PhD position -order harmonic generation spectroscopy in noble-gas liquids

We are offering a PhD position in attosecond science and strong-field physics at the Laboratory of Physical Chemistry, ETH Zürich. The project focuses on high-order harmonic generation (HHG) in noble-gas liquids, in particular liquid helium. This research aims to explore a new regime of ultrafast electron dynamics in condensed matter and to bridge the gap between gas-phase and liquid-phase HHG. The position offers the opportunity to work at the forefront of attosecond spectroscopy using state-of-the-art ultrafast laser systems and cryogenic technology.

This 4-year PhD position is funded by our SNSF grant.

Project background

High-order harmonic generation has become a cornerstone of attosecond science, enabling the observation of electron dynamics on their natural timescales. While HHG is well understood in gases and increasingly explored in solids, its extension to liquids offers intriguing opportunities to study electron scattering and delocalization properties. Noble-gas liquids, and liquid helium in particular, provide a unique platform: they combine the simplicity of atomic systems with the density of condensed matter.

Their relatively long electron mean free paths offer access to a regime where strong-field physics can be studied under conditions intermediate between gases and molecular liquids. This project aims to establish HHG spectroscopy in noble liquids, investigate the role of electron scattering and coherence, and explore new phenomena such as HHG in the superfluid phase of helium.

• Design and perform experiments on high-order harmonic generation in liquid and gas-phase targets
• Develop and operate cryogenic liquid-jet systems for noble-gas liquids
• Implement advanced ultrafast laser techniques (e.g., few-cycle pulses, two-colour fields, CEP stabilization)
• Analyze experimental data to extract information on electron dynamics (cut-off scaling, phase, emission times)
• Contribute to the development of new experimental methods in attosecond spectroscopy
• Present results at international conferences and publish in high-impact journals

• Master's degree in physics, physical chemistry, or a closely related field
• Strong interest in ultrafast laser science, attosecond physics, or strong-field phenomena
• Experimental skills and motivation to work on complex laboratory setups
• Ability to work independently and as part of a collaborative research team
• Good communication skills in English (spoken and written)

Experience in one or more of the following areas is an advantage: ultrafast optics, nonlinear optics, HHG/strong-field physics, vacuum technology, spectroscopy, or scientific programming (Python, MATLAB).

• A fully funded PhD position at ETH Zürich, one of the world's leading universities
• Access to state-of-the-art ultrafast laser systems and experimental infrastructure
• A stimulating, international research environment with strong collaborations
• Opportunities to attend international conferences and build a scientific network
• Supervision and training in cutting-edge experimental techniques in attosecond science
• Attractive working conditions and benefits according to ETH Zürich standards

In line with our values, ETH Zurich encourages an inclusive culture. We promote equality of opportunity, value diversity and nurture a working and learning environment in which the rights and dignity of all our staff and students are respected. Visit our Equal Opportunities and Diversity website to find out how we ensure a fair and open environment that allows everyone to grow and flourish.

Sustainability is a core value for us - we are consistently working towards a climate-neutral future.

Questions regarding the position should be directed to Tadas Balciunas (tadas.balciunasm.ethz.ch). Preferred start date is the first half of 2026.