to the outlet slit and the collimator is aligned so that the laser radiation is escaped through the outlet slit from the housing. The fiber laser is activatable, when the outlet slit of the housing resets on one of the workpiece. The housing rejuvenates itself toward the outlet slit in funnel-shaped manner. The laser welding tool is arranged as welding tongs with a tong frame, a lower tool arranged on the tong frame, and a displacement unit moving the housing against the tong frame. A pressure piece exists itself at the free end of the lower tool. The pressure piece and the aligned outlet opening are movable by the processing unit. The pressure piece corresponds to the form of the outlet slit. The processing unit comprises a positioning drive held on the tong frame, a housing reception and/or a linear guidance for the housing reception. The linear drive comprises a linear sled for the collimator, where the linear sled is connected with a positioning drive. A switching element is arranged on the housing and activates an energy supply of the fiber laser on one of the workpiece during resting the outlet slit. The balancing module comprises a balancing base framework for mounting on the robot arm. A linear guidance is arranged for the tong frame with movement direction like the linear guidance on the balancing base framework. The balancing module comprises a short stroke linear drive acting on the tong frame, where the flux of the linear drive is turned to a spring pressure. A weaving generator is arranged between the collimator and the carrier element of the linear drive guiding along the pre-determined moving line.

Odd prime values of the Ramanujan tau function

Abstract: We study the odd prime values of the Ramanujan tau function, which form a thin set of large primes. To this end, we define LR(p,n):=τ(p n−1) and we show that the odd prime values are of the form LR(p,q) where p,q are odd primes. Then we exhibit arithmetical properties and congruences of the LR numbers using more general results on Lucas sequences. Finally, we propose estimations and discuss numerical results on pairs (p,q) for which LR(p,q) is prime.

Palaeosecular variation in Java and Bawean Islands (Indonesia) during the Brunhes chron

Abstract: SUMMARY A palaeomagnetic study has been conducted from Indonesian lava flows and dykes. Sampling was concentrated to the Merapi and Merbabu volcanoes (central Java), the Bromo‐Tengger volcanic complex, the Lurus volcano (both east of Java), and the Bawean Island. Numerical dating indicates that the rock units sampled have ages that are well distributed within the Brunhes chron. Only a few reverse polarity flows were probably emplaced during the late Matuyama chron. Alternating field (AF) and thermal demagnetization treatments were routinely used for all sites. Results from both methods were generally in good agreement, demonstrating the reliability and the reproducibility of the palaeomagnetic determinations obtained from 36 independent sites. The large dispersion of the directions and the age distribution indicate that a large spectrum of the secular variation has been sampled. Our best estimate of the mean Brunhes field direction in Java is characterized by a zero declination and an inclination anomaly of −4.7 ◦ (with a 95 per cent confidence angle of 5.3 ◦ ). This value agrees with an axial dipolar field model, or a model to which a persisting zonal quadrupolar term of a few per cent of the geocentric axial dipole is added. This study adds new constraints to recent results which suggested that a large zone of negative inclination anomalies may have persisted in the southwestern Pacific ocean over the past 500 Kyr, and possibly extended toward the eastern Indian ocean. The present results do not support such an extension. They also suggest that the inclination anomaly may have varied over 100 Kyr, and that it was more pronounced in recent times.