A preferred embodiment of a stent provides a folded strut section that provides both structural rigidity and reduction in foreshortening of the stent mechanism. While a system is communicating in a channel, RF interference is monitored. The distal segment includes a head portion and a threaded shank portion. The devices can be operated at a low-power density for safety andor may be configured to mitigate wavelength hopping associated with unstablized laser light sources.