High power NIR fiber-optic femtosecond Cherenkov radiation and its application on nonlinear light microscopy.

We reported a record high power (>250 mW) and compact near-infrared fiber-optic femtosecond Cherenkov radiation source and its new application on nonlinear light microscopy for the first time (to our best knowledge). The high power femtosecond Cherenkov radiation was generated by 1.03 μm femtosecond pulses from a portable diode-pumped laser and a photonic crystal fiber as a compact, flexible, and highly efficient wavelength convertor. Sectioned nonlinear light microscopy images from mouse brain blood vessel network and rat tail tendon were then performed by the demonstrated light source. Due to the advantages of its high average output power (>250 mW), high pulse energy (>4 nJ), excellent wavelength conversion efficiency (>40%), compactness, simplicity in configuration, and turn-key operation, the demonstrated femtosecond Cherenkov radiation source could thus be widely applicable as an alternative excitation source to mode-locked Ti:Sapphire lasers for future clinical nonlinear microscopy or other applications requiring synchronized multi-wavelength light sources.