Researchers at MIT have designed a quantum light squeezer that reduces quantum noise in an incoming laser beam by 15 percent. It is the first system of its kind to work at room temperature, making it amenable to a compact, portable setup that may be added to high-precision experiments to improve laser measurements where quantum noise is a limiting factor.
The heart of the new squeezer is a marble-sized optical cavity, housed in a vacuum chamber and containing two mirrors, one of which is smaller than the diameter of a human hair. The larger mirror stands stationary while the other, 70-micron-wide made of alternating layers of gallium arsenide and aluminum gallium arsenide, is movable, suspended by a spring-like 55-micron-long cantilever.
The shape and makeup of this second “nanomechanical” mirror is the key to the system’s ability to work at room temperature. When a laser beam enters the cavity, it bounces between the two mirrors. The force imparted by the light makes the nanomechanical mirror swing back and forth in a way that allows the researchers to engineer the light exiting the cavity to have special quantum properties.
The system was then installed in a laser experiment built by Corbitt’s group at Louisiana State University, where the researchers made the measurements. With the new squeezer, the researchers were able to characterize the quantum fluctuations in the number of photons versus their timing, as the laser bounced and reflected off both mirrors.
The laser light can exit the system in a squeezed state, which can be used to make more precise measurements, for instance, in quantum computation and cryptology. (SciTechDaily)
The study has published in the journal Nature Physics.