Figure 2

Sensitivity study of the normalized PIL signal by changing physical properties of the sample. The transient signals were calculated using the physical properties of ethanol (see Supplementary Table S1) and changing (a) the nonlinear refractive index (affecting only \(S_{\textrm{Kerr}}\)), (b) the piezo-optic coefficient (affecting both \(S_{\textrm{ESW}}\) and \(S_{\textrm{TEW}}\)), (c) the thermo-optic coefficient (affecting only \(S_{\textrm{TD}}\)), (d) the speed of sound (affecting both \(S_{\textrm{ESW}}\) and \(S_{\textrm{TEW}}\)), (e) the refractive index (affecting only \(S_{\textrm{ESW}}\)), and (f) the optical absorption coefficient (affecting both \(S_{\textrm{TEW}}\) and \(S_{\textrm{TD}}\)). Note that changing the specific heat has the same effect as changing the reciprocal value of the optical absorption coefficient. Additionally, the volumetric thermal expansion coefficient only affects \(S_{\textrm{TEW}}\), while the mass density directly affects \(S_{\textrm{TD}}\), but also \(S_{\textrm{ESW}}\) and \(S_{\textrm{TEW}}\) because the speed of sound depends on it.