UNSEEDED VELOCITY-MEASUREMENT BY OZONE TAGGING VELOCIMETRY

Ozone tagging velocimetry is developed for unseeded velocity measureme nt of air flows. An ozone line is photochemically created by an ArF ex cimer laser. After a fixed time delay the ozone line is imaged with a KrF excimer laser sheet (248 nm) that photodissociates the ozone and p roduces vibrationally excited O-2. The O-2 is excited by the same 248- nm light through the Schumann-Runge band, B-3 Sigma(u)(-)(upsilon' = 0 , 2) <-- X(3) Sigma(g)(-)(upsilon '' = 6, 7). An intensified CCD camer a records the 0, fluorescence from the initial and the final line posi tions to permit the velocity profile along the line to be determined. (C) 1996 Optical Society of America