Figure 9: Experimental and theoretical intensity transients. (a) Lattice temperature derived from diffraction using (1) and (3), for different polarizations, along [ ] (blue dots) and [ ] (red dots), in optimally doped Bi2212. From the three-temperature model described in the text, we obtain that for //[ ] ( , red solid line) and for //[ ] ( , blue solid line). The electronic ( , dashed lines) and hot-phonon ( , solid lines) temperatures are also displayed. (b) Derivatives of the (00) diffraction intensity derived from Figure 2(a) for different polarizations. (c) Derivatives of the simulated lattice temperature within the three-temperature model, for different λ with a fixed anharmonic coupling time τ a = 2.8 ps (also shown in (b)) and for different τ a with a fixed λ = 0.26 (inset). The clear shift of the minimum position is only observed when λ is varied (black dotted lines). (d) Three-temperature model analysis for underdoped Bi2212. (e) Three-temperature model analysis for Bi2223.