High-power near-concentric Fabry–Perot cavity for phase contrast electron microscopy

• Published in: Review of scientific instruments Vol. 92; no. 5; pp. 053005 - 53013
• Main Authors: Turnbaugh, Carter, Axelrod, Jeremy J., Campbell, Sara L., Dioquino, Jeske Y., Petrov, Petar N., Remis, Jonathan, Schwartz, Osip, Yu, Zanlin, Cheng, Yifan, Glaeser, Robert M., Mueller, Holger
• Format: Journal Article
• Language: English
• Published: United States 01.05.2021
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/5.0045496

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.