Transient spectrometer for near-IR fluorescence based on parametric frequency upconversion

The authors report a unique technique for recording femtosecond time-resolved fluorescence spectra in the near IR by using idler-to-signal frequency upconversion in a 400 nm pumped femtosecond noncollinear optical parametric amplifier, in which the IR fluorescence was seeded as the idler and the corresponding amplified signal branch is recorded. The spectra of the upconverted signal carry the information of the IR fluorescence and it were used in constructing the spectra of the IR dye. The transient fluorescence spectra from the upconverted signal reconstruct the spectra of the IR dye very well after deconvolution from the pump beam. (c) 2006 American Institute of Physics.