Dr. A. F. Koenderink
FOM Institute AMOLF
Center for Nanophotonics
News
May, 2011
Congratulations Anouk and Bob
Student internships not only lead to diplomas, but also to publications! The joint work of internship students Anouk de Hoogh and Bob Hommersom, now appeared in press in Optics Express. Anouk and Bob show how a supercontinuum light source can be used to imprint any near-field enhancement in the wavelength range from 450 to 1100 nm in SU8 photo resist.They demonstrate the method on plasmon bowties and metamaterial splitrings Read out paper here: Wavelength-selective addressing of visible and near-infrared plasmon resonances for SU8 nanolithography, Optics Express 19, 11405 (2011).
December, 2010
Purcell factor breaks down for plasmonics
In 1946, Purcell proposed that the emission rate of a spontaneous emitter can be significantly enhanced if the emitter is positioned in a cavity. The enhancement factor known as Purcell factor, states that emission is enhanced in proportion to Q / V: i.e. the more optical cycles (Q), a photon is confined in as small a volume (mode volume V) as possible, the higher the light-matter interaction strenght. The Purcell factor enjoys huge success in quantum optics. Is plasmonic light-matter interaction also described by the Purcell factor ? In a new publication in Optics Letter, we show that the paradigm by Purcell breaks down in plasmonics. Firstly, we show that the mode volume is ill defined. Secondly, we show that there is no reasonable definition of mode volume that repairs the Purcell factor. Indeed, plasmonic rate enhancements always exceed the enhancement predicted by any reasonable estimate of Q and V. Read out paper here: On the use of Purcell factors for plasmon antennas, Optics Letters 35, 4208-4210 (2010).
November, 2010
FOM Program Nanoscale Quantum Optics
FOM has awarded a new Research Program Nanoscale Quantum Optics. This program, headed by Andrea Fiore at the Technical University Eindhoven, combines four leading dutch institutions in nanophotonics and quantum physics, i.e., the TU Eindhoven, Delft University, Leiden University and AMOLF. The Resonant Nanophotonics group will initiate research on gain and lasing in ultrasmall scattering structures.
May, 2010
NWO VIDI starts - Resonant Nanophotonics welcomes 2 new PhD students
The Resonant Nanophotonics group welcomes Abbas Mohtashami and Felipe Bernal Arango. They will significantly expand our efforts to interface single emitters with single photons using nanoscale plasmonic structures. This program is funded by a VIDI award that is part of NWOs 'Veni, Vidi, Vici' Innovative Research Incentive scheme.
November, 2009
Veni, Vidi....NWO awards VIDI grant to Resonant Nanophotonics
On November 24, NWO announced that they will award Femius Koenderink with a prestigious VIDI-award. The VIDI-award is part of NWOs 'Veni,Vidi,Vici' Innovative Research Incentive scheme, aimed at talented, creative researchers the opportunity to conduct their own research programme independently and promote talented researchers to enter and remain committed to the scientific profession. The VIDI award is aimed at stimulating tenure track researchers and starting group leaders.
Femius, who already received a VENI award in 2006, intends to use the 800.000&euro award to significantly expand efforts in the Resonant Nanophotonics group at AMOLF to interface single emitters to beams of single photons using nanoscale antennas (.cf. our Nano Letters). The research grant provides funding for two PhD positions.
October, 2009
First paper on metamaterials from our group accepted in Physical Review Letters
Metamaterials are artifical optical materials that act as if they are homogeneous, but in fact consist of nanoscale resonant scatterers. Together these scatterers can provide an effective homogeneous medium response, but with unconventional parameters such as a negative magnetic response. We study split ring arrays at telecom wavelengths, as already reported in 2005 by Enkrich (Karlsruhe group). Our data for arrays of different geometries shows strong coupling between split ring arrays, leading to collective modes with superradiant damping and line-shifts induced by magnetic and electric dipole-dipole coupling. These results shed new light on metamaterial design, and promises new physics for waveguiding, antennas and sensors based on metamaterial collective resonances.
We congratulate Jeroen Jacobs with his Master Diploma
On October 26th, Jeroen Jacobs received the first diploma awarded based on research in our group. Jeroen built a fluorescence microscopy set up with single molecule sensitivity, time correlated single photon counting capability, and spectral imaging capability. Jeroen received his Master in Experimental Physics at the University Utrecht. We congratulate Jeroen, and thank him for his great setup that will enable fluorescence studies of plasmonic and metamaterial structures in our group.
