Keywords: Optics, Engineering, Imaging, flow, speckle Internship Duration: 30/11/-1 - 30/11/-1
Head of the hosting team: Nathalie Westbrook
Website: Click here
Address of the host laboratory: Laboratoire Charles Fabry Team Groupe Biophotonique 2 Avenue Augustin Fresnel 91117 Palaiseau France
Supervisor 1: Frederic PainE-mail: frederic.pain@universite-paris-saclay.fr Phone: 33164533415
Supervisor 2: Arnaud Dubois
Internship description Laser speckle imaging is an established optical imaging technique to study normal or pathological the blood flow. It provides 2D imaging of relatives flows over relatively wide field of views. The current “gold standard” implementation relies on 2D imaging of the speckle pattern produced when a laser is used to illuminate homogeneously the tissue of interest. As the mobile scatterers (i.e red blood cells) move, for a given exposure time of a camera, the faster the flow, the faster the changes of the speckle pattern resulting in increased blurring and a lower contrast. Our set-ups have been used in collaboration with biologists to quantify brain activation in response to a sensory stimulus and blood flow impairments related to diseases including diabetes and obesity. Our current research is about instrumental and methodological improvements of the technique. The internship project is exploratory and consists in developing a modified optical imaging set-up for the quantification of bioflows with an expected improved sensitivity and spatial resolution. The internship will be hosted in the Biophotonics Groupe in LCF located within the Institute of Optics Graduate School. The tasks during the internship will be: • Line illumination setup. A laser will be expanded to a line using a cylindrical lens and then projected onto the area of interest using a galvo mirror. • Driving of the laser scan with a galvo mirror. Appropriate electrical signals will have to be defined using waveform generator to drive the galvo and scan the field of view. • Confocal detection. The confocal detection of the speckle pattern will be ensured using a line camera or a selected region of interest on a 2D camera. The camera acquisition will have to be synchronized with the laser scan in order build a 2D image line by line. • Characterization. The device performances will be characterized on microfluidics phantoms representative of flows and dimensions encountered in biological tissues. Spatial resolution as well as sensitivity and accuracy of flow changes estimations will be evaluated. The required instrumental components are already available in the biophotonics group as well as strong know-how in line scan confocal imaging. Thus, the internship student will have the opportunity to develop several skills in optics, instrumentation, data analysis in the context of an interdisciplinary project. We expect from you: • Enthusiasm and strong involvement in your project, the ability to address your topic as a project with milestones and deliverables • Taste for optics and instrumentation in an interdisciplinary context • Ability to work communicate and work in group
- Optical instrumentation - Laser - Scientific sCMOS camera - Galvo mirror scanner - Microfluidics
1. Soleimanzad, H. et al. Multiple speckle exposure imaging for the study of blood flow changes induced by functional activation of barrel cortex and olfactory bulb in mice. Neurophotonics 6, 015008 (2019). 2. Soleimanzad, H. et al. Obesity in Midlife Hampers Resting and Sensory-Evoked Cerebral Blood Flow in Mice. Obesity (Silver Spring) (2020) doi:10.1002/oby.23051.
