Nonlinear endomicroscopy imaging technology for translational applications

Nonlinear endomicroscopic imaging technology has emerged as a strong candidate for potentially enabling clinical translation of the powerful multiphoton imaging microscopy technology. With the development of ultrafast light sources followed by the initial demonstration of multiphoton microscopy in 1990, the field of nonlinear optical imaging has been expanded rapidly towards assessing biological tissue microstructures and functions. In this book chapter we present an overview of the underlying theory of nonlinear signal generation, tight focusing and resolution, and explore the multiple challenges associated with designing nonlinear ultracompact endoscopic probes that are needed for in vivo imaging of internal organs and the various solutions available. Specifically, we cover light delivery, beam scanning and signal collection. Finally, we review a few emerging applications, including preterm birth diagnosis, lung and breast cancer imaging.