Rapid thermal equilibration of differentially heated protein and water in bovine corneal stroma

We measure and simulate the thermal response of bovine corneal stroma to a picosecond IR heating pulse. A thermal diffusion model is developed for this tissue based on the spatial distribution and properties of protein and water constituents in the stroma. In this idealized model, differentially heated protein and water constituents thermally equilibrate with a thermalization time of 515 ps. Using transient absorption spectroscopy for picosecond protein thermometry, a significantly faster thermalization time of 165 ps is measured. The implications of this faster than expected thermalization for the energy-partition model of short-pulse mid-IR tissue ablation are discussed.