Pulsed photothermal radiometry is used to map the heat deposition in human skin after a short laser pulse. It uses an IR (HgCdTe) dectector for a rapid noncontact measurement of the skin surface temperature based on the blackbody emission in the 8-12 µ m spectrum. The heat deposited by the laser pulse in the superficial epidermis causes an immediate temperature jump, and the heat deposited in basal epidermal melanin and deep port wine stains diffuses to the surface before detection. The time course of the surface temperature T(z=0,t) , indicates the initial spatial distribution of heat, T(z,t=0) , deposited by the laser.
S. L. Jacques, J. S. Nelson, W. H. Wright, T. E. Milner, "Pulsed photothermal radiometry of port-wine-stain lesions," Appl. Opt.,32, 2439-2446 (1993).