What will you be doing?
Considerable attention has been devoted by the scientific community to the development of reliable label-free molecule identification techniques. These mechanisms can provide fast detection of a variety of molecules without prior need for labeling with fluorescent dyes and without bleaching problems. Thanks to this, cheap and fast sample analyses in medicine, personal health care, home-land security and environmental studies, could be realized. A promising candidate to achieve reliable label free molecular detection is Raman scattering. In this physical phenomenon, a photon interacts with the sample under test, exciting, at a particular wavelength, vibrational modes of the molecules. A spectral analysis of the scattered light provides the vibrational spectrum characteristic of the molecules, allowing their identification. However, since the Raman cross section per molecule is typically low (10−30 cm2/molecule), the outcome of a Raman measurement is limited to a reduced number of in-elastically scattered photons. To overcome this problem, Surface Enhanced Raman Spectroscopy (SERS), based on plasmonic nano structures, is usually employed. For example, through properly nano-patterning techniques, it is possible to realize surfaces with arrays of scatterers characterized by points of strong electromagnetic field enhancement. Such a field enhancement (FE) causes a strong emission of the molecules located on these surfaces. Nevertheless, plasmonic nanostructures although characterized by high values of FE, have the disadvantage of large absorption coefficients. This absorption poses many questions from the thermal point of view, especially due to the limited volume where such an absorption takes place. For this reason, a reduction of the absorption levels, by using not plasmonic material is of interest for the SERS community. Low loss and high refractive index dielectric materials have shown promising results and the potential to be used for SERS.
TNO and TU/e have recently proposed a new full dielectric metasurface for SERS, consisting of a periodic array of silicon dimers. The metasurface is designed in such a way that it is characterized by two resonances, with a consequent field enhancement between the dimers, at two different wavelengths. One resonance (AFE) is mostly affected by the array elements couplings and it is controlled by the array unit cell dimensions. The other resonance (DFE) is due to the single dimers and it is controlled by the geometry of the two pillars forming the dimers. To further increase the Raman signal, the metasurface has been redesigned to operate in immersion, allowing the particles to move in a fluid and be subjected to the forces generated by the electric field gradient present in correspondence of the engineered surface. This will increase the concentration of the particles on high field spots, with a consequent increase of the Raman scattering. The use of metasurfaces can allow not only the realization of properly engineered surfaces for SERS, but also the implementation of miniaturized sensors, thanks to the possibility offered by this technology to implement extremely thin multi-functional membranes that can perform the same functions of more bulky components.
The main objective of the project is to further elaborate this concept aiming at the development of a miniaturized sensor for virus detection. This will require an optimization of the metasurface including the possibility to separate particles of different dimensions and also investigating different alternatives to include sources and detectors for the realization of the system.
What do we require of you?
- We expect from you a good background in Electromagnetic Theory, Physics and Optics.
- Some knowledge in Chemistry and/or Biology might be helpful, but not strictly required.
- Experience with electromagnetic modelling tools (e.g. ANSYS HFSS, COMSOL, LUMERICAL etc.) is welcome, but it can be built-up also during the internship.
- Programming in MATLAB or Python is required.
What can you expect of your work situation?
TNO is an independent research organisation whose expertise and research make an important contribution to the competitiveness of companies and organisations, to the economy and to the quality of society as a whole. Innovation with purpose is what TNO stands for. With 3000 people we develop knowledge not for its own sake but for practical application. To create new products that make life more pleasant and valuable and help companies innovate. To find creative answers to the questions posed by society. We work for a variety of customers: governments, companies, service providers and non-governmental organisations. Working together on new knowledge, better products and clear recommendations for policy and processes. In everything we do, impact is the key. Our product and process innovations and recommendations are only worth something if our customers can use them to boost their competitiveness.
You will acquire knowledge on nanoengineered metasurfaces, Surface Enhanced Raman Spectroscopy, optical trapping and photonic integration.
Due to the restrictions and social distancing measures required by the Corona virus crisis, it will not always be possible to have face-to-face meetings and work at the TNO premises. Nevertheless, you will be provided with a dedicated laptop and you will be granted access to the TNO network. This will allow you to store data, documents and presentations on a dedicated project folder and to make use of the modelling tools available at TNO. Furthermore, regular progress meetings will be organized and you will interact with your supervisor, TNO staff members and other fellow students.
What can TNO offer you?
You want to work on the precursor of your career; an internship gives you an opportunity to take a good look at your prospective future employer. TNO goes a step further. It’s not just looking that interests us; you and your knowledge are essential to our innovation. That’s why we attach a great deal of value to your personal and professional development. You will, of course, be properly supervised during your internship and be given the scope for you to get the best out of yourself. Naturally, we provide suitable internship compensation.
Has this vacancy sparked your interest?
Then please feel free to apply on this vacancy! For further questions don’t hesitate to contact us.
Due to Covid-19 and the consequent uncertainties and restrictions, students who are not residing in the Netherlands may currently not be able to start an internship or graduation project at TNO.
Note that applications via email and third party applications are not taken into consideration.
Contact: Giampiero Gerini
Phone number: +31 (0)88-86 64188