Q-switch-pumped supercontinuum for ultra-high resolution optical coherence tomography

Abstract

In this Letter, we investigate the possibility of using a commercially available Q-switch-pumped supercontinuum (QS-SC) source, operating in the kilohertz regime, for ultra-high resolution optical coherence tomography (UHR-OCT) in the 1300 nm region. The QS-SC source proves to be more intrinsically stable from pulse to pulse than a mode-locked-based SC (ML-SC) source while, at the same time, is less expensive. However, its pumping rate is lower than that used in ML-SC sources. Therefore, we investigate here specific conditions to make such a source usable for OCT. We compare images acquired with the QS-SC source and with a current state-of-the-art SC source used for imaging. We show that comparable visual contrast obtained with the two technologies is achievable by increasing the readout time of the camera to include a sufficient number of QS-SC pulses.

Noise of supercontinuum sources in spectral domain optical coherence tomography

“…with = , where is the repetition rate of the supercontinuum. This formally states what is generally accepted by the scientific community [2,3,17,19]: that the SC excess noise is reduced by increasing either the repetition rate or the integration time.…”

“…The effect of this correlation of spectral components, or lack thereof, on the OCT noise will be treated in a later section. Secondly, averaging M pulses in a single read-out decreases the measured RIN, again due to averaging effects, which is why high repetition rate supercontinuum sources show great promise for OCT imaging [17]. Far from the edges of the supercontinuum spectrum, the RIN is well approximated by Gaussian statistics [15,18], and the observed variance will therefore decrease linearly with M. Therefore, the exact effect of supercontinuum excess noise in SD-OCT must be evaluated using the pixel bandwidth and M, the number of pulses per integration time of the spectrometer employed.…”

The value of ultrahigh resolution OCT in dermatology - delineating the dermo-epidermal junction, capillaries in the dermal papillae and vellus hairs

“…The UHR-OCT system is powered by a 320 MHz supercontinuum source (SuperK Extreme, EXR-9) from NKT Photonics. The high repetition rate provides significant averaging to reduce the noise and makes the source suitable for OCT 34,35 . The source is bandpass filtered (1000-1500 nm) and light from the this is coupled into one arm of a regular Michelson interferometer and guided evenly to a reference arm and to a sample arm, the latter terminating with a handheld probe.…”

All-depth dispersion cancellation in spectral domain optical coherence tomography using numerical intensity correlations

“…As optical source we used a 320 MHz superK Extreme EXR-9 OCT (NKT Photonics A/S, Denmark) where a longpass filter selected light in the range 1000 − 1750 nm. The high repetition rate supercontinuum is particularly suited for OCT 35 . A 50/50 fibre coupler (Goosch and Housego, Netherlands) customized for the 1300 nm wavelength band, served as the beam splitter and standard achromatic lenses collimated the light in each output arm.…”