Make 2 holes with a drill for glass (diameter about 0,8 cm). One in the upper part and one in the lower part of the vase.
Buy 5 meters of colored electrical cable of your choice. Some example here.
Buy some sheet of colored polypropylene. Best results with a thick sheet of at least 1,6 mm maximum 3 mm. Took mine here but it is 1,2 mm thick. Better search for something thicker ‘cos the upper clear part tends to bend.
Cut the polypropylene using the sketchup template I uploaded here.
Using a cutter, lightly score the polypropylene along the lines between blue and white surfaces and bend it at 90°
Join all the parts as show in the photos.
I used a g9 lamps holder with super short 15w CFC lamps like the one shown below.
If you change lamp you have to change the template according to the new dimension of your light emitter.