What is the purpose of Voyager's miniature transporter?
In Voyager's transporter room, there is an alcove on the side, and embedded in the wall is what appears to be a small transporter pad. I don't believe anyone is ever shown interacting with this, so there's no definitive explanation for what it is. Assuming it is what it appears to be, what would be the purpose of a very small transporter like this?
That's exactly the thought I had about it. (The sample return part.)
Perhaps also with a small containment field with its own power supply? Thus the smaller size would allow for more efficient use of such a field, whether by allowing it to be more secure while using the same power as a larger field or to sustain a smaller field for a longer time in cases of general power failure?
That's actually not a bad thought. Some kind of special sample transporter is certainly a possibility. It would be easier to set up a containment field around the smaller platform.