Beam is traveling left to right. The pickup is a gradient undulator. The intensity of the radiation is proportional to the
displacement of the particles. The kicker dipole undulator increments the particle energy.
The energy is changed so that particle energy corresponds with that energy closed orbit. The bypass is necessarily isochronous.
Schematic of bypass and amplifier. Cartoon of undulators and bypass at right.
The optical amplituder is a ~4mm thick crystal with index ~1.75. The amplified light is
delayed by 3mm/c. The bypass delays the electrons by that same amount +- delta phase.
Feedback schematic
L3 bypass that adds 2.7mm to charged particle path length. Linear optics consistent with sampling constraints.