We have demonstrated a monolithic (fully fused), 1.2-kW, Yb-doped fiber laser with near-single-mode beam quality. This laser employs a new generation of high-brightness, fiber-coupled pump sources based on spatially multiplexed single emitters, with each pump providing 100 W at 915 nm within 0.15 NA from a standard 105/125 μm fiber. The fiber laser is end pumped through the high-reflector FBG using a 19:1 fused-fiber pump combiner, eliminating the need for pump/signal combiners. The output wavelength is 1080 nm, with a linewidth of < 0.5 nm FWHM. A peak power of 1.5 kW was reached in modulated operation (1-ms pulse duration) with M 2 < 1.2.
A single laser diode bar design, based on the AlGaAs material system, has been developed for high power, high reliability operation at a variety of CW and QCW operating conditions. The bar has a cavity length of 75Oim and a fill factor of 40%. Typical CW operation has a threshold current of -.1OA and a conversion efficiency of >45% at 40W. A variety of lifetests have been conducted at both CW and QCW operating conditions from the same bar design. On-going 3000hr CW operation at 45C and 40W shows an extrapolated median lifetime (20% current increase) of 16,500hrs at 45C or -50,000hrs at 25C (with 0.45eV activation energy). On-going 3000hr QCW operation at 60C/60W and 35C/100W, with a pulse width of 200is and a duty factor of 2%, shows a median lifetime of -10 billion shots and -5 billion shots, respectively. In addition to single bar operation, this bar design can be stacked in various 2-D configurations. A 4 bar linear stack operating at 160W CW and a 6 bar vertical stack operating at 240W CW have been developed with superior performance. Results for high duty and low duty QCW stacks will also be presented.
While the COVID-19 pandemic has disrupted every aspect of modern life, including medical education, the response has been remarkable. Ingenuity and innovation have flourished in the face of adversity. An international community of practice has blossomed in response to the challenges posed by COVID-19. Communication and sharing of information have been a hallmark of this community.In Australasia, the Medical Education Collaborative Committee hosted a series of meetings and webinars which enabled educators from all Australian and New Zealand medical schools to share experiences, solutions and resources. This group is auspiced by the Medical Deans Australia and New Zealand, which is the peak body representing professional entry-level medical education, training and research.One of these webinars focused on the student experience, featuring a panel of Australasian medical students drawn from a range of medical schools. The discussion during this session was wide reaching, including topics such as communication, co-designing curriculum changes, the importance of compassion, innovative practice, and meaningful student participation in placements. The ideas drawn from the panel discussion augmented by rich audience participation form the basis of the twelve tips presented in this paper. While derived from the experience in Australia and New Zealand, the authors believe these lessons are likely to be relevant in other jurisdictions.
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