Michelson interferometer outfitted with a translation stage on one arm (horizontal in photo). The output is split and sent to two photodiodes, one for measuring the reference signal and the other for measuring the signal of an unknown beam.
Measured signal for an ultrashort IR pulse train (solid line) and for a coherent 532-nm source (dotted line) as the mirror in the interferometer is scanned. Variations in the scan velocity cause the fringes to be nonuniform.
Phase-compensated measurement for an ultrashort IR pulse train. Superimposed is a measurement of the same pulse train after undergoing strong dispersion, that is, chirping. The two curves are nearly indistinguishable and appear in the plot as a single curve.
The measured spectrum recovered through Fourier spectroscopy (dots) compared to that obtained using a grating spectrometer (solid line).
Pulse-duration measurement using a nonlinear autocorrelation technique (solid line). A significantly longer pulse duration results when the ultrashort pulses travel through a thick piece of glass (long dashed line).
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