Physics World special issue on the laser at 50

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May 2010 issue of Physics World marks the 50th anniversary of the invention of the laser, and can be freely downloaded.

This issue celebrates what has been one of the outstanding success stories in physics. We take a look at the laser’s huge impact on popular culture (think Goldfinger and laser-art shows) and on everyday life (DVDs, laser pointers, bar-code scanners). We also relive the race to build the world’s first working laser – a story still laced with controversy. Find out about the technological impact of lasers in fibre optics and at the quest for green-wavelength laser diodes that could let mobile phones project images onto any surface. Basic research gets a look-in, too – in terms of both ultrahigh power and ultrafast lasers. Don’t miss our special timeline of laser history and see what you think of our six experts’ predictions for where laser science will go next.


50 W CW 589nm laser

50W CW visible laser source at 589nm obtained via frequency doubling of three coherently combined narrow-band Raman fibre amplifiers

Luke R. Taylor, Yan Feng, and Domenico Bonaccini Calia

Optics Express, Vol. 18, Issue 8, pp. 8540-8555 (2010) doi:10.1364/OE.18.008540

Abstract: We demonstrate the cascaded coherent collinear combination of a seed-split triplet of 1178nm high-power narrow-band (sub-1.5MHz) SBS-suppressed CW Raman fibre amplifiers via nested free-space constructive quasi-Mach-Zehnder interferometry, after analysing the combination of the first two amplifiers in detail. Near-unity combination and cascaded-combination efficiencies are obtained at all power levels up to a maximum P1178 > 60W. Frequency doubling of this cascaded-combined output in an external resonant cavity yields P589 > 50W with peak conversion efficiency η589 ~85%. We observe no significant differences between the SHG of a single, combined pair or triplet of amplifiers. Although the system represents a successful power scalability demonstrator for fibre-based Na-D2a-tuned mesospheric laser-guide-star systems, we emphasise its inherent wavelength versatility and consider its spectroscopic and near-diffraction-limited qualities equally well suited to other applications.

This work was to demonstrate the scalability of the Raman fiber amplifier approach. As one can imagine, we had worked hard to break the published record power of 50 W by the Starfire people. 🙂