From the refractiveindex of each path it is possible with the application of some suitably crunchy computing power to produce a three-dimensional image.
Inside the BEC, the so-called refractiveindex (which measures the slowing of light) becomes enormous: as high as 100 trillion times greater than that of glass.
Shining an appropriate light on such a wire from the outside would alter its refractiveindex (a measure of how fast light travelling inside the wire can move).