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Broadband light sources provide a significant benefit for optical coherence tomography (OCT) imaging
concerning the axial resolution. Light sources with bandwidths over 200 nm result in an axial resolution up to 2
microns. Such broad band OCT imaging can be achieved utilizing super continuum (SC) light sources. The main
important disadvantage of commercial SC light sources is the overall size and the high costs. Therefore, the use
of SC light sources in small OCT setups and applications is limited. We present a new small housing and costeffective
light source, which is suitable for OCT imaging. The used light source has dimensions of 110 x 160 x
60 mm and covers a wavelength range from 390 nm up to 2500 nm.
The light source was coupled in a dual band OCT system. The light is guided into the interferometer and split in
reference and sample beam. The superimposed signal is guided to the spectrometer unit, which consists of two
spectrometers. This spectrometer system separates the light. One band centered at 800 nm with a full bandwidth
of 176 nm and a second band centered at 1250 nm with a full spectral width of 300 nm was extracted. The 800
nm interference signal is detected by a silicon line scan camera and the 1250 nm signal by an indium gallium
arsenide linear image sensor.
In this test measurement a plastic foil was used as a sample, which is composed of several plastic film layers.
Three dimensional images were acquired simultaneous with the dual band OCT setup. The images were acquired
at an A-scan rate of 1 kHz. The 1 kHz A-line rate was chosen because so far the optical power of the light source
is not optimal for high speed OCT imaging. The source provides 2 mW in the range of 390 nm to 800 nm and 25
mW in the range from 390 nm to 1650 nm. Furthermore, we coupled the light source by a 50:50 optical fiber
coupler, which also reduces the overall optical power of the light source within the OCT setup.
Nevertheless, we demonstrated that this new small-package and cost-effective light source is very suitable to
carry out OCT imaging. The use of this light source can open up new OCT applications, which require OCT
setups with very high axial resolution and small footprint.
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