Fibre‐optic nonlinear optical microscopy and endoscopy

Abstract

Summary Nonlinear optical microscopy has been an indispensable laboratory tool of high‐resolution imaging in thick tissue and live animals. Rapid developments of fibre‐optic components in terms of growing functionality and decreasing size provide enormous opportunities for innovations in nonlinear optical microscopy. Fibre‐based nonlinear optical endoscopy is the sole instrumentation to permit the cellular imaging within hollow tissue tracts or solid organs that are inaccessible to a conventional optical microscope. This article reviews the current development of fibre‐optic nonlinear optical microscopy and endoscopy, which includes crucial technologies for miniaturized nonlinear optical microscopy and their embodiments of endoscopic systems. A particular attention is given to several classes of photonic crystal fibres that have been applied to nonlinear optical microscopy due to their unique properties for ultrashort pulse delivery and signal collection. Furthermore, fibre‐optic nonlinear optical imaging systems can be classified into portable microscopes suitable for imaging behaving animals, rigid endoscopes that allow for deep tissue imaging with minimally invasive manners, and flexible endoscopes enabling imaging of internal organs. Fibre‐optic nonlinear optical endoscopy is coming of age and a paradigm shift leading to optical microscope tools for early cancer detection and minimally invasive surgery.

Minimizing Group Index Variations in a Multicore Endoscope Fiber

“…For biomedical applications there is increasing interest to translate advanced microscopy techniques to endoscopy, including laser scanning confocal and multiphoton microscopy, which can provide optically sectioned images with subcellular resolution. Conventionally, such endoscopes are realized using either distal or proximal scanning [1]. In distal scanning schemes, a conventional single core optical fiber is used and the image is formed using mechanical components at the distal end to scan the beam, either by deflecting the beam, e.g.…”

Design and Fabrication of a Multi-modal Confocal Endo-Microscope for Biomedical Imaging

“…Moreover, a MEMS scanner can be made small enough to be compatible with an endo-microscope. The third type uses fiber dynamics for scanning [14]. Since the image guide fiber bundle type microscope has the advantages of safety and robustness, the proposed endo-microscope is designed to function as the first type of endo-microscope.…”

Molecular orientation sensitive second harmonic microscopy by radially and azimuthally polarized light

“…The SHG process is based on the nonlinear polarization term of second order whereas THG and two-photon induced fluorescence are based on the third order term [9]. Thus, the nonlinear response of the medium is dependent on the second-and third-order nonlinear susceptibility χ (2) and χ (3) respectively .…”