Detection of thin oil films on the water surface with the help of UV filaments

The fluorescence of thin oil films on the water surface induced by femtosecond UV laser pulses was studied experimentally. The laser pulses were considered in a wide range of intensities, including the radiation filamentation range. The applicability of the method to femtosecond UV pulses with two central wavelengths (248 and 372 nm) was compared. It was shown that the spatial resolution of the fluorescence localization was no worse than 30 cm.