| Popis: |
A beam steerer is necessary in laser radar systems to position the narrow transmitter beam in a larger field of regard.1 A nonmechanical technique, such as that using an optical array with a cell of electronically addressed liquid crystal phase shifters,2 is expected to replace mechanical output steering mirrors in large aperture systems with high agility requirement. Many laser radars also require a passive acquisition sensor, which should share large optical components with the active channel.1 However, the grating structure of array beam steerers causes dispersion in the broadband passive channel. This work describes results of an analysis of the far-field performance of optical array beam steerers and laboratory verification measurements. The angular dispersion is many times the far-field beam diameter for typical sensor apertures, steering angles, and bandwidths, which has a detrimental effect on resolution and sensitivity. Two correction schemes are currently being investigated: deconvolution filtering and cascaded holographic gratings. The status of their analysis and implementation is also reported. |
