Laser smaller than a hair could spark a technological revolution

Laser smaller than a hair could spark a technological revolution: They used a 45 nanometer thick layer of cadmium sulfide, a compound used in solar cells and light meters. It's a photoresister, something that resists the passage of photons, but has a resistance that decreases with the amount of light it's exposed to. The cadmium sulfide was placed next to a silver surface, with a gap of 5 nanometers between them. The gap was filled with magnesium fluoride, which allows easy passage for many different wavelengths of light.

The result has been likened to a 'whispering gallery' effect. Instead of leaking here, there and everywhere, the light is passed between the surfaces of these metals and keeps itself mostly in the little gap filled with magnesium flouride. This causes less shed heat, and keeps the laser running at room temperature.