RESUMEN
Beam steering at high speed and high power is demonstrated from a 6-element optical phased array using coherent beam combining (CBC) techniques. The steering speed, defined as the inverse of the time to required to sweep the beam across the steering range, is 40 MHz and the total power is 396 mW. The measured central lobe FWHM width is 565 µrad. High on-axis intensity is maintained periodically by phase-locking the array via a stochastic-parallel-gradient-descent (SPGD) algorithm. A master-oscillator-power-amplifier (MOPA) configuration is used where the amplifier array elements are semiconductor slab-coupled-optical-waveguide-amplifiers (SCOWAs). The beam steering is achieved by LiNbO(3) phase modulators; the phase-locking occurs by current adjustment of the SCOWAs. The system can be readily scaled to GHz steering speed and multiwatt-class output.
RESUMEN
We demonstrate 40 W coherently combined output power in a single diffraction-limited beam from a one-dimensional 47-element array of angled-facet slab-coupled optical waveguide amplifiers at 1064 nm. The output from each emitter was collimated and overlapped onto a diffractive optical element combiner using a common transform lens. Phase locking was achieved via active feedback on each amplifier's drive current to maximize the power in the combined beam. The combining efficiency at all current levels was nearly constant at 87%.
RESUMEN
We have demonstrated active coherent beam combination (CBC) of up to 218 semiconductor amplifiers with 38.5 W cw output using up to eleven one-dimensional 21-element individually addressable diode amplifier arrays operating at 960 nm. The amplifier array elements are slab-coupled-optical-waveguide semiconductor amplifiers (SCOWAs) set up in a master-oscillator-power-amplifier configuration. Diffractive optical elements divide the master-oscillator beam to seed multiple arrays of SCOWAs. A SCOWA was phase actuated by adjusting the drive current to each element and controlled using a stochastic-parallel-gradient-descent (SPGD) algorithm for the active CBC. The SPGD is a hill-climbing algorithm that maximizes on-axis intensity in the far field, providing phase locking without needing a reference beam.
RESUMEN
Many social workers go into private practice, providing crucial mental health services; however, there is a dearth in the scholarship outlining the social work student training for these career options. It may be argued that social work students receive little or no clinical training on how to run a private practice providing psychotherapy services. To mend this pedagogical shortcoming, a private practice field education placement is a legitimate teaching opportunity to prepare social work students to meet the mental health needs of individuals, families, and the public. Authors drew on borderlands theory described by Gloria Anzaldua as a contested space that focuses on "both and" thinking, which resonated with a sense of navigating a border filled with cultural tension between private practice and social work. Five social workers explore their unique experiences of a private practice field education placement using borderlands theory as a lens. Qualitative analysis of autoethnography narratives resulted in six themes: (1) benefits to private practice site, (2) preparation for social work, (3) private practice is social work, (4) balanced picture, (5) practicum landscape, and (6) learning opportunities. The article concludes with recommendations for social work education and research.