Frequency Axis Calibration Using a Lone Spectral Feature

By synchronizing an oscilloscope's data collection timing with a laser's frequency scan, spectral features are collected in time. Yet, to use the spectral data it is often necesary to transition the oscilloscope's time axis to units of frequency. It is common practice to record two spectral features of known frequency separation and scale the axis according to that separation. However, this calibration method fails when there exists only one spectral feature in a given oscilloscope trace. In this work, we apply Autler-Townes (AT) splitting of an electromagnetically induced transparency (EIT) feature to calibrate an oscilloscope trace using a single EIT feature. We demonstrate that the frequency separation of the AT-split features can be deduced by varying both the power and detuning of the field used to induce AT-splitting.