Measuring semiconductors two-photon absorption with a technique based on laser power variations

Based on the F-scan technique, in this work we proposed a technique that measures semiconductors’ two-photon absorption coefficients through laser power variations. The technique, dubbed P-scan, uses an electrically-focus tunable lens to retrieve light transmittance signals in the linear and nonlinear absorption regimes. With the rate of the transmittances, a linear function with a slope proportional to the two-photon absorption coefficient could be determined. To verify the technique’s feasibility, P-scan was implemented together with F-scan and Z-scan in the same optical setup. Furthermore, the three techniques were implemented under the same experimental parameters; it was demonstrated that the same value for the effective two-photon absorption coefficient was obtained within experimental uncertainty.