Measurement of ultrashort-radiation parameters by the method of chirped-pulsed spectral interferometry

A simple and reliable method for the measurement of the contrast of ultrashort pulses was implemented. It is based on the application of the principles of chirped-pulse spectral interferometry. The method is linear in terms of the field of the investigated radiation and is based on the measurement with interferometric precision of the spectrum of an amplified chirped pulse before it passes through a temporal compressor. It is shown that, when a recording system with a dynamic range of 10² is used, measurements of the contrast up to 10⁵ are possible. The possibility of applying the method for the on-line monitoring of the parameters of the radiation of solid-state laser sources of ultrashort optical pulses is demonstrated. This is done by taking as an example the optimisation of the front end of a neodymium glass picosecond laser system generating ~1 ps pulses at its output.