The absorption of the Nd : YAG fourth harmonic in air and binary mixtures of water vapour with nitrogen and oxygen at atmospheric pressure has been measured as a function of pulse energy (peak intensity). The mixtures obtained by adding equal amounts of water vapour to dry nitrogen and oxygen have been found to differ significantly in absorption. Preliminary quantitative data have been obtained for two- and three-photon absorption cross sections of water and oxygen molecules: σ (2) (H 2 O) = (4 ± 1) × 10 -49 cm 4 s and σ (3) (O 2 ) = (5.6 ± 1.4) × 10 -78 cm 6 s 2 . The absorption of 266-nm pulses with peak intensities from 0.05 to 2 GW cm -2 in the near-surface atmosphere has been shown to be determined by two-photon absorption in water vapour and three-photon absorption in oxygen. In moist air containing 1% water vapour, the absorption coefficient for 266-nm laser pulses exceeds that in ...

中文翻译：

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水蒸气在大气吸收纳秒266 nm激光脉冲中的作用

已测量了大气压下空气和水蒸气与氮和氧的二元混合物中Nd：YAG四次谐波的吸收随脉冲能量（峰值强度）的变化。已经发现通过向干燥的氮气和氧气中添加等量的水蒸气而获得的混合物在吸收方面有显着差异。已获得水和氧分子的两个和三个光子吸收截面的初步定量数据：σ（2）（H 2 O）=（4±1）×10 -49 cm 4 s和σ（3）（ O 2）=（5.6±1.4）×10 -78 cm 6 s 2。业已表明，在近地表大气中，峰值强度为0.05至2 GW cm -2的266 nm脉冲的吸收是由水蒸气中的两光子吸收和氧中的三光子吸收确定的。在含有1％水蒸气的潮湿空气中，