On the Doppler averaging of susceptibility in pump-probe laser spectroscopy

We present an analytical study of the Doppler averaging of the susceptibility in pump-probe laser spectroscopy in an atomic vapor in the Doppler limit. Approximate analytical solutions of the susceptibility were obtained in the Doppler limit for the case when the homogeneous susceptibility has two different resonances in the Maxwell–Boltzmann velocity distribution and the detunings of the laser frequencies are not much smaller than the Doppler linewidth. The results were then applied successfully to a simple example of pump-probe laser spectroscopy for two-level atoms.