deletions | additions       diff --git a/A_laser_contains_two_types__.tex b/A_laser_contains_two_types__.tex  index 484dd9d..3460031 100644  --- a/A_laser_contains_two_types__.tex  +++ b/A_laser_contains_two_types__.tex 
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A laser contains two types of polarized light—s-polarized and p-polarized. Therefore, we can use a half wave plate (not shown) to adjust the ratio of s-polarized and p-polarized light in the beam, and then use a polarizing beam splitter (PBS) to split the beam into two, differently polarized beams of adjustable intensity.   We sent our beam through a polarizing beam splitting, adjusting the polarization so that the s-polarized light, scattered from the PBS, was much stronger that the p-polarized light, which passes through the PBS. We used the s-polarized beam as our stronger pump beam with a power of 0.72 mW, and the p-polarized beam as our weaker probe beam at 66 μW. With our setup, that means that the photodiode is detecting the weaker probe beam. The photodiode was then attached to the oscilloscope. The oscilloscope has a gain of 1,000,000. This is too much gain for the Doppler spectroscopy experiment where the incident laser beam had a power of 1 mW and saturated the oscilloscope voltage. With only 66 μW of incident power, this large gain factor gave us a maximum voltage output of ~200 mV. $~200 mV$.  The absorption curve for saturation absorption spectroscopy is a convolution between a Gaussian and a Lorentzian, with Lorentzian peaks where the probe beam is not absorbed. When we examined our data, we found that we could see evidence of hyperfine structure, but because of the oscilloscope, the amplification of our signal was not large enough for good resolution of the hyperfine structure