A blazed grating is disclosed as well as mode hop-free tunable lasers and a process for fabricating gratings of this type. The 3D display system includes a plurality of multi-viewing zone miniaturized imaging modules and an image output module. The mathematical models are analyzed to determine if collected and queued package identification data is spatially andor temporally correlated with package measurement data using vector-based ray-tracing methods, homogeneous transformations, and object-oriented decision logic so as to enable simultaneous tracking of multiple packages being transported through the scanning tunnel.