Nav: Home

Electrochemistry to benefit photonics: Nanotubes can control laser pulses

October 10, 2019

An international team of scientists led by researchers from the Laboratory of Nanomaterials at the Skoltech Center for Photonics and Quantum Materials (CPQM) has shown that the nonlinear optical response of carbon nanotubes can be controlled by electrochemical gating. This approach enabled designing a device for controlling the laser pulse duration. The results of the study were published in the prestigious international journal Nano Letters.

Optical phenomena that we encounter in our everyday life, such as reflection, refraction or absorption of light, do not depend on the intensity of incident light. However, at very high radiation intensities, a new class of phenomena arises, that causes changes in the refraction index, self-focusing of light or emergence of radiation at new wavelengths. These and other phenomena that are dependent on the intensity of light are studied by a section of physics called nonlinear optics. Normally, the efficiency of nonlinear optical response is material's invariable characteristic determined by its structure.

Using nanomaterials as an optical nonlinear medium opens up new perspectives for nonlinearity control thanks to the fact that the majority of its atoms are exposed to the surface. This enables controlling a material's electronic structure and thus changing its nonlinear optical response.

Skoltech scientists in collaboration with their colleagues from the Fiber Optics Research Center of RAS, Novosibirsk State University and the University of Warwick (UK) have proposed a method for controlling the saturable absorption of carbon nanotubes using electrochemical gating. Saturable absorption is a nonlinear optical effect when the absorption coefficient decreases with increasing power of incident light. Thus, the material gets more transparent under intense laser radiation. "We showed that magnitude of the nonlinear transparency can be controlled by placing the material in an electrochemical cell. It has been known that, if placed in the electrochemical cell, nanotubes can accumulate a considerable amount of electrical charge on their surface. What has not been known thus far is that the charge accumulation leads to a significant change in the material's nonlinear optical response and, in particular, a reduction in saturable absorption," says the first author of the study and Senior Research Scientist at Skoltech, Yuriy Gladush.

Also, the authors have looked into one of the potential practical applications of a material with a controlled nonlinear response. Saturable absorption is widely used in laser systems to generate femtosecond light pulses. All you have to do is place a saturable absorber with given parameters in the laser cavity. "We assumed that the laser generation regime can be controlled by adjusting the material's nonlinear response. To do so, we built an electrochemical cell with carbon nanotubes placed on the optical fiber surface and integrated it into the fiber optic laser cavity. We discovered that by applying voltage to the device, one can switch from continuous laser generation regime to pulsed regime in the femtosecond and microsecond ranges. This invention paves the way for universal laser systems with a controllable pulse duration that can be used in laser processing of materials, laser surgery, and aesthetic medicine," explains Albert Nasibulin, Head of Skoltech's Laboratory of Nanomaterials and Professor of RAS.
-end-


Skolkovo Institute of Science and Technology (Skoltech)

Related Carbon Nanotubes Articles:

New production method for carbon nanotubes gets green light
A new method of producing carbon nanotubes -- tiny molecules with incredible physical properties used in touchscreen displays, 5G networks and flexible electronics -- has been given the green light by researchers, meaning work in this crucial field can continue.
Growing carbon nanotubes with the right twist
Researchers synthetize nanotubes with a specific structure expanding previous theories on carbon nanotube growth.
Research shows old newspapers can be used to grow carbon nanotubes
New research has found that old newspaper provide a cheap and green solution for the bulk production of single walled carbon nanotubes.
Clean carbon nanotubes with superb properties
Scientists at Aalto University, Finland, and Nagoya University, Japan, have found a new way to make ultra-clean carbon nanotube transistors with superior semiconducting properties.
Dietary fiber effectively purifies carbon nanotubes
A dietary fiber can help separate out semiconducting carbon nanotubes used for making transistors for flexible electronics.
Why modified carbon nanotubes can help the reproducibility problem
Scientists at Tokyo Institute of Technology (Tokyo Tech) conducted an in-depth study on how carbon nanotubes with oxygen-containing groups can be used to greatly enhance the performance of perovskite solar cells.
Tensile strength of carbon nanotubes depends on their chiral structures
Single-walled carbon nanotubes should theoretically be extremely strong, but it remains unclear why their experimental tensile strengths are lower and vary among nanotubes.
New study reveals carbon nanotubes measurement possible for the first time
Swansea University scientists report an entirely new approach to manipulation of carbon nanotubes that allows physical measurements to be made on carbon nanotubes that have previously only been possible by theoretical computation.
Neural networks will help manufacture carbon nanotubes
A team of scientists from Skoltech's Laboratory of Nanomaterials proposed a neural-network-based method for monitoring the growth of carbon nanotubes, preparing the ground for a new generation of sophisticated electronic devices.
Efficient, interconnected, stable: New carbon nanotubes to grow neurons
Carbon nanotubes able to take on the desired shapes thanks to a special chemical treatment, called crosslinking and, at the same time, able to function as substrata for the growth of nerve cells, finely tuning their growth and activity.
More Carbon Nanotubes News and Carbon Nanotubes 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.