MESA+ University of Twente
Applied Nanophotonics

Research Projects - Applied Nanophotonics

On these pages, descriptions of selected current and past ANP research projects can be found. These are:


Applications of quantum optics in boson sampling or quantum information processing require quantum interference in high-dimensional optical networks. To this end, we study massively multichannel optical networks, containing millions of transmission channels. These massively multichannel networks can for instance be constructed by opaque scattering media. Adaptive spatial modulation of the light incident on these networks allows for complete control over the channels. Consequently, the functionality of the optical network is fully programmable. By sending multiple photons from a spontaneous parametric down-conversion source through these networks we observe quantum interference, which can be freely tuned and programmed.

Research group: Complex Photonic Systems (COPS) & Laser Physics and Non-Linear Optics (LPNO)
PhD student: Tom Wolterink
Supervisors: Pepijn Pinkse, Willem Vos, Klaus Boller
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Nano-Structured XUV Optics

The development of novel optical elements for Extreme UV (EUV) and Soft X-Ray (SXR) wavelengths (0.1 to 100 nm) is of high interest for applications such as X-ray fluorescence analysis. Further interest lies in EUV lithography, beam delivery and nano-focusing of X-ray free-electron lasers, and of sources based on high-harmonic generation. Due to the very short wavelengths (1-10 nm), the realization of such optics has to be done with nano-patterning. In this research project, we investigate novel types of optical components for the EUV/SXR range. The research involves the theoretical description, fabrication and optical investigation of advanced multi-nano-layers systems combined with lateral nano-structuring to realize three-dimensional photonic structures, such as Bragg-Fresnel optics, Lamellar Multilayer Gratings (LMG) or Borrman-based transmission filters.

Research group: Laser Physics and Non-Linear Optics (LPNO)
PhD student: Jonathan Barreaux
Supervisors: Bert Bastiaens, Klaus Boller
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Tunable diode lasers with narrow spectral bandwidth are of interest for a large number of applications in, e.g., coherent optical communications, precision metrology, spectroscopy or optical switching. Of particular interest is the investigation of novel types of external cavity lasers based on integrated optics and hybrid integration. In such systems an extensive spectral control can be exerted via low-loss, and high-Q waveguide resonators. This approach can be extended to entire arrays with a large number of lasers. When controlled to form a comb-like spectrum and with appropriate phasing, trains of ultra-short pulses with unprecedentedly high repetition rates in the THz regime can be synthesized. Other modes of operation of such arrays offer solutions for future applications in microwave photonics such as adaptive beam forming networks. In this project we investigate the properties of such light sources.

Research group: Laser Physics and Non-Linear Optics (LPNO)
PhD student: Youwen Fan
Supervisors: Peter van der Slot, Klaus Boller
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Smart Spectrometers

Current spectrometer devices cover a wide variety of applications with very diverse specifications, using various different operation principles and technical realizations. Most of these are large in size, costly and critically dependent on alignment and precision in fabrication.

We are interested in finding a new and universal approach to optical spectrometers that are inherently stable and small, can offer diverse specifications over a wide wavelength range, are self-calibrating and are highly tolerant to fabrication errors. Exploiting the advantages of photonic integrated circuits (PICs), specifically, based on high-contrast low-loss Si3N4 / SiO2 glass waveguides, we investigate novel spectrometer devices based on, e.g., tunable and programmable networks of micro ring resonators which provide high wavelength selectivity. An easy and flexible control of performance, self-calibration and high tolerance to fabrication errors is investigated via electronic, data driven control using, e.g., neural-network algorithms.

Research group: Laser Physics and Non-Linear Optics (LPNO)
PhD student: Caterina Taballione
Supervisors: Peter van der Slot, Klaus Boller
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Spectroscopy on PLD plasmas

The goal of this research project is to provide an improved mapping of the dynamics and the chemistry taking place in the plasma plumes that are being used in pulsed laser deposition (PLD) for thin film growth. Especially the influence of external PLD parameters, such as ablation laser fluence and background gas composition and pressure, on the plasma dynamics and chemistry are of interest to us, as we believe this is the key to an improved understanding and control of stoichiometric film growth.

We employ a combination of laser induced fluorescence (LIF) and absorption spectroscopy (AS). This allows for in-situ spatiotemporal mapping of the absolute densities of plasma constituents. A dye laser combined with second harmonic generation provides an extremely wide range of wavelengths that can be produced (250 — 900 nm) and thus a wide range of materials that can be detected. It also enables high chemical selectivity, due to a very narrow linewidth, ensuring only a single plasma constituent will be detected at any one time. Spatial resolution is provided by shaping the LIF excitation beams with special optics, allowing for mapping of thin cross-sections of the plasma plume. The short pulse length of the dye laser (7 ns FWHM), in combination with a high-speed camera, provide the temporal resolution.

