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An ambitious project teams up local photonics organizations with creative facilities to promote European photonics innovation.

Optical coherence tomography (OCT) is a contactless and non-destructive testing (NDT) technique based on lowcoherence interferometry. It has recently become a popular NDT-tool for evaluating cultural heritage. In this study, protective coatings on wood and their penetration into the wood structure were measured with a customized infrared fiber optic OCT instrument. In order to enhance the understanding of the OCT measurements of coatings on real wooden samples, an optimization of the measuring and analyzing methodology was performed by developing an averaging approach and by post-processing the data. The collected information was complemented by data obtained with hyperspectral imaging to allow data from local OCT A-scans to be used in mapping the coating thicknesses over larger areas.

Here we report the modeling, fabrication and measurement of a type II Hyperbolic Metamaterial (HMM) consisting of 10 pairs Ag/Al2O3 subwavelength layers to demonstrate the high pass filter property of type II HMM. The HMM is deposited on the hypotenuse side of a TiO2 prism and covered with a fluorescent dye doped PMMA layer. The excitation of fluorescent dye is observed only with large incident angle throughout the optical frequency and infrared, which is in accordance with theoretical calculation.

It is known that, at optical frequencies, a simple interface between a perfect dielectric and a real metal can sustain the propagation of surface plasmon polaritons only for P-polarized electromagnetic waves, being S-polarized surface plasmons are prohibited. In this work, we formally show that, strictly speaking, both polarization states are in fact prohibited and that only P-polarized pseudosurface waves are allowed, which is what is encountered in the applications. The existence of such pseudosurface modes allows one to reconcile theory and experimental evidence, but also sets limits for them to be considered as modes bound to the interface.

We study the dielectric constant dependent diffraction phenomena of single slit apertures, both theoretically and experimentally. We experimentally simulate perfect metal and real metal cases by investigating subwavelength diffraction by a single slit, both in nano-optical and in terahertz regimes, keeping the slit-width/wavelength ratio approximately the same for both of frequency regimes. The wave-front in optical regime separates itself into forward propagating beam and surface-bound 90-degree diffracted wave, i.e., surface plasmon polaritons; while the separation of modes is not observed in terahertz regime.

Detection peculiarities of an un-cooled (room temperature) 8×8 pixel array designed to image broadband THz radiation were investigated. Each pixel consists of a thin conductive film absorber on a dielectric membrane with thermopile temperature readout. It was designed and tested for four combinations of two different types of absorber and thermopile materials. The photo-response profile, determined by scanning the pixels through the focus of a THz laser beam, was wider than expected from a 2-D convolution of the Gaussian beam and the absorber surface. Also the time response did depend on the position of the beam relative to the pixel. Simulations show that those properties are due to the fact that also the thermopiles absorb THz radiation. For the best composition of absorber and thermopile, the responsivity, the noise equivalent power, and the bandwidth were estimated to be of 28 V/W, 5×10-9 W/Hz1/2 and 50 Hz, respectively.

The “Study Photonics!” brochure, aims at students and contains information regarding where to study photonics in all the consortium’s partners countries.This is the edition of Study opportunities in the Netherlands. The objective of this brochure is to promote photonics for future entrepreneurs, in order to make them want to study photonics and then create companies in this field. The brochure was distributed to students in high schools before they choose their specialization.

The “Study Photonics!” brochure, aims at students containing information regarding where to study photonics in all the consortium’s partners countries, e.g. Germany, Italy, UK or Slovakia. The objective of this brochure is to promote photonics for future entrepreneurs, in order to make them want to study photonics and then create companies in this field. The brochure was distributed to students in high schools before they choose their specialization.

Photonic sensors have recently attracted much attention in both industry and academia. High accuracy, low weight and the possibility of building a large sensor network are key benefits of photonic sensors. Another benefit is installing optical sensors in harsh environments where electronic sensors' usage is not plausible: aerospace applications where ionizing radiation is present or gas and oil pipes are some examples.Integrated photonics brings new challenges to the interrogation of multiplexed sensors in WDM. Unlike FBG sensors, whose resonance wavelength can be chosen to an accuracy better than 1.0 nm, the resonance wavelength of integrated micro-ring resonators cannot be chosen during the design stage. The main reason is the imperfections of the manufacturing process. The fact that the resonance wavelength is unpredictable is a problem for interrogators based on interferometry. Such interrogators perform the demultiplexing and demodulation in different stages: first, a spectrometer separates the optical channels; subsequently, outputs of the spectrometer are conveyed to interferometers. From the photo-receiver voltages connected to MZI outputs, the signal from the sensors can be demodulated. As the resonance value of sensors cannot be determined during design, two sensors may have their resonances in the same spectrometer's channel. As a result, the demultiplexing step fails, compromising the interrogator's operation. In Chapter 4 of this thesis, a new interrogation method is proposed. Much of the effort of interferometric interrogators is to separate the spectrum of the sensors correctly. In the Fourier Transform Interrogator, the spectrum of all sensors is sent to an array of Mach-Zehnder interferometers (MZI) with different OPDs. Using the output voltages from the photo-receivers attached to the MZIs, we derive a system of non-linear equations, whose solution provides the signal from each sensor. The demodulation and demultiplexing steps are performed simultaneously for the Fourier interrogator, which guarantees the interrogator's unique flexibility. On the other hand, the computational cost is high since the system of non-linear equations is solved using Newton's method. For each set of voltages sampled over time, a different system of equations is obtained. Chapter 4 leaves some unanswered questions: Does the system of non-linear equations have a unique solution? How many solutions are there? What is the physical meaning of each of the solutions? Is it possible to solve non-linear systems of equations for fast sensors in real-time? All these questions are answered in Chapter 5. As a consequence of the new algebraic formulation, it is possible to solve about 1 000 000 algebraic systems of equations in about 10 ns, i.e., allowing the real-time interrogation of high-speed sensors. The interrogator is a candidate for interrogating arrays of ultrasound ring resonator sensors in the tens of MHz range.

The beauty of optical birefringence lies in the fact that it provides an independent control of light over different polarization directions, which leads to many important applications in today's optical systems. This thesis describes the applications of existing naturally-occurring birefringent materials as well as the engineered formed-birefringent meta-materials via nano-fabrication. In particular the application of birefringent materials in optical trapping, waveguide engineering and imaging are discussed. The investigation methods include numerical simulation, nano-fabrication and experimental validation.