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--[[User:Zjsimmons|Zjsimmons]] ([[User talk:Zjsimmons|talk]]) 14:22, 16 February 2015 (CST)
Last few days: Little progress, having trouble digesting the new information. We have been making progress but there is still so much we want to do. Did order some parts to hopefully build a laser with a larger mode-hop-free freq sweep and as a very simple NI DAQ to use to turn RF switches on and off.
Ideally we will have evidence of EIT before the end of the month. Also would love to have a wider absorption scan of the overall (inhomogeneously broadened) absorption feature showing things like a spectral hole and side/anti- holes.
'''Things to better understand:'''
*How much power should we use? I think we need to know this if we want to know how long of EIT pulses to use as well.
*Spectral hole width: this is determined by hole-burning power, i.e. more power=larger width, but what exactly is the relationship? Does this even matter that much when talking about pumping?
*Fraction pumped back: When looking at transmission, it appears that a lot of population can be pumped back into the hole. However, this is somewhat misleading because we may have enough optical depth at that laser power to absorb our laser many times over in the crystal adjacent to that spectral hole in freq. Presumably, if we were to turn up the laser power of the probe scan to the point that it would be not totally absorbed, we would see that absolute contribution of the population pumped back from the other hyperfine ground states. Thus far, when turning up the probe power somewhat (perhaps a x10 factor) we don't see much of an intelligible change. I would expect the overall amount pumped back to appear smaller. Perhaps we just don't have enough probe sweep power, to see the difference.
Alternatively, we should look at the fluorescence. This could give us an observation that doesn't have the relative background. Fluorescence should relate directly to how much is there. We will i think want to understand this better for collecting data for our upcoming EIT experiments anyway.
'''Things to build:'''
*ULE cavity.. this could really help with our laser drift..
*Wide sweep laser, this would be great but will be some work.
*Implement switches on RF sources so we can turn them on and off through a combination of the delay box and computer.
--[[User:Zjsimmons|Zjsimmons]] ([[User talk:Zjsimmons|talk]]) 17:47, 9 February 2015 (CST)
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