Project Leader – QuMat.1-TUD-4.1C
Optical characterization of exciton-photon conversion and hybridization
Co-supervisor – QuMat.1-TUE-2.2D / 4.2B
Opto-magnonic devices / On-chip coupling of light to spin and pseudo-spin
Brief research summary over last 5 years / academic profile
Kobus Kuipers is an expert in nanooptics and light-matter interactions in nanosystems. He is in particular known for his investigation and visualization of (slow) light in complex photonic nanostructures, including plasmonic structures and photonic crystals (review: Nature Photonics 2014, Science 2001&2009). Several achievements of his early work are now taught in graduate courses and textbooks (e.g. Principles of Nano-Optics, by Lukas Novotny & Bert Hecht, Cambridge University Press 2006). He has studied many different aspects of light at the nanoscale. His work includes the measurement of photonic band structures, enabled by the direct access to nanoscale light he has mastered. By tracking femtosecond pulses in time and space, he was able to not only observe ultraslow light but also demonstrate the unwanted side effects of the increased light-matter interaction associated with slow light: enhanced scattering and ultimately, in one-dimensional waveguides, Anderson localization.
Recently, his group has focused on the topology of light itself and how it can be used to control light-matter interactions. Chirality, helicity and the optical spin (density) of light play a crucial role (Phys. Rev. X, Phys. Rev. Lett. 2018 & Nano Lett. 2019). Using access to the full vectorial nature of light at the nanoscale (njp Light Sci. & Appl. 2019), his team was able to show an imbalance in the topological charge of higher-order vortices in 2D random light-fields (Optica 2019). He was able to exploit the transverse optical spin, resulting from the spin-orbit coupling of confined photonic eigenstates, to create a one-to-one connection between the direction of emitted photons and the specific valley in a two-dimensional quantum material (Science 2018) and vice versa (Nano Lett. 2020). His group also investigates light in topologically non-trivial photonic crystal structures. A bichromatic photonic crystal was used to mimic the Harper-Aubry-André Hamiltonian and realize the photonic analog of an integer quantum Hall state (Optica 2019). With expanded and shrunken photonic crystals obeying C 6 symmetry, topological edge states were experimentally demonstrated as an analog of the spin Hall system (Science Adv. 2020). In another system that mimics the valley Hall system for electrons, the photonic band structure of the edge states was measured, and their topological robustness against scattering quantified (njp Light Sci. & Appl. 2021).
International visibility, activities, prizes, scholarships etc.
Kuipers is at the international forefront of nanophotonics. This is reflected in 6-8 accepted invitations for talks at international conferences, which includes typically one keynote or plenary lecture. He is a member of the steering committee of both the leading photonic crystal and plasmonic conference series, PECS and SPP, respectively. He is a standing member of the program committee of NFO on near-field optics and related techniques. Kuipers was a recipient of an NWO Vici subsidy and an ERC Advanced grant.
Kuipers has a strong international network. His collaborators include Thomas Krauss, Andrea Alu, Harald Giessen, Susumu Noda, Toshi Baba, Harry Atwater, Kostya Bliokh, John Sipe and many others. He was an international Partner Investigator of the CUDOS Center of Excellence of the Australian Research Council. In this context, he worked and published amongst others with Ben Eggleton, Martijn de Sterke and Yurii Kivshar on topics like soliton fission and evanescent modes at the interface of slow and fast light. Kuipers is an associate editor of Optica, the flagship journal of the Optical Society of America, and until the start of this year a board member of the oversight board of the Electromagnetic Metamaterial CDT in Exeter (UK).
In Nov. 2019 Kuipers became the first chair of the Dutch Physics Council, the national council to represent, coordinate and promote academic physics research and teaching in The Netherlands. In 2019 he also won the prestigious Physica prize of the Dutch Physical Society (NNV). In 2009 he was elected as an OSA Fellow. In 2004 he was elected to the young academy (DJA) of the royal Dutch academy of sciences (KNAW). He is a Member of Merit of the NNV and one of its ambassadors for its hundred-year celebration (2021). In 2015 he was the Chair of the International Year of Light in The Netherlands, as such he helped realize a large number of outreach activities on the general topic of light in primary schools, secondary schools, at rock concerts, etc.
5 key output/publications
Probing the magnetic field of light at optical frequencies.
M. Burresi, D. van Oosten, T. Kampfrath, H. Schoenmaker, R. Heideman, A. Leinse, and L. Kuipers
Science 326, 550-553 (2009).
First visualization of the magnetic field component of light at optical frequencies. In essence the experiment mimicked the original experiment of Hertz through extreme miniaturization.
Spatial bunching of same-index polarization singularities in two-dimensional random vector waves.
L. De Angelis, F. Alpeggiani, and L. Kuipers, Physical Review X 8, 041012 (1/10) (2018).
Experimental discovery of the unexpected bunching of same-index (or topological charge) polarization singularities in two-dimensional random light waves. With theory we proved that this was caused by inherent polarization correlations not found in 3D.
Electromagnetic helicity in complex media.
F. Alpeggiani, K.Y. Bliokh, F. Nori, and L. Kuipers, Physical Review Letters 120, 243605 (2018).
Theory paper on the first proper formal definition of optical helicity. Through this definition it has become possible to formally describe the interaction of helical light with matter.
Nanoscale chiral valley-photon interface through optical spin-orbit coupling.
S.-H. Gong, F. Alpeggiani, B. Sciacca, E.C. Garnett and L. Kuipers, Science 359, 443-447 (2018).
Demonstration of one-to-one coupling of specific valley excitons to specific eigenstates of plasmonic nanowire modes through the use of transverse optical spin.
Direct observation of topological edge states in silicon photonic crystals: spin, dispersion, and chiral routing.
N. Parappurath, F. Alpeggiani, L. Kuipers, and E. Verhagen, Science Advances 6, eaaw4137 (2020)
Experimental demonstration of momentum spin locking in edge states between topologically non-trivial photonic crystals and first experimental evidence of spin-spin scattering.