Figure 5
Measurement of the cavity transmission linewidth.
Frequency scan of the cavity assembly transmission signal (red) and error-signal (blue) from a 133Cs D2-line saturated absorption spectroscopy. The spacings between the zero crossings of the 
spectroscopy signal serve as absolute frequency marker for calibration. From this the measured cavity linewidth calculates to 
 MHz (FWHM). The signal amplitude in Volt is proportional to the photocurrent of the polarimeter.
