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diff --git a/two-photon-interference.tex b/two-photon-interference.tex index 7b15de3..85b1f30 100644 --- a/two-photon-interference.tex +++ b/two-photon-interference.tex @@ -205,7 +205,12 @@ Do your observation confirm or contradict wave theory? \end{itemize} -Once you have performed these spot-checks, and have understood the motivation for them and the obtained results, you are ready to conduct systematic measurements of intensity distribution (the photodiode voltage-output signal) as a function of detector slit position. You will make such measurements in two slit-blocker positions: when both slits are open, and when only one slit is open. You will need to take enough data points to reproduce the intensity distribution in each case. Taking points systematically every 0.05 or \unit[0.1]{mm} on the tick lines will produce a very high quality dataset. One person should turn the dial and the other should record readings directly to paper or a spreadsheet (if you do this, print it out and tape into your logbook). Estimate your uncertainties from the dial and the voltmeter. Cycle through multiple maxima and minima on both sides of the central maximum. It is a good idea to plot the data points immediately along with the data taking -- nothing beats an emerging graph for teaching you what is going on, and your graph will be pretty impressive. \emph{Note: due to large number of points you don't need to include the tables with these measurements in the lab report -- the plotted distributions should be sufficient. Be clear on your uncertainties though.} +Once you have performed these spot-checks, and have understood the +motivation for them and the obtained results, you are ready to conduct +systematic measurements of intensity distribution (the photodiode +voltage-output signal) as a function of detector slit position. You will +make such {\bf measurements in two slit-blocker positions: when both slits +are open, and when only one slit is open}. You will need to take enough data points to reproduce the intensity distribution in each case. Taking points systematically every 0.05 or \unit[0.1]{mm} on the tick lines will produce a very high quality dataset. One person should turn the dial and the other should record readings directly to paper or a spreadsheet (if you do this, print it out and tape into your logbook). Estimate your uncertainties from the dial and the voltmeter. Cycle through multiple maxima and minima on both sides of the central maximum. It is a good idea to plot the data points immediately along with the data taking -- nothing beats an emerging graph for teaching you what is going on, and your graph will be pretty impressive. \emph{Note: due to large number of points you don't need to include the tables with these measurements in the lab report -- the plotted distributions should be sufficient. Be clear on your uncertainties though.} \textbf{Slit separation calculations}: Once you have enough data points for each graph to clearly see the interference pattern, use your data to extract the information about the distance between two slits $d$. To do @@ -250,7 +255,7 @@ convenient count rate ($10^3 - 10^4$ events/second) at the central maximum. %(much lower) 'dark rate' also rising with PMT bias. Based on your graph choose the PMT bias setting at which %you are counting substantially all true photon events, but minimizing the number of ``dark events''. -\textbf{Single-photon detection of the interference pattern} Most likely the experimental results in the +\textbf{Single-photon detection of the interference pattern}. Most likely the experimental results in the previous section has demonstrated good agreement with the wave description of light. However, the PMT detects individual photons, so one can expect that now one has to describe the light beam as a stream of particles, and the wave theory is not valid anymore. To check this assumption, you will repeat the measurements and take the |