Researchers demonstrate efficient electron beam modulation using integrated photonic microresonators

Share this on social media:

Photonic integrated circuits can guide light on a chip with ultra-low low losses, and enhance optical fields using micro-ring resonators. (Image: Yujia Yan, EPFL)

Researchers have successfully demonstrated highly efficient electron beam modulation using integrated photonic microresonators.

The work could benefit transmission electron microscopy for application in materials science and structural biology.

Transmission electron microscopes (TEMs) can image molecular structures at the atomic scale by using electrons instead of light.

The past decade has seen a lot of interest in combining electron microscopy with optical excitations, trying, for example, to control and manipulate the electron beam by light. But a major challenge has been the rather weak interaction of propagating electrons with photons.

The new work, published in Nature and carried out by Swiss research institute EPFL, the Max Planck Institute for Biophysical Chemistry, and the University of Göttingen, aims to address this by joining the fields of electron microscopy and integrated photonics.

Photonic integrated circuits can guide light on a chip with ultra-low low losses, and enhance optical fields using micro-ring resonators. 

In an experiment, an electron beam was steered through the optical near field of a photonic integrated circuit, allowing the electrons to interact with the enhanced light. The researchers then probed the interaction by measuring the energy of electrons that had absorbed or emitted tens to hundreds of photon energies. The photonic chips were built in such a way that the speed of light in the micro-ring resonators exactly matched the speed of the electrons, dramatically increasing the electron-photon interaction.

The technique enables a strong modulation of the electron beam, with only a few milli-Watts from a continuous wave laser – a power level generated by a common laser pointer. The approach constitutes a dramatic simplification and efficiency increase in the optical control of electron beams, which can be seamlessly implemented in a regular transmission electron microscope, and could make the scheme much more widely applicable.

'Integrated photonics circuits based on low-loss silicon nitride have made tremendous progress and are intensively driving the progress of many emerging technologies and fundamental science such as lidar, telecommunication, and quantum computing, and now prove to be a new ingredient for electron beam manipulation,' said Professor Tobias Kippenberg of EPFL.

'Interfacing electron microscopy with photonics has the potential to uniquely bridge atomic scale imaging with coherent spectroscopy,' added Professor Claus Ropers of the Max Planck Institute for Biophysical Chemistry and the University of Göttingen. 'For the future, we expect this to yield an unprecedented understanding and control of microscopic optical excitations.'

The researchers plan to further extend their collaboration in the direction of new forms of quantum optics and attosecond metrology for free electrons.

FormFactor's fast photonic wafer probers enable rapid tests through faster photonic alignment than previously possible. (Credit: FormFactor Inc)

07 September 2021

Jose Capmany (left) is co-founder and COO of iPronics, Daniel Perez-Lopez (right) is co-founder and CTO of iPronics.

05 August 2022

The technologies include two substrates of ultra-wide bandgap semiconductors, as well as electronic computer-aided design software for the development of complex integrated circuits. (Image: Shutterstock/sdecoret)

17 August 2022

The chipset has integrated lasers directly driven from a digital signal processor without the use of any external driver chip, providing exceptional total system performance.

11 August 2022

Jose Capmany (left) is co-founder and COO of iPronics, Daniel Perez-Lopez (right) is co-founder and CTO of iPronics.

05 August 2022

Aeva’s Aeries II lidar module has a sensing range of up to 500 metres, and is able to measure velocity for each pixel. (Image: Aeva)

02 August 2022

Here two electronic driver chips are connected face down to a silicon photonics chip.The horseshoe-shaped device is an optical modulator, which can be used as part of a programmable circuit. (Image: Optoelectronics Research Centre)

28 July 2022