Shot-noise limited, supercontinuum-based optical coherence tomography

Shreesha Rao D S,Ole Bang,Mette Mogensen,Jürgen Schnekenburger,Lars Grüner-Nielsen,Björn Kemper,Jesper Toft Olsen,Mikkel Jensen,Peter Heiduschka,Niels Møller Israelsen,Martin Glud

doi:10.1038/s41377-021-00574-x

Abstract

We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of 5.9 μm at a center wavelength of 1370 nm. Current supercontinuum-based SD-OCT systems cannot be operated in the shot-noise limited detection regime because of severe pulse-to-pulse relative intensity noise of the supercontinuum source. To overcome this disadvantage, we have developed a low-noise supercontinuum source based on an all-normal dispersion (ANDi) fiber, pumped by a femtosecond laser. The noise performance of our 90 MHz ANDi fiber-based supercontinuum source is compared to that of two commercial sources operating at 80 and 320 MHz repetition rate. We show that the low-noise of the ANDi fiber-based supercontinuum source improves the OCT images significantly in terms of both higher contrast, better sensitivity, and improved penetration. From SD-OCT imaging of skin, retina, and multilayer stacks we conclude that supercontinuum-based SD-OCT can enter the domain of shot-noise limited detection.

Highlights

Optical coherence tomography (OCT) relies on white light interferometry to noninvasively image translucent samples[1]
Since OCT relies on white light interferometry, the axial resolution (Δz) of an OCT system is equal to the coherence length of the employed light source
As we show in the materials and methods section and related Fig. 6f–h, the low-noise of the all-normal dispersion (ANDi) SC source provides a remarkable 12 dB increase in sensitivity compared to the 80 MHz SuperK extreme source, which is the direct comparison in terms of repetition rate, and of 7 dB with respect to the 320 MHz SuperK extreme source

Summary

Introduction

Optical coherence tomography (OCT) relies on white light interferometry to noninvasively image translucent samples[1]. Since its invention three decades ago, OCT has undergone an exceptional technological development manifested in imaging speeds increased by more than a factor of a million[2], sensitivities improved by more than 16 dB3, and the resolution enhanced to single cell levels[4]. These improvements in speed and sensitivity are largely down to the shift from the original time-domain (TD) OCT to Fourier domain (FD) OCT5.

Methods

Results

Discussion

Conclusion