Coherently amplified ultrafast imaging in a free-electron interferometer

• DOI: 10.48550/arxiv.2305.04877
• Publication Date: 2023-01-01
• Authors: Tomer Bucher; Harel Nahari; Hanan Herzig Shei...; Ron Ruimy; Arthur Niedermayr; Raphael Dahan; Qinghui Yan; Yuval Adiv; Michael Yannai; Jialin Chen; Yaniv Kurman; Sang Tae Park; Daniel J. Masiel; Eli Janzen; James H. Edgar; Fabrizio Carbone; Guy Bartal; Shai Tsesses; Frank H. L. Koppens; Giovanni Maria Va...; Ido Kaminer
• Keywords: Electron holography; Temporal resolution

Accessing the low-energy non-equilibrium dynamics of materials and their polaritons with simultaneous high spatial temporal resolution has been a bold frontier electron microscopy in recent years. One main challenges lies ability to retrieve extremely weak signals while simultaneously disentangling amplitude phase information. Here, we present Free-Electron Ramsey Imaging (FERI), approach based on light-induced modulation that enables coherent amplification optical near-fields imaging. We provide time-, space-, phase-resolved measurements micro-drum made from hexagonal boron nitride membrane visualizing sub-cycle 2D polariton wavepackets therein. The reveals vortex-anti-vortex singularities wavefronts, together an intriguing phenomenon traveling wave mimicking profile standing wave. Our experiments show 20-fold near-field signal compared conventional imaging, resolving peak field intensities order ~W/cm2, corresponding amplitudes few kV/m. As result, our work paves way for spatio-temporal biological specimens quantum materials, exciting yet delicate samples are currently difficult investigate.