An electrode-less plasma lamps comprises generally of a bulb containing a gas-fill that is excited to produce light using radio-frequency (RF) energy. In specific embodiments, the use of grounded coupling-elements with integrated bulb assemblies simplifies manufacturability, improves resonant frequency control, and enables the use of solid, partially filled, and hollow lamp bodies. In some embodiments, a method of operating an electrodeless plasma lamp device includes transferring RF energy from the RF source to an input coupling-element and illuminating electromagnetic energy substantially from the length of a gas-filled vessel from discharge of the gas-filled vessel.