Figure 1

(a) EIT scheme in a cascaded three-level system. (b) Band structure of a GaAs QW along with the optical selection rules. (c) Schematic of energy eigenstates for the ground, one-exciton, and two-exciton states. Included are only the $1s$-exciton states and the corresponding lowest biexciton as well as the two-exciton continuum states. (d) Absorption spectra of a probe in the absence (solid lines) and presence (dashed lines) of a pump that was resonant with the hh exciton and had an energy flux of $40\mathrm{n}\mathrm{J}/{\mathrm{c}\mathrm{m}}^2$. The probe had the opposite circular polarization of the pump and was delayed 10 ps with respect to the pump.Reuse & Permissions

Figure 2

Absorption spectra measured with the probe pulse in the absence (solid lines) and presence (dot-dashed lines) of the control pulse, with the probe and control having opposite circular polarization. The shaded area shows the spectrum of the control pulse. The arrow indicates the position of the biexciton resonance from Fig. 1d. The energy flux of the control pulse is indicated in the figure, with $I_0=400\mathrm{n}\mathrm{J}/{\mathrm{c}\mathrm{m}}^2$ (corresponding to a peak intensity of order $100\mathrm{k}\mathrm{W}/{\mathrm{c}\mathrm{m}}^2$). For (a) and (b), the probe pulse arrives 1 ps before the peak of the control pulse. For (c), the probe pulse arrives 10 ps after the peak of the control pulse. Results of the full microscopic many-particle theory are shown as dotted lines.Reuse & Permissions

Figure 3

Probe absorption spectra in the absence (solid line) and presence (dashed line) of a control obtained from the cascaded three-level model. The control and probe durations are $10{\gamma }^{-1}$ and $0.1{\gamma }^{-1}$, respectively, with the probe arriving $1{\gamma }^{-1}$ before the control. The peak control intensity is indicated in the figure, with ${\Omega }_0^2=2{\gamma }^2$. The shaded area shows the control spectrum. The open and solid triangles mark the position of the nonrenormalized and renormalized (at the peak of the control pulse) resonance frequency for the exciton-to-biexciton transition, respectively. (a) Without biexciton energy renormalization, for ${\gamma }_b=0.1\gamma$ (deep EIT dip) and $10\gamma$ (no dip). (b),(c) With biexciton energy renormalization, with ${\gamma }_b=\gamma$ and $\beta =0.2{\gamma }^{-1}$, and for various control spectra and intensities.Reuse & Permissions