Spatially coherent white-light interferometer based on a point fluorescent source

We developed a point-fluorescent-source-based white-light interferometer for high-resolution reflectometry, range-gating imaging, and group-velocity-dispersion measurement. The laser-pumped point fluorescent source has 9 mW of power and a spatial coherence of 0.97, which allows it to be used like a laser beam. Owing to its 40-nm FWHM spectral width, the width of its temporal autocorrelation is only 19 fs, which corresponds to that of 14-fs Gaussian pulses.