| 摘要 |
A method for controlling and sensing in order to monitor atmospheric gases using a lidar technique whereby a laser beam is emitted at a fixed wavelength, whereby a reflected laser pulse is optionally passed through an interference filter for isolating a desired spectral region, whereafter the laser beam pulse is passed through a beam splitter and two laser beam detectors, whereby one of the beams is passed through a gas correlation cell comprising the compound to be determined in order to block out the central part of a resonance line whereby the off resonance signal is determined and recorded, and whereby the second beam is used for measuring the whole spectral distribution, any inbalance in the two determinations made indicates the presence of an external gas to be detected. |
