Doppler receiver modules (left) are enclosed (right) in an environmentally controlled vessel
The Fabry Perot etalon has three sub-apertures (left) corresponding to the filter bandpass functions labeled Edge1, Edge2 and Locking Channel in the Figure (right). Each channel has nearly identical optical properties (peak transmission, finesse, free spectral range) with a slightly different bandpass center frequency. The separation of the two edge filters is chosen so that the sensitivity of the broader molecular signal is equal to that of the narrower aerosol signal. The locking etalon peak is located such that the outgoing laser frequency is aligned to the half width half height point of the locking filter bandpass.
The TWiLiTE Team is back from field work at Palmadale, California. Several engineering flights and a successful science flight were conducted aboard an ER-2.