A team of scientists has developed a very simple laser system that could help in the search for new Earth-like planets.
Scientists at Heriot-Watt University in Edinburgh have created a green laser device similar to laser pointers sold in supermarkets for less than £5, but converting light into infrared pulses with a maximum power of 1 kilowatt. The laser emits light at a rate of a billion pulses per second, which helps create what is known as a “photofrequency comb” that can be used to measure light frequencies and time periods more accurately and easily than in the past.
Professor Derek Reid, head of the ultrafast optics group at Heriot-Watt University, said the laser has great potential to allow astronomers to detect small Earth-like planets orbiting distant stars.
According to the university, the laser reduces the cost, complexity, and power consumption of typical ultrafast laser systems by a factor of about 10.
The laser emits light at a rate of a billion pulses per second and consists of only three parts: two mirrors and a sapphire glass containing a small amount of titanium.
The team revealed the details of this hack in Express magazine “Optics”. They say they will make this technology more accessible to users from other scientific disciplines.
Professor Reid believes this could help astronomers search for exoplanets — planets that orbit stars outside of Earth’s solar system.
Using space telescopes, astronomers have already identified thousands of stars that may have exoplanets, but each must be confirmed by ground-based telescopes looking for small variations in the color of the star’s light that are signals of a planet in orbit.
These small shifts in wavelength confirm the presence of a planet in its orbit and the presence of its mass and period of revolution.
“Our new laser is a smaller and simpler version of a device we installed at the 10m Large Telescope in South Africa in 2016. The laser emits light composed of thousands of regularly spaced optical frequencies, known as a frequency comb,” says Reed.
Similar to using a ruler to accurately measure distances, a frequency comb is a “wavelength ruler” that allows astronomers to measure subtle differences in wavelengths.
He continued: “Because observations of exoplanets can take years of observation, astronomers have suggested that there are several dedicated telescopes that point to candidate stars, and our laser could be an important element in such systems.”
The design of the new system was pioneered by Hana Ostapenko, a doctoral student at Heriot-Watt, who explained: “The uniqueness of this laser is that we have shown that we can run it from a simple laser diode of about the same power. consumes like an iPhone. And unlike many previous ultra-fast lasers, our device has very few components and produces ultra-fast pulses once turned on.”