Researchers have created a new method to measure the special "terahertz light". The light travels in waves that are longer than infrared, which is far beyond the scope of the human eye. This new sampling technique preserves the relationships between time and position in a pulse terahertz radiation. Researchers can now measure the shape and width of terahertz light bullets, which are focused flashes that emit light as long as they are wide. Researchers can then learn how to use terahertz pulses in order to improve their particle accelerators. Scientists use particle accelerators to examine new materials, proteins and the building blocks of the universe. Using improved accelerators could help improve industry, medicine and scientific research.

The modern particle accelerator facilities are huge. Terahertz technology could allow them to be reduced in size. The Spallation Neutron source, a Department of Energy user facility is three football fields in length. Particles could achieve the same energy using terahertz radiation in a shorter time than an end zone. This could allow facilities to reach higher energies for scientific discoveries. Scientists will need to understand more about the behavior and characteristics of terahertz radiation. These future accelerators will be smaller thanks to this new measurement technique.

Oak Ridge National Laboratory is home to the Spallation Neutron Source user center. Scientists are exploring how to make and use Terahertz light in order to allow particle accelerators that utilize terahertz technology. Because the terahertz radiation is highly concentrated, it is possible to make terahertz light-bullet bombs using intense lasers. This creates very high acceleration fields. Researchers have developed a new measurement method that shows that terahertz light can change its shape if it is focused on its target. This could affect particle accelerator performance.

Terahertz light bullets take on a different shape due to their many terahertz frequencies. This is similar to white light, which is made up of different visible frequencies. The colors of the terahertz light bullets can split to create a rainbow just like white light colors can. This separation can cause imperfections in the shape and concentration of the light, which can lead to weaker particle acceleration. These imperfections can be measured using the new electro-optic sampling technique in conjunction with modeling tools. This information can then be used to design new optics to correct terahertz shapes. It may be possible to increase particle acceleration and improve the terahertz structure with clever optic design.

The research was published by Physical Review A.