Described is an electrode-less plasma lamp comprising a gas-fill vessel, a gas-fill contained within the gas-fill vessel, an RF electromagnetic radiation source, an RF electromagnetic resonator, an output probe that couples RF energy from the RF electromagnetic resonator to the gas-fill vessel, an input probe that couples RF energy from the RF electromagnetic radiation source to the resonator, and a grounding strap that holds a metal veneer surrounding the resonator and a portion of the gas-fill vessel at RF ground. Also described are many variations of the electrode-less plasma lamp, non-limiting examples of which include embodiments that employ other probes in a Dielectric Resonant Oscillator to drive the lamp, a lamp employing more than one resonator per gas-fill vessel, and many methods of improving light-harvesting, including raising the gas-fill vessel away from the resonator via a coaxial transmission line, and collecting light with an optical reflector.