Artificial light is one of the few great inventions: it frees mankind from dependence on sunlight. Artificial light often depends on a hot object — a filament or gas mantle — as close as possible to the temperature of the Sun. In practice, 3,000 K is good. Alternatively, fluorescent materials can be excited by ultraviolet light or electric discharges, as in gas-discharge tubes. But both types of light are deplorably inefficient.

Daedalus now recalls the free-electron laser. A beam of electrons is fired along a tube, and set wiggling by magnets lining it. Electrons sent along a wiggly wire as an ordinary current should wiggle just as much, and their sideways oscillation should emit visible light. Modern micro-deposition can probably impose 1012 wiggles per metre on a conductive pathway, so a current of 103 metres per second should emit blue light at a frequency of 1015 Hz. A high-temperature superconductor may be needed, but the thing looks feasible: an amp is some 6 × 1018 electrons a second.

DREADCO engineers are therefore depositing cuprate superconductors, and even conducting metals such as silver, onto transparent quartz plates. They are packing as many wiggles as possible into the conductor. Transformer coupling to the wiggly element should let ordinary mains electricity drive the new light. It should compete strongly with existing lamps. It will be far more efficient than they are. It will hardly get warm; indeed, it may need to be cooled, but Daedalus hopes that room-temperature superconduction will be possible soon.

The new 'electrolamp' will emit a very pure light, its frequency defined by the speed of the electrons and the size of the wiggles. The first samples will go at a vast price for visible, infrared and even ultraviolet spectrometers; these will recover the heavy development costs. When the lamp reaches commercial production, several parallel 'filaments' will each have different number of wiggles, so as to emit a graded rainbow of colours approximating to white (as with gas-discharge tubes today).

Photographers will love a special electrolamp, whose three filaments are each tuned to one of the dyes in the film. It should combine great sensitivity with accurate colour rendition. The broader, whiter electrolamp should transform the domestic scene. Equally effective on mains or battery, it will complete our victory over fitful solar illumination.