For the first time, Fluorescent proteins from jellyfish is use to create a laser. These lasers could open up research avenues in quantum physics and optical computing. It is more effective and compact than conventional ones.
Traditional polariton lasers uses inorganic semiconductors. They requires to be cool in incredibly low temperatures. Latest designs depends on organic electronics materials. Generally, it is used inside organic light-emitting diode (OLED) displays. They operates at room temperature but requires to be driven by picosecond (one-trillionth of a second) pulses of light. According to scientists, this breakthrough represents a major advance in so-called polariton lasers.
By refunctioning the fluorescent proteins, scientists creates a polariton laser. The laser operates at room temperature powered by nanosecond pulses(just billionths of a second). The proteins allows scientists to monitor process inside cells and have revolutionized biomedical imaging.
Malte Gather said, “Picosecond pulses of a suitable energy are about a thousandfold more difficult to make than nanosecond pulses. Thus it really simplifies making these polariton lasers quite significantly.” ( Gather is a professor in the School of Physics and Astronomy at the University of St. Andrews in Scotland and one of the laser’s inventors.)
“The fluorescent proteins are currently being use as a marker in living cells or living tissue. But now the researchers have started using them as a material. This work shows for the first time that their molecular structure is actually favorable for operation at high brightness as required, for example, for turning them into lasers,” he said.
Scientists genetically engineer E. coli bacteria to produce enhanced green fluorescent protein (eGFP). Then scientists filled optical microcavities with this protein before dominating them to optical pumping. The nanosecond flashes of light are used to bring the system up to the required energy to create laser light.
Pumping lots of energy in device mainly after reaching at beginning for polariton lasing result in conventional lasing. According to Gather, it helps to confirm the first emission was due to polariton lasing. This is what something other approaches using organic materials have been unable to demonstrate so far.
Through the fact that photons can amplified by excited atoms in the laser’s gain medium, conventional lasers create their acute beams. This is made up of inorganic materials like glasses, crystals or gallium-based semiconductors.
Their is no huge difference between Polariton laser light and conventional laser light. But the physical process that generates it depends on a quantum phenomenon to amplify the light.
Conventional lasers needs above half of the atoms in the gain medium to enter an excited state before laser light generates. This is not the case in polariton lasers. It means, they require less energy to be pump into the system.
One main advantage of the new approach, the light-emitting part of the protein molecules are protected within a nanometer-scale cylindrical shell. It prevents them from interfering with each other.
Stéphane Kéna-Cohen said, “This overcomes a major problem that has plagued previous designs. This allows the laser to operate with much longer pump pulses, which are easier to generate and allows for simpler implementations. At the moment, many challenges remain for such lasers to be useful because the [excitation] threshold is so high. But they are a fascinating platform for studying physics that normally occur only at ultralow temperatures.”
Gather said, “The fundamental physics suggests design improvements should eventually allow polariton lasers with considerably lower thresholds than conventional ones. This will allow them to be much more efficient and compact.”
“This makes the new study promising for the field of optical computing. A tiny laser depends on biomaterials could also potentially be insert in the human body for medical applications. In the meantime, they are a useful model for investigating fundamental questions in quantum physics.”