Fig. 8: Emission of a few ps light pulse by frequency-selected QDs in a switched QDM. | Light: Science & Applications

Fig. 8: Emission of a few ps light pulse by frequency-selected QDs in a switched QDM.

From: Tailoring the properties of quantum dot-micropillars by ultrafast optical injection of free charge carriers

Fig. 8

The streak camera image is obtained for a 1.6 µm diameter switched QDM (Q = 2000), and temporal profile of the PL signal that is collected for three 1 meV-wide frequency windows, positioned below (1.383 eV for W1), or above (1.395 eV for W2, 1.391 eV for W3), the frequency of the fundamental mode in the unswitched QDM \(\hbar{\omega_m^\circ}=1.384\,{\rm{eV}}\). A single pump pulse at around t = 0 ps is used to excite and switch the QDM. Switching conditions are defined by Ep = 1.7 eV, P = 200 pJ/pulse; the switching amplitude is around 20 meV. The same linear scale is used for the three PL profiles. Please note that in this photon energy range, the emission is predominantly related to optical transitions between excited states of the QDs. The lower energy tail of the emission of the wetting layer may also contribute to the PL signal above 1.4 eV, under such strong pumping conditions (see SI).

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