We have a new publication online now: multiwatts narrow linewidth fiber Raman amplifiers. Basically, the paper shows fiber Raman amplifier can be used to amplify narrow linewidth laser to a useful power level, while linewidth keeping narrow. This would be a surprise to most laser researchers. In this specific report, we have obtained 4.8 W, ~10MHz 1178nm laser with 27dB gain and more than 10% efficiency. The tricks and reason are explained in the paper.
We obtained 1.1 W 589nm orange laser yesterday by an approach of fiber Raman amplifier and external frequency doubling. It is only a brief test, so we are rather confidence to scale the power to over 2W in next tryments. The laser is linear polarized and the linewidth is below 2GHz, which is good for laser guide star application. Compared to what I had done one and half years ago, it is a big improvement.
1 W level compact orange laser has big market already. We are thinking of the potential to scale up to >10W. The only obstacle seems to be the nonlinear crystal.
19/08/05 update: I was too optimistic. We could get up to 1.6W only. Many problem with the crystals.
23/08/05 update: We get 2.9W now, with efficiency ~23%.