Researchers create microdroplet 3-D laser system

Dec. 13, 2010—Slovenia researchers recently demonstrated full 3-D tunable lasing in laser dye-doped cholesteric liquid-crystal (CLC) microdroplets from 15µm to 50µm in diameter—a first, according to an article in the Dec. 10 issue of Optics Express, an international online journal of The Optical Society.

The droplets, which are spontaneously self-assembled by the millions in seconds by dispersing a small amount of CLC in a non-miscible fluid such as glycerol, are embedded in an isotropic carrier fluid, according to an OSA news release.

“The lasing wavelength depends solely on the natural helical period of the cholesteric, and can be tuned by varying the temperature,” the Slovenia researchers reported. “Millions of microlasers can be formed simply by mixing a liquid crystal, a laser dye and a carrier fluid, thus providing microlasers for soft-matter photonic devices.”

At left, the researchers show a droplet that is fluorescing uniformly below the lasing threshold, while a bright spot of radiating monochromatic light is visible at the lasing threshold in the center image. At right, lasing becomes intense at a 12 mJ/cm². Watch a quick video demonstration of this process below.

Potential applications of the microlasers include holography, telecommunications, optical computing, imaging, sensing and light sources that emit coherent light in all directions. Click for a PDF format of the Optics Express article.