Rick S, Michael R
Yesterday Rick found the PSL output power was about 20 W too low. Some AEI people suggested we increase the pump light to get back our power, so today we went inside to adjust the pump diode current and temperatures. We made the following current and temperature changes:
Temperature changes were applied to all the diodes in one box, we did not adjust individual diode temperatures.
When we were adjusting diode box temperatures, we expected to get more power as we moved the center of the pump light spectrum toward 807.5 nm. However, we found each box was optimized at a different wavelength:
The diode boxes are closer to 100% than before, but are still a few percent off. We could bring them back to 100% but the output power of the laser would drop, and we couldn't get the power back by adjusting temperature. DB3 in particular wouldn't cooperate, and is now at 95.7%. Another unusual thing about DB3 is the EPICs readout of the current on this box is 101 A. However, the power supply box in the diode room is reading the correct 50.9 A. The green bar on the Beckhoff screen displaying the diode current shows this 101 A as well, but the numerical value is still at 50.9 A. We're not sure why this is.