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Jared lab notebook: Difference between revisions
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I thoroughly checked the timings today. I checked the shape of each pulse by putting the photodiode at a distance from the fiber launch that was similar to the distance the laser would travel before reaching the FORT atoms. I averaged over many pulses on the O-Scope, saved the waveform, and then moved the photo diode to the next laser. I would align the pulse of this laser to the saved waveform. I then repeated this for the final laser in the EIT sequence. I had to repeat the entire setup for the second EIT pulse. In the end, I found that the timings were up to 5 ns off, but it doesn't look like this caused the asymmetry in features from switching the two coupling beams.
--[[User:Jmiles2|Jmiles2]] ([[User talk:Jmiles2|talk]]) 17:32, 11 September 2014 (CDT)
Fort Became unaligned after replacing the RF generators with the small NOVATECH instrument. A coupling beam was also misaligned, so I went through the alignment process for all the beams and also checked the spot sizes of the coupling beams. Beam sizes are about 1.24mm X 1.15mm.
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The asymmetry problem still occurs, and is very apparent depending on which beam's frequency I scan over. For a standing wave from 3 to 40 mW, scanning over the higher power coupling beam, around 16mW, causes a large slope in the standing wave data. The slope is also there if I turn the Lower power beam off, and use the high power coupling beam for two consecutive EIT pulses. If I scan over the weaker beam, I don't see this slope in the data.
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