Description: The purpose of this project is to develop techniques that make it possible to reduce the size and weight of non-mechanical LiDAR beam steering systems. Previous work has shown that LiDAR beam steering with diffractive components based on spatial modulation of geometrical phase is feasible and useful. Most previous work with this technology has concentrated on steering techniques that are polarization sensitive. Under the current project, these techniques will be extended to LiDAR beam steering that is polarization-insensitive. This would allow reduced weight and/or size of such steering systems because it would allow the LiDAR receiver to use all of the optical power returned from a target, rather than only returned radiation of one polarization. Since transitioning from a polarization-sensitive beam steering system to a polarization-insensitive beam steering system would require an increase in the number of optical substrates, the most weight benefit of such a transition would be gained if the substrate weight is minimized. Therefore, an analysis of options for lightweight optical substrates will be performed in order to make it possible to further reduce the weight of future LiDAR systems. Another related technical issue with non-mechanical beam steering is the switching speed among pointing directions. Additional system weight reduction may be possible if switching speed of the pointing system is increased beyond the speed of currently-available optical switches. Methods for leveraging recent developments in liquid crystal technology to increase switching speed will be analyzed, thereby enabling the use of higher pulse rates in LiDAR systems, which may further reduce the size and weight of these systems in some applications.

Benefits: Compact, low SWaP, non-mechanical, hence, robust, LiDARs with reliable and fast data acquisition capability that meet requirements for a space landing vehicle could be used for other NASA missions including asteroid flybys, swarms of cubesats, etc. due to higher precision guidance and navigation systems. An additional potential application of this technology is to transceiver steering for free-space optical communications systems.

Numerous non-NASA applications include autonomous navigation systems for cars, drones, and robots, and commercial free-space optical communications.