Optical coherence tomography (OCT) is an emerging technology for non-invasive cross-sectional imaging of
biological tissue and material with um resolution. In the field of pulmonary medicine, non-invasive high resolution
cross-sectional imaging is desired for investigation of diseases in lung. So far, a few works have been reported about
OCT imaging of lung. Since the lung consists of alveoli separated by thin wall, ultrahigh resolution (UHR) OCT is
supposed to be effective for the imaging of fine structure in lung tissue.
In this work, ex vivo cross-sectional imaging of isolated rat and hamster lungs was demonstrated using UHR-OCT. A
120 nm-wide, high-power, Gaussian-like supercontinuum (SC) was generated at wavelength of 0.8 um region. The
generated SC was used in a time-domain OCT system, and UHR-OCT imaging was demonstrated. An ultrahigh
resolution of 2.9 um in air and 2.1 um in tissue was obtained. The achieved sensitivity was 105 dB. Using this system,
ex vivo UHR-OCT imaging of isolated rat and hamster lungs was demonstrated for the first time. The structures of the
trachea, visceral pleura, and alveoli were observed clearly. When saline was instilled into the lung, the penetration depth
was improved, and clear images of the fine structure of the lung, including alveoli, were observed owing to the index
We have also demonstrated the UHR-OCT imaging of lung tissue using 1.3 um and 1.7 um SC sources. As the
results, owing to the precise structures of lung tissues and index matching by saline, the finest images were observed
with 0.8 um UHR-OCT system.