Picosecond pulse shaping of single photons using quantum dots

• Published in: Nature communications Vol. 9; no. 1; p. 115
• Main Authors: Pursley, B. C., Carter, S. G., Yakes, M. K., Bracker, A. S., Gammon, D.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.01.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 140/133; 639/624/399/1017; 639/766/400/482; 639/766/483/3925; Humanities and Social Sciences; multidisciplinary; Photons; Picosecond pulses; Pulse duration; Pulse shape; Quantum dots; Quantum phenomena; Quantum theory; Radiative lifetime; Science; Science (multidisciplinary); Shape memory
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02552-7

Quantum dots (QDs) are an excellent single-photon source that can be combined with a spin quantum memory. Many quantum technologies require increased control over the characteristics of emitted photons. A powerful approach is to trigger coherent Raman photons from QDs with a Λ energy-level system, such as the spin singlet–triplet system in two coupled QDs. The temporal and spectral behavior of single Raman photons can be varied simply by modifying the excitation source. Here, we demonstrate control of the single-photon pulse shape in a solid-state system on a timescale much shorter than the radiative lifetime, in addition to control of the frequency and bandwidth. We achieve a photon pulse width of 80 ps—an order of magnitude shorter than the exciton lifetime. Possible applications include time-bin encoding of quantum information, matching photons from different sources, and efficient single-photon transfer in a quantum network. Tailoring single photons’ pulse shapes could have applications such as time-bin encoding or interfacing different photon emitters. Here, the authors achieve pulse shaping of Raman single photons from InGaAs quantum dots on a picosecond timescale, much shorter than the radiative lifetime.