ABSTRACT
A multilayer mirror arrangement is used to measure the polarisation characteristics of high harmonics (59 th and 61 st order, λ ≈ 17 nm) with a high degree of accuracy. The reflectivity of the Mo/Si multilayer mirror is about 60 %, and its polarization analyzing power is close to unity at a wavelength of 17 nm. We observed for the harmonics in the cutolf region that there is no rotation with respect to the fundamental light. For linear and slightly elliptical laser polarization the harmonics still remain linear polarized.
