Scientists for the first time have developed LASER (light amplification by stimulated emission of radiation) from fluorescent jellyfish proteins that were grown in bacteria. The first of its kind represents a major advance breakthrough in so-called polariton lasers operating at room temperature. What is Laser? A laser is a device that emits light through a process of optical amplification based on the stimulated emission ofelectromagnetic radiation. Major difference between laser and other sources of light is that, laser emits light coherently. What is Polariton laser? Polariton laser works by passing photons back and forth between excited molecules. Unlike conventional lasers, the photons in Polariton laser are released and reabsorbed within the device itself before zooming out as laser light. Key Facts To develop the fluorescent Polariton laser, scientists had engineered barrel-shaped fluorescent proteins from jellyfish DNA. They had filled optical microcavities (between two mirrors) with this protein before subjecting them to optical pumping. Nanosecond flashes of blue light from an external laser were used to bring the system up to the required energy to create laser light. After the threshold was reached for polariton lasing, scientists pumped more energy into the device setup that resulted in conventional lasing. Significance: These lasers have the potential to be far more efficient and compact than conventional ones. It could open up research avenues in quantum physics and optical computing. Consumes less energy compared to conventional lasers. It can be used for the purpose more efficient optical communications or in medical lasers that are less destructive to living tissue.