A new tutorial with yambo_nl on pump and probe spectroscopy is available on the wiki: Pump & Probe .  This tutorial explains how to calculate pump&probe response without de-phasing or radiative lifetime effects. This kind of calculations can be useful to estimated exciton-exciton transitions and they can be compared with transient absorption/transmission.

Here the tutorial: Pump and Probe
and the reference paper: Exciton-Exciton transitions involving strongly bound Frenkel excitons: an ab-initioapproach