Spatial Overlap Modulation Nonlinear Optical Microscopy for Background-Free Deep Imaging

Abstract

Near-infrared light that provides maximum optical transparency in biological systems is a powerful tool to image deeper inside biological samples. Recently, the use of nonlinear optical microscope using near-infrared light has been widely spread in deep tissue imaging. Nevertheless, it is difficult to observe a highly scattering sample at a deeper penetration depth. This is because background noise is generated from out-of-focus regions. In this review, we explain the mechanism of background generation in nonlinear optical microscopy and introduce some methods to suppress the background noise.