  The present study focuses on the application of a picosecond (ps) TALIF
technique in krypton (Kr) at variable pressure (0.1-10 mbar). The laser
intensity (I, units W.cm$^{-2}$) is tuned between 1 and 480 MW.cm$^{-2}$, and
the depletion of the density of the Kr 5p'[3/2]$_2$ fluorescing state through
photoionization (PIN) and amplified stimulated emission (ASE) is investigated.
This is done by combining TALIF experiments with a simple 0D numerical model.
We demonstrate that for a gas pressure of 3 mbar and 15 < $\le$ 480
MW.cm$^{-2}$, a saturated fluorescence signal is obtained, which is largely
attributed to PIN, ASE being negligible. Also, a broadening of the two-photon
absorption line (i.e. 4p$^6$ $^1$S0$\to$5p'[3/2]$_2$) is recorded due to the
production of charged species through PIN, inducing a Stark effect. For
I$\le$15 MW.cm$^{-2}$, though, PIN is significantly limited, the absorption
line is noticeably narrowed, and the quadratic dependence of the TALIF signal
intensity versus the laser energy is obtained. Thus, in this case, the
investigated Kr TALIF scheme, using the 5p'[3/2]$_2\to$5s[3/2]$_1$ fluorescence
channel, can be used for calibration purposes in ps-TALIF experiments. These
results are of interest for fundamental research since most ps-TALIF studies
performed in Kr do not investigate in detail the role of PIN and ASE on the
depletion of the Kr 5p'[3/2]$_2$ state density. Moreover, this work contributes
to the development of ps-TALIF for determining absolute densities and quenching
coefficients of H and N atoms in plasmas. This is useful in numerous
plasma-based applications (e.g. thin film synthesis, biomedical treatments,
plasma-assisted combustion, ...), for which the knowledge of the
density/kinetics of reactive atoms is essential.
