Researchers have created the smallest room-temperature laser, a breakthrough that could lead to faster optical computers.
A group at the University of California at San Diego published a paper in Nature today that describes a new method for making lasers smaller than ever before. The technique allows for low-power lasers smaller than one micron in diameter. A human hair is about 600 microns wide and air-borne particles such as pollen are as small as 10 microns.
The advance in producing a low-power laser opens up many applications, according to the UC San Diego team. Nanolasers could be used to send data across optical computer chips or in the construction of high-resolution displays and microscopic biosensors that produce images of viruses and DNA molecules. The lasers could also be use to analyze and produce metamaterials that scatter light to make objects invisible.
The challenge with making very small lasers has been the amount of power required to generate a sustained beam of light. To get around this "threshold" energy level, the UCSD team created a laser with a similar structure to a coaxial cable.
This tiny coaxial cable, or "nanocavity," is a metal rod encased by a semiconductor material. The construction avoids the electromagnetic effects normally caused by at this scale, allowing for smaller laser resonators. The lasers can be comparable in size the wavelengths of light they produce, according to the researchers.
The lasers built for their experiments aren't going to show up in DVD players or computers any time soon. The researchers are still exploring the theory behind laser construction at this scale and seeking out potential applications.