A simple drop of olive oil in a system photons Bouncing between two mirrors has revealed universal aspects of phase transitions in physics.
The researchers of the AMOLF Institute for Fundamental PhysicsIn the Netherlands, they used an oil-filled optical cavity in which light undergoes phase transitions similar to those of boiling water. The system they studied has memory because the oil makes the photons interact with themselves. By varying the distance between the two mirrors and measuring the light transmission through the cavity, they discovered a universal law that describes phase transitions in memory systems. These results have been published in Physical Review Letters.
AMOLF's interactive photon research group studies nonlinearity and noise in photonic systems. One of these systems is a cavity, formed by two mirrors facing each other at close range. Inside the cavity, light bounces from side to side as it is reflected from the mirrors. Putting something inside said optical cavity changes the properties of the system. "We created a memory system by placing a drop of olive oil inside the cavity," group leader Said Rodriguez said in a statement. "The oil mediates effective photon-photon interactions, which we can see by measuring the transmission of laser light through this cavity."
Rodríguez and the PhD students Zou Geng and Kevin Peters They analyzed the transmission while increasing and decreasing the distance between the two mirrors at different speeds. They discovered that the amount of light transmitted through the cavity depends on the direction of movement of the mirrors. "The light transmission through the cavity is not linear. At a certain distance between the mirrors, the amount of transmitted light depends on whether we are opening or closing the cavity," Rodríguez explains. "This behavior is called hysteresis. It is also seen in certain phase transitions, such as in boiling water or magnetic materials."
However, in the olive oil cavity, hysteresis is not always present, the researchers observed when they increased the speed at which the cavity opens and closes. "On faster scans, we saw that the hysteresis faded as a function of the scan speed. This happens at a universal speed, independent of parameters such as light intensity or the intensity of nonlinearity. The equations that describe how The behavior of light in our oil-filled cavity is similar to that described by collections of atoms, superconductors, and even high-energy physics. uni behaviorversal that we discovered is also observed in such systems"explains Rodríguez.
While it would be interesting to investigate universal-scale behavior in other memory systems, Rodríguez will keep his focus on oil-filled cavities. "Our system has strong optical non-linearity at room temperature, which offers opportunities for possible applications, "he says." We are currently investigating what happens when we join two or more cavities. Because each system has memory, a series of cavities could be useful as a computational tool, or perhaps even in detection applications. "