prof.dr. Ewold Verhagen

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Group leader: Photonic Forces


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Ewold Verhagen studies the physics of light confined at the nanoscale. He is particularly interested in the interactions between light and nanomechanical motion, the applications of field enhancement in micro-/nanocavities and plasmonic resonators, and efficient coupling of light to subwavelength volumes.

During his PhD research at the FOM Institute for Atomic and Molecular Physics (AMOLF), he performed experimental and theoretical research in the emerging fields of plasmonics and metamaterials. He studied the behavior and applications of light confined to subwavelength length scales in metallic nanostructures in the form of surface plasmon polaritons.

He demonstrated efficient nanofocusing of light on a chip to deeply subwavelength dimensions, showing how surface plasmons were compressed adiabatically in a tapered gold waveguide and guided below the diffraction limit. In a series of experiments, he demonstrated strongly enhanced absorption and emission rates in emitters coupled to plasmonic resonators, of particular interest for enhancing LEDs and solar cells. Finally, he described how light waves in nanoscale waveguides can be made to run ‘backwards’, described by a negative index of refraction. This led to the discovery of a new class of three-dimensional ‘metamaterials’, which can exhibit an isotropic negative index of refraction at optical frequencies.

His postdoc work in the Laboratory of Photonics and Quantum Measurement of Tobias Kippenberg at the EPFL focused on the interaction between light in high-Q microcavities and mechanical motion, in the newly arising field of quantum optomechanics. He developed novel silica microresonators exhibiting strong optomechanical coupling, and used these in a cryogenic experiment to cool a mechanical mode to an average occupancy of 1.7 motional quanta by radiation pressure sideband cooling. He demonstrated that the optomechanical coupling rate can exceed both the optical and the mechanical decoherence rate in the system, thus enabling quantum control of a mechanical oscillator with light (Nature, 2012).

Since the end of 2012, he leads the new research group Photonic Forces at the FOM Institute AMOLF. His group studies photonics in high-quality microcavities and nanophotonic waveguides, with a special interest in the coupling between light and nanomechanical motion through radiation pressure forces in nanophotonic systems. In 2014, he was awarded the NWO Vidi grant to perform quantum measurements in nano-optomechanical systems.