Nonprofit research institute Laser Zentrum Hannover e.V. (LZH) is working on three subprojects in the research priority, Hybrid Numerical Optics, of the Hannover Centre for Optical Technologies (HOT) at Gottfried Wilhelm Leibniz University Hannover. The priority is being supported by the initiative Niedersächsisches Vorab, which provides about €1 million in funding until the fall of 2018. Working in a new competence center for optical simulation, the LZH will address subprojects in the areas of high-power glass fiber amplifiers, dielectric coatings and light propagation in fluid columns. In the subproject “Dynamic light propagation in high-output glass fiber amplifiers,” LZH scientists will work to increase the laser power of continuous and pulsed systems for the next three years. Presently the maximum usable output power of high power fiber systems is limited by the transverse mode instability (TMI), at which point the laser beam profile begins to fluctuate above a certain output threshold. With a simulation model, LZH wants to more closely examine the interactions and processes in the fiber amplifier and thus better understand TMI. The researchers said they plan to examine another peak power-dependent phenomenon: the effects of Kerr nonlinearity on the pulse propagation in fused fiber couplers. In the subproject “Structural and optical properties of dielectric coatings,” LZH researchers will combine different simulation techniques in order to optimize coating processes in order to understand how the coating properties and damage behavior is influenced by coating parameters. They are combining classical growth models with quantum-mechanical simulation techniques to determine the structural, optical and electronic properties of the coating structures produced. In the subproject “Simulation of the light-guiding properties in coaxially flowing fluid pairs using wave-optical light propagation in fluid-dynamically and thermally superimposed refractive index distributions,” the researchers will simulate beam guidance in flowing liquids to predict light propagation in fluid or gaseous light waveguides using a hybrid approach. In the subproject “Simulation of the light-guiding properties in coaxially flowing fluid pairs using wave-optical light propagation in fluid-dynamically and thermally superimposed refractive index distributions,” a laser beam (green) will be coupled into a liquid column with a core fluid (red) and a jacket fluid (blue). Courtesy of LZH. To this end, the researchers said they will simulate a flowing liquid column using a two-fluid system and will also investigate the propagation of light in the liquid column; connecting both methods is the main goal of this subproject. A liquid-guided laser beam can be used, for example, for laser materials processing. Founded in 1986 and currently employing over 170 individuals as an independent, nonprofit R&D and consulting organization, LZH is focused on the fields of optical components and systems, optical production technologies, and biomedical photonics.