Ultrashort Electron Wave Packets via Frequency-Comb Synthesis

Single-electron sources are vital for modern nanoelectronics, enabling advances in the emerging field of electron quantum optics. However, their performance is limited by the current method for generating single electrons by applying Lorentzian voltage pulses on the Fermi sea of a quantum conductor. The authors introduce a Fourier synthesis-based voltage pulse generator, allowing the generation and in-situ characterization of a 27-ps electron wave packet in an electronic Mach-Zehnder interferometer. This advancement can potentially enable the study of ultrafast dynamics in quantum nanoelectronic systems and the generation of high-frequency flying-electron qubits.