Effect of pulse asymmetry and nonlinear chirp on the accuracy of ultrafast pulsed laser interferometry

摘要

Ultrafast pulsed laser interferometry (PLI) can measure picometer displacements at sub-nanosecond time scales, such as acoustic waves and vibrations in microstructures. In this Letter, the effects of pulse characteristics on the accuracy of PLI are investigated through measurements and modeling. The results show that the effective wavelength of PLI, lambda(eff), varies significantly as a function of overlap between the interfering pulses due to pulse asymmetry and nonlinear chirp. This variation presents a serious limitation on the accuracy of PLI if unaddressed. However, it is shown that a continuouswave laser interferometer can be used to determine lambda(eff) with an uncertainty near 0.01%, making it possible to use PLI for accurate displacement measurements.