Non-Paraxial Beam Splitter for Dot Projectors

Dot projectors, capable of splitting an incoming beam into a densely populated array of discrete spots, have seen a rapid increase in applications in recent history. To achieve the required high number of spots, these devices typically combine highly divergent source panels with beam splitters.

Striking the right balance between accuracy and speed in the simulation of systems like these can be quite challenging: On the one hand, the small structures of the beam splitter demand the application of rigorous methods, which tend to be computationally heavy. On the other, the simulation should be agile enough to produce results within reasonable bounds of memory use and time. Besides, often, the system will comprise not just the dot projector, but also, at least, propagation in free space, if not other, additional, optical components, such as lenses.

The extremely flexible approach of interoperability of modeling techniques on a single platform offered by the optical modeling and design software VirtualLab Fusion is just the ticket here. It permits the application of the rigorous Fourier Modal Method/Rigorous Coupled Wave Analysis (FMM/RCWA) to model the non-paraxial splitter with the necessary accuracy, while at the same time avoiding computational overkill by combining this technique with other, much faster, approaches for other potential elements in the system, whether they be propagation in free space, through lenses, or both. And all of this on a single software platform with a consistent light model, meaning that no important information is lost changing from one modeling technique to another, and also obviating the need for any cumbersome back-and-forth between different packages.

In this week’s newsletter we showcase just such a dot-projector system, providing both an analysis of the working principle of the device and a document covering its design.