Here, we report on the use of an ultracompact femtosecond fiber laser for high-resolution tissue imaging. In particular, the development of the PRISM AWARD 2024 winning multimodal multiphoton tomograph based on an ultracompact air-cooled 50/80 MHz fiber laser operating at 780 nm is presented. The 18x9x3.5 cm3 laser head, consisting of a pulse compression unit and a SHG crystal, is positioned inside the 360° imaging head. An optical arm or a fiber delivery for transmitting the ultrashort near-infrared laser beam is no longer required. Interestingly, the femtosecond laser pulses, used for two-photon autofluorescence and SHG imaging, are also employed to realize simultaneous high-resolution (submicron) one-photon confocal microscopy. In addition, optical metabolic imaging (OMI) by time-correlated single photon counting and fluorescence lifetime imaging (FLIM) of autofluorescent coenzymes can be performed. The fifth imaging modality of this multimodal device is white LED far-field imaging for dermoscopy and to define regions of interest for confocal and multiphoton analysis. The novel “green” 230 W femtosecond fiber laser tomograph can be operated by batteries and charged by sunlight due to the reduced power consumption by 75 % when using the fiber laser system compared to the tunable titanium:sapphire laser. High-resolution confocal and multiphoton imaging with compact fiber lasers in remote areas and on the bedside of the patient becomes a reality. |
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