Semiconductor nanowires are prototypical quasi one dimensional materials that range from simple uniform alloys to complex heterostructures incorporating different materials.   These nanowire materials can now be grown with high crystalline quality and thus explored for their intrinsic physics.  We discuss in particular recent results on cylindrical quantum wells embedded within a nanowire, namely quantum well tubes.  We bring to bear a variety of optical techniques to study the strong quantum effects which can be controlled in these structures, with particular attention to exciton localization caused by disorder which has yet to be controlled.  We then introduce a new optical technique, transient Rayleigh scattering, that is shown to provide unique insights into the electron-hole dynamics in nanowires.  We show that such laser light scattering experiments make it possible to investigate single nanostructures in the mid-IR energy range where standard optical techniques fail.