What blender is required to create an emulsion?
An emulsion, like mayonnaise, can be made with a fork, a hand whisk, an electric whisk, a stick blender, or a traditional blender with a jar. I've made mayo, at some point or another, with just about all of these.  For home use, the hand whisk is often the most convenient if you are handy with the technique.  However, I find a stick blender to be the best option, for speed and easy cleanup.  One caveat is that the container you are making the mayo in should be just slightly larger than the blade end of the stick blender.  For me, a cocktail shaker is perfect.