OCT: Ultrahigh Resolution Optical Coherence Tomography at Visible to Near-Infrared Wavelength Region

Abstract

Optical coherence tomography (OCT) is an imaging modality using a low coherence interferometer with a spectrally broadband light source, which allows us to perform non-invasive observations of internal structures of living samples with a micrometer-scale resolution. Since recent advancements of OCT technologies have offered significant improvement in image acquisition speed, OCT is now used in a wide variety of medical fields, especially in ophthalmology. In our group, we have been working on the development of ultra-broadband light sources, so-called supercontinuum (SC) light sources, and ultrahigh-resolution OCT systems with the SC light sources. While the 0.8 μm wavelength window is typically used for OCT systems and 0.8 μm, OCTs offer high axial resolution in tissue imaging, and the 1.7 μm wavelength window has begun to be recognized as an excellent choice to achieve high penetration depth due to the lower scattering coefficient and the existence of a local minimum of light absorption by water in the wavelength band. In this chapter, we give a brief overview of the basic principle of OCT imaging and our recent works in the development of ultrahigh-resolution OCT imaging techniques.