A Single-photon Source Based on a Lateral n-i-p Junction Driven by a Surface Acoustic Wave

Single-photon sources are essential building blocks in quantum photonic networks, where quantum-mechanical properties of photons are utilised to achieve quantum technologies such as quantum cryptography and quantum computing. In this thesis, a single-photon source driven by a surface acoustic wave (SAW) is developed and characterised. This single-photon source is based on a SAW-driven lateral n-i-p junction in a GaAs quantum-well structure. On this device, the lateral n-i-p junction is formed by gate-induced electrons and holes in two adjacent regions. The SAW potential minima create dynamic quantum dots in a 1D channel between these two regions, and are able to transport single electrons to the region of holes along the channel. Single-photon emission can therefore be generated as these electrons consecutively recombine with holes. After characterisation and optimisation in four batches of devices, clear SAW-driven charge transport and the corresponding electroluminescence (EL) can be observed on an optimised SAW-driven n-i-p junction. Time-resolved measurements have been carried out to study the dynamics of SAW-driven electrons. Time-resolved EL signals indicate that a packet of electrons is transported to the region of holes in each SAW minimum. In addition, the carrier lifetime of SAW-driven electrons in the region of holes is shown to be $\sim 100$ ps, which is much shorter than the SAW period of $860$ ps. Hence, it is promising to observe single-photon emission in the optimised device. In order to test single-photon emission, a Hanbury Brown-Twiss experimental setup has been employed to record an autocorrelation histogram of the SAW-driven EL signal at the single-electron regime. Suppression of autocorrelation coincidences at time delay $\Delta t = 0$ is evidence of photon antibunching. By fitting theoretical functions describing the SAW-driven EL signal, it is found that the second-order correlation function shows g⁽²⁾(0) = 0.39 \pm 0.05, which is lower than the common criterion for a single-photon source g⁽²⁾(0) < 0.5. Moreover, theoretical calculation and simulation suggest that, if a constant background signal can be filtered out, $\sim 80 \%$ of the SAW-driven EL is single-photon emission.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2018

Author dc:creator

• Hsiao, Tzu-Kan

Advisor dc:contributor.advisor

• Ford, Chris

• surface acoustic wave
• single-photon source
• quantum information
• quantum computing
• undoped GaAs quantum well
• lateral n-i-p junction

Licence

• https://www.repository.cam.ac.uk/bitstreams/9c99f092-4bce-49a2-a8df-bfc75a18fff1/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

en

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.30552

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/283189