This paper presents an experimental technique for measurement of the contra
st ratio of ultrashort UV pulses. As a multiple-shot device based on the sc
heme of difference frequency generation this is, to our knowledge, the only
cross correlator in the UV so far, which offers a dynamic range of 10(7) a
nd operates with input pulse energies as low as 5 mu J. By changing the cro
ss correlator into single-shot mode, the temporal shape of the UV pulse can
be measured.