title: Bimodal endoscopic probe combining white-light microscopy and optical coherence tomography.
abstract: We present a novel bimodal endoscopic imaging probe that can simultaneously provide full-field white-light video microscopy and confocal optical coherence tomography (OCT) depth scans. The two modalities rely on spectrally separated optical paths that run partially in parallel through a micro-optical bench system, which has a cross-section of only 2  mm×2.76  mm and is realized via standard silicon micromachining techniques. With a numerical aperture of 0.061, the video modality has a resolution and field of view of 9.3 and 1240  μm×1080  μm, respectively. The resolution is limited by the pixel spacing of the coherent fiber bundle, which relays the acquired image from the distal to the proximal end. A custom-designed diffractive optical element placed within the video imaging path significantly improves the image contrast by up to 45% in the medium frequency range. The OCT modality is optimized for 830 nm center wavelength, and works in a confocal arrangement with an NA of 0.018. It provides single-point depth probing at the center of the video image with a lateral resolution of 20 μm. Through its compact footprint and enhanced functionality, the probe can provide depth-resolved guiding capability for existing laparoscopes and represents a major step toward a new class of multimodal endoscopic imaging probes.
authors.forename: M
authors.initials: M
authors.lastname: Blattmann
authors.forename: S
authors.initials: S
authors.lastname: Kretschmer
authors.forename: S
authors.initials: S
authors.lastname: Thiele
authors.forename: C
authors.initials: C
authors.lastname: Ataman
authors.forename: H
authors.initials: H
authors.lastname: Zappe
authors.forename: A
authors.initials: A
authors.lastname: Herkommer
authors.forename: A
authors.initials: A
authors.lastname: Seifert