Temporary "compression" of femtosecond pulses in the focus of truncated microellipsoid

Truncated ellipsoid which all parallel incident rays collects on it's flat surface is designed. Simulation by (FD) 2TD method of focusing of femtosecond pulse (duration 1.24 fs and the carrier wavelength λ 0 = 532 nm) by a silica truncated microellipsoid with smaller cross-sectional diameter of 1.16 mm showed that the ellipsoid gives an elliptical focus spot with a smaller diameter FWHM = 0,38 λ. At the same time the pulse duration at the focus of a few percent smaller than the duration of the incoming pulse.