Miniature side-view dual axes confocal endomicroscope for repetitive in vivo imaging.

A side-view dual axes confocal endomicroscope is demonstrated that can be inserted repetitively in hollow organs of genetically engineered mice for in vivo real-time imaging in horizontal and vertical planes. Near infrared (NIR) excitation at λex = 785 nm was used. A monolithic 3-axis parametric resonance scan mirror was fabricated using micro-electro-mechanical systems (MEMS) technology to perform post-objective scanning in the distal end of a 4.19 mm diameter instrument. Torsional and serpentine springs were designed to "switch" the mode of imaging between vertical and horizontal planes by tuning the actuation frequency. This system demonstrated real-time in-vivo images in horizontal and vertical planes with 310 µm depth and 1.75 and 7.5 µm lateral and axial resolution. Individual cells and discrete mucosal structures could be identified.

Polymer Ring Resonator with a Partially Tapered Waveguide for Biomedical Sensing: Computational Study.

Ring resonators are well-known optical biosensors thanks to their relatively high Q-factor and sensitivity, in addition to their potential to be fabricated in large arrays with a small footprint. Here, we investigated the characteristics of a polymer ring resonator with a partially tapered waveguide for Biomedical Sensing. The goal is to develop a more sensitive biosensor with an improved figure of merit. The concept is more significant field interaction with the sample under test in tapered segments. Waveguide width is hereby gradually reduced to half. Sensitivity improves from 84.6 to 101.74 [nm/RIU] in a relatively small Q-factor reduction from 4.60 × 103 for a strip waveguide to 4.36 × 103 for a π/4 partially tapered one. After the study, the number of tapered parts from zero to fifteen, the obtained figure of merit improves from 497 for a strip ring to 565 for a π/4 tapered ring close to six tapered ones. Considering the fabrication process, the three-tapered one is suggested. The all-polymer material device provides advantages of a low-cost, disposable biosensor with roll-to-roll fabrication compatibility. This design can also be applied on silicon on isolator, or polymer on silicon-based devices, thereby taking advantage of a higher Q-factor and greater sensitivity.