Electrodes for integrated optical circuits: Application to dielectrophoresis

Master thesis / PFE   (5 to 6 month)
Electrodes for integrated optical circuits: Application to dielectrophoresis

IMEP-LaHC is one of the leading laboratories in the field of integrated optics, and more specifically of photonics on glass. Striving for innovation, one of our goals is to fabricate integrated devices dedicated to sensing applications such as bacteria detection. Indeed, monitoring of bacterial growth is critical in various fields such as agri-food or cosmetics industries.
The design and fabrication of compact and portable sensors is thus crucial for efficient and continuous in-situ measurements. In order to propose an innovative solution, we aim at co-integrating optical waveguides with metallic electrodes for dielectrophoresis (DEP) applications¹,².The electrodes will be embedded in a microfluidic chamber and designed in order to create a non-uniform electric field. The application of an alternative voltage can then trap polarizable particles such as bacteria close to an optical waveguide, leading to a change of its refractive index.
This Master’s thesis is focused on the electrodes fabrication. The main specifications are:

•         The optimization of the metal deposition (thickness, uniformity and adhesion on glass)
• The proper design of the electrodes
•  The co-integration of the electrodes with optical waveguides in order to minimize the optical losses while maintaining the interaction of both elements.
• The quantitative measurement of the optical losses in the NIR spectral range.

To fulfill these objectives, the student will be get familiar with the subject through a bibliographic research on integrated electrodes dedicating to DEP. He/she will also be trained for various techniques of design and fabrication. The training includes in particular:

• Clean room processes for the metallic deposition and integrated optics
• Integrated optics on glass technology (ion diffusion on glass)
• Simulation tools dedicated to electrodes design and optical guided propagation
• Optical characterizations of integrated waveguides

This Master’s subject is a preliminary work for a future PhD subject, dealing with the integration of a full bacteria sensor3. Depending on the student’s motivation and progress, a last task could deal withthe integration of the electrodes in a more complex circuit.

Advisors:
Elise GHIBAUDO elise.ghibaudo@grenoble-inp.fr – 04 56 52 95 31
Lionel BASTARD lionel.bastard@grenoble-inp.fr – 04 56 52 95 30

Laboratoire IMEP – LaHC
MINATEC – INPG, 3 Parvis Louis Néel BP 257 38016 Grenoble Cedex 1 – France

1 L. Cui, T. Zhang and H. Morgan, J. Micromech. Microeng. 12 (2002) 7–12
2 J. Suehiro et al, J. Phys. D: Appl. Phys. 32 (1999) 2814
3 S. Tokonami, T. Iida, Analytica Chimica Acta 988 (2017) 1-16

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