Multiphase flow measurements play a crucial role in monitoring productions processes in many industries. To guarantee the safety of processes involving multiphase flows, it is important to detect changes in the flow conditions before they can cause damage, often in fractions of seconds. Here we demonstrate how the scattering pattern of a laser beam passing a two-phase flow under an oblique angle to the flow direction can be used to detect derivations from the desired flow conditions in microseconds. Applying machine-learning techniques to signals obtained from three photo-detectors we achieve a compact, versatile, low-cost sensor design for safety applications.
Society becomes increasingly dependent on photonics technologies; however there is an alarming lack of technological awareness among secondary school students. They associate photonics with experiments and components in the class room that seem to bear little relevance to their daily life. The Rocard Report  highlights the need for fostering students’ scientific skills and technological awareness and identifies inquiry based learning (IBL) as a means to achieve this. Students need to actively do science rather than be silent spectators. The ‘Photonics Explorer’ kit was developed as an EU funded project to equip teachers, free-of-charge, with educational material designed to excite, engage and educate European secondary school students using guided inquiry based learning techniques. Students put together their own experiments using up-to-date versatile components, critically interpret results and relate the conclusions to relevant applications in their daily life. They work hands-on with the material, thus developing and honing their scientific and analytical skills that are otherwise latent in a typical class room situation. A qualitative and quantitative study of the impact of the kit in the classroom was undertaken with 50 kits tested in 7 EU countries with over 1500 students in the local language. This paper reports on the results of the EU wide field tests that show the positive impact of the kit in raising the self-efficacy, scientific skills and interest in science among students and the effectiveness of the kit in implementing IBL strategies in classrooms across EU.
There is an imminent shortage of skilled workforce facing Europe’s hi-tech industries mainly due to the declining interest of young people in science and engineering careers. To avert this trend the European Union funded the development of the ‘Photonics Explorer’ – an intra-curricular educational kit designed to engage, excite and educate students about the fascination of working with optics hands-on, in their own classrooms! Each kit equips teachers with class sets of experimental components provided within a supporting didactic framework based on guided inquiry based learning techniques. The material has been specifically designed to integrate into the curriculum and enhance and complement the teaching and learning of science in the classroom. The kits are provided free of charge to teachers, in conjunction with teacher training courses. The main challenge of this program was the development of educational material that seamlessly integrates into the various national curricula across Europe. To achieve this, the development process included a preparatory EU wide curricula survey and a special ‘Review and Revise’ process bringing together the expertise of over 35 teachers and pedagogic experts. This paper reports on the results of the preparatory study which identified two specific age groups at secondary schools for photonics educational material, the didactic content of the Photonics Explorer kit resulting from a pan-European collaboration of key stakeholders, EU wide dissemination and sustainability of the program.
The ‘Photonics Explorer’ is a unique intra-curricular optics kit designed to engage, excite and educate secondary school students about the fascination of working with light – hands-on, in their own classrooms. Developed with a pan European collaboration of experts, the kit equips teachers with class sets of experimental material provided within a supporting didactic framework, distributed in conjunction with teacher training courses. The material has been specifically designed to integrate into European science curricula. Each kit contains robust and versatile components sufficient for a class of 25-30 students to work in groups of 2-3. The didactic content is based on guided inquiry-based learning (IBL) techniques with a strong emphasis on hands-on experiments, team work and relating abstract concepts to real world applications. The content has been developed in conjunction with over 30 teachers and experts in pedagogy to ensure high quality and ease of integration. It is currently available in 7 European languages. The Photonics Explorer allows students not only to hone their essential scientific skills but also to really work as scientists and engineers in the
classroom. Thus, it aims to encourage more young people to pursue scientific careers and avert the imminent lack of scientific workforce in Europe. 50 Photonics Explorer kits have been successfully tested in 7 European countries with over 1500 secondary school students. The positive impact of the kit in the classroom has been qualitatively and quantitatively evaluated. A non-profit organisation, EYESTvzw [Excite Youth for Engineering Science and Technology], is responsible for the large scale distribution of the Photonics Explorer.
We study the second-harmonic generation via transversely-matched interaction of two counter-propagating ultra-short
pulses in χ<sup>(2)</sup> photonic structures with either random ferroelectric domains or annular periodic poling. The
profile of the transverse second-harmonic signal is given by the cross-correlation of the pulses and can be used
to characterise the temporal structure of the pulses.
We generate conical second-harmonic waves through the parametric frequency conversion in a two-dimensional annular, periodically poled nonlinear photonic structure under the transverse excitation with a fundamental Gaussian beam. We explain the effects observed experimentally by applying the concept of nonlinear Bragg diffraction to the case of the conical frequency generation. We study the polarization properties of the conical emission at the second-harmonic
frequency and demonstrate that each of the parametrically generated waves represents a superposition of the Bessel beams.
We review our experimental development in the field of optical lattices, emphasizing their unique properties for
control of linear and nonlinear propagation of light. We draw some important links between optical lattices and
photonic crystals, pointing towards practical applications in the fields of optical communications and computing,
beam shaping, and bio-sensing.
We consider the femtosecond phase-matched noncollinear second-harmonic generation (SHG) in Strontium Barium Niobate (SBN) crystals with random ferroelectnc domains. We study both planar and radial second-harmonic (SH) radiation for the average input power P<sub>f</sub> up to 600 mW. We show that the effect of thermal self-focusing of the fundamental wave occurring at P<sub>f</sub> > 250 mW results in novel effects including the spatial localization of SHG, a change of the SH efficiency slope, and significant spectral broadening of both fundamental and SH beams
We study theoretically arid generate experimentally two-dimensional nonlinear optically-induced photonic lattices with periodic phase modulation of different geometries in a photorefractive medium, including the periodicnonlinear waves with an internal energy flow or vortex lattices. We demonstrate that the light-induced periodically modulated nonlinear refractive index is highly anisotropic and nonlocal, and it depends on the orientation of a two-dimensional lattice relative to the crystal axis. We discuss stability of such optically-induced photonic two-dimensional structures and demonstrate experimentally their waveguiding properties.
We report on the first experimental observation of a large spatial lateral shift in the interaction of obliquely oriented spatial-dark soliton stripes. We demonstrate by numerical simulations that this new effect can be attributed to the specific features of optical media with nonlocal nonlinear response.