Deep Tissue High-Resolution Optical Imaging in the Third Near Infrared Window

We present our recent progress on the development of high-resolution optical microscopy with the third near infrared window (NIR-III) light for deep tissue imaging. Recently, we developed optical coherence microscopy (OCM) and two-photon excited fluorescence microscopy with NIR-III light. The developed OCM allows us to perform label-free three-dimensional imaging with the lateral and axial resolution of 3.4 and 3.8 μm in tissue imaging, and mouse brain imaging at a depth of up to 1.8 mm was also demonstrated. By using the developed two-photon excited fluorescence microscope with NIR-III light, we demonstrated two-photon imaging with the lateral and axial resolution of 2.4 and 7.7 μm at a depth of 2.2 mm in the mouse brain. Both results show that NIR-III light is a promising choice for deep tissue imaging.