Research group: Laser Physics and Non-Linear Optics (LPNO)
PhD student: Kasper van Orsel
Supervisors: Bert Bastiaens, Klaus Boller
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High Harmonic generation from atoms and ions

The goal of this research project is to develop a tunable EUV radiation source using high-order harmonic generation (HHG). The high-order harmonics will be generated in a gas-filled capillary waveguide using a Ti:Sapphire laser producing 35 fs pulses. Efficient high order harmonic generation requires phase matching and pressure tuning is used for the capillary system. The capillary inner radius will be optimized for a maximum drive laser pulse energy of about 7 mJ. Coherent control of the driver laser is used to study the influence of drive laser pulse on the HHG process.

To reach shorter wavelength, we are also investigating high-order harmonic generation from an ionized noble gas instead of neutral atoms. Since pressure tuning is not possible any more, we are investigating quasi-phase matching techniques to improve the efficiency of HHG from noble gas ions, in particular we are looking into ion density modulation techniques.

Research group: Laser Physics and Non-Linear Optics (LPNO)
PhD student: Yin Tao
Supervisors: Bert Bastiaens, Peter van der Slot, Klaus Boller
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Functional hybrid technologies for Si3N4 waveguides

The development of optical devices on the scale of microchips requires exceptional control over light traveling through waveguides. For example, one needs the ability to modulate and switch the light, or to force it to flow in one direction (isolation). This research aims to combine glass waveguides with active elements or materials, such as semiconductors, to study novel methods for on-chip modulation, switching, and isolation. This can give access to a wealth of novel options in integrated photonics.

Research group: Laser Physics and Non-Linear Optics (LPNO)
PhD students: Jesse Mak, Marco Garcia Porcel
Supervisors: Bert Bastiaens, Peter van der Slot, Carsten Fallnich, Klaus Boller
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Photonic free electron laser

In a photonic free-electron laser (pFEL), the longitudinal periodicity of a photonic structure is used to slow down the phase velocity of an electromagnetic (EM) wave, such that it moves synchronously with a copropagating electron beam. The interaction of the EM wave with the electrons results in bunching of the electrons and consequently coherent amplification of the EM wave.

The photonic structure is chosen to allow multiple electron beams to propagate through the structure. The transverse periodicity of the photonic crystal results in the establishment of a single transversely coherent EM wave (the transverse scattering allows the electron beams to ‘communicate’ with each other through the EM wave, so that they become phase locked). The output power of such an device can be scaled by increasing the number of electron beams propagating in parallel and simultaneously increasing the transverse dimension of the photonic crystal. In this research program, we investigate various aspects of this novel type of laser.

Research group: Laser Physics and Non-Linear Optics (LPNO)
Student: Ron Amran
Postdoc: Joanna Krowka
Supervisors: Peter van der Slot
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Simulation of free-electron lasers

The unique properties of free-electron lasers makes it an ideal tool for pushing the frontier of scientific research. The combination of femtosecond time duration for the generated optical pulses at sub-nanometer wavelength with the highest peak brightness currently available, allows to investigate ultrafast dynamical processes with atomic resolution. Using a combination of tools, i.e., dedicated models for the gain, such as Genesis 1.3 and Minerva, and a dedicated model for the optical propagation outside the gain section of the free-electron laser, we model various types of systems ranging from FEL oscillators at various wavelength, to regenerative FEL amplifiers and self-amplified spontaneous emission FELs.

Research group: Laser Physics and Non-Linear Optics (LPNO)
Responsible: Peter van der Slot
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Nanophotonic manipulation of biological emitters

We are exploring nanophotonic manipulation and control of biological emitters – nanobiophotonics. Using the nanophotonics toolbox we not only passively observe, but actively manipulate the emission from biomolecules.

Certain aspects of the photophysical properties of complex emitters like fluorescent proteins (VFPs) cannot be analyzed with conventional methods. VFPs are known to form mixtures between emitting and nonemitting states that cannot be separated. All conventional methods to determine the quantum efficiency average over the dark and the emitting states. We have overcome these limitation by using nanophotonic manipulation to determine for the first time the fluorescence quantum efficiency of exclusively emitting states of visible fluorescent proteins (VFPs) without the influence from dark states.

