Two- and three-photon absorption in chemical vapor deposition diamond

We report on the nonlinear optical properties (absorption and refraction) of monocrystalline chemical vapor deposition diamond studied by photoluminescence and Z-scan measurements. The studied spectral interval 2.8–6.2 eV can be divided into three regions in which the one-, two- and three-photon absorption (1PA, 2PA, 3PA) dominate. We obtained the values of 2PA and 3PA coefficients of diamond (α2=0.9 cm/GW at 4 eV and α3=2.3×10−4 cm3/GW2 at 3.1 eV) and of the nonlinear refractive index (8×10−7 cm2/GW at 2.9 eV) for several irradiation photon energies. We interpret the measured spectral dependence of nonlinear absorption coefficients in terms of direct and indirect multiphoton absorption.