Spectral phase shift and residual angular dispersion of an acousto-optic programmable dispersive filter

Abstract

Spectral phase shift and both types of wavelength dependent angular deviation introduced by an acousto-optic programmable dispersive filter (AOPDF) into a femtosecond laser beam at 800 nm have been measured with high precision. With the use of spectrally and spatially resolved interferometry, we have proved experimentally that the AOPDF controls the group delay dispersion (GDD) and third-order dispersion (TOD) with an accuracy of better than 1% and 3% of the preset values within the range of 10–1000 fs2 and 1000–40,000 fs3, respectively. The values of angular deviation and angular dispersion are primarily dependent on the set absolute value of GDD of the AOPDF when it is operating in continuous mode. Besides of a small offset value, there is no added angular dispersion at 0 fs2, while it can increase up to 0.2 μrad/nm at 10,000 fs2.