Beam pulsing device for use in charged-particle microscopy

A charged-particle microscope comprising: - A charged-particle source, for producing a beam of charged particles that propagates along a particle-optical axis; - A sample holder, for holding and positioning a sample; - A charged-particle lens system, for directing said beam onto a sample held on the sample holder; - A detector, for detecting radiation emanating from the sample as a result of its interaction with the beam; - A beam pulsing device, for causing the beam to repeatedly switch on and off so as to produce a pulsed beam, wherein the beam pulsing device comprises a unitary resonant cavity disposed about said particle-optical axis and having an entrance aperture and an exit aperture for the beam, which resonant cavity is embodied to simultaneously produce a first oscillatory deflection of the beam at a first frequency in a first direction and a second oscillatory deflection of the beam at a second, different frequency in a second, different direction. The resonant cavity may have an elongated (e.g. rectangular or elliptical) cross-section, with a long axis parallel to said first direction and a short axis parallel to said second direction.