A Fluorimeter on the Basis of a Femtosecond Cr+4: Forsterite Laser

An apparatus for measuring luminescence lifetimes using the femtosecond up-conversion method is presented. A laser system based on a chromium–forsterite crystal with a lasing wavelength of 1250 nm is used to generate ultrashort pulses. Luminescence is excited in a sample by optical harmonics that are generated in nonlinear optical crystals. The width of the instrument function of the system is 200 fs. Methods for optimizing the signal-to-noise ratio in measurements are discussed. The results of measurements of the fluorescence- decay dynamics and the anisotropy of aqueous solutions of an inclusion complex of the 4-DASPI styrene dye in cucurbit[6]uril on short (5 ps) and long (500 ps) time scales are presented.