Fiberoptic Confocal Microscopy Using a 1.55-$\mu$m Fiber Laser for Multimodal Biophotonics Applications

We have experimentally demonstrated a fiberoptic confocal microscope using a 1.55-mum laser source. A compact and efficient Er-doped fiber laser source and conventional single-mode fiber components were used to construct a near-infrared fiberoptic confocal microscope system with 3-D scanning capability. A broadband 1.55-mum light source was used to reduce fringe patterns and interferences that occur when a highly coherent source is used. Our system showed a lateral resolution as high as 1.1 mum with a 60times objective lens, which is close to the theoretical limit. The system can be used in various multimodal biophotonics platforms including precise 3D imaging, biosensing, and laser tissue ablation due to its high water absorption characteristics while maintaining low thermomechanical and self-focusing damage from high-power lasers.