Free-electron interaction with nonlinear optical states in microresonators

Abstract

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.

Editor’s summary

Electron microscopes provide imaging capability on the tiniest of scales. The electron beams that scatter off the samples are generally energetically stable and spatially uniform. Being able to modulate the beam to access spatiotemporal information about the sample would be extremely useful but is technically challenging. Yang et al . demonstrate that the nonlinear optical states induced in a microresonator can interact with the electron beam and imprint the nonlinear optical states onto the beam (see the Perspective by Polman and García de Abajo). This interaction provides access to ultrafast modulation of the electron beam and broadens the application of electron microscopes for spatiotemporal imaging and spectroscopy. —Ian S. Osborne

The interaction of free electrons and nonlinear optical states enables ultrafast electron beam modulation.

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.

Editor’s summary

Electron microscopes provide imaging capability on the tiniest of scales. The electron beams that scatter off the samples are generally energetically stable and spatially uniform. Being able to modulate the beam to access spatiotemporal information about the sample would be extremely useful but is technically challenging. Yang et al . demonstrate that the nonlinear optical states induced in a microresonator can interact with the electron beam and imprint the nonlinear optical states onto the beam (see the Perspective by Polman and García de Abajo). This interaction provides access to ultrafast modulation of the electron beam and broadens the application of electron microscopes for spatiotemporal imaging and spectroscopy. —Ian S. Osborne

The interaction of free electrons and nonlinear optical states enables ultrafast electron beam modulation.

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.

Editor’s summary

Electron microscopes provide imaging capability on the tiniest of scales. The electron beams that scatter off the samples are generally energetically stable and spatially uniform. Being able to modulate the beam to access spatiotemporal information about the sample would be extremely useful but is technically challenging. Yang et al . demonstrate that the nonlinear optical states induced in a microresonator can interact with the electron beam and imprint the nonlinear optical states onto the beam (see the Perspective by Polman and García de Abajo). This interaction provides access to ultrafast modulation of the electron beam and broadens the application of electron microscopes for spatiotemporal imaging and spectroscopy. —Ian S. Osborne

The interaction of free electrons and nonlinear optical states enables ultrafast electron beam modulation.