Nav: Home

How to control polarization of light

October 03, 2016

The results of this case can be used in the manufacture of the so-called spatial light modulators serving as a base for all LCDs, for example. They are arranged so that each pixel can switch the light with some speed, making it brighter or weaker, and this switching is performed by the rotation of the polarization of light. According to one of the authors, Tatyana Dolgova, senior researcher of the Laboratory of Nanophotonics and Metamaterials, Faculty of Physics, MSU, the new fast spatial light modulators can be used when creating a holographic memory, three-dimensional displays, as well as the accurate refractive index sensors and magnetic field sensors.

The recording speed in the three-dimensional holographic memory is directly dependent on the spatial light modulator's switching speed. This speed is highly limited in liquid crystals, as they perform the polarization rotation by rotating the LCD molecule itself, which takes tens of milliseconds. Scientists have proposed to carry out the rotation not by a mechanical turn, but by the effect, discovered by Faraday. Its essence lies in the fact that the plane of polarization of the light is rotated as it passes through a magnetized material.

In 1998, one of the authors of the article, Japanese physicist Mitsuteru Inoue proposed the concept of spatial light modulators based on new nanostructures - magnetophotonic crystals. These micro crystals contain optical resonators - a system of two parallel mirrors. Today the main scope of its use is a significant "slowing down" the light. A photon caught in such a resonator, moves between the mirrors and comes out after a significant delay. So if a polarized light passing through the crystal is placed to the magnetic field, the Faraday effect increases with each pass from mirror to mirror, and ultimately becomes much more noticeable.

"We are working on magnetophotonic crystals together with Professor Inoue almost from the beginning, and during these fifteen years have learned a lot about these amazing nanostructures," says Tatyana Dolgova. "And finally we got to the ultra-fast light modulation. In our experiments with the real crystals we have ensured that the light is about ten times slower than if it is simply in the air. And it increases the Faraday rotation by an order of magnitude!"

According to Dolgova, there is no paradox between the "slowing down" the light and the resulting ultrafast modulation. "The 'slow' light is actually only relatively slow compared to the speed of light in a vacuum, but it is still incomparably fast compared to the speed of the liquid crystal molecules rotation."

In their experiments, the MSU physics have ensured that the plane of polarization of the "slow" light is turned so quickly that it is significantly different even between the beginning and the "tail" of a 200-femtosecond laser pulse. (Femtosecond is one quadrillionth of a second, or one millionth of a nanosecond) Dolgova said that the magnitude of the effect obtained in the Moscow State University is still insufficient for practical use, however, the limitations are not fundamental. Physicists have shown clearly: ultrafast modulation of light in magnetophotonic crystals is possible and has more than good prospects.

Despite the fact that the liquid crystal modulation rate is enough for conventional screens the super switching speed is necessary in the such devices in nanophotonics where photons are used instead of electrons to perform some logic or counting, photonic switching, optical recording, - namely, for the prospect of creation of photonic computers. And now a group of Professor Inoue demonstrates the samples of the three-dimensional holographic memory and displays for playback of 3D images and video, working with fast magnetophotonic spatial light modulators.
-end-


Lomonosov Moscow State University

Related Magnetic Field Articles:

Origins of Earth's magnetic field remain a mystery
The existence of a magnetic field beyond 3.5 billion years ago is still up for debate.
New research provides evidence of strong early magnetic field around Earth
New research from the University of Rochester provides evidence that the magnetic field that first formed around Earth was even stronger than scientists previously believed.
Massive photons in an artificial magnetic field
An international research collaboration from Poland, the UK and Russia has created a two-dimensional system -- a thin optical cavity filled with liquid crystal -- in which they trapped photons.
Adhesive which debonds in magnetic field could reduce landfill waste
Researchers at the University of Sussex have developed a glue which can unstick when placed in a magnetic field, meaning products otherwise destined for landfill, could now be dismantled and recycled at the end of their life.
Earth's last magnetic field reversal took far longer than once thought
Every several hundred thousand years or so, Earth's magnetic field dramatically shifts and reverses its polarity.
A new rare metals alloy can change shape in the magnetic field
Scientists developed multifunctional metal alloys that emit and absorb heat at the same time and change their size and volume under the influence of a magnetic field.
Physicists studied the influence of magnetic field on thin film structures
A team of scientists from Immanuel Kant Baltic Federal University together with their colleagues from Russia, Japan, and Australia studied the influence of inhomogeneity of magnetic field applied during the fabrication process of thin-film structures made from nickel-iron and iridium-manganese alloys, on their properties.
'Magnetic topological insulator' makes its own magnetic field
A team of U.S. and Korean physicists has found the first evidence of a two-dimensional material that can become a magnetic topological insulator even when it is not placed in a magnetic field.
Scientists develop a new way to remotely measure Earth's magnetic field
By zapping a layer of meteor residue in the atmosphere with ground-based lasers, scientists in the US, Canada and Europe get a new view of Earth's magnetic field.
Magnetic field milestone
Physicists from the Institute for Solid State Physics at the University of Tokyo have generated the strongest controllable magnetic field ever produced.
More Magnetic Field News and Magnetic Field Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.