Efficient generation of picosecond coherent tunable radiation between 190 and 212 nm by sum-frequency mixing from Raman and optical parametric radiations

An efficient sum-frequency mixing of optical parametric radiation and stimulated Raman radiation has been used to generate picosecond continuously tunable coherent radiation ranging from 190 to 212 nm with energies of
20-40 \mu
J. An ordinary KDP crystal was phase-matched by using a combination of long and short wavelength incident waves.