An apparatus includes a pulsed laser source that produces a pulsed laser beam at an input repetition rate and an input pulse power, a passive pulse splitter that receives the pulsed laser beam and outputs a signal including a plurality of sub-pulses for each input pulse of the pulsed laser beam, a sample, and a detector. The output signal has a repetition rate that is greater than the input repetition rate and the powers of each of the sub-pulses are less than the input pulse power. The sample is placed in the path of a sample beam that is formed from the beam that exits the pulse splitter. The detector receives a signal of interest emitted from the sample.