A wide illumination range photoluminescent lamp utilizes a primary set of electrodes positioned to generate an plasma discharge along a serpentine channel to produce a high level of visible light. A pair of secondary electrodes may be activated to alter the discharge path for the plasma discharge such that a low level of visible output light is produced. The lamp includes a light guide diffuser over a transparent cover to diffuse the light in the low operational mode and generate uniform light over a wide range of illumination levels. The secondary electrodes may be mechanically activated or automatically activated based on the amount of ambient light.