Pulse-dilation enhanced gated optical imager with 5 ps resolution (invited)

Area of Science:

• Physics
• Instrumentation
• Optics

Background:

• Conventional gated framing cameras have limitations in temporal resolution.
• Electron pulse dilation offers a method to improve temporal gating.
• Radio frequency (RF) excited photocathodes present unique challenges in electron imaging.

Purpose of the Study:

• To demonstrate a 5 picosecond (ps) gated framing camera using electron pulse dilation.
• To investigate and address challenges associated with RF excited photocathodes.
• To examine X-ray image formation and photometric calculations for fusion experiments.

Main Methods:

• Utilized pulse dilation by accelerating photoelectrons with a time-varying potential.
• Employed a drift region with a strong axial magnetic field to prevent image defocusing.
• Investigated RF excited photocathode issues numerically and constructed a prototype instrument.
• Measured temporal resolution using a frequency-tripled femtosecond laser at 266 nm.

Main Results:

• Demonstrated a 5 ps gated framing camera with 20x temporal magnification.
• Successfully reduced the effective gating time compared to conventional cameras.
• Presented results from temporal resolution measurements and X-ray imaging strategies.

Conclusions:

• The demonstrated electron pulse dilation technique significantly enhances temporal resolution in framing cameras.
• The developed instrument shows promise for high-resolution imaging in scientific research, including fusion diagnostics.
• Further examination of X-ray imaging and photometric calculations is relevant for inertial confinement fusion research.