OBSERVATION OF THE 2-PHOTON RESONANT PARAMETRIC 4-WAVE-MIXING IN THE NO C-2-PI (V=0) STATE

When the laser frequency was tuned through the C-2 Pi (upsilon = 0) <- - X(2) Pi (upsilon '' = 0) two-photon transition of NO, near-IR as wel l as UV radiations were ejected along the laser propagation with a nar row solid angle. It was shown that the UV wave corresponds to the A(2) Sigma(+) (upsilon' = 0) --> X(2) Pi (upsilon '' = 0) transition. Temp oral profiles and polarization properties of output waves indicate tha t the parametric four wave mixing (PFWM) process is mainly responsible for the simultaneous generation of near-IR and UV radiations. Excitat ion spectra corresponding to the C-2 Pi (upsilon = 0) <-- X(2) Pi (ups ilon '' = 0) band exhibited an excellent S/N ratio, implying that the PFWM technique might be utilized as a novel spectroscopic method which can interrogate the two-photon resonant levels.