Nonlinearity Engineering
Scientific Direction
How do nonlinear feedback and fluctuations — amplified rather than suppressed — give rise to emergent structure?
For over two decades, this question has guided our research, shaping a programme that spans laser physics and laser–matter interaction.
Our long-term goal is programmable emergence: the predictive and ultimately prescriptive control of emergent order through engineered nonlinear feedback.
We pursue this agenda using lasers in two roles: as highly controllable model systems of self-organised emergence and as precision tools for interacting with matter.
In lasers, this means shaping the dynamics that determine how light organises itself in space and time. In materials, the custom laser systems we develop excite nonlinear responses and generate spatio-temporal gradients with exceptional control. This allows us to steer collective dynamics so that structure forms spontaneously from engineered interaction rules rather than being written point by point. Control over structure is achieved through dynamics rather than geometry and is not fundamentally limited by optical diffraction.
A focal convergence of this programme is the Atom Printer: a framework in which laser-engineered feedback guides atomic self-assembly beyond the geometric limits imposed by optical diffraction.
Experimental Platforms
We design and build ultrafast lasers that the physics demands, rather than adapting research questions to existing technology.
Building on decades of accumulated expertise and purpose-built laboratory infrastructure, we construct laser architectures ranging from new forms of mode-locking to powerful burst-mode systems with repetition rates of ~100 GHz and beyond. We integrate these sources into specialized laser–matter platforms, leveraging our microscopy and holography expertise, and operate across ambient, aqueous, and vacuum environments.
Extreme repetition-rate interactions of ultrashort pulses with matter enable engineered collective effects, memory, and intrinsic feedback that are fundamentally inaccessible in conventional single-pulse approaches.
News
Job opening for postdoctoral researcher (m/f/d) focusing on ultrafast laser physics
NLE is dedicated to exploring the fundamentals, as well as practical imlementation of how to design and experimentally realize nonlinear systems to achieve a certain pattern, structure or functionality to which the system will evolve largely by itself. We use modelocking of lasers and complex laser-matter interactions both as model systems and experimental tools to this end. Our interdisciplinary research involves laser physics, light-matter interactions, nonlinear and self-organized phenomena using a combination of experimental and theoretical work. While the research of NLE is motivated firstly by scientific curiosity, and a step-by-step systematic effort tackle the open questions, we also pursue and exploit its applications and technological implications, from advancing laser technology, material processing, and laser surgery, to the long-term vision to develop an "Atom Printer" based on laserdriven self-organization.
Workshop "Complex Optics and Modelocking: Synergies on the Horizon" on 22. November.
Modelocking enables the generation of ultrashort pulses of light from laser cavities, a breakthrough that has led to four Nobel Prizes. The process of generating ultrashort pulses is so seamless and reliable that it is easy to overlook that modelocking is a self-organized phenomenon, arguably one of the most impactful in science. Thousands of frequency modes within a laser cavity spontaneously lock their phases, producing pulses that are orders of magnitude shorter than the cavity itself.
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New publication in Nature Photonics titled "Driven by feedback, unlimited by diffraction".
By exploiting nonlinear feedback arising from the interaction of ultrafast laser pulses, self-organized nanolines that appear to defy the limits of diffraction are shown to cut, dice, and structure optical materials, fabricating true zero-order sapphire waveplates and crystalline micro-prisms.
Ömer Ilday erhält Alexander von Humboldt-Professur
Die Bundesministerin für Bildung und Forschung Bettina Stark-Watzinger und der Präsident der Alexander von Humboldt-Stiftung Prof. Dr. Robert Schlögl haben am 13. Mai 2024 in Berlin die Alexander von Humboldt-Professuren verliehen.
New co-optations: Prof. Dr. Serim Ilday and Humboldt Professor Prof. Dr. F. Ömer Ilday
On January 31, the Faculty Council of the Faculty of Physics and Astronomy approved the co-optations of Prof. Dr. Serim Ilday and Prof. Dr. F. Ömer Ilday.
F. Ömer Ilday comes to Ruhr University
The renowned physicist receives the most highly endowed research award in Germany. In Bochum, he is to open up new fields of research in materials science and establish a research centre.
Alexander von Humboldt Professorship 2024 Fatih Ömer İlday
F. Ömer İlday has played a seminal role in developing ultrafast laser technology, transforming the field of non-linear laser-matter interactions in the last few years. He is now invited to join Ruhr-Universität Bochum to explore new research fields in materials science and establish a world-class research centre.
Dr. Ilday bringt ERC Advanced Grant, UniLase, an die Ruhr-Universität
F. Ömer İlday promovierte 2003 an der Cornell University, Ithaca, USA, und arbeitete ab 2003 als Postdoc und ab 2005 als Forschungswissenschaftler am Massachusetts Institute of Technology, USA. Im Jahr 2006 wechselte er als Professor für Physik an die Bilkent-Universität in Ankara, Türkei. Von 2014 bis 2023 war er dort Professor für Physik und Elektrotechnik.