We manipulated the local density of optical states (LDOS) of VFPs by positioning the VFPs at defined distances (with nanometer precision) to a metallic mirror. This results in characteristic changes in the fluorescence decay rate that we used to determine the radiative and nonradiative decay rates of the fluorophore. Since only the emitting species contribute to the change in total decay rate, only these emitting states are characterized.

Research group: NanoBioPhyscis (NBP) and COPS
PhD student: Martijn Stopel (NBP)
Supervisors: Christian Blum (NBP), Vinod Subramaniam
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Surface Enhanced Fluorescence with silver nanoparticles

The enhanced EM field near metal nanoparticles the support surface plasmons can modify the emission of molecules. For single particles, the benefit of the excitation enhancement by the enhanced EM field is mostly overcome by the very low QY of the emission because of quenching by the metal. However, in between particles (the ‘hot spot’), the field enhancement is much larger than for single particles, and the emission QY is higher.

In this research, the enhancement of fluorescence from dye-labeled biomolecules is studies, together with new biochemical methods to position the dyes at the hot spots. The end goal is to apply these principles to create more efficient biosensors.

Research group: Nanobiophysics (NBP)
Responsible: Ron Gill
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Characterization of alpha-synuclein oligomers

The neuronal protein alpha-synuclein is considered to play a critical role in the onset and progression of Parkinson’s disease. Growing evidence suggest that the oligomeric aggregation intermediates of alpha-synuclein play a primary role in the mechanisms of this neurodegenerative disease. Molecular insights into the structure and composition of these oligomeric aggregates are essential for understanding the aggregation process and ultimately the cause of the disease.

By using a variety of biochemical and biophysical methods, including high-resolution optical and scanning probe microscopy, single-molecule spectroscopy, and super resolution microscopy, we aim to get detailed insights into the molecular details of alpha-synuclein oligomers.

Simplified representation of the aggregation process. Alpha-synuclein monomers can aggregate and form oligomers, which in turn can form fibrillar structures, which are the main component of Lewy Bodies that are found in the brain of patients having Parkinson’s disease.

Research group: NanoBioPhysics (NBP)
PhD student: Niels Zijlstra
Supervisors: Christian Blum, Vinod Subramaniam
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High Harmonic Generation

The goal of this project is to develop a tunable, stable, coherent high brightness High-Harmonic Generation (HHG) sources with the aim of seeding FERMI@Elettra free-electron laser (FEL) at wavelengths of 40 nm and lower. To achieve this goal, we will use neutral gas filled capillary for seeding at 40 nm and ion based plasma waveguides at 4 nm. Also a novel scheme utilizing coherent control in collaboration with OS (Optical Science) group will be implemented for tuning and selective enhancement of harmonic orders. With successful seeding, both femto-second timescales and atomic length-scales research can be achieved in the future.

Research group: Laser Physics and Non-Linear Optics (LPNO)
PhD students: Jean Goh & Yin Tao
Supervisors: Bert Bastiaens, Peter van der Slot, Klaus Boller
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SMILE2: Smart Multilayer Interactive Optics for Lithography at Extreme UV Wavelengths

Modern generations of photolithography wafer scanners use very complex optics to enable the smallest chip features. The first generations of systems using 13.5 nm wavelength are being explored now in pre-production. Future systems may require advanced optics containing dynamic adaptive optical elements to maintain the highest resolution and stability. The Smart Multilayer Interactive Optics for Lithography at Extreme UV Wavelengths (SMILE) project combines active material (piezoelectric, pyroelectric) techniques and the multilayer Bragg reflecting optical systems in order to demonstrate such adaptive optics: it will allow to dynamically correct the degradations in the projected wavefront and eventually to tune the multilayer spacing to increase the total reflected optical power.

Research group: Industrial Focus Group XUV Optics (XUV) and IMS
PhD student / Postdoc: Sasha Antonov, Ben Wylie van Eerd, Huiyu Yuan
Supervisors: Dr A.E. Yakshin (XUV/TNW)
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Semiconductor photonic structures, especially microcavities, are widely used in science and technology. To switch them on ultrafast time scales, i.e., changing their optical properties while light travels through them, promises new insights in cavity quantum electrodynamics (QED) and is essential in applications such as integrated photonic circuits.

The goal of our study is to switch semiconductor microcavities independent of material constraints. We want then to manipulate the spontaneous emission of emitters inside the cavities on ultrafast time scales.

Research group: Complex Photonic Systems (COPS)
PhD students: Emre Yüce, Nasser Hosseini
Postdoc: Georgios Ctistis
Supervisor: Willem L. Vos
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