Nonlinear optical endoscope based on a compact two axes piezo scanner and a miniature objective lens.

We report on a nonlinear optical endoscope that adopts a hollow core photonic crystal fiber for single-mode illumination delivery and a multimode one for signal collection. Femtosecond laser pulses up to 100 mW can be delivered at a centered wavelength of 800 nm. The two-photon fluorescence response of our system is shown to have axial and lateral resolutions of 5.8 microm and 0.6 microm respectively. Fluorescence detection was obtained at different wavelengths between 790 and 840 nm which could allow SHG detection for example. The maximal field-of-view of the acquired images is 420 microm x 420 microm. Detection efficiency is greater by using an avalanche photodiode in comparison to a photo multiplier tube. Results presented here demonstrate the ability of the system to resolve cellular details and the potential of the device for future in vivo imaging diagnosis.