Free-electron interaction with nonlinear optical states in microresonators

• DOI: 10.1126/science.adk2489
• Publication Date: 2024-01-11T19:01:18Z
• Authors: Yujia Yang; Jan-Wilke Henke; Arslan S. Raja; F. Jasmin Kappert; Guanhao Huang; Germaine Arend; Zheru Qiu; Armin Feist; Rui Ning Wang; Aleksandr Tusnin; Alexey Tikan; Claus Ropers; Tobias J. Kippenberg
• Keywords: 0301 basic medicine; 03 medical and health sciences; FOS: Physical sciences; Pattern Formation and Solitons (nlin.PS); Nonlinear Sciences - Pattern Formation and Solitons; Physics - Optics; Optics (physics.optics)

The short de Broglie wavelength and strong interaction empower free electrons to probe structures and excitations in materials and biomolecules. Recently, electron-photon interactions have enabled new optical manipulation schemes for electron beams. In this work, we demonstrate the interaction of electrons with nonlinear optical states inside a photonic chip–based microresonator. Optical parametric processes give rise to spatiotemporal pattern formation corresponding to coherent or incoherent optical frequency combs. We couple such “microcombs” to electron beams, demonstrate their fingerprints in the electron spectra, and achieve ultrafast temporal gating of the electron beam. Our work demonstrates the ability to access solitons inside an electron microscope and extends the use of microcombs to spatiotemporal control of electrons for imaging and spectroscopy.