In the last few decades, lasers have become an important part of our lives, with applications ranging from laser pointers and CD players to medical and research uses. Lasers typically have a very well-defined direction of propagation and very narrow and well-defined emission color. We usually imagine a laser as an electrical device we can hold in our hands or as a big box in the middle of a research laboratory.
Fluorescent dyes have also become commonplace, being routinely used in research and diagnostics to identify specific cell and tissue types. Illuminating a fluorescent dye makes it emit light with a distinctive color. The color and intensity are used as a measure, for example, of concentrations of various chemical substances such as DNA and proteins, or to tag cells. The intrinsic disadvantage of fluorescent dyes is that only a few out of tens of different colors can be distinguished.
In a combination of the two technologies, researchers know that if a dye is placed in an optical cavity—a device that confines light, such as two mirrors, for example—they can create a laser.
Taking it all a step even further, our research, described in the journal Nature Photonics, shows that we can create a miniature laser that can emit light inside a single live cell.
Tiny, Tiny Lasers
