A novel way to generate coherent light in the ultraviolet spectral zone, which indicates the possibility of developing powerful desktop X-ray sources, has been produced from research led by the University of Strathclyde, in Scotland. It is the first mini particle accelerator to operate a laser.
The technology uses light sources based on electron beams, also known as fourth generation light sources. This approach employs a free electron laser (FEL), which when operating an inverter manages to convert the energy of the electron beam into X-rays.
A dance of free electrons
The free electron laser shares the optical properties of conventional lasers, emitting a coherent beam of electromagnetic radiation that is capable of reaching high power. However, a different physical principle is based, since it does not excite electrons at different energy levels.
Instead, use a electron beam accelerated at relativistic speeds to generate the laser. These electrons are not bound to atoms, but move freely in a magnetic field. The first free electron laser was built by John Madey in 1976.
According to a Press release, the new technology for produce coherent radiation It could revolutionize light sources. The most interesting thing is that it could make them compact, taking them to a size that would make it possible to use them on a table. The reduction in size would not affect their power: they would be capable of producing ultra-short duration pulses of light, with greater efficiency than can be achieved with other technologies.
Accessible to universities
In a free electron laser, the grouping of electrons causes the light to be amplified and its coherence increased. The coherent light It is one that is formed by light waves with an affine phase, and therefore they retain a permanent relationship.
However, this effect usually takes a long time, necessitating the use of corrugators that can be more than one hundred meters long. The accelerators that drive these free electron lasers to produce X-rays have kilometers long, a condition that makes them impractical and expensive. Now, the new research that has been published in Scientific Reports could make them accessible to any university or academic center.
In a room
In the same vein, research carried out at the Shanghai Institute of Optics and Fine Mechanics in China has succeeded in using a small accelerator to power a device that also uses free electron laser (FEL) technology. The team, with a 12 meter length, could mark another breakthrough in the field of mini particle accelerators.
According to a Press release from the Chinese Academy of Sciences, the new device can be used to detect the internal structure of materials or study the process of interaction of light with atoms, molecules and condensed matter. Both areas of study could lead to advances in areas such as physics, chemistry, structural biology, medicine, materials design or energy.
The new study, published in the journal Nature, highlights that the free electron laser developed in China uses a chain of three 1,5 meter long corrugators. Thanks to this, the equipment is small enough to fit in a room of generous dimensions.
To get an idea of the differences in sizes, the world’s first X-ray laser, the Linac Coherent Light Source (LCLS), which was introduced in 2009, requires a 3-kilometer-long linear accelerator in order to function.
Vacuum ultraviolet coherent undulator radiation from attosecond electron bunches. Brunetti, E., van der Geer, B., de Loos, M. et al. Scientific Reports (2021) .DOI: https: //doi.org/10.1038/s41598-021-93640-8
Free-electron lasing at 27 nanometres based on a laser wakefield accelerator. Wang, W., Feng, K., Ke, L. et al. Nature (2021).DOI:https://doi.org/10.1038/s41586-021-03678-x
Photo: From the laser target (left) to the inverters (blue) and the electromagnetic spectrometer (right), the novel free electron laser created by Chinese specialists is only 12 meters long. Credit: Shanghai Institute of Optics and Fine Mechanics.
Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.