Semiconductor non-linear absorption coefficients measured by optical pump with THz probe

Summary form only given. An optical pump, THz probe method is used to determine nonlinear absorption coefficients at 800 nm and 1300 nm for the semiconductors GaAs, InP, ZnSe and ZnTe. Using InP as an example, first linearly absorbed 800 nm pump light is used to determine the THz extinction cross-section per electron-hole pair. This cross-section is used to compute the free carrier density vs. 1300 nm fluence from the THz transmittance data for photon 1300 nm pump. The two photon absorption coefficient for InP at 1300 nm can then be calculated.