Wigner function and photon number distribution of a superradiant state in semiconductor laser structures

TL;DR

This paper uses time-domain optical homodyne tomography to visualize and analyze the quantum state of superradiant emission in semiconductor lasers, revealing non-classical features like negative Wigner function regions.

Contribution

It demonstrates the quantum nature of superradiant states in semiconductor lasers through Wigner function reconstruction and photon statistics analysis.

Findings

Reconstructed Wigner functions show negative regions indicating non-classicality.

Photon statistics deviate from Poissonian distribution during superradiance.

Superradiant state resembles a displaced Fock state in quantum characteristics.

Abstract

For the visualization of quantum states, the approach based on Wigner functions can be very effective. Homodyne detection has been extensively used to obtain the density matrix, Wigner functions and tomographic reconstructions of optical fields for many thermal, coherent or squeezed states. Here, we use time-domain optical homodyne tomography for the quantum state recognition and reconstruction of the femtosecond optical field from a nonequilibrium superradiant coherent electron-hole state formed in a semiconductor laser structure. We observe severe deviations from the Poissonian statistics of the photons associated with the coherent laser state when the transformation from lasing to superradiance occurs. The reconstructed Wigner functions show large areas of negative values, a characteristic sign of non-classicality, demonstrating the quantum nature of the generated superradiant emission. The photon number distribution and Wigner function of the SR state are very similar to those of the displaced Fock state