Joseph Jacobson

Observation of dressed‐exciton oscillating emission over a wide wavelength range in a semiconductor microcavity

We have observed the dressed‐exciton oscillating emission in the time domain and the associated spectral splitting in the frequency domain from a GaAs single quantum well microcavity over a very broad range of cavity resonant wavelengths. The spectral splitting and temporal oscillation period have been measured to be nearly constant over two orders of magnitude variation of pump intensity, which confirms the linear bosonic feature of Wannier excitons in the weak excitation regime.

Quantum limit for the atom-light interferometer

AbstractThe standard quantum limit is calculated for the atom-light interferometer. It is shown that the smallest detectable phase is

Phonon-assisted exciton–polariton emission in a microcavity

\delta \phi _{\min } = \frac{1}{2}[N_{atoms} + 4N_{photons} )/N_{atoms} N_{photons} ]^{1/2} .

Stimulated Emission of Microcavity Exciton Polariton

Therefore, in practical experiments, the accuracy is limited by the square root of the number of atoms. We propose a novel correlated atom-photon state interferometer which makes a transition to the Heisenberg limit, δφmin ∝ 1/Natoms, as the atoms approach a Bose condensate. Such an interferometer may serve as a sensitive probe of the onset of Bose condensation. Finally, we point out that the correlated atom-photon state preparation scheme we propose may be used in a different way to approach the Heisenberg limit for non-Bose-condensed atoms.

SEMICONDUCTOR CAVITY QED IN HIGH-Q REGIME

The thermodynamic limits on the efficiency of different types of lasers are calculated both classically and quantum mechanically. In the classical case, the limit is derived from the inequality provided by the population inversion. In the quantum mechanical case, the limit is derived from the inequality of the change of entropy. The Shannon and von Neuman entropies of different light states are worked out.

Phonon-polariton interaction in a microcavity

Quantum-well excitons in a semiconductor microcavity are studied by photoluminescence and input–output experiments. Emission peaks at both longer and shorter wavelengths are observed, indicating the importance of exciton –acoustic-phonon interaction at low temperature. Pump–probe experiments show that the probe beam can be either amplified or attenuated, depending on the energies of the pump and the probe. The dynamics of this process are described by a simple rate-equation model.

Particle Statistics and Quantum Dynamics in a Semiconductor Quantum-Well Microcavity

Quantum-well exciton superradiance and exciton cavity polarization formation both require a substantial spatial coherence area in order to become the dominant exciton field interaction. In both interaction processes the quantum-well (in-plane) momentum is conserved. Momentum scattering, which is due, e.g., to interaction with a phonon reservoir, quickly localizes an initially delocalized exciton and randomizes the excitation momentum. We take a close look at how momentum scattering influences measurements of excitonic superradiance and of exciton cavity polariton splitting. An important conclusion is that, in general, measurements of the emitted light do not correspond to the evolution of the system as a whole. Therefore, e.g., the measured decay rates do not correspond to the true decay rate of the system.

Exciton-Polaritons in Microcavities

The interaction of a bosonic or fermionic particle with a single bosonic field has been an important topic in the study of cavity quantumelectrodynamics. Experimental studies of this interaction have so far been studied in two systems, atoms inside a high Q cavity and quantum well excitons inside a microcavity. In this proceeding, we present results of photoluminescence and pump-probe experiments performed on the latter system. We show that amplification and attenuation of the probe beam (seed) can occur depending on the exciton density which show the bosonic feature of exciton polaritons and importance of exciton-acoustic phonon interaction at low temperature.