## 3 Results
### Tunable NIR Pump
The application of ablated tin nanoparticles as the media for harmonic generation at the fluence similar to the one used for the ignition of plasma in the case of the tin bulk target (F = 1.4 J cm\({}^{-2}\)) allowed for the increase of the conversion efficiency of a whole set of harmonics (Figure 4, middle panel). The harmonics were extended up to the 31 st order. However, no variations from the featureless plateau-like pattern of the envelope of the gradually decaying harmonic distribution were achieved in this case, except for some insignificant differences in the intensities of H29 and neighboring orders. This difference in the harmonic spectra produced from the plasmas ignited on the bulk Sn and Sn NP targets was attributed to an insufficient amount of ionized single-particle species in the latter case. Changing the ablation conditions of the Sn NP target can lead to the appearance of single-particle species and additional excited states of ions that can, to some extent, amplify the neighboring harmonics. Among different types of ablated substances, tin plasma can be considered as an interesting subject for study since it allows for the modification of the excitation of various autoionizing states, depending on the ablation conditions of the bulk target. The variations of target ablation conditions could allow for the analysis of the nonlinear response of such plasma by comparing the amplification of different harmonics, provided that they coincide or remain close to those autoionizing states responsible for harmonic enhancement. It is interesting to consider this process in the case of the ablation of the targets containing nanoparticles since the modification of their morphology or even the disintegration of NPs onto the small species and atoms can drastically change the distribution of harmonics in the region of interest, where strong ionic transitions can cause the enhancement of harmonics in the case of an atomic/ionic plasma medium. The fluence of heating 370 ps pulses was increased up to F = 2 J cm\({}^{-2}\) to produce a sufficient amount of Sn ions in the plasma ignited on the NP-containing surface. These conditions of ablation proved to be non-optimal for the efficient generation of harmonics. In this case, we observed the worsening of the phase-matching conditions, leading to a decrease in the conversion efficiency of the lower-order harmonics (bottom panel of Figure 4). The appearance of a large number of free electrons at stronger ablation caused the phase mismatch between the harmonic and driving waves, due to the growing group of velocity dispersion in such LIPs. In the meantime, we achieved the enhancement of a single harmonic and a few following harmonic orders in the area of strong ionic transitions of tin. H29, in this case, was notably stronger than any nearby lower-order harmonic, down to H19. Probably, at these conditions of nanoparticle ablation, they disintegrated in smaller nanoparticles, clusters, and single-atomic species, which can be presented in an ionic state, thus allowing the resonance-related enhancement of harmonics. To further analyze the observed process of the variation of harmonic distribution at different conditions of DP-LIP interactions, we performed the tuning of the driving NIR pulses in the case of two plasmas. The line-outs of Figure 5A demonstrate the harmonic spectra generated in the plasmas produced on the bulk tin and tin NP powder. The three upper panels show the HHG spectra in the plasma produced on the tin bulk target at optimal conditions of ablation when the maximal yield of harmonics was achieved. The upper panel was obtained in the case of the SCP (1355 nm) of the plasma produced on the bulk Sn. One can see the weakly enhanced harmonic (H29) lying far from the whole set of the observed lower-order harmonics. We also used the TCP (1355 nm and 678 nm) of plasma at a similar wavelength of NIR pulses. Again, as in the case of the SCP, H29 and two neighboring harmonics can be clearly distinguished in the 46-48 nm spectral range.