A team of researchers from the Hebrew University of Jerusalem and the Vienna University of Technology (TU
How to absorb light energy?
This is not the first time scientists have figured out howabsorb light energy. But the new "light trap" method that scientists have developed is the only one that can absorb light energy even in very thin and weak media.
In a new experiment, scientists have shown how to implement this process very efficiently.For example, scientists have demonstrated that laser light of any shape can be completely absorbed even by a very "weak" medium.For example, a thin film or a slightly contaminated piece of glass, scientists explain in an interview with Interesting Engineering.
Installation of a light trap.
Photo: Omri Chaim
Now researchers are building carefullyan engineered cavity around an absorbent medium that does not allow light to pass through. It enters the cavity, where it passes through such a medium several times until it is completely absorbed and nothing remains of it.
Why do you need a light trap?
Capturing light energy is very important, butdifficult. And storing it effectively is even more difficult. That is why scientists are trying to convert it into other forms of energy. “From being absorbed by plants to detecting light in a cell phone camera, the energy carried by light waves or photons needs to be converted into other forms in order to be usable,” the scientists explain.
For example, the light that the user sees onsmartphone display, is first stored as chemical energy in a battery. The circuit board inside the phone allows it to be converted into electrical energy, and finally it becomes the light that makes the screen glow.
Direct absorption of light can significantlyimprove both the design and technology of the devices people use on a daily basis. Researchers believe that light capture underlies many important processes in science, technology and nature. The potential of this process will come in handy to improve the performance of spectral selective detectors (they absorb light rays of different frequencies) and devices of the future that are powered by light.
How does the "ideal light trap" work?
Researchers have developed a cavity in whichmany mirrors and lenses surround a thin light-absorbing medium. They arranged the mirrors and lenses in such a way (as shown in the figure below) that when a light beam enters the cavity, it begins to move in a circle. In the end, the light beam is left with no choice but to be absorbed by the thin medium.
Diagram showing the path of a light beam in a trap.
Credit: Technical University of Vienna
In addition to the absorbing medium, it is a light-trappingThe device is equipped with a partially transparent mirror, a reflective mirror and two convex lenses. The first mirror remains partially transparent to allow light to enter the cavity, the researchers said. However, it can also go
To prevent this, scientists usedwave interference. Let us remember that this is a mutual increase or decrease in the resulting amplitude of two or more coherent waves when they are superimposed on each other. It is accompanied by alternating intensity maxima and minima in space. The result of interference depends on the phase difference between the superimposed waves.
As a result, when the laser beam falls partlytransparent mirror, it is divided into two parts. After hitting the lenses, the absorbing medium and the reflecting mirror, the rays overlap each other. The entire light beam is blocked in this position. He cannot “escape” and is absorbed by the subtle medium.
What's the bottom line?
The researchers claim that the technique is so perfect that even frequent changes in temperature or air pressure do not affect it.
It is noteworthy that the device operates on only one frequency of incoming light. While scientists are working on expanding to a more broadband design.
</ p>Read more:
Earth-sized sunspot grows 10 times in 2 days: it is directed at us
This is the "twin" of the Earth in the past: a unique planet-ocean was found not far from us
Einstein was right again: after half a century, physicists proved the stability of black holes
Cover photo