Raman shifting of KrF laser radiation for tropospheric ozone measurements.

The differential absorption lidar (DIAL) measurement of tropospheric ozone requires use of high average power ultraviolet lasers operating at two appropriate DIAL wavelengths. Laboratory experiments have demonstrated that a KrF excimer laser can be used to generate several wavelengths with good energy conversion efficiencies by stimulated Raman shifting using hydrogen (H2) and deuterium (D(2)). Computer simulations for an airborne lidar have shown that these laser emissions can be used for the pecise (less than 5% random error) high resolution (200-m vertical, 3-km horizontal) measurement of ozone across the troposphere using the DIAL technique. In the region of strong ozone absorption, laser wavelengths of 277.0 and 291.7 nm were generated using H(2) and D(2), respectively. In addition, a laser wavelength at 302.0 nm was generated using two cells in series, with the first containing D(2) and the second containing H(2). The energy conversion efficiency for each wavelength was between 14 and 27%.