Zero roll-off retinal MHz-OCT using an FDML-Laser

TL;DR

This paper introduces a high-speed, zero roll-off retinal OCT system using a Fourier Domain Mode Locked-Laser, enabling ultra-widefield imaging with minimal signal loss over a 4.6 mm depth range.

Contribution

The paper presents the first implementation of a zero roll-off 1060 nm FDML-Laser for retinal OCT at 1.7 MHz, with improved dispersion compensation and frequency regulation.

Findings

Virtually no signal loss over 4.6 mm depth range

High dynamic range maintained across imaging depth

Stable point-spread function without roll-off effects

Abstract

Optical coherence tomography (OCT) applications like ultra-widefield and full eye-length imaging are of high interest for various diagnostic purposes. In swept-source OCT these techniques require a swept light source, which is coherent over the whole imaging depth. We present a zero roll-off 1060 nm Fourier Domain Mode Locked-Laser (FDML-Laser) for retinal OCT imaging at 1.7 MHz A-scan rate and first long-range imaging results with it. Several steps such as improved dispersion compensation and frequency regulation were performed and will be discussed. Besides virtually no loss in OCT signal over the maximum depth range of 4.6 mm and very good dynamic range was observed. Roll-off measurements show no decrease of the point-spread function (PSF), while maintaining a high dynamic range.