High-power near-concentric Fabry–Perot cavity for phase contrast electron microscopy
Carter Turnbaugh, Jeremy J. Axelrod, Sara L. Campbell, Jeske Y. Dioquino, Petar N. Petrov, Jonathan Remis, Osip Schwartz, Zanlin Yu, Yifan Cheng, Robert M. Glaeser, Holger Mueller
Abstract
Transmission electron microscopy (TEM) of vitrified biological macromolecules (cryo-EM) is limited by the weak phase contrast signal that is available from such samples. Using a phase plate would thus substantially improve the signal-to-noise ratio. We have previously demonstrated the use of a high-power Fabry–Perot cavity as a phase plate for TEM. We now report improvements to our laser cavity that allow us to achieve record continuous wave intensities of over 450 GW/cm2, sufficient to produce the optimal 90° phase shift for 300 keV electrons. In addition, we have performed the first cryo-EM reconstruction using a laser phase plate, demonstrating that the stability of this laser phase plate is sufficient for use during standard cryo-EM data collection.