The Quantum and Laser Photonics Group at DTU Fotonik, Department of Photonics Engineering at the Technical University of Denmark, is seeking candidates for Postdoc positions in the field of design and simulations of highly efficient solid-state sources of single indistinguishable photons. The positions are offered with support from the Independent Research Fund Denmark and 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 generally require near-unity efficiency and a high single-photon purity as well as indistinguishable photon emission. Furthermore, the ideal single-photon source (SPS) should be deterministic and not involve heralding. A promising platform for a deterministic SPS is based on the semiconductor quantum dot (QD) in a solid-state environment. However, for a QD in a bulk material, the symmetry of the quantum dot leads to light emission in all directions, and furthermore the QD interacts with the solid-state environment leading to decoherence due to phonons and fluctuating charges. A major challenge in realizing a SPS is thus to establish control of the light emission.
Responsibilities and tasks
The Postdoc will participate in a project team with several Postdocs and PhD students, which will design and fabricate SPSs meeting all the requirements of the quantum information applications. The structures to be investigated include both vertically emitting structures (micropillars, photonic nanowires) and on-chip designs with in-plane emission (ridge waveguides). The fabrication and characterization of the vertically emitting sources will take place in-house, whereas the on-chip designs will be fabricated at the Technical University of Berlin. The activity benefits from synergy with the H2020 MSCA Innovative Training Network “Quantum Dots for Photonic Quantum Information Technologies (QUDOT-TECH)” coordinated by DTU Fotonik.
The optical simulations will be performed using the modal method, representing state-of-the-art in optical simulations of single-photon sources. While the method offers great insight into the governing physics, convergence is not easily obtained in particular for the planar structures, and we may rely on additional simulation methods, e.g. finite elements modelling. In addition, the indistinguishability of the emitted photons in the presence of phonon-induced decoherence mechanisms will be calculated using an open quantum system master equation approach.
The overall responsibility of the postdoc is to set up the numerical simulations framework to be used in the analysis of high-performance SPSs in collaboration with the PhD students, who will focus on the design work itself. In a collaborative effort, the team will analyse and propose novel SPS designs allowing for a good compromise between offering high performance and representing a robust design compatible with fabrication constraints. The tasks for the postdoc include setting up a modal method to be used both for vertical and in-plane designs and improving the performance of the code e.g. by implementing support for parallelization. Furthermore, the postdoc will build codes for the analysis of the photon indistinguishability. Additional responsibility of the postdoc includes supervision of the PhD students working on the theory and the designs and of MSc and BSc students associated with the project.
The candidate is thus expected to
- Construct a home-made modal method software package compatible with multiple eigenmode solvers and implementing support for Bloch-wave formalism, dipole emitters and parallelization.
- Set up a framework based on commercial software, e.g. finite elements modelling, allowing analysis of the most demanding structures.
- Build a code based on an open quantum systems master equation approach to analyse the indistinguishability.
- Supervise the design work of PhD students as well as MSc/BSc student projects.
Candidates should have a PhD degree or equivalent. In addition, the candidate should have
- Knowledge of quantum optics.
- Knowledge of cavity quantum electrodynamics and of quantum emitters in nanophotonic structures.
- Experience with numerical simulations of the electromagnetic field.
- Experience with Matlab, Python or a similar scientific programming language.
- Previous experience with the Modal Method (e.g. Fourier Modal Method, Differential Method, Eigenmode Expansion Technique) or a similar modal expansion technique is recommended.
- Willingness to work in close collaboration with an internal project team consisting both of theoreticians and experimentalists.
- Willingness to supervise PhD, MSc and BSc students.
DTU is a leading technical university globally recognized for the excellence of its research, education, innovation and scientific advice. We offer a rewarding and challenging job in an international environment. We strive for academic excellence in an environment characterized by collegial respect and academic freedom tempered by responsibility.
Salary and terms of employment
The appointment will be based on the collective agreement with the Danish Confederation of Professional Associations. The allowance will be agreed upon with the relevant union. The period of employment is three years.
The start date is May 1st 2020 (with some flexibility).
You can read more about career paths at DTU here.
Further information may be obtained from Niels Gregersen, email@example.com, tel.: +45 4525 3789.
You can read more about DTU Fotonik at www.fotonik.dtu.dk.
- Application (cover letter)
- Diploma (MSc/PhD)
- List of publications
All interested candidates irrespective of age, gender, disability, race, religion or ethnic background are encouraged to apply.
DTU Fotonik has 220 employees with competences in optics. In a typical year, DTU Fotonik educates 55 PhD students from more than 25 countries and our student numbers are constantly growing. As one of Europe’s largest public photonics research departments, DTU Fotonik covers a multitude of optical disciplines ranging from fundamental light-matter interaction and optical telecommunications to applied research and innovation. Our research topics include optical sensors, lasers, LEDs, photovoltaics, ultra-high speed optical transmission systems, bio-photonics, nano-optics and quantum photonics.
Technology for people
DTU develops technology for people. With our international elite research and study programmes, we are helping to create a better world and to solve the global challenges formulated in the UN’s 17 Sustainable Development Goals. Hans Christian Ørsted founded DTU in 1829 with a clear vision to develop and create value using science and engineering to benefit society. That vision lives on today. DTU has 11,500 students and 6,000 employees. We work in an international atmosphere and have an inclusive, evolving, and informal working environment. Our main campus is in Kgs. Lyngby north of Copenhagen and we have campuses in Roskilde and Ballerup and in Sisimiut in Greenland.
Deadline: 8 March 2020
Unit: DTU Fotonik
Read the job description and apply online
Post expires on Sunday March 8th, 2020