In this proposal (continuation of experiment MA-5167 at ESRF), we aim to quantify the absolute value of the in-plane and out-of-plane lattice parameters of a piezo- plate, and the attached MoO3 crystal, in order to obtain absolute strain values. Both developing practical strategies to introduce controlled strain fields in nanomaterials to reversibly vary their crystalline structure and a precise quantification of the strain field in terms of magnitude and anisotropy are fundamental for tailoring the polaritons' propagation properties in the nanomaterial. Now, we aim to quantify the absolute value of the in-plane and out-of-plane lattice parameters of the piezo-plate, and the attached MoO3 crystal (we will use the "rainbow" technique). Based on these results, the obtained strain field will be used as an input parameter to simulate the optical response of the material.