The Optical Nanomaterial Laboratory in the Physics Department at ETH Zurich is looking for a PhD student in nonlinear optics for analog computing.

A complex medium (also known as disordered or random medium) is an optical system that mixes the spatial and temporal degrees of freedom of an incident field, resulting in a scrambled intensity distribution at its output. The large number of internal degrees of freedom makes the output intensity pattern random, yet deterministic. Consequently, it is possible to characterize – and even control – the propagation of light through the medium, allowing the disordered system to perform a variety of tasks when combined with programmable modulators. Applications include the control of various properties of light, such as intensity, polarization, spectrum, and coherence.

In the Optical Nanomaterial group, we have introduced an additional layer of complexity to random media: optical nonlinearity. The nonlinear disordered medium is composed of nanodomains characterized by a second-order susceptibility tensor. As such, each nanodomain generates second-harmonic (SH) waves with random amplitude and phase when excited by a fundamental beam. The interference of the generated waves leads to efficient nonlinear light generation without stringent conditions on the polarization and wavelength of the fundamental light, which is not possible with bulk crystals. Our material provides a unique platform to study the combined effect of nonlinear light generation and multiple scattering.

The PhD project aims to exploit the large number of modes supported by the random structure to enable large-scale nonlinear optical operators for photonic machine learning and quantum optics. The former relies on the second harmonic generation to implement a large reservoir of nonlinear operations, while the latter involves the theoretical and experimental characterization of the spontaneous parametric down-conversion (SPDC) process in nonlinear disordered media, and the subsequent control of the generated quantum states.

The project will include all steps from: fabrication of the nonlinear disordered samples, carried out in the group’s chemistry lab, followed by optical and material characterization; investigation of the fundamental properties of the interplay between multiple scattering and nonlinear generation; design  and implementation of photonic neural network based on the large reservoir of random nonlinear operations; theoretical and experimental investigation of the SPDC process in random nonlinear media and the control of the generated photons’ state.

The preferred starting date is June 2024.

The successful candidate should be creative, well-organized, and highly motivated to work in a photonic laboratory, with emphasis on free-space optics experiments with nonlinear disordered systems. The candidate should have a Master’s degree in physics, quantum engineering, electrical engineering, photonics or related fields.

ETH Zurich is a family-friendly employer with excellent working conditions. You can look forward to an exciting working environment, cultural diversity and attractive offers and benefits.

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.

We look forward to receiving your application including

• a cover letter
• CV
• transcripts of Bachelor’s and Master’s degrees
• contact information of two referees.

For further information please contact Prof. Rachel Grange (grange@phys.ethz.ch) or visit our website. Only applications submitted via the online tool will be considered.

ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000 people from more than 120 countries find our university to be a place that promotes independent thinking and an environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we work together to develop solutions for the global challenges of today and tomorrow.