Temporal Behavior Of The Optical Stark Effects On The Stacking Fault Exciton States In BiI/sub 3/

On a characteristic exciton system, we present the time-resolved optical Stark effect (OSE) with high spectral resolution. In layered crystal BiI₃, several sharp absorption lines appear near the absorption edge. ¹⁾ The lines have been attributed to the excitons having quasi-two-dimensional nature at a stacking fault (called stacking fault excitons, SFE's). ²⁾ Figure 1(a) shows a typical absorption spectrum of BiI₃. The sharp lines R, S and T are due to three transitions of the SFE states. ³⁾ On this exciton system, large peak-shifts induced by the OSE appear under the excitation frequencies (ħω) of off- and on-resonance. The large dipole matrix element and the large nonlinear susceptibility of the SFE have been obtained. ⁴⁾