Proceedings Article | 5 April 2018
KEYWORDS: Optical coherence tomography, Optical resolution, Supercontinuum sources, Light sources, Q switched lasers, Q switching, Mode locking, Absorbance, Biological research, Visible radiation
Supercontinuum (SC) light source is certainly one of the best option for ultra-high resolution optical coherence tomography (UHR-OCT). Over the last few years several demonstrations have been done for each commonly used wavelength range [1-2-3]. Nowadays, SC dedicated to UHR-OCT is a mature technology with turn-key commercially available system [4]. The new challenge to answer for SC source is the cost reduction one.
In this study, we demonstrate that a Q-switched based SC (QS-SC) could be an alternative to the current state of the art SC based on a Mode-Locked laser (ML-SC). This QS-SC, whose cost is less than 15 % of the ML-SC, offers similar possibilities in terms of bandwidth, beam quality and optical density within the OCT band [5]. We demonstrate the usefulness of such a source by direct comparison with the ML-SC source commonly used. Our study includes a comparison of the pulse to pulse stability of both sources over the OCT wavelength range, where it is shown that the QS-SC is much more stable than the ML-SC. Also, a noise analysis conducted from the OCT point of view shows that the source repetition rate is a key parameter for any SC based OCT system. A comparison of images acquired from biological and non-biological samples is performed with emphasis on their contrast. Our conclusion is that a QS-SC can be used a useful source for UHR-OCT if compromise can be done in terms of speed of the detection unit. Finally, our study has been done at a central wavelength of 1270 nm, however the ultra-broad flat spectrum of the QS-SC makes it an interesting source for the 800 nm or visible range OCT too, opening the door for low-cost multi-band or multi-modal OCT.
REFERENCES
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4. http://www.nktphotonics.com/lasers-fibers/product/superk-oct-broadband-sources-optical-coherence-tomography/
5. http://www.nktphotonics.com/lasers-fibers/product/superk-compact-supercontinuum-lasers/
