Figure 1

(a) Energy level diagram of the $D^{0}X$ and $D^0$ states at $0\mathrm{T}$. In PLE experiments we probe the excited state populations via the two-electron satellite transitions. (b) Energy level diagram of the $D^0$ $1s$ state and the lowest $D^{0}X$ state in an applied magnetic field. To measure $T_1$ we optically pump and probe the $D^0$ state using the $A$ ($\pi$-polarized) transition. We detect the photoluminescence from the $A^{*}$ ($\sigma$-polarized) transition. A complete energy diagram of the $\mathrm{GaAs}$ $D^{0}X$ states in a magnetic field can be found in Ref. 12.Reuse & Permissions

Figure 2

(a) Typical data obtained during the pump-probe experiment. Time-resolved photoluminescence from the $A^{*}$ line is collected at $9.9\mathrm{T}$. Optical pumping can be observed during the first $20\mathrm{\mu }\mathrm{s}$ of the pump pulse. Partial recovery is observed after the $30\mathrm{\mu }\mathrm{s}$ delay. (b) Pump-probe programmed intensities.Reuse & Permissions

Figure 3

Single laser PLE scans (solid lines) and double laser PLE scans (dashed lines) at $9.9\mathrm{T}$. In the single laser PLE scans, a $\pi$-polarized (black) and $\sigma$-polarized (gray) laser is scanned over the $D^{0}X$ transitions. Photoluminescence (PL) is collected from an $\mid m_h=-\frac{1}{2}⟩$ transition and is proportional to population in the $D^{0}X$ $A$ state. Overall intensity is weak due to optical pumping. In the two laser PLE scans, a second laser is fixed resonantly on the $A^{*}$ transition as the first laser scans over the $D^{0}X$ transitions. A large enhancement in PL intensity is observed for transitions originating from the $\mid -\frac{1}{2}⟩$ state.Reuse & Permissions

Figure 4

(Color online) Log-log plot of the bound electron spin lifetime $T_1$ dependence on $B$ field. A strong power-law dependence on $B$-field is observed for $B>5\mathrm{T}$. Recovery times measured at $B\le 4\mathrm{T}$ are limited by the experimental apparatus and are only a lower bound on the electron $T_1$. Inset: Example exponential fit of the pump-probe data at $6\mathrm{T}$.Reuse & Permissions