Prof. F. Ömer Ilday

Department of Electrical and Electronics Engineering,
Department of Physics, and UNAM
Phone: +90-312-290-8076
Address: EE-506, Bilkent University, Çankaya, Ankara 06800, Turkey

Research interests:

When I look how structure and functionality arise in nature, the role of emergent phenomena is evident. It is inspiring that emergence of structure and functionality is ubiquitous, from pattern formation in an inanimate sand pile to primitive life forms, all the way up, in complexity, to the primate brain and modern human social constructs. It is also evident that the degree of complexity forms a continuum, starting from relatively simple nonlinear or delay-feedback systems to full-fledged complex behavior.

In contrast, when I look at man-made systems, I rarely see deliberate use of these principles. An engineering marvel, such as a modern jet, is extremely complicated, but it is possible, at least in principle, to predict its entire functionality by starting from either the lowest or the uppermost level and working one’s way up or down in its hierarchy of structure, accompanied, typically, with a polynomial increase in computational complexity. This is in sharp contrast to a bacterium; even though we understand much of its sub-units, this knowledge does not translate into prediction of its behavior at the system level. Is it not already time that we start developing technological devices that incorporate the same principles of operation and adaptability that govern, say, a bacterium?

I have a specific proposal, which I refer to as nonlinearity engineering: I propose to exploit complex nonlinear and stochastic dynamics to achieve superior technological functionalities, which may be difficult or even impossible to achieve with linear systems. This requires first and foremost deep understanding of the underlying dynamics as well as the right tools of control over the system under study. Ultrafast lasers and nanophotonic systems are ideal candidates for tools of control and target platform, respectively.

For additional information, see the web pages of Ultrafast Optics and Lasers Laboratory (UFOLAB).

If this is interesting to you:

For postdoctoral work, we are not actively looking, but always have the possibility to create a position for an exceptional candidate.

We routinely host visiting researchers, typically within the framework of an existing collaboration agreement, but we are always open to new proposals.

For MS and PhD work, you need to be first admitted to a graduate program in any of the following: Electrical and Electronics Engineering, Physics, Material Science and Nanotechnology and Neuroscience at Bilkent University.

For undergraduates volunteer work, internship or formal research course work, please contact me directly. At any moment there are many undergraduate students working at UFOLAB. There is naturally a limit of how many student we can host at any given time, but simply ask. If helps, if you have analytic, computer, electronic, mechanical or other technical skills.


Ten selected publications [full list is here]:

1. G. Makey, Ö. Yavuz, D. K. Kesim, A. Turnalı, P. Elahi, S. Ilday, O. Tokel, F. Ö. Ilday, “Breaking crosstalk limits to dynamic holography using orthogonality of high-dimensional random vectors,” Nature Photon. 13, 251 (2019).
2. F. Kalantarifard, P. Elahi, G. Makey, O. M. Marago, F. Ömer Ilday, G. Volpe, “Intracavity optical trapping of microscopic particles in a ring-cavity fiber laser,” Nature Commun. 10, 2683 (2019).
3. (invited) H. Kalaycioglu, P. Elahi, F. Ö. Ilday, Ö. Akcaalan, “High-repetition-rate ultrafast fiber lasers for material processing,” IEEE J. Sel. Topics Quantum Electron. 24, 8800312 (2018).
4. O. Tokel, A. Turnalı, G. Makey, P. Elahi, T. Çolakoğlu, E. Ergeçen, Ö. Yavuz, R. Hübner, M. Zolfaghari Borra, I. Pavlov, A. Bek, R. Turan, D. K. Kesim, S. Tozburun, S. Ilday, F. Ö. Ilday, “In-chip microstructures and photonic devices fabricated by nonlinear laser lithography deep inside silicon,” Nature Photon. 11, 639–645(2017).
5. S. Ilday, G. Makey, G. B. Akgüç, Ö. Yavuz, O. Tokel, I. Pavlov, O. Gülseren, F. Ö. Ilday, “Rich complex behavior of self-assembled nanoparticles far from equilibrium,” Nature Commun. 8, 14942 (2017).
6. C. Kerse, H. Kalaycıoğlu, P. Elahi, B. Çetin, D. K. Kesim, Ö. Akçaalan, S. Yavaş, M. D. Aşık, B. Öktem, H. Hoogland, R. Holzwarth, and, F. Ö. Ilday, “Ablation-cooled material removal with ultrafast bursts of pulses,” Nature 537, 84–88 (2016).
7. S. Ilday, F. Ö. Ilday, R. Hübner, T. J. Prosa, I. Martin, G. Nogay, I. Kabacelik, Z. Mics, M. Bonn, D. Turchinovich, H. Toffoli, D. Toffoli, D. Friedrich, B. Schmidt, K.-H. Heinig, and R. Turan, “Multiscale self-assembly of silicon quantum dots into an anisotropic three-dimensional random network,” Nano Lett. 16, 1942–1948 (2016).
8. B. Öktem, I. Pavlov, S. Ilday, H. Kalaycıoglu, A. Rybak, S. Yavas, M. Erdogan and F. Ö. Ilday, “Nonlinear laser lithography for indefinitely large-area nanostructuring with femtosecond pulses,” Nature Photon. 7, 897–901 (2013).
9. B. Oktem, C. Ülgüdür and F. Ö. Ilday, “Soliton-similariton fibre laser,” Nature Photon. 4, 307 (2010).
10. F. Ö. Ilday, J. Buckley, and F. W. Wise, “Self-similar evolution of parabolic pulses in a laser cavity,” Phys. Rev. Lett. 92, 213902-1 (2004).


“Before the Gates of Excellence the high Gods have placed sweat.”

(Hesiod, Works and Days)