Anomalous optical diffraction by a phase grating induced by a local field effect in semiconductor quantum dots

Y Mitsumori, T Watanuki, Y Sato, K Edamatsu… - Physical Review B, 2017 - APS
Y Mitsumori, T Watanuki, Y Sato, K Edamatsu, K Akahane, N Yamamoto
Physical Review B, 2017APS
We demonstrate the use of laser-induced phase gratings to control the emission
characteristics of self-assembled semiconductor quantum dots. The microscopic Coulomb
interaction between the photoinduced charge densities in a dot, referred to as the local field
effect, affects the macroscopic optical properties of a dot ensemble even with
inhomogeneous broadening, and forms a phase grating by spatially modulating the exciton
resonant frequency. In the low excitation regime, the diffracted light intensity (observed using …
Abstract
We demonstrate the use of laser-induced phase gratings to control the emission characteristics of self-assembled semiconductor quantum dots. The microscopic Coulomb interaction between the photoinduced charge densities in a dot, referred to as the local field effect, affects the macroscopic optical properties of a dot ensemble even with inhomogeneous broadening, and forms a phase grating by spatially modulating the exciton resonant frequency. In the low excitation regime, the diffracted light intensity (observed using photon echoes) gradually rose with time delay—a result very different from the conventional instantaneous response to pulse excitation. With increasing excitation intensity, the response of the diffracted signal became more immediate and exhibited a biexponential decay. The change in the temporal profile can be systematically explained by analyzing the dynamics of the phase grating. Our findings suggest an optical switching mechanism using this intrinsic property of semiconductor quantum dots.
American Physical Society
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