PhD scholarship on Strong Light-Matter Interactions in Nanocavities Coupled to 2D Materials

The Centre for Nanophotonics (NanoPhoton) at DTU Department of Photonics Engineering (DTU Fotonik) is looking for an excellent candidate for a PhD position to explore light-matter interactions between semiconducting two-dimensional (2D) materials and novel topology-optimized dielectric cavities confining intense electromagnetic fields on the nanometer scale [1]. Our ambition is to explore light-matter interactions at the quantum level in nanocavities combining the confinement of light usually only achievable in plasmonic structures with the low losses found in dielectric photonic crystal cavities. This project aims at extending our fundamental understanding of the interaction between electromagnetic fields and excitons in a yet unexplored class of nanocavities. This explorative experimental work will lay the ground for future applications ranging from low-noise nanolasers [2] to polaritonic lasers [3] and single-photon blockade devices working at room temperature [4].

The project is part of NanoPhoton and will take place at DTU Fotonik, who has expertise in the design, fabrication, and characterization of dielectric nanocavities, and the project will benefit from synergies with the Centre for Nanostructured Graphene (CNG) that has internationally recognized experience in the preparation and nanofabrication of 2D materials.

The project
Extremely confined electromagnetic fields in topologically-optimized dielectric cavities offer a new platform to explore light-matter interactions in regimes of cavity parameters where the field confinement is similar to that of plasmonic systems, yet with large quality factors not achievable by metallic structures [1]. Combined with 2D materials showing excellent optical properties at room temperature [5], we will be able to explore a new range of light-matter coupling parameters not achievable otherwise.

In this project, you will learn the basic principles behind strong light-matter interactions, dielectric nanocavities, and the excitonic properties of low-dimensional materials, working with samples that are fabricated within NanoPhoton at DTU Fotonik [6]. Your primary task will be to investigate the coupling dynamics between excitons in the 2D materials and photons in the cavities by use of ultra-fast spectroscopy. You will also have the opportunity to be trained and use near-field scanning optical microscopy to probe optical properties of the fabricated structures with a spatial resolution better than 20 nanometers [6]. You will analyse the experimental data and compare them with theoretical models in order to get a deeper understanding of light-matter interaction in these new structures. Based on your results, you will assess the possibility of designing novel platforms for low-noise lasers [2], polaritonic lasers [3], or single-photon blockade devices [4] for future applications in quantum technologies.  

The ideal candidate
We are looking for an engineer or physicist with a MSc level or equivalent who has excellent academic records and/or has already demonstrated scientific achievements. We are interested in working with candidates who are highly motivated, self-driven and have demonstrated during their Master thesis excellence in experimental photonics, quantum optics or 2D materials. Other qualities of the successful candidate:

• Is academically curious and think deeply and creatively
• Takes responsibility for the progress and quality of their projects.
• Communicates well in both written and spoken English
• Is empathetic and enjoy working with others from diverse backgrounds.

You must have a two-year master's degree (120 ECTS points) in physics, photonics, quantum optics, and materials science or a similar degree with an academic level equivalent to a two-year master's degree.

Approval and Enrolment
The scholarship for the PhD degree is subject to academic approval, and the candidates 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 Professor Jesper Mørk, Assoc. Prof. Nicolas Stenger, Assoc. Prof. Martijn Wubs and Senior Researcher Philip Trøst Kristensen.

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: Prof. Jesper Mørk ([email protected]), Assoc. Prof. Nicolas Leitherer-Stenger ([email protected]), Sen. Res. Philip Trøst Kristensen ([email protected]), and Assoc. Prof. Martijn Wubs ([email protected]). 

You can read more aboutDTU Fotonik at www.fotonik.dtu.dk/english and the NanoPhoton center at https://nawinophoton.dtu.dk/ .   

If you are applying from abroad, you may find useful information on working in Denmark and at DTU at DTU – Moving to Denmark .   

Application procedure
Your complete online application must be submitted no later than 1 November 2021 (Danish 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 )

Incomplete applications will not be considered. You may apply prior to ob­tai­ning your master's degree but cannot begin before having received it.

All interested candidates irrespective of age, gender, race, disability, religion or ethnic background are encouraged to apply.

NanoPhoton
The research vision of NanoPhoton - Center for Nanophotonics (https://nanophoton.dtu.dk/ ) – is to explore the hitherto inaccessible regime of extreme dielectric confinement of light in optical cavities and to apply the associated enhanced light-matter interaction to solve fundamental outstanding challenges in chipscale information technology. To this end, we will develop the science and technology for a new class of optical nanostructures by combining fundamental electromagnetic and quantum optical theory with state-of-the-art nanofabrication and advanced experimental characterization techniques.

The Nanophotonics Section at DTU Fotonik
The Nanophotonics section combines expertise in the synthesis and handling of nanomaterials, the fabrication of nanoscale devices, and theoreticians employing a wide palette of analytical and numerical techniques to provide better understanding of and control over the fundamental properties of light-matter interactions and in this way realizing new nanophotonic devices for emerging information and quantum technology.

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 12,900 students and 6,000 employees. We work in an international atmosphere and have an inclusive, evolving, and informal working environment. DTU has campuses in all parts of Denmark and in Greenland, and we collaborate with the best universities around the world.

References:
[1]:Wang, F., Christiansen, R. E., Yu, Y., Mørk, J., and Sigmund, O. Maximizing the quality factor to mode volume ratio for ultra-small photonic crystal cavities . Applied Physics Letters 113, 241101 (2018).
[2]: Mørk, J., and Yvind. K. Squeezing of intensity noise in nanolasers and nanoLEDs with extreme dielectric confinement . Optica 7, 1641 (2020).
[3]:Sanvitto, D., and Kéna-Cohen, S. The road towards polaritonic devices. Nature Materials 15, 1061 (2016).
[4]:Denning, E. V., Wubs, M., Stenger, N., Mørk, J., and Kristensen, P. T. Cavity-induced exciton localisation and polariton blockade in two-dimensional semiconductors coupled to an electromagnetic resonator. arXiv preprint arXiv:2103.14484 (2021).
[5]:Geisler, M., et al. . Single-crystalline gold nanodisks on WS2 mono-and multilayers for strong coupling at room temperature . ACS Photonics 6, 994 (2019).
[6]: Albrechtsen, M., et al.. Nanometer-scale photon confinement inside dielectrics . arXiv preprint arXiv:2108.01681 (2021)