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The Mueller group studies nanoscale light-matter coupling phenomena in quantum materials. We use polaritons to shrink light to the nanoscale and employ ultrafast nonlinear optical techniques to bridge phenomena in the typically separate mid-infrared and visible spectral ranges. We aim to advance the understanding of 2D quantum materials, activate new coupling channels to convert light between different spectral ranges, and engineer materials through hybrid light-matter states. Our group is funded by the Emmy Noether Programme of the German Research Society (DFG). We closely collaborate with research groups at the department, the neighboring Fritz Haber Institute, and partners around the world.

For more information see our website:


Job description:
As a PhD student, you will work within the DFG-funded project ‘Luminescence Upconversion Nanoscopy – LUNA’, which aims to bridge the traditionally separate research fields of mid-infrared and visible nanophotonics.

You will help establish a new laboratory equipped with cutting edge experimental techniques, including a near-field optical microscope and an ultrafast laser system featuring tunable outputs in both the mid-infrared and visible spectral ranges.

Your research will focus on 2D quantum materials and their heterostructures to activate novel coupling channels between material excitations. This involves, for example, phonon polaritons, facilitating nanoscale waveguiding of mid-infrared light, and excitons, which serve as bright visible-light emitters in optoelectronic devices.

You will closely work with collaboration partners from around the world, communicate your research at international conferences, and work towards publications in renowned journals.

Requirements:
Master’s degree in physics or a related discipline, completed by the start of the position.

Desirable:

• You have experience in at least one of the following fields: nanophysics, nanophotonics, 2D materials, nonlinear optics, solid-state physics
• You have proven experience with experimental work through your Master’s thesis, preferably with optics setups
• You have Python programming skills, preferably also for lab instrument automation
• You are fluent in English and have communicated your work in English, for example, through reports or presentations
• You enjoy working in a team and are highly motivated to tackle complex tasks that have no obvious solution

Please include the following documents with your application:

1. A motivation letter
2. Your CV
3. Copies of your certificates, including transcripts for your Bachelor’s and Master’s studies. If you have not yet completed your Master’s degree, please provide a current transcript of records and indicate your expected graduation date
4. Names and email addresses of two references who may be contacted

For further information, please contact Dr. Niclas Müller (niclas.mueller@fu-berlin.de / +49-30-838-68326).

Applications should be sent by e-mail, together with significant documents, indicating the reference code, no later than August 7^th, 2025 in PDF format (preferably as one document) to Dr. Niclas Müller: niclas.mueller@fu-berlin.de or postal to

Freie Universität Berlin
Fachbereich Physik
Institut für Experimentalphysik
AG Müller - DFG Drittmittelprojekt 'Luminescence Upconversion Nanoscopy - LUNA'
Dr. Niclas Müller
Arnimallee 14
14195 Berlin (Dahlem)

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Freie Universität Berlin is an equal opportunity employer.