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Postdoc in Fabrication and characterization of quantum light sources

Technical University of Denmark

The Quantum and Laser Photonics Group at DTU Fotonik, Department of Photonics Engineering at the Technical University of Denmark, is seeking a candidate for a Postdoc position. The Postdoc will work in the field of microfabrication and quantum optical characterization of sources of single indistinguishable photons based on semiconductor quantum dots. The position is offered with support from the European Research Council.
Solid-state sources of single photons are expected to play an important role in various quantum information applications, such as secure communications, quantum computation and metrology. These applications require deterministic on-demand emission as well as high efficiency, purity and indistinguishability of the emitted photons. A promising platform for a deterministic single-photon source (SPS) is based on the semiconductor quantum dot (QD) in a solid-state environment. Until now the activities at DTU Fotonik have been limited to theory and modelling of SPSs, but with this opening we are launching also an experimental activity in this field.
Responsibilities and tasks:
You will participate in a project team with several Postdocs and PhD students, which will design and fabricate quantum-dot-based SPSs meeting all the requirements of the quantum information applications. Your overall responsibility will be to lead the experimental activities including the microfabrication and the optical characterization of the devices.
We will grow wafers with cavities with Stranski-Krastanov randomly distributed semiconductor InAs QDs surrounded by distributed Bragg reflectors. We will subsequently identify the randomly positioned QDs using an optical imaging technique, and we will etch pillar structures around the QDs. The lithography will be done using a combination of UV and e-beam lithography, and the etching will be performed using reactive ion etching, and possibly also wet chemical etching. The structures will be electrically contacted in order to use the Stark effect for stabilization of the local charge environment. For the optical characterization, the devices will be characterized placed in a cryostat and the QDs will be excited using resonant or quasi-resonant optical excitation. We will then characterize the single-photon emission in terms of purity, indistinguishability and efficiency. The experimental activity will take place in a close feedback loop with the theoretical activity to take into account the experimental results in subsequent design iterations, and the entire project team will discuss promising opportunities for next-generation SPS designs.
The candidate is thus expected to
• Take responsibility for and lead an experimental activity.
• Perform spectroscopy and optical imaging of QDs.
• Perform UV and e-beam lithography.
• Perform reactive ion etching and wet chemical etching.
• Perform metal deposition.
• Implement a setup for optical device characterization.
• Characterize the devices in terms of efficiency, purity (Hanbury Brown-Twiss) and indistinguishability (Hong-Ou-Mandel).
• Supervise experimental PhD students as well as project students.
• Contribute to the development of new SPS designs.
Application deadline: November 24th 2020

How to apply

Instructions for applying are provided at the DTU job offer webpage: deadline: November 24th 2020

Niels Gregersen Apply for this job

Published on November 03, 2020

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