  Multimodal nonlinear endoscopes have been a topic of intense research over
the past two decades, enabling sub-cellular and label-free imaging in areas not
reachable with table-top microscopes. They are sophisticated systems that can
be implemented on an optical table in a lab environment, but they cannot be
easily moved within or out of the lab. We present here a multimodal and
flexible nonlinear endoscope system able to perform two photon excited
fluorescence and second harmonic generation imaging with a stand-alone and
moveable kart integrating a compact ultrashort laser source. In addition, the
system can perform three photon excited fluorescence and third harmonic
generation thanks to a delivery optical fiber used to deliver ultrashort pulses
from massive and not movable laser systems into the stand-alone kart. The
endoscopic fiber probes and delivery optical fibers are based on functionalized
negative curvature hollow core fibers. The endoscope distal head has a diameter
<2.2mm and can perform nonlinear imaging at max 10 frames/s over a field of
view up to 600 $\mu$m with a ~1 $\mu$m spatial resolution.
