I'm still waiting for the FCC or ITU to define a band for electrodeless plasma lamps. For the uninitiated, these are microwave-driven light sources that are ab

I'm still waiting for the FCC or ITU to define a band for electrodeless plasma lamps. For the uninitiated, these are microwave-driven light sources that are about half as efficient as the best LEDs, but still way more efficient than incandescent. The light output spectrum is continuous and single-peaked, and in the case of sulfur lamps, so close to solar that they are routinely used as a "synthetic sunlight" for testing solar panels. The MW band used in existing appliances is generally the 2.45 GHz Bluetooth and microwave oven band, because it's unregulated, but the high output power and the need for a transparent housing means that they can interfere with other consumer electronics. There is virtually no risk of two bulbs interfering with each other, so even a relatively narrow dedicated band should work fine. As I understand it, the light output is continuous — no flicker — and anyway the beam power of a circularly polarized microwave should be continuous. Usually, microwaves are created using magnetrons — vacuum tubes — which have a high minimum power output (think floodlight). Microwave diodes do exist, although they haven't yet been applied to electrodeless lamps, because consumers won't be interested in using a light bulb that kills Bluetooth. But it is physically possible for us to enjoy an efficient light source that looks nice. There are just a few kinks to work out.