Optical Coherence Tomography: Technical Aspects - Biomedical Optical Imaging Technologies: Design and Applications - page 175

Fig. 5.7 Water absorption spectrum (The original data consult from http://omlc.ogi.edu/spectra/
water/index.html )

compromise between water absorption, wavelength dispersion, and scattering loss
exists, where the water absorption profile has a local minimum (a 0:015 mm 1
at D 1;060 nm [ 23 ], as compared to a 0:0023 mm 1 at D 800 nm [ 13 ]). This
results in a reduction of the detectable light signal from the retina from 89:4%at
800 nm to about 48.4% at 1,060 nm.

5.4.5 Optical Sources for OCT

In case of OCT, the image resolution and quality is an important factor for governing
its clinical utility. The resolution of OCT images in the axial and transverse
directions is determined by different mechanisms. The axial resolution is determined
by the coherence length of the light source and which is decoupled from the
beam focussing optics. Since the coherence length of a light source is inversely
proportional to its bandwidth, broad-bandwidth optical sources are required to
improve the OCT axial resolution. The axial resolution is inversely proportional
to the spectral width of the used light source, and the generation of broadband