800-nm-centered swept laser for spectroscopic optical coherence tomography

Abstract

The isosbestic point of oxy- and deoxy-hemoglobin at 800 nm is an important point in biomedical optical spectroscopic imaging. We have developed a novel swept laser centered at 800 nm and demonstrated its performance for spectroscopic optical coherence tomography. The measured −10 dB spectral bandwidth of the swept laser was 40 nm and averaged laser output power per sweep was 4 mW. This swept laser was incorporated into our OCT system and used to measure non-scattering liquid phantoms and blood samples. The measured maximum sensitivity and roll-off rate over a range of image depths were 112 dB and − 1.45 dB mm−1, respectively. The minimum axial resolution of the OCT system was 8.06 μm at a depth of 2.4 mm. Quantitative and localized absorption spectra were recovered from the non-scattering liquid phantoms. In addition, the measured localized wavelength-dependent attenuation difference of oxygenated and deoxygenated blood was 4.6-fold.