Sweden's powerful laser system generates ultra short laser pulses

For the first time, researchers at Umeå University, Sweden, have demonstrated the full capabilities of their large-scale laser facility. The team reports generating a combination of ultrashort laser pulses, extreme peak power, and precisely controlled waveforms that make it possible to explore the fastest processes in nature.

Umeå’s laser is 11 m long and generates very short pulses

László Veisz and colleagues built Umeå’s new laser

The custom-built laser system, called the Light Wave Synthesizer 100 (LWS100), measures 11 meters in length and 1.5 meters in width – far larger than many commercial lasers which can be comparable in size to a pencil or a book. The size of the LWS100 is necessary to generate and amplify ultrashort laser pulses to extreme peak power.

The work is described in a study published in Nature Photonics (see more, below).

At its peak it generates 100 terawatts. Umeå states that this output is “equivalent to five times the average power consumption of the world – although only for a few millionths of a billionth of a second.” This makes the system the most powerful laser in Sweden and opens the doors to groundbreaking applications, such as understanding ultrafast processes in biomolecules, developing light-driven electronics, and improving solar panel efficiency.

‘Filming’ electron movements
What sets the system apart, continues the Umeå announcement, is that the pulses are not only extremely short (4.3 femtoseconds) and powerful – they also have a reproducible and controlled electric field waveform, identical from pulse to pulse.

Achieving this level of control is particularly challenging in large-scale laser systems, but critical for many advanced applications. This can generate even shorter attosecond x-ray pulses that can be used to “film” the movement of electrons in real time.

“We can now show that the system delivers exactly what we envisioned when it was built. This is a milestone for our research,” said Laszlo Veisz, Professor at Umeå University.

A wide range of experiments are planned for this laser system, taking advantage of its extreme temporal and spatial light concentration. By shaping and focusing ultrashort pulses, attosecond electron bunches can be accelerated to ultra-relativistic energies in compact micro-accelerators, or next-generation X-ray sources can be created to advance attosecond science.

The laser system was installed and inaugurated at the Department of Physics at Umeå University in 2022. This newly-published Nature Photonics paper is the first scientific study to demonstrate its full performance.

Nature Photonics paper abstract

“We report an enhanced optical parametric chirped pulse amplifier system that produces light pulses with a peak power of about 100 TW and a pulse duration as short as 4.3 fs with full waveform control. Coherent field synthesis generates a broadband spectrum, spanning from the visible to the near infrared, through three cascaded amplification stages, each housing two optical parametric amplifiers that sequentially boost complementary spectral regions.

“The resulting light transients are waveform-stabilized to <300 mrad and focused to an intensity of 1021 W cm−2 and exhibit an outstanding high dynamic range in temporal contrast. Together, these characteristics render the system well suited for demanding relativistic laser–plasma experiments.”

Source: optics.org