Yb-doped tapered double-clad fibers with polarization maintenance for half-kW power amplifiers.

Amplifying short pulses directly within a single fiber laser system has proven to be a challenging task, primarily due to thermally induced transverse mode instabilities and detrimental nonlinear effects. Another demanding aspect is preserving the linear polarization state at high power levels, which is even more pronounced for ultra-large-mode area fibers. This study demonstrates significant advancement in the direct amplification of narrow linewidth short pulses from tens of mW to several hundreds of Watts in a single-stage amplification, maintaining a high degree of linear polarization at the maximum output power.

[HEALTH AND SATISFACTION WITH THE HEALTH CARE SYSTEM AS FACTORS IN THE QUALITY OF LIFE OF THE OLDER GENERATION OF METROPOLITAN RESIDENTS].

Unlabelled: In the context of an aging population in megacities, it is important to maintain the health and activity of older people, improving their quality of life. To do this, it is necessary to study the factors affecting longevity, including individual health characteristics and perception of the health system (accessibility, responsiveness, effectiveness, ageism).

The Purpose Of The Study: to identify an assessment of the quality of life of elderly Muscovites and the influence of factors related to health and the assessment of the health care system on it.

Topic models with elements of neural networks: investigation of stability, coherence, and determining the optimal number of topics.

Topic modeling is a widely used instrument for the analysis of large text collections. In the last few years, neural topic models and models with word embeddings have been proposed to increase the quality of topic solutions. However, these models were not extensively tested in terms of stability and interpretability.

Double-clad ytterbium-doped tapered fiber with circular birefringence as a gain medium for structured light.

Amplifying radially and azimuthally polarized beams is a significant challenge due to the instability of the complex beam shape and polarization in inhomogeneous environment. In this Letter, we demonstrated experimentally an efficient approach to directly amplify cylindrical-vector beams with axially symmetric polarization and doughnut-shaped intensity profile in a picosecond MOPA system based on a double-clad ytterbium-doped tapered fiber. To prevent polarization and beam shape distortion during amplification, for the first time to the best of our knowledge, we proposed using the spun architecture of the tapered fiber.