- Researchers want to blast holes in the clouds to transmit information at high rates.
- To do this, they will use ultrashort high-intensity laser filaments.
- The technology doesn’t leave any negative impact on the atmosphere.
Today’s long-range information is transmitted by either radio waves (via satellites) or underground optical fiber. However, the flow of information is significantly increasing every year and soon it won’t be possible to fulfill the daily demand by transmitting data through radio waves only.
Since the radio waves have longer wavelengths (compared to laser), they restrict the amount of data to be transferred. Also, its available frequency bands are limited and progressively expensive.
That’s why researchers are now shifting their focus on laser techniques, which are much more complex than radio frequencies but have numerous advantages in terms of security. At present, atmospheric barriers are one of the major issues for free space optical communications (FSO).
Now, researchers at the University of Geneva, Switzerland have come up with a technique that involves blasting holes in the clouds to pave the way for information transmitted through laser from a satellite.
Piercing the Clouds
Lasers with ultrashort wavelengths can carry ten thousand times more data than radio waves, and there is no limit to the number of channels. However, these ultrashort beams can’t penetrate fog and clouds. Thus, in bad weather, you can’t actually transmit any data with lasers.
To solve this problem, researchers are now developing more ground stations that can receive laser signals in different regions. The aim is to select station(s) targeted by satellite(s) as per the weather.
This type of solutions already exist, but transmitting data still depends on weather situations. Also, it changes the configuration of satellite(s) – a serious issue that must be processed upstream of the communication.
For now, the only effective solution is to create a hole through the clouds to transmit the laser beam that carries information. In this study, authors have done something similar: they have built an ultrashort high-intensity laser that heats the air to more than 1750 Kelvin and generates a shock wave to radially expel the water droplets out of the beam from the air it sweeps. This produces a several-centimeter-wide hole over the complete thickness of the cloud.
They used the same laser technology that has been awarded the 2018 Nobel Prize for Physics (optical tweezers). You just need to keep the beam on the cloud and it will carry high bit-rate telecom data, as its frequency lies in the kilohertz range.
Credit: UNIGE/Xavier Ravinet
According to the researchers, this is the first active method that opens an optical link through clouds and fogs. The high peak power laser produces a local cloudless pathway with decreased Mie scattering for the second, modulated beam. They also claimed that their technology doesn’t leave any negative impact on the atmosphere.
How Long Does It Take To Implement This?
Researchers are currently testing the lasers on artificial clouds that have a thickness of only 50 centimeters but are 10,000 times more denser than atmospherics clouds. The lasers work great in this setup, even when the cloud is moving.
In the next testing phase, they will use thicker fog and clouds (up to 1,000 meters thick) with different densities and altitudes. It’s a crucial step towards the commercial laser satellite communication, and researchers believe that technology will be globally implemented by 2025.