Experimental setup for two-color femtosecond pump-probe spectroscopy.
Time-resolved waveforms measured in GaN single crystals for pump-photon energies of (solid line), (dash-dot line), (dashed line), and (dotted line) (corresponding wavelengths are 267, 270, 277, and , respectively). The NIR probe wavelengths were, correspondingly, 801, 810, 831, and . (a) Actual collected transients, normalized to the trace obtained for the pump photons. (b) The transients from (a) independently normalized to their peak values. The inset in (a) shows the same transients, but presented in the long, -wide time window.
The amplitudes (a) of the waveforms shown in Fig. 2(a) and the rise times (b) of the waveforms shown in Fig. 2(b) vs the pump-photon energy. The representative error bar is shown for the data. The solid lines were obtained as the best step like function fits, but should be regarded mainly as guides to the eyes. The thin dashed lines indicate the value of the intervalley energy threshold.
Time evolution of the population. The dots are experimental data obtained by subtracting the trace from the trace, both shown in Fig. 2(a). The solid line is the numerical solution of our three-state rate equations [Eq. (5)] with and as fitting parameters.
Article metrics loading...
Full text loading...