Real-time, ultrahigh-resolution, optical coherence tomography with an all-fiber, femtosecond fiber laser continuum at 15 µm

TLDR

A 51‑MHz, 100‑mW linearly chirped Er‑doped fiber laser is stretched, compressed, and coupled into a normally dispersive highly nonlinear fiber to produce a low‑noise supercontinuum spanning 180 nm with 38 mW output. The resulting broadband source enables real‑time, ultrahigh‑resolution OCT in the 1.4–1.7 µm band, achieving in vivo human‑skin imaging at ~5.5 µm resolution and 99‑dB sensitivity.

Abstract

Real-time, ultrahigh-resolution optical coherence tomography (OCT) is demonstrated in the 1.4–1.7‐µm wavelength region with a stretched-pulse, passively mode-locked, Er-doped fiber laser and highly nonlinear fiber. The fiber laser generates 100-mW, linearly chirped pulses at a 51-MHz repetition rate. The pulses are compressed and then coupled into a normally dispersive highly nonlinear fiber to generate a low-noise supercontinuum with a 180-nm FWHM bandwidth and 38 mW of output power. This light source is stable, compact, and broadband, permitting high-speed, real-time, high-resolution OCT imaging. In vivo high-speed OCT imaging of human skin with ∼5.5‐µm resolution and 99-dB sensitivity is demonstrated.