Optical properties of dental enamel in the mid-IR determined by pulsed photothermal radiometry

Time-resolved thermal emission measurements were used to determine the abso rption coefficients of dental enamel at 9.6, 10.3, and 10.6 mu m. Time reso lved thermal emission from the enamel surface was modeled using numerical s imulations of heat conduction coupled with radiative heat transfer. Thermal emission was measured using HgCdZnTe detectors during IR laser irradiation with lambda = 9.6, 10.3 and 10.6 mu m CO2 laser pulses of 2-mu s duration. The method was verified in regions of low absorption for which absorption coefficients were available using direct transmission measurements. The abs orption coefficients were determined to be 8000, 1125, and 825 cm(-1) at 9. 6, 10.3, and 10.6 mu m, respectively, These results have important implicat ions in the development of CO2 lasers for the ablation and modification of dental hard tissue.