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Tiny crystals used to make energy-efficient, multicolor lasers

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A team at Brown University is developing a new kind of laser that can cheaply and efficiently emit light in a wide range of colors.

Brown University colored laser
Brown University colored laser

Researchers at Brown University are developing a new kind of laser that produces a variety of different colors and could eventually be used in "high-performance digital displays." Lasers that can produce red, green, and blue light already exist, but the problem is that you actually need three different lasers for each color. The new technique does away with this and can use one single laser to produce "a variety of laser colors all at once." The key is a tiny material called a quantum dot (or nanocrystal). The dots are produced by a company called QD Vision, which makes them available in liquid form so that they can then be painted on a square of glass. Once the liquid evaporates the glass is covered with a number of layers of quantum dots of many different sizes, with each size producing a different color.

The glass is then placed between two mirrors so that it can produce colors when stimulated by laser light. According to the team, this laser — officially known as a colloidal-quantum-dot vertical-cavity surface-emitting laser — not only produces a variety colors from a single source, but is also inexpensive to make and requires "1,000 times less power to produce laser light than previous attempts at the technology." While the technology is probably still a long way off from any sort of commercial application, it is receiving attention from a number of notable places — the US Department of Energy, Air Force Office for Scientific Research, and National Science Foundation are all supporting the research.