New Effects in Picosecond Stimulated Raman Scattering Near the Liquid-Air Interface

Stimulated Raman scattering in water and liquid nitrogen is studied near the liquid-air interface at picosecond (15 and 57 ps) laser excitation. For the first time, it is shown that Raman threshold on the interface is crucially reduced (up to 30-fold due to the effect of new liquid Raman laser discovered by us) in comparison with the bulk liquid, and the new spectral component at the interface of water-air near 3000 cm
^-1
is appeared as a parametric ring around the known axial beam component at 3400 cm
^-1
.