Two spectral shaping methods of a broadband fibre source for biomedical OCT imaging

The authors report two investigation methods into the spectral shaping of an optical broadband source (BBS) to be used in Optical Coherence Tomography (OCT). The BBS spectrum extends from 450 nm to 1750 nm and is selectively used in multiple spectral wavebands. Spectral shaping is performed with: (i) an optical filter unit (a combination of dichroic and bandpass filters at different incident angles) and (ii) a double-pass prism sequence (a cube beam splitter, two equilateral prisms and a metallic mirror) which allow the freedom to select the characteristics of the spectrum (central wavelength, spectral bandwidth). BBS can allow imaging with a depth resolution of 2 μm or better. Such a high depth resolution makes BBS suitable for OCT imaging in embryology, cells culture and eye imaging, investigations which will complement the more traditional fluorescence labelling and confocal imaging.