Electromagnetically induced transparency resulting from exciton spin coherence is demonstrated in transient optical response in GaAs quantum wells. The spin coherence is induced via correlations between excitons with opposite spins, including correlations associated with bound and unbound biexcitons.
We report experimental studies of electromagnetically induced transparency (EIT) arising from exciton spin coherence in the transient optical response of GaAs quantum wells. The exciton spin coherence, which is a direct result of Coulomb correlations between excitons with opposite spins, is induced via bound or unbound two-exciton states. Theoretical analyses based on a three-level model illustrate the manifestation of EIT in a transient regime and provide qualitative guidance for understanding the transient behaviors observed in the EIT experiments. Additional studies of the effects of exciton energy renormalization on optical Stark splitting also provide insights on how exciton many-body interactions can lead to unusual time-dependent asymmetric EIT line shapes.
Electromagnetically induced transparency (EIT) was observed with transient optical response of exciton correlation in GaAs/AlGaAs quantum well structure. Decoherence of EIT was increased with temperature (12-60 K), which could be simulated by increasing non-radiation decay rate between coherently coupled ground states in Bloch equation for Lambda type three level. The non-radiation decay was mainly due to hole spin dephasing in the system for EIT via coulomb correlation. The hole spin dephasing rate was found with increasing lattice temperature and well accorded to the past results of time resolving method with n-doping material.
We report an experimental demonstration and theoretical analysis of electromagnetically induced transparency in a GaAs quantum well, in which the absorption of an exciton resonance is reduced by more than twentyfold. The destructive quantum interference in this scheme is set up by a control pulse that couples to a resonance of biexcitons. These studies illustrate that many-particle interactions, which are inherent in semiconductors and are often detrimental to quantum coherences, can also be harnessed to manipulate these coherences.
We report the experimental demonstration of coherent Raman resonance from electron spin coherence in GaAs quantum wells. Coherent Raman resonance, which is a precursor for electromagnetically induced transparency, appears in the differential transmission response from localized excitons in an external magnetic field applied in Voigt geometry. The spectral domain spin study reveals that the optical processes involved differ from those in the transient domain, leading to distinct polarization and intensity dependences.