May, 2009
FOM awards projectruimte for metamaterials for quantum optics
In the FOM projectruimte competition, FOM has awarded our group the project metamaterials for quantum optics. In this project a new PhD student will seek to control spontaneous emitters using perfect lenses or cloaks, fabricated from metamaterials. Well-known predictions by Pendry claim that perfect lenses can create perfect images of subdiffraction objects such as emitters, or that perfect cloaks can be made, that completely shields the space inside the cloak from light outside the cloak . What happens to the spontaneous emission rate when a perfect lens images one atom perfectly onto another? Or if a source is cloaked?
January, 2009
Cathodoluminescence and surface plasmon polaritons
Scanning electron microscopes are normally used to generate images of a samples nanoscale topography, by mapping the flux of backscattered electrons as a function of the position of a narrow electron beam, that is raster scanned over the sample. However, many samples emit light in response to the electron beam. This phenomenon, named 'cathodoluminescence' can provide rich information about the optical modes of the sample. The paper Local density of states, spectrum, and far-field interference of surface plasmon polaritons probed by cathodoluminescence by M. Kuttge, E. J. Vesseur, A. F. Koenderink, H. J. Lezec, H. A. Atwater, F. J. García de Abajo and A. Polman reports that cathodoluminescence is in fact a method to measure the `local density of states ' of surface plasmon polaritons. The authors report that the cathodoluminescence of surface plasmons generated in front of a plasmon mirror shows typical oscillations with wavelength and electron beam position that are analogous to oscillations in molecular decay rate observed for molecules close to a mirror in a seminal experiment by Drexhage in the 1960's. Phys. Rev. B 79, 113405:1-4 (2009).
July, 2008
Fractional decay of quantum dots in real photonic crystals
When a molecule, quantum dot or atom is in an excited state it will usually fluoresce according to Fermi's Golden Rule. This rule means that the probability of finding the molecule in the excited state irreversibly decays exponentially to zero with time. Exceptions to this rules can occur in systems where photons are confined long enough that `strong coupling' where the emitter can reversibly interact with its own photon. Fractional decay is such a non-classical phenomenon, where the probability to find the emitter excited decays to a non-zero value. Whether such fractional decay is in fact observable has remained unclear, as the only systems for which it has been predicted are idealized, unphysical photonic band gap systems. In the paper Fractional decay of quantum dots in real photonic crystals, by P. Kristensen, A. F. Koenderink, P. Lodahl, B. Tromborg, J. Mørk, we show that such decay is in fact observable in real Si inverse opal photonic crystals that have been fabricated in several labs. This work results from a collaboration of the Technical University of Denmark and the FOM Institute AMOLF. Read about the result here: Opt. Lett. 33, 1557-1559 (2008).
June, 2008
Quantum interactions of single atoms on huge length scales
Observing the interaction of neutral atoms or molecules in space and time is extremely difficult, since such interactions only occur on ultra small length scales (0.1 nm), and ultra fast time scales. A team of researchers at the University of Amsterdam, the FOM Institute for Atomic and Molecular Physics (AMOLF) and Auburn University have recently for the first time shown that they can record a `movie’ of such interactions by magnifying the length scale of the interaction to a spectacular 50 microns (the thickness of a hair, or a million times the size of an atom) and slowing down the time scale at which such `dipole-dipole’ interactions occur by 10,000 times.
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The researchers first cooled a cloud of rubidium atoms (shown in blue) so that all atoms remained frozen during the experiment. Then they prepared two different species (labelled|0> and|1>) of `magnified’ rubidium, using two pulsed laser beams. They recorded the transfer of energy from one species to the other across a separation of 50 microns, even though no atoms physically moved during the interaction. |
There are two essential tricks: the first is to magnify the atoms themselves by exciting the outer electron to an orbit very far removed from the atomic nucleus.
The second trick is to cool the atoms to ultra low temperatures, so that they don’t move during the recording of the movie. The experiment reported by the authors provides an interesting model system for resolving ‘dipole-dipole’ interactions simultaneously in time and space. ‘Dipole-dipole’ interactions are of fundamental interest, and are ubiquitous in for instance biophysics, plasmonics and quantum optics. Furthermore, the experiment is a first step towards realizing a quantum computing system in which neutral atoms act as quantum bits of information, and for which researchers can resolve the coherent transport of quantum information in space and time. On June 20th, the researchers published their results in the leading scientific journal Physical Review Letters.
C. S. van Ditzhuijzen, A. F. Koenderink, J. V. Hernández, F. Robicheaux, L. D. Noordam, and H. B. van den Heuvell.
Spatially Resolved Observation of Dipole-Dipole Interaction between Rydberg Atoms.
