Polarization-resolved endoscopy using twisted photonic crystal fibers
The PolarEndo project aims to develop a new type of multiphoton endoscope capable of measuring molecular orientations in various samples related to biological sciences, environmental studies, and health. This endoscope utilizes an original micro-structured twisted optical fiber that has the property of preserving the circular polarization states of light as it propagates through the fiber, regardless of its curvature. Any incident linear polarization in the fiber is then split into right- and left-handed circular polarizations and exits linearly from the fiber. This makes possible to probe a sample with different linear polarization states and deduce molecular order parameters, such as the average orientation and deviation from this orientation. To perform these polarimetric measurements at each point of a sample, the fiber will be integrated into a resonant piezoelectric scanner, which will be inserted into a 2 mm diameter distal optical endoscopic head. This setup allows for multiphoton imaging (2-photon fluorescence, second harmonic generation - SHG) over a 400 µm field at a rate of 10 images per second with micron-level lateral and axial resolutions. The endoscopic head can be inserted into tissues or manually operated to locally probe samples. By sequentially capturing images for each incident linear polarization state, we will obtain molecular orientation images of fluorescent or auto-fluorescent molecules, or those exhibiting SHG at a rate of several images per second. We will demonstrate the instrument's usefulness for studying the orientation of actin filaments (2-photon imaging) and collagen (SHG) in cells and tissues. This project brings together the expertise in advanced optical fibers from the Friedrich-Alexander University of Erlangen (DE) and the expertise in multiphoton endoscopy and polarization-resolved molecular imaging from the Fresnel Institute (Marseille-FR).
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Imported from OpenAIRE Germany | Grant ANR-25-CE42-3213.
Open sourceOverview
Grant agreement ANR-25-CE42-3213 | PolarEndo
Open sourceThe PolarEndo project aims to develop a new type of multiphoton endoscope capable of measuring molecular orientations in various samples related to biological sciences, environmental studies, and health. This endoscope utilizes an original micro-structured twisted optical fiber that has the property of preserving the circular polarization states of light as it propagates through the fiber, regardless of its curvature. Any incident linear polarization in the fiber is then split into right- and left-handed circular polarizations and exits linearly from the fiber. This makes possible to probe a sample with different linear polarization states and deduce molecular order parameters, such as the average orientation and deviation from this orientation. To perform these polarimetric measurements at each point of a sample, the fiber will be integrated into a resonant piezoelectric scanner, which will be inserted into a 2 mm diameter distal optical endoscopic head. This setup allows for multiphoton imaging (2-photon fluorescence, second harmonic generation - SHG) over a 400 µm field at a rate of 10 images per second with micron-level lateral and axial resolutions. The endoscopic head can be inserted into tissues or manually operated to locally probe samples. By sequentially capturing images for each incident linear polarization state, we will obtain molecular orientation images of fluorescent or auto-fluorescent molecules, or those exhibiting SHG at a rate of several images per second. We will demonstrate the instrument's usefulness for studying the orientation of actin filaments (2-photon imaging) and collagen (SHG) in cells and tissues. This project brings together the expertise in advanced optical fibers from the Friedrich-Alexander University of Erlangen (DE) and the expertise in multiphoton endoscopy and polarization-resolved molecular imaging from the Fresnel Institute (Marseille-FR).