Re: Lenses for laser-patterns
The type of "lens" you describe is called a diffraction transmission hologram. It is an image originally made by a laser, and in most cases, can only be viewed (or projected) by one.
If you put one under a very powerful microscope, it would look a lot like those diffraction grating glasses that turn ordinary light into a rainbow. Only in this case, an image is encoded onto the diffractive element which causes the laser beam hitting it to diffract or bend.
I'm not exactly sure how diffraction-based holograms are made, so this is about where my helpfulness ends.
The underlying technology isn't very different from those "offical merchandise" stickers found on MLB merchandise, the UL tag on Christmas lights, or the "eagle" found on some types of bank cards. The difference is that these are examples of white-light reflection holograms; but they are still holograms made made with a laser.
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