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Fermi edge polaritons in a microcavity containing a high density two-dimensional electron gas
A Gabbay1, Yulia Preezant, E Cohen
1Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Physical Review Letters
|November 13, 2007
Summary
This study reveals that sharp spectral lines in GaAs/AlGaAs microcavities arise from strong coupling between photon-like modes and electron-hole excitations above the 2D electron gas Fermi edge, forming cavity polaritons.
Area of Science:
- Semiconductor physics
- Optoelectronics
- Quantum well physics
Background:
- Modulation doped quantum wells (MDQW) with a high-density two-dimensional electron gas (2DEG) are crucial for advanced electronic devices.
- Microcavities (MC) enhance light-matter interactions in semiconductor nanostructures.
Purpose of the Study:
- To investigate the optical properties of modulation doped quantum wells embedded in microcavities.
- To analyze the formation and characteristics of spectral lines in these coupled systems.
Main Methods:
- Reflection and photoluminescence spectroscopy were employed to study GaAs/AlGaAs structures.
- Optical susceptibility calculations for the MDQW were performed.
- The transfer matrix method was used to analyze the spectral data.
Main Results:
- Sharp spectral lines near the band gap were observed in both reflection and photoluminescence.
- Evidence of level anticrossings and Rabi splittings was found, indicating strong coupling.
- Calculated spectra confirmed the presence of k{ parallel}=0 cavity polaritons.
Conclusions:
- The observed spectral lines are attributed to cavity polaritons formed by electron-hole excitations above the 2DEG Fermi edge.
- These polaritons exhibit strong coupling with microcavity-confined photons.
- The findings are analogous to those in undoped quantum well microcavity systems.
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