26. February 2019

Hervé Rigneault

Multiphoton imaging endoscopy

Institut Fresnel / Marseille, France

I will present advances to bring nonlinear multiphoton imaging into flexible fibered probes that can perform images deep into living tissues. Using dedicated optical fibers that can transmit ultra-short pulses to (1) deliver the excitation pulses together and (2) collect the generated nonlinear signals, we have developed two multiphoton endoscope technologies. The first one has a distal diameter of 2mm, it uses a piezo scanning scheme to perform coherent Raman, pump-probe, 2photon and harmonic generation images over a field of view of 400 microns at a frame rate of 10 images/s. The second endoscope technology as a diameter of 300 microns which is the size of the optical fiber itself. It uses wavefront shaping in a multicore fiber and performs coherent beam combining to focus and scan the beam at the endoscope distal tip. This ultra-thin endoscope can perform 2photon imaging over a field of view of 200 microns and its imaging properties are resilient to fiber bending. I will present applications of these endoscopes in the fields of label free cells and tissues imaging and brain activity imaging.