Transient dual-energy lasing in a semiconductor microcavity.

Area of Science:

• Optics and Photonics
• Condensed Matter Physics
• Quantum Optics

Background:

• Microcavities are crucial for controlling light-matter interactions.
• Understanding lasing dynamics is key to developing advanced optical devices.
• Polarization properties offer insights into the underlying physical processes.

Purpose of the Study:

• To demonstrate sequential lasing at two distinct energies in a photoexcited planar microcavity.
• To investigate the polarization properties of these spatially overlapped lasing states.
• To analyze the temporal evolution and underlying mechanisms of the high-energy and low-energy lasing states.

Main Methods:

• Utilizing a highly photoexcited planar microcavity at room temperature.
• Employing circularly polarized nonresonant 2 ps pulse excitation.
• Analyzing the emergence and duration of high-energy (HE) and low-energy (LE) lasing states using time-resolved measurements.

Main Results:

• Observed sequential lasing at two energies separated by more than 5 meV.
• A transient, circularly polarized HE state emerged within 10 ps, followed by a longer-lived LE state (20-50 ps).
• The HE state exhibited high circular polarization due to spin-preserving stimulated emission, while the LE state showed reduced polarization from diminishing spin imbalance.

Conclusions:

• Sequential lasing with distinct polarization properties can be achieved in microcavities.
• The observed phenomena are governed by spin dynamics and stimulated emission processes.
• This work provides a foundation for controlling and utilizing polarization in microcavity-based optical systems.