Time-resolved optical measurements with spread spectrum excitation.

We propose a novel method for measuring time-dependent optical quantities. A train of excitation pulses modulated by a pseudorandom bit sequence is used as the light source, and a cross-correlation scheme is used to retrieve the impulse response. Simulation results of the temporal point-spread function of a diffusive wave are provided, as well as experimental results of a fluorescence decay profile. It is demonstrated that our new time-resolved technique can lead to high signal-to-noise ratios and short data acquisition times. A fluorescence-time-dependent suppression process was also been discovered.