Photon statistics of Quantum Dot Superluminescent Diodes at the transition from amplified spontaneous emission to stimulated emission

Quantum Dot Superluminescent Diodes (QD-SLDs) have shown their superior potential to generate “new” light with fascinating 1
^st
and 2
^nd
order coherence properties due to their emission out of quantum dot states at the border of Amplified Spontaneous Emission (ASE) and Stimulated Emission (SE) [1,2]. Recently it has been demonstrated, that the photon statistics from a QD-SLD can be significantly influenced by cooling the device below 200K. Thereby, a reduction of the 2
^nd
order coherence degree g
⁽²⁾
(0) - the central value of the normalized temporal intensity correlation function g
⁽²⁾
(τ)=〈 I(t+τ)I(t)〉/〈I(t)〉
²
- from a value of 2, reflecting thermal bunched photon statistics, to a value of 1.33, close to coherent Poissonian photon statistics was observed [3].