Since bulk sample from LMA are rectangular, we needed a rectangular mount. We ordered the parts to be assembled and, after some trouble with metric and imperial lengths and screw threads, we succeded attach the magnets at the mount properly. (See Figure1 and Figure2 )

The sample of suprasil312 has a thickness of 20mm and a nominal absorption of 1.5-1.6ppm/cm.

I used the maximum power available setting the LD current at 7.5A. The measured power at the end of the pump path is 9.3W. I used the calibration factor R = 0.51 1/W  which was measured on the high absorbing reference sample.

The scan along the z axis shows that the  first surface is not absorbing but the second surface gives a big signal (600ppm). See Figure3 and Figure4.

Figure5 is a zoom of figure4 and it show the absorption inside the bulk (between 2 and 15mm) which has a value of 4ppm, while the noise outside the bulk is about 1ppm. This means that the measured absorption is 3ppm. About the double of the nominal value.