PhD scholarship in Design and Simulations of Quantum Light Sources

fredag 07 feb 20

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Frist 23. februar 2020
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The Quantum & Laser Photonics group at DTU Fotonik is seeking a candidate for a PhD position in the field of design and simulations of efficient sources of single indistinguishable photons. The position is funded by the project “Quantum Light On-A-Chip (QLIGHTCHIP)” granted by the Independent Research Fund Denmark.

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 or spontaneous downwards conversion. A potential platform for such a source is a quantum emitter, e.g. an InAs quantum dot, embedded in a semiconductor material. However, in a bulk material, the symmetry of the quantum dot leads to light emission in all directions. Major challenges in realizing an efficient source include establishing control of the light emission as well as avoiding decoherence effects due to interaction with the solid-state environment.

The PhD project will take place in the Nanophotonics section at DTU Fotonik led by Prof. Jesper Mørk. The activities of the section are centered on the fabrication, characterization and theoretical analysis of opto-electronic components for use in information, communication and sensing applications. QLIGHTCHIP is one of several recently granted projects on single-photon source engineering. The candidate will thus be a part of a team consisting of several PhD students and postdoc working with both design and fabrication of quantum light sources. In addition, the candidate will benefit from synergy with the H2020 MSCA Innovative Training Network “Quantum Dots for Photonic Quantum Information Technologies (
QUDOT-TECH)” coordinated by DTU Fotonik.

Responsibilities and tasks
Your overall responsibility will be to perform numerical simulations of the optical field generated by photon emission from a quantum dot and to employ a series of optical engineering tools including cavity quantum electrodynamics, adiabatic transmission and dielectric screening effects to ensure near-unity coupling to the waveguide as well as near-unity indistinguishability in the presence of phonon-induced decoherence. You will perform calculations using several optical simulations methods including the Fourier Modal Method representing state-of-the-art in optical simulations of single-photon sources as well as commercial finite elements modeling tools. In addition you will model the spontaneous emission taking into account the influence of the solid-state environment, in particular phonon-induced decoherence, on the photon emission.

You will be expected to:
 

  • Develop software codes from scratch using MATLAB/Python/C++/etc.
  • Construct a numerical simulation technique based on the Fourier Modal Method for optical simulations of the light emission.
  • Construct a numerical code to calculate photon indistinguishability based on an open quantum system master equation approach.
  • Analyse the limitations of current cavity- and waveguide-based single-photon source designs with respect to total efficiency and indistinguishability.
  • Propose new single-photon source designs overcoming these limitations to be fabricated by other PhD students.
Qualifications
Candidates should have a two-year master's degree (120 ECTS points) or a similar degree with an academic level equivalent to a two-year master's degree. Additionally, the candidate must have passed an introductory course on quantum mechanics and also have previous experience with numerical simulations of physical problems.

The candidate
must describe his/her previous experience with quantum mechanics and with numerical simulations in the cover letter (see below). 

Approval and Enrolment
The scholarship for the PhD degree is subject to academic approval, and the candidate will be enrolled in one of the general degree programmes at DTU. For information about our enrolment requirements and the general planning of the PhD study programme, please see the
DTU PhD Guide


Assessment
The assessment of the applicants will be made by Assoc. Prof. Niels Gregersen and Prof. Jesper Mørk. 

We offer
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 appointment terms
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 3 years. 

You can read more about career paths at DTU here.  

Further information
Further information may be obtained from Assoc. Prof. Niels Gregersen, ngre@fotonik.dtu.dk
, tel.: +45 45253789. (Applications submitted by email will not be considered, instead you should use the on-line portal described below.) 

You can read more about DTU Fotonik at
www.fotonik.dtu.dk/english

Application
Please submit your online application no later than 23 February 2020 at 23:59 (local time)Applications must be submitted as one PDF file containing all materials to be given consideration. To apply, please open the link "Apply online", fill out the online application form, and attach all your materials in English in one PDF file. The file must include: 
  • A letter motivating the application (cover letter)
  • Curriculum vitae
  • Grade transcripts and BSc/MSc diploma
  • Excel sheet with translation of grades to the Danish grading system (see guidelines and Excel spreadsheet here)
Candidates may apply prior to obtaining their master's degree but cannot begin before having received it. In addition, candidates must be in the first four years (full-time equivalent research experience) of their research careers and not yet have been awarded a PhD degree.

Applications and enclosures received after the deadline will not be considered.

All interested candidates irrespective of age, gender, race, disability, 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.