Fast label-free point-scanning super-resolution imaging for endoscopy

TL;DR

This paper introduces a fast, label-free, point-scanning super-resolution imaging system for endoscopy that uses diffractive optical elements and a digital micromirror device to achieve high-speed, miniaturized imaging without mechanical scanning.

Contribution

The authors develop a novel super-resolution endoscopic imaging system employing a phase-only diffractive optical element and a high-speed DMD, enabling rapid, label-free, super-resolution imaging without mechanical scanning.

Findings

Achieved super-resolution imaging with a 0.47 Airy spot.

Demonstrated high-speed imaging at kHz rates.

Successfully imaged label-free test targets and fluorescent cells.

Abstract

Optical endoscopy plays a crucial role in minimally invasive medical diagnostics and therapeutic procedures. Nonetheless, state-of-the-art endoscopic zoom objectives are bulky, requiring multi-element lens actuation, which can limit continued miniaturization. Point-scanning super-resolution approaches improve spatial resolution by illuminating the scene with a reduced-width focused spot, yet mechanical scanning requirements limit applicability in clinical settings. Here, we experimentally demonstrate a Fast label-free point-scanning super-resolution (Flaps) microscopy system, which exploits a multi-level phase-only diffractive optical element (DOE) to generate super-resolution spot(s) and uses a high-speed digital micromirror device (DMD) to deliver the illumination without mechanical scanning. Two imaging architectures are explored: a single super-resolution spot (0.47 Airy spot) or a 5 times 5 super-resolution spot array (0.52 Airy spot) in the far-field; the DMD scans the spot or spot array in the object plane at kHz rates. To demonstrate super-resolution imaging with high-speed acquisition using optical elements suitable for future deployment in endoscopy, we image a label-free resolution test target and fluorescently labelled cells.