At the Faculty of Mechanical Engineering at the Technion, a world record was set for light intensity
Newspaper Physical Review Reports on the development of an optical resonator, unprecedented in its resonant amplification capabilities. The resonator was developed by Yaakov Khair-Aldin while he was studying in Prof. Tal Karmon's laboratory.
A resonator is a device that contains waves and amplifies them by returning them from wall to wall in a process called resonance enhancement. Today in the world there are sophisticated and sophisticated resonators of various types, but also simple resonators familiar to all of us - for example, the sound box of a guitar, which amplifies the sounds produced by the strings, or the body of the bagpipe, which amplifies the sounds created by the mouthpiece of the instrument.
The guitar and the bagpipe are resonators acoustic in which the sound resonates between the walls of the resonator. In physics there are also resonators optical, for example in laser devices. According to Prof. Carmon, a resonator is one of the most important devices in optics - "it is the optician's transistor."
Resonators need at least two mirrors, but they can also contain more than two - for example, three mirrors that reflect the light in a triangular path, four in a square, and so on. It is also possible to arrange many mirrors in an almost circular way so that the light rotates in an almost circular way, and as we increase the number of mirrors in the said ring we get closer to the structure of a perfect circle.
But this is not the end of the story, as the ring limits the movement of light to a single plane. The solution is of course a structure spherical, which allows the light to rotate in all the planes passing through the center of the circle, regardless of their tilt, i.e. in the three-dimensional space.
Now we move from physics to engineering: how to produce a resonator that is as clean, smooth and accurate as possible, so that the light will circulate inside it as many times as possible and thus be maximally amplified? This challenge occupied many research groups and yielded, among other things, a tiny glass resonator in the shape of a ball or ring, which is held next to the precise optical fiber that couples the light into it. An example of this was presented by Prof. Tal Carmon two years ago in the journal Nature.
However, the spherical glass resonator is not the end of the story either, as it is the connection point His to the optical fiber creates a distortion in its spherical shape. This is where the desire to produce was born Floating resonator – A resonator that is not held by any material object.
The world's first microresonator was demonstrated in the 70s by Arthur Ashkin, winner of the 2018 Nobel Prize in Physics, who did present a hovering resonator. Despite the achievement, this line of research was soon abandoned. Now, inspired by Ashkin's pioneering work, the Technion researchers present the hovering resonator that exhibits a resonant amplification of 10,000,000 revolutions of light, compared to about 300 revolutions in Ashkin's resonator.
The hovering resonator
In a resonator made of mirrors that reflect 99.9999 percent of the light, the light will rotate about a million revolutions or "circular trips", as they are called in scientific language. If we take a light with a power of 1 watt, similar to the light of the flash on a cell phone, and let it rotate back and forth between these mirrors, the light power will increase to one million watts - the power equal to the electricity consumption of a large neighborhood in Haifa. We can use the high light output, for example, to stimulate a mutual reaction between light and a transparent material located between the mirrors.
In fact, the million watts consist of that single light particle passing back and forth through the material, but the material does not "know" that it is the same light particle moving over and over again through the material, and only "feels" the high power. In this type of device, it is also important that the million watts pass through a small cross-sectional area, and indeed, the device developed by Khir-Aldin conducts the light in 10 million circular trips, with the light focused into a beam area that is 10,000 times smaller than the cross-sectional area of a hair. In doing so, Khair-Al-Din broke the world record for resonant amplification of light.
The resonator developed by the Technion researchers is made of a tiny drop of oil with a diameter of about 20 microns - a quarter of the thickness of a hair. The drop is held in the air using light in a technique called "optical tweezers". This technology, which makes it possible to hold particles using light, is used here to hold the droplet in the air without a material support - a fiber or another pillar - that could damage its spherical shape or contaminate the droplet. According to Prof. Carmon, "This ingenious optical invention, the optical tongs, is used a lot in the life sciences, chemistry, microflow devices and more, and the opticians hardly ever use it - a bit like a cobbler who goes barefoot. In the present study we show that the optical tweezers have a huge potential in the field of optical engineering. It is possible, for example, to build an optical circuit using multiple optical tweezers that hold many resonators and control the position of the resonators and their shape as needed."
Even the tiny dimensions of the drop help to improve its spherical integrity, because the force of gravity hardly deforms it, since it is marginal in these dimensions relative to the surface tension forces of the liquid that give it a spherical shape.
In the unique system developed by Technion researchers, the drop of oil is held by a laser beam and receives the light from another fiber, which also receives the light back after passing through the resonator. According to the properties of the light reflected in the fiber, the researchers can tell what happened inside the drop. For example, they can turn off the light entering the resonator and test how long a photon will survive in the resonator before fading, and based on this figure and the speed of light calculate the number of revolutions the photon makes (on average) in the drop. Here, as mentioned, it is a world record in light amplification: 10,000,000 revolutions passing through a cross-sectional area of about a square micron and amplifying the light 10 million times.
Also participating in the study were Shai Ma'ini, Mark Davidson and Leonardo Martin from the Technion and Lev Deitz from the Faculty of Physics at Queens College of CUNY. The research was conducted within the Center of Excellence "Circle of Light" of the National Science Foundation and the Committee on Planning and Budgeting (ICORE), the US-Israel Science Foundation (BSF), the American Science Foundation (NSF), and the National Science Foundation (ISF).
for the article in the journal Physical Review
More of the topic in Hayadan:
4 תגובות
Where does the multiplied energy of the photon in the resonator come from?
Peace
Do you think such a resonator can be integrated into advanced computers?
You should let someone professional look at what the PR people write.
After 10 million turns the light was not amplified 10 million times, in fact if there was no amplifying medium it would not amplify at all. It's likely that it wasn't boosted, it just did up to 10 million rounds until it was ejected - that's how it's usually measured. There is no world record here in fluctuating amplification, but in the preservation of light intensity inside a resonator.
Ashkin invented the optical tweezers - he received a Nobel Prize for this.
They said the phrase "not even wrong" about the nonsense about the power of a neighborhood in Haifa.
trainer.