Abstract
For the GKSS Raman lidar, a combined system for the measurement of optical particle properties, ozone, and mois- ture, a polychromator for temperature measurements with the rotational Raman technique was developed. Since early 1998, this instrument has proved its reliability and high performance in three field campaigns. Temperature data could be taken even in the presence of clouds and up to heights of more than 40 km. The main feature of the receiver is a new design with a cascading mount of the individual channels. Interference filters are used with small angles of inci- dence. They serve for selecting the desired wavelength band and reflecting the remaining spectrum. High signal trans- mittance and high blocking of the elastically backscattered light in the rotational Raman channels could b e ac hieved simultaneously. In this contribution the optimization procedure that preceded the implementation is presented. The parameters that were considered are the primary wavelength, the blocking of the elastically backscattered light for the rotational Raman channels, and the filter center wavelengths and bandwidths. It is explained which compromises were made to reconcile theoretical requirements with actual filter technology.
