Scan-less confocal phase microscopy based on dual comb spectroscopy of two-dimensional-image-encoding optical frequency comb

TL;DR

This paper introduces a novel scan-less confocal phase microscopy technique using dual-comb spectroscopy of an optical frequency comb, enabling high-resolution 3D imaging without mechanical scanning.

Contribution

It presents a new hybrid microscopy method that combines confocal and phase imaging using 2D spectral encoding with optical frequency combs, achieving high depth resolution.

Findings

Confocal image with 62.4 μm depth resolution achieved.

Phase image with 13.7 nm depth resolution obtained.

Scan-less imaging demonstrated with dual-comb spectroscopy.

Abstract

Confocal imaging and phase imaging are powerful tools in life science research and industrial inspection. To coherently link the two techniques with different depth resolutions, we introduce an optical frequency comb (OFC) to microscopy. Two-dimensional (2D) image pixels of a sample were encoded onto OFC modes via 2D spectral encoding, in which OFC acted as an optical carrier with a vast number of discrete frequency channels. Then, a scan-less full-field confocal image with a depth resolution of 62.4 um was decoded from a mode-resolved OFC amplitude spectrum obtained by dual-comb spectroscopy. Furthermore, a phase image with a depth resolution of 13.7 nm was decoded from a mode-resolved OFC phase spectrum under the above confocality. The phase wrapping ambiguity can be removed by the match between the confocal depth resolution and the phase wrapping period. The proposed hybrid microscopy approach will be a powerful tool for a variety of applications.