Multiphoton skin biopsy

High-resolution optical in vivo and in vitro skin biopsies with subcellular resolution and metabolic information can be provided by multimodal multiphoton tomography. We report on the use of an ultracompact air-chilled 50/80 MHz femtosecond fiber laser for two-photon autofluorescence excitation, generation of higher harmonics, fluorescence lifetime imaging, and confocal reflectance imaging. The 18cm long laser head is placed into a 360° imaging head without requiring an optical arm. The tomograph operates efficiently with a total energy consumption of only 235 watts. This energy efficiency enables portability, allowing operation with batteries even in remote areas, with the added convenience of recharging via foldable flexible photovoltaics. Multiphoton and confocal reflectance images of in vivo human skin are presented. Furthermore, rapid, wide-field ("mosaicking"), and deep skin imaging of label-free fresh skin biopsies in a clinical environment is demonstrated.