Controlling the gain contribution of background emitters in few-quantum-dot microlasers. (15th February 2018)

• Record Type: Journal Article
• Authors: Gericke, F; Segnon, M; von Helversen, M; Hopfmann, C; Heindel, T; Schneider, C; Höfling, S; Kamp, M; Musiał, A; Porte, X; Gies, C; Reitzenstein, S
• Is Part Of: New journal of physics. Volume 20:Number 2(2018:Feb.)
• Publication Date: 2018-02-15
• Subjects: nanolasers -- cavity QED -- high-β lasing -- quantum dot–micropillar cavities -- single quantum dot laser -- semiconductor laser; 78.55.Cr -- 78.67.Hc; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aaa477
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: We provide experimental and theoretical insight into single-emitter lasing effects in a quantum dot (QD)-microlaser under controlled variation of background gain provided by off-resonant discrete gain centers. For that purpose, we apply an advanced two-color excitation concept where the background gain contribution of off-resonant QDs can be continuously tuned by precisely balancing the relative excitation power of two lasers emitting at different wavelengths. In this way, by selectively exciting a single resonant QD and off-resonant QDs, we identify distinct single-QD signatures in the lasing characteristics and distinguish between gain contributions of a single resonant emitter and a countable number of off-resonant background emitters to the optical output of the microlaser. Our work addresses the important question whether single-QD lasing is feasible in experimentally accessible systems and shows that, for the investigated microlaser, the single-QD gain needs to be supported by the background gain contribution of off-resonant QDs to reach the transition to lasing. Interestingly, while a single QD cannot drive the investigated micropillar into lasing, its relative contribution to the emission can be as high as 70% and it dominates the statistics of emitted photons in the intermediate excitation regime below threshold.