The ultimate in small lasers.
A cw photonic crystal nanolaser has a lasing threshold of only 1.2 mW and a modal volume of 0.028 µm3.
Using slight defects engineered into a photonic crystal, researchers created the ultimate in small lasers, with a cavity mode volume of only 0.019 µm3—close to the diffraction limit of light. Kengo Nozaki, Shota Kita and Toshihiko Baba at Yokohama National University in Japan built a room-temperature continuous GaInAsP laser that operates on only a microwatt of power (Opt. Express 15, 7506).
The patterning of the holes in the photonic crystal prevents light at most wavelengths from existing in the structure, but enhances wavelengths that can exist in the region around the defect.
Previous photonic crystal lasers either required lower temperatures to operate or produced pulses, but not continuous emission. Continuous emission could be useful as a light source in active optical integrated circuits. Alternatively, because the laser is very efficient and has a very low threshold, it could be used for instruments or other applications that require only a few photons at a time.
[Yvonne Carts-Powell is a freelance science writer who specializes in optics and photonics. ]