Physical Review Letters 100 (2008) 243201
February 1, 2008 - New group Resonant Nanophotonics at AMOLF
Starting february 1, I will set up new research at AMOLF in Resonant Nanophotonics. The philosophy is to use plasmonic and metamaterial resonances as building blocks in a multiple scattering toolkit of subwavelenth resonators to create complex optical structures. These structures are expected to have high potential as `optical nanocircuits' and as alternatives to high-Q dielectric microcavities for quantum optics.
Positions for talented Ph.D. students and Master students are available immediately (click on the links to read the project descriptions). Applications should be directed to the AMOLF personnel department and need to be accompanied by a CV, grade list, and written motivation for the specific project. For information contact me at f.koenderink@amolf.nl
December 10, 2007 - Switching a microcavity
Read our Optics Express contribution to the focus issue on microresonators on the near-field imaging of a photonic crystal microcavity with a Q of 55 000 and a mode volume of just about 0.25 cubic wavelengths. Not only is this probably the smallest high-Q microcavity mode ever imaged in the near-field, we also show that the near-field probe is a gentle cavity tuner: it shifts the resonance without damaging the Q. This was work done at the Nano-Optics Group ETH Zurich, and the group of Martin Kamp at Wurzburg University. Read about it here !
November 14, 2007 - Plasmon chain dispersion
We have measured for the first time the dispersion relation of silver and gold plasmon nanoparticle chain waveguides with ultrasmall pitches of 75 nm to 150 nm using angle-resolved extinction measurements. Contrary to the popular quasi-electrostatic picture in which excitations are supposedly guided by near-field nearest neighbor interactions between adjacent plasmon resonances, we find a dispersion relation that is dominated by far-field effects, interference and retardation, even for spacings down to a fifth of the wavelength. Read the paper by A.F. Koenderink, R. de Waele, J.C. Prangsma and A. Polman that just appeared as a Phys. Rev. B Rapid Communications here.
September 25, 2007 - Spontaneous emision near metal spheres
Read Hans Mertens' in-depth analysis of spontaneous emission lifetime and quantum efficiency near real metal spheres. This paper, published last week in Physical Review B, describes the expected lifetime changes based on an exact Green's dyadic model, and compares the results to the approximate model by Gersten and Nitzan that can be extended also to anisotropic particles. (Link to paper)
July 12, 2007 - Photonics: chains light up
Read the Nature News & Views feature by Niek van Hulst about our recent Nano Letters paper "Tunable nanoscale localization of energy on plasmon particle arrays"
(click on image)
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July 10, 2007 - Plasmon antennas
First evidence for a new type of plasmon antenna appears in Nano Letters 7, 2004-2008 (2007) .
The paper "Tunable nanoscale localization of energy on plasmon particle arrays" by Rene de Waele, Femius Koenderink and Albert Polman describes an experiment that shows that arrays of resonant plasmon particles can act just like multi-element array antennas for radio and TV signals, yet at optical frequencies! As first proposed by our coworkes Jesus Hernandez, Francis Robicheaux and Bart Noordam, using multiple dipole scatterers to build plasmon antennas allows to achieve strong focusing of EM power in a small volume in a manner that is very frequency sensitive, and sensitive to the incoming angle. This technique of optimizing interferences for optimum field enhancement is complementary to and can hopefully be combined with currentplasmon antennas that depend on local shape singularities, such as bow-tie antennas.
April 30, 2007 - Review paper on nano-mechanical manipulation
Read the review paper on Nano-mechanical manipulation and nano-optical characterization of photonic crystal devices by Sushil Mujumdar, Femius Koenderink, Robert Wüest and Vahid Sandoghdar that just appeared in a topical issue on optics and MEMS in the IEEE Journal of Selected Topics in Quantum Electronics.
Abstract
We describe the application of scanning near-field optical microscopy (SNOM) for the high-resolution visualization of light propagation in photonic crystal structures. We also demonstrate that nanoscopic elements such as sharp tips could be used for the mechanical manipulation of the optical properties of photonic crystals. In particular, our theoretical and experimental results show that narrow resonances of a photonic crystal cavity
can be tuned without a substantial influence on its quality factor.
Furthermore, we discuss the modification of the fluorescence of a
nanoscopic emitter as a function of its location close to a photonic
crystal.
February 9, 2007 - Plasmon lithography
The paper A. F. Koenderink, J. V. Hernandez, Robicheaux, L. D. Noordam and A. Polman, Programmable nanolithography with plasmon nanoparticles was accepted for publication in Nano Letters.
Abstract
We describe how optical contact lithography based on plasmon resonant particle array masks allows to generate a large number of different subwavelength exposure patterns using a single mask. Illumination with unfocused light allows to optically address particles either individually or in controlled configurations; which pattern will be exposed by the mask is programmed by varying the wavelength, incidence angle and polarization of the incident wave.