Zach Notebook
GitHub
Magnetic Response Verification (2016)
8/30
1.) This week Nick and I made boxes out of black poster board and black cloth around the AOMs and the photdiodes. The significantly cut down on light.
2.) The pickoff efficiency was determined to actually be 1.5%.
3.) Solved the rest of the calibration issues. The solutions were: have the right pickoff efficiency, keep careful track of which photodiode youre using and what its gain is, and make sure both pickoff reflections are hitting the photodiode.
4.) We tried increasing the power through the SHG cavity to try and do Rabi flopping. We had to change the SRS amplifiers from the low noise setting to the high bandwidth setting so that they would respond fast enough to see the flopping. However, there were significant power fluctuations in the lazer. We weren't able to see any flopping
8/23/2015
1.) Pickoff efficiency is 1%. This was determined by having two photodiodes on each side of the pickoff and comparing the voltage readouts. Both reflections were focused onto the photodiode with a lens.
2.) Blue Photodiode 1 reads out a voltage that is 89% that of Blue Photodiode 2. This was determined by using a 50/50 (really 52/48 determined with power meter) non-polarizing beam splitter and comparing the outputted voltages. This difference could not be fixed by using the bias voltage or input current offset settings on the SRS570 amplifier.
3.) We bought some black poster board this week to block scattered light. It works very well
Undated
1.) DAQ can have voltage offsets depending on grounding setup. Make sure this is checked for different setups.
2.) High SHG piezo voltages seem to output slightly less laser powers.
3.) RF 3 jumps in power output every 5 dBm (i.e. at 0.0 dBm, -5 dBm, 5 dBm...). RF 1 does not. They were originally switched (RF 3 was RF 1) but we switched them because of the jump in power from the current RF 3. They are both Rohde & Schwarz SIMQ 038.
4.) RF generator/AOM needs to warm up after being turned on. It also needs to readjust after changing the dBm when the dBm setting is high (i.e. changing from 3 dBm to 5 dBm).