Fiber endoscopic probe for minimally invasive spectroscopic characterization of biological tissue using directly integrated, low-cost multimode supercontinuum sources

Hyaline cartilage is one of the body's connective and supporting tissues, and is essential for the proper functioning of the musculoskeletal system. As part of the investigations, a setup was implemented and evaluated that enables minimally invasive spectroscopic examination of hyaline cartilage, bone, fat, and muscle tissue based on an imaging microscopic fiber probe and a supercontinuum broadband laser source. An investigation was conducted into a highly repetitive nanosecond fiber laser in conjunction with various commercially available multimode fibers for supercontinuum generation, achieving spectral power densities in the VIS-IR range of up to 1 mW/nm. In the course of the investigation, a comparative analysis was conducted on commercially available graded-index multimode fibers and large-mode-area fibers. The utilization of laser sources characterized by low beam quality was the subject of investigation, thereby facilitating the emergence of novel application domains. The employment of fiber micro-optics in conjunction with notch filtering of the excitation laser facilitates the execution of microscopic spectroscopic characterization of biological tissue in the NIR range (800-1700 nm). The fiber probe with micro-optics, with a diameter of less than 400 μm, enables minimally invasive endoscopic examination.